Functional imaging studies in cannabis users.

PubMed

Chang, Linda; Chronicle, Edward P

2007-10-01

Cannabis remains the most widely used illegal drug in the United States. This update examines the available literature on neuroimaging studies of the brains of cannabis users. The majority of studies examining the acute effects of delta-9-tetrahydrocannabinol (THC) administration used PET methods and concluded that administration of THC leads to increased activation in frontal and paralimbic regions and the cerebellum. These increases in activation are broadly consistent with the behavioral effects of the drug. Although there is only equivocal evidence that chronic cannabis use might result in structural brain changes, blood-oxygenation-level-dependent-fMRI studies in chronic users consistently show alterations, or neuroadaptation, in the activation of brain networks responsible for higher cognitive functions. It is not yet certain whether these changes are reversible with abstinence. Given the high prevalence of cannabis use among adolescents, studies are needed to evaluate whether cannabis use might affect the developing brain. Considerable further work, employing longitudinal designs, is also required to determine whether cannabis use causes permanent functional alterations in the brains of adults.

Do recreational cannabis users, unlicensed and licensed medical cannabis users form distinct groups?

PubMed

Sznitman, Sharon R

2017-04-01

This study aims to gain a more nuanced perspective on the differences between recreationally and medically motivated cannabis use by distinguishing between people who use cannabis for recreational purposes, unlicensed and licensed medical users. Data collection was conducted online from a convenience sample of 1479 Israeli cannabis users. Multinomial regression analysis compared unlicensed medical users (38%) with recreational (42%) and licensed medical (5.6%) users in terms of sociodemographics, mode, frequency and problematic cannabis use. There were more variables distinguishing unlicensed from licensed users than there were distinguishing features between unlicensed and recreational users. Recreational users were more likely to be male, less likely to eat cannabis, to use cannabis frequently and to use alone and before midday than unlicensed users. Licensed users were older than unlicensed users, they reported less hours feeling stoned, less cannabis use problems and they were more likely to report cannabis use patterns analogous of medication administration for chronic problems (frequent use, vaping, use alone and use before midday). This study suggests that a sizable proportion of cannabis users in Israel self-prescribe cannabis and that licensed medical cannabis users differ from unlicensed users. This is, in turn, suggestive of a rigorous medicalized cannabis program that does not function as a backdoor for legal access to recreational use. However, due to methodological limitations this conclusion is only suggestive. The most meaningful differences across recreational, unlicensed and licensed users were mode and patterns of use rather than cannabis use problems. Current screening tools for cannabis use problems may, however, not be well suited to assess such problems in medically motivated users. Indeed, when screening for problematic cannabis use there is a need for a more careful consideration of whether or not cannabis use is medically motivated

Structural and functional imaging studies in chronic cannabis users: a systematic review of adolescent and adult findings.

PubMed

Batalla, Albert; Bhattacharyya, Sagnik; Yücel, Murat; Fusar-Poli, Paolo; Crippa, Jose Alexandre; Nogué, Santiago; Torrens, Marta; Pujol, Jesús; Farré, Magí; Martin-Santos, Rocio

2013-01-01

The growing concern about cannabis use, the most commonly used illicit drug worldwide, has led to a significant increase in the number of human studies using neuroimaging techniques to determine the effect of cannabis on brain structure and function. We conducted a systematic review to assess the evidence of the impact of chronic cannabis use on brain structure and function in adults and adolescents. Papers published until August 2012 were included from EMBASE, Medline, PubMed and LILACS databases following a comprehensive search strategy and pre-determined set of criteria for article selection. Only neuroimaging studies involving chronic cannabis users with a matched control group were considered. One hundred and forty-two studies were identified, of which 43 met the established criteria. Eight studies were in adolescent population. Neuroimaging studies provide evidence of morphological brain alterations in both population groups, particularly in the medial temporal and frontal cortices, as well as the cerebellum. These effects may be related to the amount of cannabis exposure. Functional neuroimaging studies suggest different patterns of resting global and brain activity during the performance of several cognitive tasks both in adolescents and adults, which may indicate compensatory effects in response to chronic cannabis exposure. However, the results pointed out methodological limitations of the work conducted to date and considerable heterogeneity in the findings. Chronic cannabis use may alter brain structure and function in adult and adolescent population. Further studies should consider the use of convergent methodology, prospective large samples involving adolescent to adulthood subjects, and data-sharing initiatives.

Structural and Functional Imaging Studies in Chronic Cannabis Users: A Systematic Review of Adolescent and Adult Findings

PubMed Central

Batalla, Albert; Bhattacharyya, Sagnik; Yücel, Murat; Fusar-Poli, Paolo; Crippa, Jose Alexandre; Nogué, Santiago; Torrens, Marta; Pujol, Jesús; Farré, Magí; Martin-Santos, Rocio

2013-01-01

Background The growing concern about cannabis use, the most commonly used illicit drug worldwide, has led to a significant increase in the number of human studies using neuroimaging techniques to determine the effect of cannabis on brain structure and function. We conducted a systematic review to assess the evidence of the impact of chronic cannabis use on brain structure and function in adults and adolescents. Methods Papers published until August 2012 were included from EMBASE, Medline, PubMed and LILACS databases following a comprehensive search strategy and pre-determined set of criteria for article selection. Only neuroimaging studies involving chronic cannabis users with a matched control group were considered. Results One hundred and forty-two studies were identified, of which 43 met the established criteria. Eight studies were in adolescent population. Neuroimaging studies provide evidence of morphological brain alterations in both population groups, particularly in the medial temporal and frontal cortices, as well as the cerebellum. These effects may be related to the amount of cannabis exposure. Functional neuroimaging studies suggest different patterns of resting global and brain activity during the performance of several cognitive tasks both in adolescents and adults, which may indicate compensatory effects in response to chronic cannabis exposure. Limitations However, the results pointed out methodological limitations of the work conducted to date and considerable heterogeneity in the findings. Conclusion Chronic cannabis use may alter brain structure and function in adult and adolescent population. Further studies should consider the use of convergent methodology, prospective large samples involving adolescent to adulthood subjects, and data-sharing initiatives. PMID:23390554

Objective and subjective memory ratings in cannabis-dependent adolescents.

PubMed

McClure, Erin A; Lydiard, Jessica B; Goddard, Scott D; Gray, Kevin M

2015-01-01

Cannabis is the most widely used illicit substance worldwide, with an estimated 160 million users. Among adolescents, rates of cannabis use are increasing, while the perception of detrimental effects of cannabis use is declining. Difficulty with memory is one of the most frequently noted cognitive deficits associated with cannabis use, but little data exist exploring how well users can identify their own memory deficits, if present. The current secondary analysis sought to characterize objective verbal and visual memory performance via a neurocognitive battery in cannabis-dependent adolescents enrolled in a pharmacotherapeutic cannabis cessation clinical trial (N = 112) and compare this to a single self-reported item assessing difficulties with memory loss. Exploratory analyses also assessed dose-dependent effects of cannabis on memory performance. A small portion of the study sample (10%) endorsed a "serious problem" with memory loss. Those participants reporting "no problem" or "serious problem" scored similarly on visual and verbal memory tasks on the neurocognitive battery. Exploratory analyses suggested a potential relationship between days of cannabis use, amount of cannabis used, and gender with memory performance. This preliminary and exploratory analysis suggests that a sub-set of cannabis users may not accurately perceive difficulties with memory. Further work should test this hypothesis with the use of a control group, comprehensive self-reports of memory problems, and adult populations that may have more years of cannabis use and more severe cognitive deficits. © American Academy of Addiction Psychiatry.

Internalizing and externalizing personality and subjective effects in a sample of adolescent cannabis users.

PubMed

García-Sánchez, Sara; Matalí, Josep Lluís; Martín-Fernández, María; Pardo, Marta; Lleras, Maria; Castellano-Tejedor, Carmina; Haro, Josep Maria

2016-10-06

Cannabis is the illicit substance most widely used by adolescents. Certain personality traits such as impulsivity and sensation seeking, and the subjective effects experienced after substance use (e.g. euphoria or relaxation) have been identified as some of the main etiological factors of consumption. This study aims to categorize a sample of adolescent cannabis users based on their most dominant personality traits (internalizing and externalizing profile). Then, to make a comparison of both profiles considering a set of variables related to consumption, clinical severity and subjective effects experienced. From a cross-sectional design, 173 adolescents (104 men and 69 women) aged 13 to 18 asking for treatment for cannabis use disorder in an Addictive Behavior Unit (UCAD) from the hospital were recruited. For the assessment, an ad hoc protocol was employed to register consumption, the Millon Adolescent Clinical Inventory (MACI) and the Addiction Research Center Inventory (ARCI) 49-item short form were also administered. Factor analysis suggested a two-profile solution: Introverted, Inhibited, Doleful, Dramatizing (-), Egotistic (-), Self-demeaning and Borderline tendency scales composed the internalizing profile, and Submissive (-), Unruly, Forceful, Conforming (-) and Oppositional scales composed the externalizing profile. The comparative analysis showed that the internalizing profile has higher levels of clinical severity and more subjective effects reported than the externalizing profile. These results suggest the need to design specific intervention strategies for each profile.

"CAN Stop"--implementation and evaluation of a secondary group prevention for adolescent and young adult cannabis users in various contexts--study protocol.

PubMed

Baldus, Christiane; Miranda, Alejandra; Weymann, Nina; Reis, Olaf; Moré, Kerstin; Thomasius, Rainer

2011-04-18

Current research shows that overall numbers for cannabis use among adolescents and young adults dropped in recent years. However, this trend is much less pronounced in continuous cannabis use. With regard to the heightened risk for detrimental health- and development-related outcomes, adolescents and young adults with continuous cannabis use need special attention. The health services structure for adolescents and young adults with substance related problems in Germany, is multifaceted, because different communal, medical and judicial agencies are involved. This results in a rather decentralized organizational structure of the help system. This and further system-inherent characteristics make the threshold for young cannabis users rather high. Because of this, there is a need to establish evidence-based low-threshold help options for young cannabis users, which can be easily disseminated. Therefore, a training programme for young cannabis users (age 14-21) was developed in the "CAN Stop" project. Within the project, we seek to implement and evaluate the training programme within different institutions of the help system. The evaluation is sensitive to the different help systems and their specific prerequisites. Moreover, within this study, we also test the practicability of a training provision through laypersons. The CAN Stop study is a four-armed randomized wait-list controlled trial. The four arms are needed for the different help system settings, in which the CAN Stop training programme is evaluated: (a) the drug addiction aid and youth welfare system, (b) the out-patient medical system, (c) the in-patient medical system and (d) prisons for juvenile offenders. Data are collected at three points, before and after the training or a treatment as usual, and six months after the end of either intervention. The CAN Stop study is expected to provide an evidence-based programme for young cannabis users seeking to reduce or quit their cannabis use. Moreover, we seek to

"CAN Stop" - Implementation and evaluation of a secondary group prevention for adolescent and young adult cannabis users in various contexts - study protocol

PubMed Central

2011-01-01

Background Current research shows that overall numbers for cannabis use among adolescents and young adults dropped in recent years. However, this trend is much less pronounced in continuous cannabis use. With regard to the heightened risk for detrimental health- and development-related outcomes, adolescents and young adults with continuous cannabis use need special attention. The health services structure for adolescents and young adults with substance related problems in Germany, is multifaceted, because different communal, medical and judicial agencies are involved. This results in a rather decentralized organizational structure of the help system. This and further system-inherent characteristics make the threshold for young cannabis users rather high. Because of this, there is a need to establish evidence-based low-threshold help options for young cannabis users, which can be easily disseminated. Therefore, a training programme for young cannabis users (age 14-21) was developed in the "CAN Stop" project. Within the project, we seek to implement and evaluate the training programme within different institutions of the help system. The evaluation is sensitive to the different help systems and their specific prerequisites. Moreover, within this study, we also test the practicability of a training provision through laypersons. Methods/Design The CAN Stop study is a four-armed randomized wait-list controlled trial. The four arms are needed for the different help system settings, in which the CAN Stop training programme is evaluated: (a) the drug addiction aid and youth welfare system, (b) the out-patient medical system, (c) the in-patient medical system and (d) prisons for juvenile offenders. Data are collected at three points, before and after the training or a treatment as usual, and six months after the end of either intervention. Discussion The CAN Stop study is expected to provide an evidence-based programme for young cannabis users seeking to reduce or quit

Exposure to cannabis in popular music and cannabis use among adolescents.

PubMed

Primack, Brian A; Douglas, Erika L; Kraemer, Kevin L

2010-03-01

Cannabis use is referenced frequently in American popular music, yet it remains uncertain whether exposure to these references is associated with actual cannabis use. We aimed to determine if exposure to cannabis in popular music is associated independently with current cannabis use in a cohort of urban adolescents. We surveyed all 9th grade students at three large US urban high schools. We estimated participants' exposure to lyrics referent to cannabis with overall music exposure and content analyses of their favorite artists' songs. Outcomes included current (past 30 days) and ever use of cannabis. We used multivariable regression to assess independent associations between exposures and outcomes while controlling for important covariates. Each of the 959 participants was exposed to an estimated 27 cannabis references per day [correction added on 19 January 2010, after first online publication: 40 has been changed to 27] (standard deviation = 73 [correction added on 19 January 2010, after first online publication: 104 has been changed to 73]). Twelve per cent (n = 108) were current cannabis users and 32% (n = 286) had ever used cannabis. Compared with those in the lowest tertile of total cannabis exposure in music, those in the highest tertile of exposure were almost twice as likely to have used cannabis in the past 30 days (odds ratio = 1.83; 95% confidence interval = 1.04, 3.22), even after adjusting for socio-demographic variables, personality characteristics and parenting style. As expected, however, there was no significant relationship between our cannabis exposure variable and a sham outcome variable of alcohol use. This study supports an independent association between exposure to cannabis in popular music and early cannabis use among urban American adolescents.

Medial temporal structures and memory functions in adolescents with heavy cannabis use

PubMed Central

Ashtari, Manzar; Avants, Brian; Cyckowski, Laura; Cervellione, Kelly L.; Roofeh, David; Cook, Philip; Gee, James; Sevy, Serge; Kumra, Sanjiv

2011-01-01

Converging lines of evidence suggest an adverse effect of heavy cannabis use on adolescent brain development, particularly on the hippocampus. In this preliminary study, we compared hippocampal morphology in 14 “treatment-seeking” adolescents (aged 18-20) with a history of prior heavy-cannabis use (5.8 joints/day) after an average of 6.7 months of drug abstinence, and 14 demographically matched normal controls. Participants underwent a high-resolution 3D MRI as well as cognitive testing including the California Verbal Learning Test (CVLT). Heavy-cannabis users showed significantly smaller volumes of the right (p< .04) and left (p< .02) hippocampus, but no significant differences in the amygdala region compared to controls. In controls, larger hippocampus volumes were observed to be significantly correlated with higher CVLT verbal learning and memory scores, but these relationships were not observed in cannabis users. In cannabis users, a smaller right hippocampus volume was correlated with a higher amount of cannabis use (r= - .57, p< .03). These data support a hypothesis that heavy-cannabis use may have an adverse effect on hippocampus development. These findings, after an average 6.7 month of supervised abstinence, lend support to a theory that cannabis use may impart long-term structural and functional damage. Alternatively, the observed hippocampal volumetric abnormalities may represent a risk factor for cannabis dependence. These data have potential significance for understanding the observed relationship between early cannabis exposure during adolescence and subsequent development of adult psychopathology reported in the literature for schizophrenia and related psychotic disorders. PMID:21296361

Cannabis Use Disorder in Adolescence.

PubMed

Simpson, Annabelle K; Magid, Viktoriya

2016-07-01

Cannabis use in the adolescent population poses a significant threat of addiction potential resulting in altered neurodevelopment. There are multiple mechanisms of treatment of cannabis use disorder including behavioral therapy management and emerging data on treatment via pharmacotherapy. Recognizing the diagnostic criteria for cannabis use disorder, cannabis withdrawal syndrome, and mitigating factors that influence adolescent engagement in cannabis use allows for comprehensive assessment and management in the adolescent population. Copyright © 2016 Elsevier Inc. All rights reserved.

Nicotine dependence predicts cannabis use disorder symptoms among adolescents and young adults.

PubMed

Dierker, Lisa; Braymiller, Jessica; Rose, Jennifer; Goodwin, Renee; Selya, Arielle

2018-06-01

We evaluate if cigarette smoking and/or nicotine dependence predicts cannabis use disorder symptoms among adolescent and young adult cannabis users and whether the relationships differ based on frequency of cannabis use. Data were drawn from seven annual surveys of the NSDUH to include adolescents and young adults (age 12-21) who reported using cannabis at least once in the past 30 days (n = 21,928). Cannabis use frequency trends in the association between cigarette smoking, nicotine dependence and cannabis use disorder symptoms were assessed using Varying Coefficient Models (VCM's). Over half of current cannabis users also smoked cigarettes in the past 30 days (54.7% SE 0.48). Cigarette smoking in the past 30 days was associated with earlier onset of cannabis use, more frequent cannabis use and a larger number of cannabis use disorder symptoms compared to those who did not smoke cigarettes. After statistical control for socio-demographic characteristics and other substance use behaviors, nicotine dependence but not cigarette smoking quantity or frequency was positively and significantly associated with each of the cannabis use disorder symptoms as well as the total number of cannabis symptoms endorsed. Higher nicotine dependence scores were consistently associated with the cannabis use disorder symptoms across all levels of cannabis use from 1 day used (past month) to daily cannabis use, though the relationship was strongest among infrequent cannabis users. Prevention and treatment efforts should consider cigarette smoking comorbidity when addressing the increasing proportion of the US population that uses cannabis. Copyright © 2018 Elsevier B.V. All rights reserved.

Poor School Satisfaction and Number of Cannabis Using Peers within School Classes as Individual Risk Factors for Cannabis Use among Adolescents

ERIC Educational Resources Information Center

Hoff, Dominic A.; Andersen, Anette; Holstein, Bjorn E.

2010-01-01

There is little information available on the topic of poor school satisfaction as a risk factor for cannabis use among adolescents. We examined if there was an association between poor school satisfaction, school class cannabis use and individual cannabis use. Further, we investigated if many cannabis users within the school class statistically…

Gyrification brain abnormalities associated with adolescence and early-adulthood cannabis use.

PubMed

Mata, Ignacio; Perez-Iglesias, Rocio; Roiz-Santiañez, Roberto; Tordesillas-Gutierrez, Diana; Pazos, Angel; Gutierrez, Agustin; Vazquez-Barquero, Jose Luis; Crespo-Facorro, Benedicto

2010-03-04

Although cannabis is the most widely used illicit drug in the world, the long-term effect of its use in the brain remains controversial. In order to determine whether adolescence and early-adulthood cannabis use is associated with gross volumetric and gyrification abnormalities in the brain, we set up a cross-sectional study using structural magnetic resonance imaging in a sample of general population subjects. Thirty cannabis-using subjects (mean age, 25.7 years; mean duration of regular use, 8.4 years, range: 3-21) with no history of polydrug use or neurologic/mental disorder and 44 non-using control subjects (mean age, 25.8 years) were included. Cannabis users showed bilaterally decreased concavity of the sulci and thinner sulci in the right frontal lobe. Among non-users, age was significantly correlated with decreased gyrification (i.e., less concave sulci and more convexe gyri) and decreased cortical thickness, supporting the notion of age-related gyrification changes. However, among cannabis users gyrification indices did not show significant dependency on age, age of regular cannabis use initiation, or cumulative exposure to cannabis. These results suggest that cannabis use in adolescence and early-adulthood might involve a premature alteration in cortical gyrification similar to what is normally observed at a later age, probably through disruption of normal neurodevelopment. 2009 Elsevier B.V. All rights reserved.

The Adolescent Community Reinforcement Approach for Adolescent Cannabis Users, Cannabis Youth Treatment (CYT) Series, Volume 4.

ERIC Educational Resources Information Center

Godley, Susan Harrington; Meyers, Robert J.; Smith, Jane Ellen; Karvinen, Tracy; Titus, Janet C.; Godley, Mark D.; Dent, George; Passetti, Lora; Kelberg, Pamela

This publication was written for therapists and their supervisors who may want to implement the adolescent community reinforcement approach intervention, which was one of the five interventions tested by the Center for Substance Abuse Treatment's (CSAT's) Cannabis Youth Treatment (CYT) Project. The CYT Project provided funding to support a study…

Gender Differences in the Correlates of Adolescents' Cannabis Use

PubMed Central

Tu, Andrew W.; Ratner, Pamela A.; Johnson, Joy L.

2008-01-01

Adolescents' gender-specific cannabis use rates and their correlates were examined. Data were obtained via a cross-sectional survey conducted in 2004 in British Columbia, Canada, funded by the Canadian Institutes of Health Research. School districts were invited to participate, and schools within consenting districts were recruited. In total, 8,225 students (50% male)from Grades 7 to 12 participated. About 73% were “White” and 47% had used cannabis in their lifetime. Cannabis users were grouped according to their frequency of use: “never users” “frequent users” or “heavy users” Male heavy cannabis users (14.3% of boys) were more likely to be in Grade 9 or higher; be Aboriginal; report poorer economic status; never feel like an outsider; frequently use alcohol and tobacco; and have lower satisfaction with family, friends, and school compared with boys that never used. Female heavy users (8.7% of girls) were more likely to be in a higher grade; report poorer economic status, mental health, and academic performance; frequently use alcohol and tobacco; and have lower satisfaction with their school compared with female never users. Three important gender differences in the multivariate analysis of the correlates of cannabis use were noted: school grade (for boys only), Aboriginal status (for boys only), and mental health (for girls only). Despite the limitations of relying on self-reports, a subset of youth appears to be at risk for excessive cannabis use that may impair life opportunities and health. The gender differences may be important in the design and implementation of prevention or treatment programs for adolescents. PMID:18696378

Implicit Associations and Explicit Expectancies toward Cannabis in Heavy Cannabis Users and Controls

PubMed Central

Beraha, Esther M.; Cousijn, Janna; Hermanides, Elisa; Goudriaan, Anna E.; Wiers, Reinout W.

2013-01-01

Cognitive biases, including implicit memory associations are thought to play an important role in the development of addictive behaviors. The aim of the present study was to investigate implicit affective memory associations in heavy cannabis users. Implicit positive-arousal, sedation, and negative associations toward cannabis were measured with three Single Category Implicit Association Tests (SC-IAT’s) and compared between 59 heavy cannabis users and 89 controls. Moreover, we investigated the relationship between these implicit affective associations and explicit expectancies, subjective craving, cannabis use, and cannabis related problems. Results show that heavy cannabis users had stronger implicit positive-arousal associations but weaker implicit negative associations toward cannabis compared to controls. Moreover, heavy cannabis users had stronger sedation but weaker negative explicit expectancies toward cannabis compared to controls. Within heavy cannabis users, more cannabis use was associated with stronger implicit negative associations whereas more cannabis use related problems was associated with stronger explicit negative expectancies, decreasing the overall difference on negative associations between cannabis users and controls. No other associations were observed between implicit associations, explicit expectancies, measures of cannabis use, cannabis use related problems, or subjective craving. These findings indicate that, in contrast to other substances of abuse like alcohol and tobacco, the relationship between implicit associations and cannabis use appears to be weak in heavy cannabis users. PMID:23801968

[Consumption of cannabis in adolescents].

PubMed

Phan, O; Obradovic, I; Har, A

2017-01-01

Over the past 10 years, the consumption of cannabis among adolescents has dramatically increased. Today, adolescent cannabis use is a major public health problem. Two forms of cannabis are commonly smoked: herb (marijuana) and resin. These forms have a high concentration of tetrahydrocannabinol, the active molecule of cannabis. Recent research has helped understand how the cannabinoid system works. This system combines specific receptors and specific molecules: the endocannabinoids. The effects of cannabis use are now well documented. Some adolescents report subjective positive effects. They use it not only on a recreational basis, but also to deal with their emotions. Over the long term, cannabis increases the risk of depression and schizophrenia for those adolescents who are at risk. Use, misuse, and dependence are frequently associated with heavy psychopathologic problems such as vulnerability and depression. Many cannabis dependence psychotherapies have shown their efficacy and efficiency. Motivational interviews, cognitive behavioral therapy, multidimensional family therapy (MDFT), and residential treatment have proved highly effective. MDFT seems very effective, especially in cases of heavy use. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

A controlled family study of cannabis users with and without psychosis.

PubMed

Proal, Ashley C; Fleming, Jerry; Galvez-Buccollini, Juan A; Delisi, Lynn E

2014-01-01

Cannabis is one of the most highly abused illicit drugs in the world. Several studies suggest a link between adolescent cannabis use and schizophrenia. An understanding of this link would have significant implications for legalization of cannabis and its medicinal value. The present study aims to determine whether familial morbid risk for schizophrenia is the crucial factor that underlies the association of adolescent cannabis use with the development of schizophrenia. Consecutively obtained probands were recruited into four samples: sample 1: 87 non-psychotic controls with no drug use; sample 2: 84 non-psychotic controls with cannabis use; sample 3: 32 patients with a schizophrenia spectrum psychosis with no drug use; sample 4: 76 patients with schizophrenia spectrum psychosis with cannabis use. All cannabis using subjects used this drug during adolescence, and no other substance, with the exception of alcohol. Structured interviews of probands and family informants were used to obtain diagnostic information about probands and all their known relatives. There was an increased morbid risk for schizophrenia in relatives of the cannabis using and non-using patient samples compared with their respective non-psychotic control samples (p=.002, p<.001 respectively). There was no significant difference in morbid risk for schizophrenia between relatives of the patients who use or do not use cannabis (p=.43). The results of the current study suggest that having an increased familial morbid risk for schizophrenia may be the underlying basis for schizophrenia in cannabis users and not cannabis use by itself. Published by Elsevier B.V.

The brain effects of cannabis in healthy adolescents and in adolescents with schizophrenia: a systematic review.

PubMed

James, Anthony; James, Christine; Thwaites, Thomas

2013-12-30

Cannabis is widely used in adolescence; however, the effects of cannabis on the developing brain remain unclear. Cannabis might be expected to have increased effects upon brain development and cognition during adolescence. There is extensive re-organisation of grey (GM) and white matter (WM) at this time, while the endocannabinoid (eCB) system, which is involved in the normal physiological regulation of neural transmission, is still developing. In healthy adolescent cannabis users there is a suggestion of greater memory loss and hippocampal volume changes. Functional studies point to recruitment of greater brain areas under cognitive load. Structural and DTI studies are few, and limited by comorbid drug and alcohol use. The studies of cannabis use in adolescent-onset schizophrenia (AOS) differ, with one study pointing to extensive GM and WM changes. There is an intriguing suggestion that the left parietal lobe may be more vulnerable to the effects of cannabis in AOS. As in adult schizophrenia cognition does not appear to be adversely affected in AOS following cannabis use. Given the limited number of studies it is not possible to draw firm conclusions. There is a need for adequately powered, longitudinal studies. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Reaching out towards cannabis: approach-bias in heavy cannabis users predicts changes in cannabis use

PubMed Central

Cousijn, Janna; Goudriaan, Anna E; Wiers, Reinout W

2011-01-01

Aims Repeated drug exposure can lead to an approach-bias, i.e. the relatively automatically triggered tendencies to approach rather that avoid drug-related stimuli. Our main aim was to study this approach-bias in heavy cannabis users with the newly developed cannabis Approach Avoidance Task (cannabis-AAT) and to investigate the predictive relationship between an approach-bias for cannabis-related materials and levels of cannabis use, craving, and the course of cannabis use. Design, settings and participants Cross-sectional assessment and six-month follow-up in 32 heavy cannabis users and 39 non-using controls. Measurements Approach and avoidance action-tendencies towards cannabis and neutral images were assessed with the cannabis AAT. During the AAT, participants pulled or pushed a joystick in response to image orientation. To generate additional sense of approach or avoidance, pulling the joystick increased picture size while pushing decreased it. Craving was measured pre- and post-test with the multi-factorial Marijuana Craving Questionnaire (MCQ). Cannabis use frequencies and levels of dependence were measured at baseline and after a six-month follow-up. Findings Heavy cannabis users demonstrated an approach-bias for cannabis images, as compared to controls. The approach-bias predicted changes in cannabis use at six-month follow-up. The pre-test MCQ emotionality and expectancy factor were associated negatively with the approach-bias. No effects were found on levels of cannabis dependence. Conclusions Heavy cannabis users with a strong approach-bias for cannabis are more likely to increase their cannabis use. This approach-bias could be used as a predictor of the course of cannabis use to identify individuals at risk from increasing cannabis use. PMID:21518067

Cannabis use in early adolescence: Evidence of amygdala hypersensitivity to signals of threat.

PubMed

Spechler, Philip A; Orr, Catherine A; Chaarani, Bader; Kan, Kees-Jan; Mackey, Scott; Morton, Aaron; Snowe, Mitchell P; Hudson, Kelsey E; Althoff, Robert R; Higgins, Stephen T; Cattrell, Anna; Flor, Herta; Nees, Frauke; Banaschewski, Tobias; Bokde, Arun L W; Whelan, Robert; Büchel, Christian; Bromberg, Uli; Conrod, Patricia; Frouin, Vincent; Papadopoulos, Dimitri; Gallinat, Jurgen; Heinz, Andreas; Walter, Henrik; Ittermann, Bernd; Gowland, Penny; Paus, Tomáš; Poustka, Luise; Martinot, Jean-Luc; Artiges, Eric; Smolka, Michael N; Schumann, Gunter; Garavan, Hugh

2015-12-01

Cannabis use in adolescence may be characterized by differences in the neural basis of affective processing. In this study, we used an fMRI affective face processing task to compare a large group (n=70) of 14-year olds with a history of cannabis use to a group (n=70) of never-using controls matched on numerous characteristics including IQ, SES, alcohol and cigarette use. The task contained short movies displaying angry and neutral faces. Results indicated that cannabis users had greater reactivity in the bilateral amygdalae to angry faces than neutral faces, an effect that was not observed in their abstinent peers. In contrast, activity levels in the cannabis users in cortical areas including the right temporal-parietal junction and bilateral dorsolateral prefrontal cortex did not discriminate between the two face conditions, but did differ in controls. Results did not change after excluding subjects with any psychiatric symptomology. Given the high density of cannabinoid receptors in the amygdala, our findings suggest cannabis use in early adolescence is associated with hypersensitivity to signals of threat. Hypersensitivity to negative affect in adolescence may place the subject at-risk for mood disorders in adulthood. Copyright © 2015. Published by Elsevier Ltd.

A multi-site proof-of-concept investigation of computerized approach-avoidance training in adolescent cannabis users.

PubMed

Jacobus, Joanna; Taylor, Charles T; Gray, Kevin M; Meredith, Lindsay R; Porter, Anna M; Li, Irene; Castro, Norma; Squeglia, Lindsay M

2018-06-01

Few effective treatment options exist for cannabis-using youth. This pilot study aimed to test Approach-Avoidance Training to reduce cannabis use with non-treatment-seeking adolescents. Eighty cannabis-using non-treatment-seeking adolescents (average age 19) were recruited from San Diego, California and Charleston, South Carolina, and randomized to complete either six sessions of Cannabis Approach-Avoidance Task Training (CAAT-training) designed to reduce automatic approach biases for cannabis cues or CAAT-sham training. Change in two primary outcome variables was examined: 1) cannabis approach bias and 2) percent cannabis use days over study enrollment. Change in percent alcohol use days over study enrollment was explored as a secondary outcome. A mixed models repeated measures analysis confirmed the group by time interaction effect for approach bias failed to reach statistical significance (p = .06). Significant group by time interaction effects (ps < 0.05) predicted percent days of cannabis and alcohol use over study enrollment. Participants randomized to the avoid cannabis condition (CAAT-training) reported 7% fewer days of cannabis use compared to 0% change for sham; unexpectedly, those in the avoid cannabis condition reported 10% percent more alcohol use days compared to 3% more for sham. Computerized cognitive bias modification paradigms may have utility in reducing adolescent cannabis use. Future work should consider developing a paradigm that addresses both cannabis and alcohol, as well as alternative computerized approaches for coping with addictive behavior in conjunction with bias modification. Copyright © 2018 Elsevier B.V. All rights reserved.

Associations between adolescent cannabis use and neuropsychological decline: a longitudinal co-twin control study.

PubMed

Meier, Madeline H; Caspi, Avshalom; Danese, Andrea; Fisher, Helen L; Houts, Renate; Arseneault, Louise; Moffitt, Terrie E

2018-02-01

This study tested whether adolescents who used cannabis or met criteria for cannabis dependence showed neuropsychological impairment prior to cannabis initiation and neuropsychological decline from before to after cannabis initiation. A longitudinal co-twin control study. Participants were 1989 twins from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative birth cohort of twins born in England and Wales from 1994 to 1995. Frequency of cannabis use and cannabis dependence were assessed at age 18. Intelligence quotient (IQ) was obtained at ages 5, 12 and 18. Executive functions were assessed at age 18. Compared with adolescents who did not use cannabis, adolescents who used cannabis had lower IQ in childhood prior to cannabis initiation and lower IQ at age 18, but there was little evidence that cannabis use was associated with IQ decline from ages 12-18. For example, adolescents with cannabis dependence had age 12 and age 18 IQ scores that were 5.61 (t = -3.11, P = 0.002) and 7.34 IQ points (t = -5.27, P < 0.001) lower than adolescents without cannabis dependence, but adolescents with cannabis dependence did not show greater IQ decline from age 12-18 (t = -1.27, P = 0.20). Moreover, adolescents who used cannabis had poorer executive functions at age 18 than adolescents who did not use cannabis, but these associations were generally not apparent within twin pairs. For example, twins who used cannabis more frequently than their co-twin performed similarly to their co-twin on five of six executive function tests (Ps > 0.10). The one exception was that twins who used cannabis more frequently than their co-twin performed worse on one working memory test (Spatial Span reversed; β = -0.07, P = 0.036). Short-term cannabis use in adolescence does not appear to cause IQ decline or impair executive functions, even when cannabis use reaches the level of dependence. Family background factors explain why adolescent cannabis users

Randomized controlled trial of motivational enhancement therapy with nontreatment-seeking adolescent cannabis users: a further test of the teen marijuana check-up.

PubMed

Walker, Denise D; Stephens, Robert; Roffman, Roger; Demarce, Josephine; Lozano, Brian; Towe, Sheri; Berg, Belinda

2011-09-01

Cannabis use adversely affects adolescents and interventions that are attractive to adolescents are needed. This trial compared the effects of a brief motivational intervention for cannabis use with a brief educational feedback control and a no-assessment control. Participants were randomized into one of three treatment conditions: Motivational Enhancement Therapy (MET), Educational Feedback Control (EFC), or Delayed Feedback Control (DFC). Those who were assigned to MET and EFC were administered a computerized baseline assessment immediately following randomization and completed assessments at the 3- and 12-month follow-up periods. Participants in the DFC condition were not assessed until the 3-month follow-up. Following the completion of treatment sessions, all participants were offered up to four optional individual treatment sessions aimed at cessation of cannabis use. The research was conducted in high schools in Seattle, Washington. The participant s included 310 self-referred adolescents who smoked cannabis regularly. The main outcome measures included days of cannabis use, associated negative consequences, and engagement in additional treatment. At the 3-month follow-up, participants in both the MET and EFC conditions reported significantly fewer days of cannabis use and negative consequences compared to those in the DFC. The frequency of cannabis use was less in MET relative to EFC at 3 months, but it did not translate to differences in negative consequences. Reductions in use and problems were sustained at 12 months, but there were no differences between MET and EFC interventions. Engagement in additional treatment was minimal and did not differ by condition. Brief interventions can attract adolescent cannabis users and have positive impacts on them, but the mechanisms of the effects are yet to be identified. (c) 2011 APA, all rights reserved.

Randomized Controlled Trial of Motivational Enhancement Therapy with Non-treatment Seeking Adolescent Cannabis Users: A Further Test of the Teen Marijuana Check-Up

PubMed Central

Walker, Denise D.; Stephens, Robert; Roffman, Roger; DeMarce, Josephine; Lozano, Brian; Towe, Sheri; Berg, Belinda

2011-01-01

Aims Cannabis use adversely affects adolescents and interventions that are attractive to adolescents are needed. This trial compared the effects of a brief motivational intervention for cannabis use with a brief educational feedback control and a no-assessment control. Design Participants were randomized into one of three treatment conditions: Motivational Enhancement Therapy (MET), Educational Feedback Control (EFC) or Delayed Feedback Control (DFC). Those assigned to MET and EFC were administered a computerized baseline assessment immediately following randomization and completed assessments at the 3- and 12-month follow-up periods. Participants in the DFC condition were not assessed until the 3-month follow-up. Following the completion of treatment sessions, all participants were offered up to 4 optional individual treatment sessions aimed at cessation of cannabis use. Setting High schools in Seattle, WA, USA. Participants 310 self-referred adolescents who smoked cannabis regularly. Measurements Main outcome measures included days of cannabis use, associated negative consequences, and engagement in additional treatment. Findings At the 3-month follow-up, participants in both the MET and EFC conditions reported significantly fewer days of cannabis use and negative consequences compared to DFC. Frequency of cannabis use was less in MET relative to EFC at 3 months, but did not translate to differences in negative consequences. Reduction in use and problems were sustained at 12-months but there were no differences between MET and EFC interventions. Engagement in additional treatment was minimal and not different by condition. Conclusions Brief interventions can attract and have positive impacts on adolescent cannabis users, but the mechanisms of the effects are yet to be identified. PMID:21688877

Evidence for the Risks and Consequences of Adolescent Cannabis Exposure.

PubMed

Levine, Amir; Clemenza, Kelly; Rynn, Moira; Lieberman, Jeffrey

2017-03-01

This review of the scientific literature examines the potential adult sequelae of exposure to cannabis and related synthetic cannabinoids in adolescence. We examine the four neuropsychiatric outcomes that are likely most vulnerable to alteration by early cannabinoid use, as identified within both the clinical and preclinical research: cognition, emotional functioning, risk for psychosis, and addiction. A literature search was conducted through PubMed, PsychInfo, and Google Scholar with no publication date restrictions. The search terms used were "adolescent" and "adult," and either "cannabis," "marijuana," "delta-9-tetra-hydrocannabinol," or "cannabinoid," which was then crossed with one or more of the following terms: "deficit," "impairment," "alteration," "long-term," "persistent," "development," "maturation," and "pubescent." The majority of the clinical and preclinical data point to a strong correlation between adolescent cannabinoid exposure and persistent, adverse neuropsychiatric outcomes in adulthood. Although the literature supports the hypothesis that adolescent cannabis use is connected to impaired cognition and mental health in adults, it does not conclusively demonstrate that cannabis consumption alone is sufficient to cause these deficits in humans. The animal literature, however, clearly indicates that adolescent-onset exposure to cannabinoids can catalyze molecular processes that lead to persistent functional deficits in adulthood, deficits that are not found to follow adult-onset exposure and that model some of the adverse outcomes reported in humans among adult populations of early-onset cannabis users. Based on the data in the current literature, a strong association is found between early, frequent, and heavy adolescent cannabis exposure and poor cognitive and psychiatric outcomes in adulthood, yet definite conclusions cannot yet be made as to whether cannabis use alone has a negative impact on the human adolescent brain. Future research will

Tentative Evidence for Striatal Hyperactivity in Adolescent Cannabis Using Boys: A Cross-Sectional Multicenter fMRI Study

PubMed Central

Jager, Gerry; Block, Robert I.; Luijten, Maartje; Ramsey, Nick F.

2013-01-01

Adolescents' risk-taking behavior has been linked to a maturational imbalance between reward (“go”) and inhibitory-control (“stop”) related brain circuitry. This may drive adolescent drug-taking, such as cannabis use. In this study we assessed the non-acute effects of adolescent cannabis use on reward-related brain function. We performed a two-site (United States and Netherlands; pooled data) functional magnetic resonance imaging (fMRI) study with a cross-sectional design. Twenty-one abstinent but frequent cannabis-using boys were compared with 24 non-using peers on reward-related brain function, using a monetary incentive delay task with fMRI. Focus was on anticipatory and response stages of reward and brain areas critically involved in reward processing like the striatum. Performance in users was normal. Region-of-interest analysis indicated striatal hyperactivity during anticipatory stages of reward in users. Intriguingly, this effect was most pronounced during non-rewarding events. Striatal hyperactivity in adolescent cannabis users may signify an overly sensitive motivational brain circuitry. Frequent cannabis use during adolescence may induce diminished ability to disengage the motivational circuit when no reward can be obtained. This could strengthen the search for reinforcements like drugs of abuse, even when facing the negative (non-rewarding) consequences. PMID:23909003

Tentative evidence for striatal hyperactivity in adolescent cannabis-using boys: a cross-sectional multicenter fMRI study.

PubMed

Jager, Gerry; Block, Robert I; Luijten, Maartje; Ramsey, Nick F

2013-01-01

Adolescents' risk-taking behavior has been linked to a maturational imbalance between reward ("go") and inhibitory-control ("stop")-related brain circuitry. This may drive adolescent drug-taking, such as cannabis use. In this study, we assessed the non-acute effects of adolescent cannabis use on reward-related brain function. We performed a two-site (United States and Netherlands; pooled data) functional magnetic resonance imaging (fMRI) study with a cross-sectional design. Twenty-one abstinent but frequent cannabis-using boys were compared with 24 non-using peers on reward-related brain function, using a monetary incentive delay task with fMRI. Focus was on anticipatory and response stages of reward and brain areas critically involved in reward processing like the striatum. Performance in users was normal. Region-of-interest analysis indicated striatal hyperactivity during anticipatory stages of reward in users. Intriguingly, this effect was most pronounced during non-rewarding events. Striatal hyperactivity in adolescent cannabis users may signify an overly sensitive motivational brain circuitry. Frequent cannabis use during adolescence may induce diminished ability to disengage the motivational circuit when no reward can be obtained. This could strengthen the search for reinforcements like drugs of abuse, even when facing the negative (non-rewarding) consequences.

Cannabis use and memory brain function in adolescent boys: a cross-sectional multicenter functional magnetic resonance imaging study.

PubMed

Jager, Gerry; Block, Robert I; Luijten, Maartje; Ramsey, Nick F

2010-06-01

Early-onset cannabis use has been associated with later use/abuse, mental health problems (psychosis, depression), and abnormal development of cognition and brain function. During adolescence, ongoing neurodevelopmental maturation and experience shape the neural circuitry underlying complex cognitive functions such as memory and executive control. Prefrontal and temporal regions are critically involved in these functions. Maturational processes leave these brain areas prone to the potentially harmful effects of cannabis use. We performed a two-site (United States and The Netherlands; pooled data) functional magnetic resonance imaging (MRI) study with a cross-sectional design, investigating the effects of adolescent cannabis use on working memory (WM) and associative memory (AM) brain function in 21 abstinent but frequent cannabis-using boys (13-19) years of age and compared them with 24 nonusing peers. Brain activity during WM was assessed before and after rule-based learning (automatization). AM was assessed using a pictorial hippocampal-dependent memory task. Cannabis users performed normally on both memory tasks. During WM assessment, cannabis users showed excessive activity in prefrontal regions when a task was novel, whereas automatization of the task reduced activity to the same level in users and controls. No effect of cannabis use on AM-related brain function was found. In adolescent cannabis users, the WM system was overactive during a novel task, suggesting functional compensation. Inefficient WM recruitment was not related to a failure in automatization but became evident when processing continuously changing information. The results seem to confirm the vulnerability of still developing frontal lobe functioning for early-onset cannabis use. 2010 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Cognitive Function in Individuals With Psychosis: Moderation by Adolescent Cannabis Use

PubMed Central

Hanna, Rebecca C.; Shalvoy, Alexandra; Cullum, C. Munro; Ivleva, Elena I.; Keshavan, Matcheri; Pearlson, Godfrey; Hill, S. Kristian; Sweeney, John A.; Tamminga, Carol A.; Ghose, Subroto

2016-01-01

Prior cannabis use, compared to nonuse, is reported to be associated with less cognitive impairment in schizophrenia. The age of cannabis use and the persistent influence of cannabis use on cognitive function has not been examined across the psychosis dimension. Ninety-seven volunteers with psychosis (schizophrenia, schizoaffective, or bipolar psychosis) and 64 controls were recruited at the Dallas site of the Bipolar-Schizophrenia Network on Intermediate Phenotypes consortium. Cannabis use history obtained in a semi-structured manner was used to categorize subjects into nonusers, adolescent-onset users, and late-onset users. The a priori hypothesis tested was that individuals with psychosis and a history of adolescent cannabis use (ACU) would have better global neuropsychological performance, as measured by the Brief Assessment of Cognition in Schizophrenia (BACS) battery, compared to those with psychosis and no cannabis use history. BACS Composite scores were significantly higher in individuals with psychosis with ACU compared to individuals with psychosis and no prior cannabis use. In subgroup analyses, ACU influenced global cognition in the schizophrenia/schizoaffective (SCZ) subgroup but not the bipolar psychosis subgroup. Exploratory analyses within the SCZ group, suggest that ACU was associated with better performance in specific domains compared to non-ACU groups. There are distinct associations between age of cannabis use and neuropsychological function across psychotic illnesses. Specifically, ACU is associated with better cognitive function in SCZ but not bipolar psychosis. This age-dependent and diagnosis-specific influence of cannabis may need to be factored into the design of future cognitive studies in SCZ. PMID:27033329

Cannabis and creativity: highly potent cannabis impairs divergent thinking in regular cannabis users.

PubMed

Kowal, Mikael A; Hazekamp, Arno; Colzato, Lorenza S; van Steenbergen, Henk; van der Wee, Nic J A; Durieux, Jeffrey; Manai, Meriem; Hommel, Bernhard

2015-03-01

Cannabis users often claim that cannabis has the potential to enhance their creativity. Research suggests that aspects of creative performance might be improved when intoxicated with cannabis; however, the evidence is not conclusive. The aim of this study was to investigate the acute effects of cannabis on creativity. We examined the effects of administering a low (5.5 mg delta-9-tetrahydrocannabinol [THC]) or high (22 mg THC) dose of vaporized cannabis vs. placebo on creativity tasks tapping into divergent (Alternate Uses Task) and convergent (Remote Associates Task) thinking, in a population of regular cannabis users. The study used a randomized, double-blind, between-groups design. Participants in the high-dose group (n = 18) displayed significantly worse performance on the divergent thinking task, compared to individuals in both the low-dose (n = 18) and placebo (n = 18) groups. The findings suggest that cannabis with low potency does not have any impact on creativity, while highly potent cannabis actually impairs divergent thinking.

Cigarette smoking during an N-acetylcysteine-assisted cannabis cessation trial in adolescents

PubMed Central

McClure, Erin A.; Baker, Nathaniel L.; Gray, Kevin M.

2014-01-01

Background and Objectives Tobacco and cannabis use are both highly prevalent worldwide. Their co-use is also common in adults and adolescents. Despite this frequent co-occurrence, cessation from both substances is rarely addressed in randomized clinical trials. Given evidence that tobacco use may increase during cannabis cessation attempts, and additionally that tobacco users have poorer cannabis cessation outcomes, we explored tobacco outcomes, specifically cigarette smoking, from an adolescent cannabis cessation trial that tested the efficacy of N-acetylesteine (NAC). Methods Cannabis-dependent adolescents (ages 15–21; n=116) interested in cannabis treatment were randomized to NAC (1200 mg bid) or matched placebo for 8 weeks. Participants did not need to be cigarette smokers or be interested in smoking cessation to qualify for inclusion. Results Approximately 59% of enrolled participants were daily and non-daily cigarette smokers, and only differed from non-smoking participants on the compulsion sub-scale of the Marijuana Craving Questionnaire. Among cigarette smokers who were retained in the study, there was no change in cigarettes per day for either NAC or placebo groups during the 8-week treatment phase. Being a cigarette smoker did not appear to influence the effects of NAC on cannabis abstinence, though there was a trend in the placebo group of poorer cannabis outcomes for cigarette smokers vs. non-smokers. Conclusions No evidence was found of compensatory cigarette smoking during this cannabis cessation trial in adolescents. Further work assessing interventions to reduce both cannabis and tobacco use in this population is greatly needed. PMID:24720376

Cannabis Use and Performance in Adolescents

ERIC Educational Resources Information Center

Malhotra, Anil; Biswas, Parthasarathy

2006-01-01

Cannabis is a widely used illicit drug among adolescents, many of whom perceive little risk from cannabis. Cannabis use is associated with poor academic performance and increased school drop-outs. It is also associated with high-risk behaviors in adolescents like crime, violence, unprotected sexual encounters, and car accidents. Many of these…

Design and validation of a Cannabis Use Intention Questionnaire (CUIQ) for adolescents.

PubMed

Lloret Irles, Daniel; Morell-Gomis, Ramón; Laguía, Ana; Moriano, Juan A

2018-01-01

In Spain, one in four 14 to 18-year-old adolescents has used cannabis during the last twelve months. Demand for treatment has increased in European countries. These facts have prompted the development of preventive interventions that require screening tools in order to identify the vulnerable population and to properly asses the efficacy of such interventions. The Theory of Planned Behaviour (TPB), widely used to forecast behavioural intention, has also demonstrated a good predictive capacity in addictions. The aim of this study is to design and validate a Cannabis Use Intention Questionnaire (CUIQ) based on TPB. 1,011 teenagers answered a set of tests to assess attitude towards use, subjective norms, self-efficacy towards non-use, and intention to use cannabis. CUIQ had good psychometric properties. Structural Equation Modelling results confirm the predictive model on intention to use cannabis in the Spanish adolescent sample, classified as users and non-users, explaining 40% of variance of intention to consume. CUIQ is aimed at providing a better understanding of the psychological processes that lead to cannabis use and allowing the evaluation of programmes. This can be particularly useful for improving the design and implementation of selective prevention programmes.

The role of general parenting and cannabis-specific parenting practices in adolescent cannabis and other illicit drug use.

PubMed

Vermeulen-Smit, E; Verdurmen, J E E; Engels, R C M E; Vollebergh, W A M

2015-02-01

To investigate general and cannabis-specific parenting practices in relation to adolescent cannabis and other illicit drug use. Data were derived from the Dutch National School Survey on Substance Use among students (N=3209; aged 12-16 years) and one of their parents in 2011. Logistic regression analyses revealed that 1) parental cannabis use was significantly related to more adolescent lifetime and recent cannabis use, and 2) restrictive cannabis-specific parental rules were associated with less adolescent recent cannabis and lifetime use of other illicit drugs, even when controlled for sociodemographic factors, general parenting, adolescent tobacco use, and tobacco-specific parenting. In addition, no significant interaction was observed between parental cannabis use and cannabis-specific rules in their relation to adolescent cannabis and other illicit drug use, indicating that cannabis rules are evenly associated with adolescent drug use for families with and without parental cannabis experience. In addition to general parenting practices, restrictive cannabis-specific rules are related to lower adolescent cannabis and other illicit drug rates. Parents who ever used cannabis have children with a higher prevalence of cannabis use. However, their restrictive cannabis-specific rules are equally related to a lower chance of adolescent cannabis use. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Blunted stress reactivity in chronic cannabis users.

PubMed

Cuttler, Carrie; Spradlin, Alexander; Nusbaum, Amy T; Whitney, Paul; Hinson, John M; McLaughlin, Ryan J

2017-08-01

One of the most commonly cited reasons for chronic cannabis use is to cope with stress. Consistent with this, cannabis users have shown reduced emotional arousal and dampened stress reactivity in response to negative imagery. To our knowledge, the present study represents the first to examine the effects of an acute stress manipulation on subjective stress and salivary cortisol in chronic cannabis users compared to non-users. Forty cannabis users and 42 non-users were randomly assigned to complete either the stress or no stress conditions of the Maastricht Acute Stress Test (MAST). The stress condition of the MAST manipulates both physiological (placing hand in ice bath) and psychosocial stress (performing math under conditions of social evaluation). Participants gave baseline subjective stress ratings before, during, and after the stress manipulation. Cortisol was measured from saliva samples obtained before and after the stress manipulation. Further, cannabis cravings and symptoms of withdrawal were measured. Subjective stress ratings and cortisol levels were significantly higher in non-users in the stress condition relative to non-users in the no stress condition. In contrast, cannabis users demonstrated blunted stress reactivity; specifically, they showed no increase in cortisol and a significantly smaller increase in subjective stress ratings. The stress manipulation had no impact on cannabis users' self-reported cravings or withdrawal symptoms. Chronic cannabis use is associated with blunted stress reactivity. Future research is needed to determine whether this helps to confer resiliency or vulnerability to stress-related psychopathology as well as the mechanisms underlying this effect.

The co-use of tobacco and cannabis among adolescents over a 30-year period.

PubMed

Webster, Lauren; Chaiton, Michael; Kirst, Maritt

2014-03-01

This study explores the patterns of use and co-use of tobacco and cannabis among Ontario adolescents over 3 decades and if characteristics of co-users and single substance users have changed. Co-use trends for 1981-2011 were analyzed using the Centre for Addiction and Mental Health Ontario Student Drug Use and Health Survey, which includes 38,331 students in grades 7, 9, and 11. A co-user was defined as someone reporting daily tobacco and/or cannabis use in the past month. Trends over time (by gender and academic performance) were analyzed with logistic regression. The prevalence of tobacco-only use, cannabis-only use, and co-use fluctuated considerably. During 1981-1993, there were more tobacco-only users than co-users and cannabis-only users; since 1993 the prevalence of tobacco use has decreased dramatically. Co-use prevalence peaked at 12% (95% confidence interval: 9, 15) in 1999, when prevalence of overall use of both substances was highest. In 2011, 92% of tobacco users also used cannabis, up from 16% in 1991. In 2011 nearly all students who smoke tobacco daily also use cannabis. Non-regular use of either substance is highest now compared with the past 3 decades. Contemporary tobacco and cannabis co-users are significantly different than past users. Youth prevention programs should understand the changing context of cannabis and tobacco among youth. © 2014, American School Health Association.

Neural Correlates of Social Influence Among Cannabis Users.

PubMed

Gilman, Jodi M

2017-06-01

Although peer influence is an important factor in the initiation and maintenance of cannabis use, few studies have investigated the neural correlates of peer influence among cannabis users. The current review summarizes research on the neuroscience of social influence in cannabis users, with the goal of highlighting gaps in the literature and the need for future research. Brain regions underlying peer influence may function differently in cannabis users. Compared to non-using controls, regions of the brain underlying reward, such as the striatum, show greater connectivity with frontal regions, and also show hyperactivity when participants are presented with peer information. Other subcortical regions, such as the insula, show hypoactivation during social exclusion in cannabis users, indicating that neural responses to peer interactions may be altered in cannabis users. Although neuroscience is increasingly being used to study social behavior, few studies have specifically focused on cannabis use, and therefore it is difficult to draw conclusions about social mechanisms that may differentiate cannabis users and controls. This area of research may be a promising avenue in which to explore a critical factor underlying cannabis use and addiction.

Neural Correlates of Social Influence Among Cannabis Users

PubMed Central

Gilman, Jodi M.

2017-01-01

Purpose of review Although peer influence is an important factor in the initiation and maintenance of cannabis use, few studies have investigated the neural correlates of peer influence among cannabis users. The current review summarizes research on the neuroscience of social influence in cannabis users, with the goal of highlighting gaps in the literature and the need for future research. Recent findings Brain regions underlying peer influence may function differently in cannabis users. Compared to non-using controls, regions of the brain underlying reward, such as the striatum, show greater connectivity with frontal regions, and also show hyperactivity when participants are presented with peer information. Other subcortical regions, such as the insula, show hypoactivation during social exclusion in cannabis users, indicating that neural responses to peer interactions may be altered in cannabis users. Summary Although neuroscience is increasingly being used to study social behavior, few studies have specifically focused on cannabis use, and therefore it is difficult to draw conclusions about social mechanisms that may differentiate cannabis users and controls. This area of research may be a promising avenue in which to explore a critical factor underlying cannabis use and addiction. PMID:29057199

Self-reported cannabis use characteristics, patterns and helpfulness among medical cannabis users.

PubMed

Bonn-Miller, Marcel O; Boden, Matthew Tyler; Bucossi, Meggan M; Babson, Kimberly A

2014-01-01

Little research has investigated the demographic and symptom profile of medical cannabis users in states in the USA that have legalized cannabis use. In the present cross-sectional study, we investigated the demographic profile of 217 adults currently receiving medical cannabis, as well as differences in problematic use and perceived helpfulness in terms of (i) symptoms of psychological disorders and pain, and (ii) motives for use. Findings indicated that medical cannabis users (i) use and perceive cannabis to be beneficial for multiple conditions, some for which cannabis is not specifically prescribed or allowed at the state level; and (ii) report similar rates of disordered use as compared with population estimates among regular users. Furthermore, problematic cannabis use was predicted by several symptoms of psychological disorders (e.g. depression) and a variety of use motives (e.g. coping), while cannabis was reported as particularly helpful among those with several psychological symptoms (e.g. traumatic intrusions), as well as those reporting use for social anxiety reasons. Results are discussed in terms of future directions for research given the current debates regarding legalization of cannabis for medical purposes and, more generally, the lack of empirical data to inform such debates.

Cognitive Function in Individuals With Psychosis: Moderation by Adolescent Cannabis Use.

PubMed

Hanna, Rebecca C; Shalvoy, Alexandra; Cullum, C Munro; Ivleva, Elena I; Keshavan, Matcheri; Pearlson, Godfrey; Hill, S Kristian; Sweeney, John A; Tamminga, Carol A; Ghose, Subroto

2016-11-01

Prior cannabis use, compared to nonuse, is reported to be associated with less cognitive impairment in schizophrenia. The age of cannabis use and the persistent influence of cannabis use on cognitive function has not been examined across the psychosis dimension. Ninety-seven volunteers with psychosis (schizophrenia, schizoaffective, or bipolar psychosis) and 64 controls were recruited at the Dallas site of the Bipolar-Schizophrenia Network on Intermediate Phenotypes consortium. Cannabis use history obtained in a semi-structured manner was used to categorize subjects into nonusers, adolescent-onset users, and late-onset users. The a priori hypothesis tested was that individuals with psychosis and a history of adolescent cannabis use (ACU) would have better global neuropsychological performance, as measured by the Brief Assessment of Cognition in Schizophrenia (BACS) battery, compared to those with psychosis and no cannabis use history. BACS Composite scores were significantly higher in individuals with psychosis with ACU compared to individuals with psychosis and no prior cannabis use. In subgroup analyses, ACU influenced global cognition in the schizophrenia/schizoaffective (SCZ) subgroup but not the bipolar psychosis subgroup. Exploratory analyses within the SCZ group, suggest that ACU was associated with better performance in specific domains compared to non-ACU groups. There are distinct associations between age of cannabis use and neuropsychological function across psychotic illnesses. Specifically, ACU is associated with better cognitive function in SCZ but not bipolar psychosis. This age-dependent and diagnosis-specific influence of cannabis may need to be factored into the design of future cognitive studies in SCZ. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Dopaminergic function in cannabis users and its relationship to cannabis-induced psychotic symptoms.

PubMed

Bloomfield, Michael A P; Morgan, Celia J A; Egerton, Alice; Kapur, Shitij; Curran, H Valerie; Howes, Oliver D

2014-03-15

Cannabis is the most widely used illicit drug globally, and users are at increased risk of mental illnesses including psychotic disorders such as schizophrenia. Substance dependence and schizophrenia are both associated with dopaminergic dysfunction. It has been proposed, although never directly tested, that the link between cannabis use and schizophrenia is mediated by altered dopaminergic function. We compared dopamine synthesis capacity in 19 regular cannabis users who experienced psychotic-like symptoms when they consumed cannabis with 19 nonuser sex- and age-matched control subjects. Dopamine synthesis capacity (indexed as the influx rate constant [Formula: see text] ) was measured with positron emission tomography and 3,4-dihydroxy-6-[(18)F]-fluoro-l-phenylalanine ([(18)F]-DOPA). Cannabis users had reduced dopamine synthesis capacity in the striatum (effect size: .85; t36 = 2.54, p = .016) and its associative (effect size: .85; t36 = 2.54, p = .015) and limbic subdivisions (effect size: .74; t36 = 2.23, p = .032) compared with control subjects. The group difference in dopamine synthesis capacity in cannabis users compared with control subjects was driven by those users meeting cannabis abuse or dependence criteria. Dopamine synthesis capacity was negatively associated with higher levels of cannabis use (r = -.77, p < .001) and positively associated with age of onset of cannabis use (r = .51, p = .027) but was not associated with cannabis-induced psychotic-like symptoms (r = .32, p = .19). These findings indicate that chronic cannabis use is associated with reduced dopamine synthesis capacity and question the hypothesis that cannabis increases the risk of psychotic disorders by inducing the same dopaminergic alterations seen in schizophrenia. Copyright © 2014 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Four Mechanistic Models of Peer Influence on Adolescent Cannabis Use.

PubMed

Caouette, Justin D; Feldstein Ewing, Sarah W

2017-06-01

Most adolescents begin exploring cannabis in peer contexts, but the neural mechanisms that underlie peer influence on adolescent cannabis use are still unknown. This theoretical overview elucidates the intersecting roles of neural function and peer factors in cannabis use in adolescents. Novel paradigms using functional magnetic resonance imaging (fMRI) in adolescents have identified distinct neural mechanisms of risk decision-making and incentive processing in peer contexts, centered on reward-motivation and affect regulatory neural networks; these findings inform a theoretical model of peer-driven cannabis use decisions in adolescents. We propose four "mechanistic profiles" of social facilitation of cannabis use in adolescents: (1) peer influence as the primary driver of use; (2) cannabis exploration as the primary driver, which may be enhanced in peer contexts; (3) social anxiety; and (4) negative peer experiences. Identification of "neural targets" involved in motivating cannabis use may inform clinicians about which treatment strategies work best in adolescents with cannabis use problems, and via which social and neurocognitive processes.

Abnormal maximal finger tapping in abstinent cannabis users.

PubMed

Flavel, Stanley C; White, Jason M; Todd, Gabrielle

2013-11-01

To investigate movement speed and rhythmicity in abstinent cannabis users, we hypothesized that abstinent cannabis users exhibit decreased maximal finger tapping frequency and increased variability of tapping compared with non-drug users. The study involved 10 healthy adult cannabis users and 10 age-matched and gender-matched controls with no history of illicit drug use. Subjects underwent a series of screening tests prior to participation. Subjects were then asked to tap a strain gauge as fast as possible with the index finger of their dominant hand (duration 5 s). The average intertap interval did not significantly differ between groups, but the coefficient of variation of the intertap interval was significantly greater in the cannabis group than in controls (p=0.011). The cannabis group also exhibited a slow tapping frequency at the beginning of the task. Rhythmicity of finger tapping is abnormal in individuals with a history of cannabis use. The abnormality appears to be long lasting and adds to the list of functional changes present in abstinent cannabis users. Copyright © 2013 John Wiley & Sons, Ltd.

Prospective Assessment of Cannabis Withdrawal in Adolescents with Cannabis Dependence: A Pilot Study

ERIC Educational Resources Information Center

Milin, Robert; Manion, Ian; Dare, Glenda; Walker, Selena

2008-01-01

A study to identify and assess the withdrawal symptoms in adolescents afflicted with cannabis dependence is conducted. Results conclude that withdrawal symptoms of cannabis were present in adolescents seeking treatment for this substance abuse.

Executive function deficits in short-term abstinent cannabis users.

PubMed

McHale, Sue; Hunt, Nigel

2008-07-01

Few cognitive tasks are adequately sensitive to show the small decrements in performance in abstinent chronic cannabis users. In this series of three experiments we set out to demonstrate a variety of tasks that are sufficiently sensitive to show differences in visual memory, verbal memory, everyday memory and executive function between controls and cannabis users. A series of three studies explored cognitive function deficits in cannabis users (phonemic verbal fluency, visual recognition and immediate and delayed recall, and prospective memory) in short-term abstinent cannabis users. Participants were selected using snowball sampling, with cannabis users being compared to a standard control group and a tobacco-use control group. The cannabis users, compared to both control groups, had deficits on verbal fluency, visual recognition, delayed visual recall, and short- and long-interval prospective memory. There were no differences for immediate visual recall. These findings suggest that cannabis use leads to impaired executive function. Further research needs to explore the longer term impact of cannabis use. Copyright 2008 John Wiley & Sons, Ltd.

Cannabis Liberalization and Adolescent Cannabis Use: A Cross-National Study in 38 Countries

PubMed Central

Shi, Yuyan; Lenzi, Michela; An, Ruopeng

2015-01-01

Aims To assess the associations between types of cannabis control policies at country level and prevalence of adolescent cannabis use. Setting, Participants and Design Multilevel logistic regressions were performed on 172,894 adolescents 15 year of age who participated in the 2001/2002, 2005/2006, or 2009/2010 cross-sectional Health Behaviour in School-Aged Children (HBSC) survey in 38 European and North American countries. Measures Self-reported cannabis use status was classified into ever use in life time, use in past year, and regular use. Country-level cannabis control policies were categorized into a dichotomous measure (whether or not liberalized) as well as 4 detailed types (full prohibition, depenalization, decriminalization, and partial prohibition). Control variables included individual-level sociodemographic characteristics and country-level economic characteristics. Findings Considerable intra-class correlations (.15-.19) were found at country level. With respect to the dichotomized cannabis control policy, adolescents were more likely to ever use cannabis (odds ratio (OR) = 1.10, p = .001), use in past year (OR = 1.09, p = .007), and use regularly (OR = 1.26, p = .004). Although boys were substantially more likely to use cannabis, the correlation between cannabis liberalization and cannabis use was smaller in boys than in girls. With respect to detailed types of policies, depenalization was associated with higher odds of past-year use (OR = 1.14, p = .013) and regular use (OR = 1.23, p = .038), and partial prohibition was associated with higher odds of regular use (OR = 2.39, p = .016). The correlation between cannabis liberalization and regular use was only significant after the policy had been introduced for more than 5 years. Conclusions Cannabis liberalization with depenalization and partial prohibition policies was associated with higher levels of regular cannabis use among adolescents. The correlations were heterogeneous between genders and

Bidirectional Associations Between Cannabis Use and Depressive Symptoms From Adolescence Through Early Adulthood Among At-Risk Young Men.

PubMed

Womack, Sean R; Shaw, Daniel S; Weaver, Chelsea M; Forbes, Erika E

2016-03-01

Previous studies have established a relationship between cannabis use and affective problems among adolescents and young adults; however, the direction of these associations remains a topic of debate. The present study sought to examine bidirectional associations between cannabis use and depressive symptoms, specifically testing the validity of two competing hypotheses: the cannabis effect hypothesis, which suggests that cannabis use contributes to the onset of later depressive symptoms; and the self-medication hypothesis, which posits that individuals increase their use of a substance to alleviate distressing psychological symptoms. Participants in this study were 264 low-socioeconomic-status males assessed at ages 17, 20, and 22. Cross-lag panel models were fit to test bidirectional associations between cannabis use frequency and depressive symptoms across the transition from adolescence to early adulthood. In addition, analyses were conducted within two high-risk subsamples to examine whether associations between cannabis use frequency (ranging from never used to daily use) and depressive symptoms differed among regular cannabis users (used cannabis more than once per week) or subjects reporting at least mild levels of depressive symptoms. Cannabis use and depressive symptoms were concurrently correlated. Cannabis use predicted increases in later depressive symptoms, but only among the mild-depression subsample. Depressive symptoms predicted only slight increases in later cannabis use, among the subsample of regular cannabis users. Temporal patterns of cannabis use and depressive symptoms provide evidence for the cannabis effect but limited evidence for the self-medication hypothesis. Adolescents higher in depressive symptoms may be vulnerable to the adverse psychological effects of using cannabis. Results are discussed in terms of implications for basic research, prevention, and intervention.

Bidirectional Associations Between Cannabis Use and Depressive Symptoms From Adolescence Through Early Adulthood Among At-Risk Young Men

PubMed Central

Womack, Sean R.; Shaw, Daniel S.; Weaver, Chelsea M.; Forbes, Erika E.

2016-01-01

Objective: Previous studies have established a relationship between cannabis use and affective problems among adolescents and young adults; however, the direction of these associations remains a topic of debate. The present study sought to examine bidirectional associations between cannabis use and depressive symptoms, specifically testing the validity of two competing hypotheses: the cannabis effect hypothesis, which suggests that cannabis use contributes to the onset of later depressive symptoms; and the self-medication hypothesis, which posits that individuals increase their use of a substance to alleviate distressing psychological symptoms. Method: Participants in this study were 264 low-socioeconomic-status males assessed at ages 17, 20, and 22. Cross-lag panel models were fit to test bidirectional associations between cannabis use frequency and depressive symptoms across the transition from adolescence to early adulthood. In addition, analyses were conducted within two high-risk subsamples to examine whether associations between cannabis use frequency (ranging from never used to daily use) and depressive symptoms differed among regular cannabis users (used cannabis more than once per week) or subjects reporting at least mild levels of depressive symptoms. Results: Cannabis use and depressive symptoms were concurrently correlated. Cannabis use predicted increases in later depressive symptoms, but only among the mild-depression subsample. Depressive symptoms predicted only slight increases in later cannabis use, among the subsample of regular cannabis users. Conclusions: Temporal patterns of cannabis use and depressive symptoms provide evidence for the cannabis effect but limited evidence for the self-medication hypothesis. Adolescents higher in depressive symptoms may be vulnerable to the adverse psychological effects of using cannabis. Results are discussed in terms of implications for basic research, prevention, and intervention. PMID:26997187

Are adolescents more vulnerable to the harmful effects of cannabis than adults? A placebo-controlled study in human males.

PubMed

Mokrysz, C; Freeman, T P; Korkki, S; Griffiths, K; Curran, H V

2016-11-29

Preclinical research demonstrates that cannabinoids have differing effects in adolescent and adult animals. Whether these findings translate to humans has not yet been investigated. Here we believe we conducted the first study to compare the acute effects of cannabis in human adolescent (n=20; 16-17 years old) and adult (n=20; 24-28 years old) male cannabis users, in a placebo-controlled, double-blind cross-over design. After inhaling vaporized active or placebo cannabis, participants completed tasks assessing spatial working memory, episodic memory and response inhibition, alongside measures of blood pressure and heart rate, psychotomimetic symptoms and subjective drug effects (for example, 'stoned', 'want to have cannabis'). Results showed that on active cannabis, adolescents felt less stoned and reported fewer psychotomimetic symptoms than adults. Further, adults but not adolescents were more anxious and less alert during the active cannabis session (both pre- and post-drug administration). Following cannabis, cognitive impairment (reaction time on spatial working memory and prose recall following a delay) was greater in adults than adolescents. By contrast, cannabis impaired response inhibition accuracy in adolescents but not in adults. Moreover, following drug administration, the adolescents did not show satiety; instead they wanted more cannabis regardless of whether they had taken active or placebo cannabis, while the opposite was seen for adults. These contrasting profiles of adolescent resilience (blunted subjective, memory, physiological and psychotomimetic effects) and vulnerability (lack of satiety, impaired inhibitory processes) show some degree of translation from preclinical findings, and may contribute to escalated cannabis use by human adolescents.

Are adolescents more vulnerable to the harmful effects of cannabis than adults? A placebo-controlled study in human males

PubMed Central

Mokrysz, C; Freeman, T P; Korkki, S; Griffiths, K; Curran, H V

2016-01-01

Preclinical research demonstrates that cannabinoids have differing effects in adolescent and adult animals. Whether these findings translate to humans has not yet been investigated. Here we believe we conducted the first study to compare the acute effects of cannabis in human adolescent (n=20; 16–17 years old) and adult (n=20; 24–28 years old) male cannabis users, in a placebo-controlled, double-blind cross-over design. After inhaling vaporized active or placebo cannabis, participants completed tasks assessing spatial working memory, episodic memory and response inhibition, alongside measures of blood pressure and heart rate, psychotomimetic symptoms and subjective drug effects (for example, ‘stoned', ‘want to have cannabis'). Results showed that on active cannabis, adolescents felt less stoned and reported fewer psychotomimetic symptoms than adults. Further, adults but not adolescents were more anxious and less alert during the active cannabis session (both pre- and post-drug administration). Following cannabis, cognitive impairment (reaction time on spatial working memory and prose recall following a delay) was greater in adults than adolescents. By contrast, cannabis impaired response inhibition accuracy in adolescents but not in adults. Moreover, following drug administration, the adolescents did not show satiety; instead they wanted more cannabis regardless of whether they had taken active or placebo cannabis, while the opposite was seen for adults. These contrasting profiles of adolescent resilience (blunted subjective, memory, physiological and psychotomimetic effects) and vulnerability (lack of satiety, impaired inhibitory processes) show some degree of translation from preclinical findings, and may contribute to escalated cannabis use by human adolescents. PMID:27898071

Adolescent cannabis use and brain systems supporting adult working memory encoding, maintenance, and retrieval.

PubMed

Tervo-Clemmens, Brenden; Simmonds, Daniel; Calabro, Finnegan J; Day, Nancy L; Richardson, Gale A; Luna, Beatriz

2018-04-01

Given prior reports of adverse effects of cannabis use on working memory, an executive function with a protracted developmental course during adolescence, we examined associations between developmental patterns of cannabis use and adult working memory (WM) processes. Seventy-five adults with longitudinal assessments of cannabis use (60 with reported use, 15 with no reported use) and prenatal drug exposure assessment completed a spatial WM task during fMRI at age 28. All subjects passed a multi-drug urine screen on the day of testing and denied recreational drug use in the past week. A fast event-related design with partial trials was used to separate the BOLD response associated with encoding, maintenance, and retrieval periods of the WM task. Behavioral results showed that subjects who began using cannabis earlier in adolescence had longer reaction times (RT) than those with later initiation. Cannabis age of onset was further associated with reduced posterior parietal cortex (PPC) encoding BOLD activation, which significantly mediated age of onset WM RT associations. However, cannabis age of onset brain-behavior associations did not differ between groups with a single reported use and those with repeated use, suggesting age of onset effects may reflect substance use risk characteristics rather than a developmentally-timed cannabis exposure effect. Within repeated cannabis users, greater levels of total cannabis use were associated with performance-related increases in dorsolateral prefrontal cortex (DLPFC) activation during maintenance. This pattern of significant results remained unchanged with inclusion of demographic and prenatal measures as covariates. Surprisingly, however, at the group level, cannabis users generally performed better than participants who reported never using cannabis (faster RT, higher accuracy). We extend previous investigations by identifying that WM associations with cannabis age of onset may be primary to PPC stimulus encoding activity

Four Mechanistic Models of Peer Influence on Adolescent Cannabis Use

PubMed Central

Caouette, Justin D.; Feldstein Ewing, Sarah W.

2017-01-01

Purpose of review Most adolescents begin exploring cannabis in peer contexts, but the neural mechanisms that underlie peer influence on adolescent cannabis use are still unknown. This theoretical overview elucidates the intersecting roles of neural function and peer factors in cannabis use in adolescents. Recent findings Novel paradigms using functional magnetic resonance imaging (fMRI) in adolescents have identified distinct neural mechanisms of risk decision-making and incentive processing in peer contexts, centered on reward-motivation and affect regulatory neural networks; these findings inform a theoretical model of peer-driven cannabis use decisions in adolescents. Summary We propose four “mechanistic profiles” of social facilitation of cannabis use in adolescents: (1) peer influence as the primary driver of use; (2) cannabis exploration as the primary driver, which may be enhanced in peer contexts; (3) social anxiety; and (4) negative peer experiences. Identification of “neural targets” involved in motivating cannabis use may inform clinicians about which treatment strategies work best in adolescents with cannabis use problems, and via which social and neurocognitive processes. PMID:29104847

Online survey characterizing vaporizer use among cannabis users.

PubMed

Lee, Dustin C; Crosier, Benjamin S; Borodovsky, Jacob T; Sargent, James D; Budney, Alan J

2016-02-01

Along with changes in cannabis laws in the United States and other countries, new products for consuming cannabis are emerging, with unclear public health implications. Vaporizing or "vaping" cannabis is gaining popularity, but little is known about its prevalence or consequences. This study characterized the prevalence and current patterns of vaping cannabis among a large national sample of cannabis users. An online survey was distributed through Facebook ads targeting individuals with interests related to cannabis use. The sample comprised 2910 cannabis users (age: 18-90, 84% male, 74% Caucasian). A majority (61%) endorsed lifetime prevalence of ever vaping, 37% reported vaping in the past 30 days, 20% reported vaping more than 100 lifetime days, and 12% endorsed vaping as their preferred method. Compared to those that had never vaped, vaporizer users were younger, more likely to be male, initiated cannabis at an earlier age, and were less likely to be African American. Those that preferred vaping reported it to be healthier, better tasting, produced better effects, and more satisfying. Only 14% reported a reduction in smoking cannabis since initiating vaping, and only 5% mixed cannabis with nicotine in a vaporizer. Many cannabis users report vaping cannabis, but currently only a small subset prefers vaping to smoking and reports frequent vaping. Increases in availability and marketing of vaping devices, and the changing legal status of cannabis in the United States and other countries may influence patterns of use. Frequent monitoring is needed to assess the impact of changing cannabis laws and regulations. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Online Survey Characterizing Vaporizer Use among Cannabis Users

PubMed Central

Lee, Dustin C.; Crosier, Benjamin S.; Borodovsky, Jacob T.; Sargent, James D.; Budney, Alan J.

2016-01-01

Background Along with changes in cannabis laws in the United States and other countries, new products for consuming cannabis are emerging, with unclear public health implications. Vaporizing or “vaping” cannabis is gaining popularity, but little is known about its prevalence or consequences. Methods This study characterized the prevalence and current patterns of vaping cannabis among a large national sample of cannabis users. An online survey was distributed through Facebook ads targeting individuals with interests related to cannabis use. The sample comprised 2,910 cannabis users (age: 18-90, 84% male, 74% Caucasian). Results A majority (61%) endorsed lifetime prevalence of ever vaping, 37% reported vaping in the past 30 days, 20% reported vaping more than 100 lifetime days, and 12% endorsed vaping as their preferred method. Compared to those that had never vaped, vaporizer users were younger, more likely to be male, initiated cannabis at an earlier age, and were less likely to be African American. Those that preferred vaping reported it to be healthier, better tasting, produced better effects, and more satisfying. Only 14% reported a reduction in smoking cannabis since initiating vaping, and only 5% mixed cannabis with nicotine in a vaporizer. Many cannabis users report vaping cannabis, but currently only a small subset prefers vaping to smoking and reports frequent vaping. Conclusion Increases in availability and marketing of vaping devices, and the changing legal status of cannabis in the United States and other countries may influence patterns of use. Frequent monitoring is needed to assess the impact of changing cannabis laws and regulations. PMID:26774946

Neighbourhood crime and adolescent cannabis use in Canadian adolescents.

PubMed

de Looze, Margaretha; Janssen, Ian; Elgar, Frank J; Craig, Wendy; Pickett, William

2015-01-01

Although neighbourhood factors have been proposed as determinants of adolescent behaviour, few studies document their relative etiological importance. We investigated the relationship between neighbourhood crime and cannabis use in a nationally representative sample of Canadian adolescents. Data from the 2009/10 Canadian Health Behaviour in School-aged Children (HBSC) survey (n=9134 14- and 15-year-olds) were combined with area-level data on crime and socioeconomic status of the neighbourhood surrounding the schools (n=218). Multilevel logistic regression analyses showed that after individual and contextual differences were held constant, neighbourhood crime related to cannabis use (OR 1.29, CI 1.12-1.47 per 1.0 SD increase in crime). This association was not moderated by parental support nor having cannabis-using friends. The amount of explained variance at the neighbourhood level was 19%. Neighbourhood crime is an important factor to consider when designing interventions aimed at reducing adolescent cannabis use. Interventional research should examine the effectiveness of community-based interventions that target adolescents through parents and peers. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Validation of the Cannabis Expectancy Questionnaire (CEQ) in adult cannabis users in treatment.

PubMed

Connor, Jason P; Gullo, Matthew J; Feeney, Gerald F X; Young, Ross McD

2011-06-01

Outcome expectancies are a key cognitive construct in the etiology, assessment and treatment of Substance Use Disorders. There is a research and clinical need for a cannabis expectancy measure validated in a clinical sample of cannabis users. The Cannabis Expectancy Questionnaire (CEQ) was subjected to exploratory (n=501, mean age 27.45, 78% male) and confirmatory (n=505, mean age 27.69, 78% male) factor analysis in two separate samples of cannabis users attending an outpatient cannabis treatment program. Weekly cannabis consumption was clinically assessed and patients completed the Severity of Dependence Scale-Cannabis (SDS-C) and the General Health Questionnaire (GHQ-28). Two factors representing Negative Cannabis Expectancies and Positive Cannabis Expectancies were identified. These provided a robust statistical and conceptual fit for the data. Internal reliabilities were high. Negative expectancies were associated with greater dependence severity (as measured by the SDS) and positive expectancies with higher consumption. The interaction of positive and negative expectancies was consistently significantly associated with self-reported functioning across all four GHQ-28 scales (Somatic Concerns, Anxiety, Social Dysfunction and Depression). Specifically, within the context of high positive cannabis expectancy, higher negative expectancy was predictive of more impaired functioning. By contrast, within the context of low positive cannabis expectancy, higher negative expectancy was predictive of better functioning. The CEQ is the first cannabis expectancy measure to be validated in a sample of cannabis users in treatment. Negative and positive cannabis expectancy domains were uniquely associated with consumption, dependence severity and self-reported mental health functioning. Crown Copyright © 2010. Published by Elsevier Ireland Ltd. All rights reserved.

Neural correlates of performance monitoring in chronic cannabis users and cannabis-naïve controls

PubMed Central

Fridberg, Daniel J; Skosnik, Patrick D; Hetrick, William P; O’Donnell, Brian F

2014-01-01

Chronic cannabis use is associated with residual negative effects on measures of executive functioning. However, little previous work has focused specifically on executive processes involved in performance monitoring in frequent cannabis users. The present study investigated event-related potential (ERP) correlates of performance monitoring in chronic cannabis users. The error-related negativity (ERN) and error positivity (Pe), ERPs sensitive to performance monitoring, were recorded from 30 frequent cannabis users (mean usage=5.52 days/week) and 32 cannabis-naïve control participants during a speeded stimulus discrimination task. The “oddball” P3 ERP was recorded as well. Users and controls did not differ on the amplitude or latency of the ERN; however, Pe amplitude was larger among users. Users also showed increased amplitude and reduced latency of the P3 in response to infrequent stimuli presented during the task. Among users, urinary cannabinoid metabolite levels at testing were unrelated to ERP outcomes. However, total years of cannabis use correlated negatively with P3 latency and positively with P3 amplitude, and age of first cannabis use correlated negatively with P3 amplitude. The results of this study suggest that chronic cannabis use is associated with alterations in neural activity related to the processing of motivationally-relevant stimuli (P3) and errors (Pe). PMID:23427191

Inspired by Mary Jane? Mechanisms underlying enhanced creativity in cannabis users.

PubMed

LaFrance, Emily M; Cuttler, Carrie

2017-11-01

Previous research suggests cannabis may enhance some aspects of creativity, although the results remain somewhat equivocal. Moreover, it is unclear whether differences in cannabis users' personalities may account for any potentially beneficial effects of cannabis on creativity. This study was designed to examine whether sober cannabis users demonstrate superior self-reported and objective creativity test performance relative to non-users, and to determine whether any of the Big 5 personality domains underlie these effects. A sample of sober cannabis users (n=412) and non-users (n=309) completed measures of cannabis consumption, personality, self-reported and objective creativity. Relative to non-users, sober cannabis users self-reported higher creativity, and performed significantly better on a measure of convergent thinking. Controlling for cannabis users' higher levels of openness to experience abolished these effects. Therefore, while cannabis users appear to demonstrate enhanced creativity, these effects are an artifact of their heightened levels of openness to experience. Copyright © 2017 Elsevier Inc. All rights reserved.

Longitudinal study of hippocampal volumes in heavy cannabis users.

PubMed

Koenders, L; Lorenzetti, V; de Haan, L; Suo, C; Vingerhoets, Wam; van den Brink, W; Wiers, R W; Meijer, C J; Machielsen, Mwj; Goudriaan, A E; Veltman, D J; Yücel, M; Cousijn, J

2017-08-01

Cannabis exposure, particularly heavy cannabis use, has been associated with neuroanatomical alterations in regions rich with cannabinoid receptors such as the hippocampus in some but not in other (mainly cross-sectional) studies. However, it remains unclear whether continued heavy cannabis use alters hippocampal volume, and whether an earlier age of onset and/or a higher dosage exacerbate these changes. Twenty heavy cannabis users (mean age 21 years, range 18-24 years) and 23 matched non-cannabis using healthy controls were submitted to a comprehensive psychological assessment and magnetic resonance imaging scan at baseline and at follow-up (average of 39 months post-baseline; standard deviation=2.4). Cannabis users started smoking around 16 years and smoked on average five days per week. A novel aspect of the current study is that hippocampal volume estimates were obtained from manual tracing the hippocampus on T1-weighted anatomical magnetic resonance imaging scans, using a previously validated protocol. Compared to controls, cannabis users did not show hippocampal volume alterations at either baseline or follow-up. Hippocampal volumes increased over time in both cannabis users and controls, following similar trajectories of increase. Cannabis dose and age of onset of cannabis use did not affect hippocampal volumes. Continued heavy cannabis use did not affect hippocampal neuroanatomical changes in early adulthood. This contrasts with prior evidence on alterations in this region in samples of older adult cannabis users. In young adults using cannabis at this level, cannabis use may not be heavy enough to affect hippocampal neuroanatomy.

Longitudinal study of hippocampal volumes in heavy cannabis users

PubMed Central

Koenders, L; Lorenzetti, V; de Haan, L; Suo, C; Vingerhoets, WAM; van den Brink, W; Wiers, RW; Meijer, CJ; Machielsen, MWJ; Goudriaan, AE; Veltman, DJ; Yücel, M; Cousijn, J

2017-01-01

Background: Cannabis exposure, particularly heavy cannabis use, has been associated with neuroanatomical alterations in regions rich with cannabinoid receptors such as the hippocampus in some but not in other (mainly cross-sectional) studies. However, it remains unclear whether continued heavy cannabis use alters hippocampal volume, and whether an earlier age of onset and/or a higher dosage exacerbate these changes. Methods: Twenty heavy cannabis users (mean age 21 years, range 18–24 years) and 23 matched non-cannabis using healthy controls were submitted to a comprehensive psychological assessment and magnetic resonance imaging scan at baseline and at follow-up (average of 39 months post-baseline; standard deviation=2.4). Cannabis users started smoking around 16 years and smoked on average five days per week. A novel aspect of the current study is that hippocampal volume estimates were obtained from manual tracing the hippocampus on T1-weighted anatomical magnetic resonance imaging scans, using a previously validated protocol. Results: Compared to controls, cannabis users did not show hippocampal volume alterations at either baseline or follow-up. Hippocampal volumes increased over time in both cannabis users and controls, following similar trajectories of increase. Cannabis dose and age of onset of cannabis use did not affect hippocampal volumes. Conclusions: Continued heavy cannabis use did not affect hippocampal neuroanatomical changes in early adulthood. This contrasts with prior evidence on alterations in this region in samples of older adult cannabis users. In young adults using cannabis at this level, cannabis use may not be heavy enough to affect hippocampal neuroanatomy. PMID:28741422

An Item Response Theory Analysis of DSM-IV Cannabis Abuse and Dependence Criteria in Adolescents

PubMed Central

Hartman, Christie A.; Gelhorn, Heather; Crowley, Thomas J.; Sakai, Joseph T.; Stallings, Michael; Young, Susan E.; Rhee, Soo Hyun; Corley, Robin; Hewitt, John K.; Hopfer, Christian J.

2008-01-01

Objective To examine three aspects of adolescent cannabis problems: 1) do DSM-IV cannabis abuse and dependence criteria represent two different levels of severity of substance involvement, 2) to what degree do each of the 11 abuse and dependence criteria assess adolescent cannabis problems, and 3) do the DSM-IV items function similarly across different adolescent populations? Method We examined 5587 adolescents aged 11–19, including 615 youth in treatment for substance use disorders, 179 adjudicated youth, and 4793 youth from the community. All subjects were assessed with a structured diagnostic interview. Item response theory was utilized to analyze symptom endorsement patterns. Results Abuse and dependence criteria were not found to represent different levels of severity of problem cannabis use in any of the samples. Among the 11 abuse and dependence criteria, Problems cutting down and Legal problems were the least informative for distinguishing problem users. Two dependence criteria and three of the four abuse criteria indicated different severities of cannabis problems across samples. Conclusions We found little evidence to support the idea that abuse and dependence are separate constructs for adolescent cannabis problems. Furthermore, certain abuse criteria may indicate severe substance problems while specific dependence items may indicate less severe problems. The abuse items in particular need further study. These results have implications for the refinement of the current substance use disorder criteria for DSM-V. PMID:18176333

When Cannabis Is Available and Visible at School--A Multilevel Analysis of Students' Cannabis Use

ERIC Educational Resources Information Center

Kuntsche, Emmanuel

2010-01-01

Aims: To investigate the links between the visibility of cannabis use in school (measured by teachers' reports of students being under the influence of cannabis on school premises), the proportion of cannabis users in the class, perceived availability of cannabis, as well as adolescent cannabis use. Methods: A multilevel regression model was…

Responsible and controlled use: Older cannabis users and harm reduction.

PubMed

Lau, Nicholas; Sales, Paloma; Averill, Sheigla; Murphy, Fiona; Sato, Sye-Ok; Murphy, Sheigla

2015-08-01

Cannabis use is becoming more accepted in mainstream society. In this paper, we use Zinberg's classic theoretical framework of drug, set, and setting to elucidate how older adult cannabis users managed health, social and legal risks in a context of normalized cannabis use. We present selected findings from our qualitative study of Baby Boomer (born 1946-1964) cannabis users in the San Francisco Bay Area. Data collection consisted of a recorded, in-depth life history interview followed by a questionnaire and health survey. Qualitative interviews were analyzed to discover the factors of cannabis harm reduction from the users' perspectives. Interviewees made harm reduction choices based on preferred cannabis derivatives and routes of administration, as well as why, when, where, and with whom to use. Most interviewees minimized cannabis-related harms so they could maintain social functioning in their everyday lives. Responsible and controlled use was described as moderation of quantity and frequency of cannabis used, using in appropriate settings, and respect for non-users. Users contributed to the normalization of cannabis use through normification. Participants followed rituals or cultural practices, characterized by sanctions that helped define "normal" or "acceptable" cannabis use. Users contributed to cannabis normalization through their harm reduction methods. These cultural practices may prove to be more effective than formal legal prohibitions in reducing cannabis-related harms. Findings also suggest that users with access to a regulated market (medical cannabis dispensaries) were better equipped to practice harm reduction. More research is needed on both cannabis culture and alternative routes of administration as harm reduction methods. Copyright © 2015 Elsevier B.V. All rights reserved.

Reduced response to reward in smokers and cannabis users.

PubMed

Martin-Soelch, Chantal; Kobel, Maja; Stoecklin, Markus; Michael, Tanja; Weber, Simone; Krebs, Bigna; Opwis, Klaus

2009-01-01

Cannabis is one of the most commonly used illicit drugs. Reduced neural and behavioral reactions to reward have been demonstrated in other forms of addiction, as expressed by reduced mood reactivity and lack of striatal activation to rewards, but this effect has not yet been investigated in cannabis users. We hypothesized that cannabis users and tobacco smokers would evidence lower positive mood ratings in rewarded conditions than control participants and that this reduction would be greater in cannabis users than in smokers. We examined the influence of reward on mood and performance in a group of regular cannabis users, a group of tobacco smokers and a group of nonsmokers while they performed a spatial recognition task with delayed response that incorporated 3 levels of difficulty. Correct responses were either not reinforced or reinforced with money. We measured the accuracy of reactions, reaction times and mood ratings throughout the trials. Cannabis users rated their mood as significantly worse than the smokers and nonsmokers during the easiest level of the rewarded condition. A significant positive correlation between mood ratings and monetary reward was found in the nonsmokers but not in the cannabis users and smokers. The groups did not differ with regard to task performance. Our results suggest that regular cannabis use affects certain aspects of motivation and that both tobacco smoking and cannabis use lead to similar motivational changes. However, the use of cannabis seems to affect motivation in a stronger way than does tobacco smoking alone. 2009 S. Karger AG, Basel

Cognitive measures in long-term cannabis users.

PubMed

Pope, Harrison G; Gruber, Amanda J; Hudson, James I; Huestis, Marilyn A; Yurgelun-Todd, Deborah

2002-11-01

The cognitive effects of long-term cannabis use are insufficiently understood. Most studies concur that cognitive deficits persist at least several days after stopping heavy cannabis use. But studies differ on whether such deficits persist long term or whether they are correlated with increasing duration of lifetime cannabis use. The authors administered neuropsychological tests to 77 current heavy cannabis users who had smoked cannabis at least 5000 times in their lives, and to 87 control subjects who had smoked no more than 50 times in their lives. The heavy smokers showed deficits on memory of word lists on Days 0, 1, and 7 of a supervised abstinence period. By Day 28, however, few significant differences were found between users and controls on the test measures, and there were few significant associations between total lifetime cannabis consumption and test performance. Although these findings may be affected by residual confounding, as in all retrospective studies, they suggest that cannabis-associated cognitive deficits are reversible and related to recent cannabis exposure rather than irreversible and related to cumulative lifetime use.

Responsible and controlled use: Older cannabis users and harm reduction

PubMed Central

Lau, Nicholas; Sales, Paloma; Averill, Sheigla; Murphy, Fiona; Sato, Sye-Ok; Murphy, Sheigla

2015-01-01

Background Cannabis use is becoming more accepted in mainstream society. In this paper, we use Zinberg’s classic theoretical framework of drug, set, and setting to elucidate how older adult cannabis users managed health, social and legal risks in a context of normalized cannabis use. Methods We present selected findings from our qualitative study of Baby Boomer (born 1946–1964) cannabis users in the San Francisco Bay Area. Data collection consisted of a recorded, in-depth life history interview followed by a questionnaire and health survey. Qualitative interviews were analyzed to discover the factors of cannabis harm reduction from the users’ perspectives. Results Interviewees made harm reduction choices based on preferred cannabis derivatives and routes of administration, as well as why, when, where, and with whom to use. Most interviewees minimized cannabis-related harms so they could maintain social functioning in their everyday lives. Responsible and controlled use was described as moderation of quantity and frequency of cannabis used, using in appropriate settings, and respect for non-users. Users contributed to the normalization of cannabis use through normification. Conclusion Participants followed rituals or cultural practices, characterized by sanctions that helped define “normal” or “acceptable” cannabis use. Users contributed to cannabis normalization through their harm reduction methods. These cultural practices may prove to be more effective than formal legal prohibitions in reducing cannabis-related harms. Findings also suggest that users with access to a regulated market (medical cannabis dispensaries) were better equipped to practice harm reduction. More research is needed on both cannabis culture and alternative routes of administration as harm reduction methods. PMID:25911027

Cognitive functioning of long-term heavy cannabis users seeking treatment.

PubMed

Solowij, Nadia; Stephens, Robert S; Roffman, Roger A; Babor, Thomas; Kadden, Ronald; Miller, Michael; Christiansen, Kenneth; McRee, Bonnie; Vendetti, Janice

2002-03-06

Cognitive impairments are associated with long-term cannabis use, but the parameters of use that contribute to impairments and the nature and endurance of cognitive dysfunction remain uncertain. To examine the effects of duration of cannabis use on specific areas of cognitive functioning among users seeking treatment for cannabis dependence. Multisite retrospective cross-sectional neuropsychological study conducted in the United States (Seattle, Wash; Farmington, Conn; and Miami, Fla) between 1997 and 2000 among 102 near-daily cannabis users (51 long-term users: mean, 23.9 years of use; 51 shorter-term users: mean, 10.2 years of use) compared with 33 nonuser controls. Measures from 9 standard neuropsychological tests that assessed attention, memory, and executive functioning, and were administered prior to entry to a treatment program and following a median 17-hour abstinence. Long-term cannabis users performed significantly less well than shorter-term users and controls on tests of memory and attention. On the Rey Auditory Verbal Learning Test, long-term users recalled significantly fewer words than either shorter-term users (P =.001) or controls (P =.005); there was no difference between shorter-term users and controls. Long-term users showed impaired learning (P =.007), retention (P =.003), and retrieval (P =.002) compared with controls. Both user groups performed poorly on a time estimation task (P<.001 vs controls). Performance measures often correlated significantly with the duration of cannabis use, being worse with increasing years of use, but were unrelated to withdrawal symptoms and persisted after controlling for recent cannabis use and other drug use. These results confirm that long-term heavy cannabis users show impairments in memory and attention that endure beyond the period of intoxication and worsen with increasing years of regular cannabis use.

Approach to cannabis use disorder in primary care: focus on youth and other high-risk users.

PubMed

Turner, Suzanne D; Spithoff, Sheryl; Kahan, Meldon

2014-09-01

To review the clinical features and complications of at-risk cannabis use and cannabis use disorder, and to outline an office-based protocol for screening, identifying, and managing this disorder. PubMed was searched for controlled trials, observational studies, and reviews on cannabis use among adolescents and young adults; cannabis-related medical and psychiatric harms; cannabis use disorder and its treatment; and lower-risk cannabis use guidelines. Physicians should ask all patients about cannabis use. They should ask adolescents and young adults and those at highest risk of cannabis-related harms (those with concurrent psychiatric or substance use disorders) more frequently. Physicians should also ask about cannabis use in patients who have problems that could be caused by cannabis, such as mood disorders, psychosis, and respiratory symptoms. In patients who report cannabis use, physicians should inquire about frequency and amount, tolerance and withdrawal symptoms, attempts to reduce use, and cannabis-related harms. Lower-risk cannabis users smoke, inhale, or ingest cannabis occasionally without evidence of school, work, or social dysfunction; those with problematic use often use cannabis daily or almost daily, have difficulty reducing their use, and have impaired school, work, or social functioning. Physicians should offer all patients with problematic use brief advice and counseling, focusing on the health effects of cannabis and setting a goal of abstinence (some higher-risk groups should not use cannabis at all) or reduced use, and they should provide practical strategies to reduce cannabis use. Physicians should incorporate simple motivational interviewing techniques into the counseling sessions. They should refer those patients who are unable to reduce use or who are experiencing harms from cannabis use to specialized care, while ensuring those patients remain connected to primary care. As well, physicians should give information on lower-risk cannabis

Perceived support for medical cannabis use among approved medical cannabis users in Canada.

PubMed

Leos-Toro, Cesar; Shiplo, Samantha; Hammond, David

2018-06-05

Very little is known about the social experience of medical cannabis use, including the experience of stigma among approved users. The current study examined perceptions of support from physicians, family and friends as well as the prevalence of 'hiding' medicinal cannabis use. An online cross-sectional survey (N = 276) was conducted from 29 April to 8 June 2015. No public sampling frame was available from which to sample approved medical cannabis users (MCU). Eligible respondents were approved MCUs, aged 18 years or older, and reported cannabis use in the past 30 days for health reasons. Logistic regression analyses were used to assess aspects of stigma, including perceived support from their immediate social environment as well as behaviours reflecting a perceived social disapproval. Approximately one-third of respondents (32.6%) reported that their physician had refused to provide a medical document, and the vast majority of respondents (79.3%) reported hiding their medical cannabis use, most commonly to avoid judgement. Fewer than half of approved users perceived that their doctor was 'supportive' (38%), whereas two-thirds perceived support from family (66.3%) and friends (66.3%). Perceptions of support were similar across most socio-demographic sub-groups. Substantial proportions of approved MCUs in Canada report a lack of support and most have made some effort to conceal their medical cannabis use. Overall, the findings suggest that social norms around medical cannabis use remain unfavourable for many users, despite that fact that medical cannabis has been legal in Canada for more than a decade. © 2018 Australasian Professional Society on Alcohol and other Drugs.

Cannabis Users' Recommended Warnings for Packages of Legally Sold Cannabis: An Australia-Centered Study.

PubMed

Malouff, John M; Johnson, Caitlin E; Rooke, Sally E

2016-01-01

Introduction: Although cannabis use creates health risks, governments have recently been legalizing either medical use or leisure use. These governments can mandate health warnings on cannabis packages. Prior research examined recommended warnings of cannabis experts. The aim of this study was to obtain suggested cannabis health and safety warnings from cannabis users. Methods: We used a media release, Facebook postings, and announcements in university classes to seek individuals who had used cannabis at least once according to their own report. Using online data collection software that keeps participants anonymous, we asked the individuals to suggest a warning that governments could mandate on cannabis packages. Results: In total, 288 users suggested warnings. Categorizing the warnings into content categories led to six warning topics: (1) risk of harm to mental health and psychological functioning; (2) risk of operating machinery while under the influence; (3) short-term physical side effects; (4) responsible use; (5) long-term negative physical effects; and (6) dependence, addiction, or abuse. The user-suggested warnings overlapped with six expert-recommended warnings identified in prior survey research and included two content areas that did not feature in expert-recommended warnings: short-term physical side effects and the importance of responsible use. Conclusions: The results are consistent with prior findings that some youths perceive cannabis use as potentially harmful. The current findings provide possible new content for warnings on cannabis packages.

Sex Differences in Cannabis Use and Effects: A Cross-Sectional Survey of Cannabis Users

PubMed Central

Cuttler, Carrie; Mischley, Laurie K.; Sexton, Michelle

2016-01-01

Abstract Introduction: Despite known sex differences in the endocannabinoid system of animals, little attention has been paid to sex differences in human's cannabis use patterns and effects. The purpose of the present study was to examine sex differences in cannabis use patterns and effects in a large sample of recreational and medical cannabis users. Methods: A large sample (n=2374) of cannabis users completed an anonymous, online survey that assessed their cannabis use practices and experiences, including the short-term acute effects of cannabis and withdrawal effects. A subsample of 1418 medical cannabis users further indicated the medical conditions for which they use cannabis and its perceived efficacy. Results: The results indicated that men reported using cannabis more frequently and in higher quantities than did women. Men were more likely to report using joints/blunts, vaporizers, and concentrates, while women were more likely to report using pipes and oral administration. Men were more likely than women to report increased appetite, improved memory, enthusiasm, altered time perception, and increased musicality when high, while women were more likely than men to report loss of appetite and desire to clean when high. Men were more likely than women to report insomnia and vivid dreams during periods of withdrawal, while women were more likely than men to report nausea and anxiety as withdrawal symptoms. Sex differences in the conditions for which medical cannabis is used, and its efficacy, were trivial. Conclusions: These results may be used to focus research on biological and psychosocial mechanisms underlying cannabis-related sex differences, to inform clinicians treating individuals with cannabis use disorders, and to inform cannabis consumers, clinicians, and policymakers about the risks and benefits of cannabis for both sexes. PMID:28861492

Sex Differences in Cannabis Use and Effects: A Cross-Sectional Survey of Cannabis Users.

PubMed

Cuttler, Carrie; Mischley, Laurie K; Sexton, Michelle

2016-01-01

Introduction: Despite known sex differences in the endocannabinoid system of animals, little attention has been paid to sex differences in human's cannabis use patterns and effects. The purpose of the present study was to examine sex differences in cannabis use patterns and effects in a large sample of recreational and medical cannabis users. Methods: A large sample ( n =2374) of cannabis users completed an anonymous, online survey that assessed their cannabis use practices and experiences, including the short-term acute effects of cannabis and withdrawal effects. A subsample of 1418 medical cannabis users further indicated the medical conditions for which they use cannabis and its perceived efficacy. Results: The results indicated that men reported using cannabis more frequently and in higher quantities than did women. Men were more likely to report using joints/blunts, vaporizers, and concentrates, while women were more likely to report using pipes and oral administration. Men were more likely than women to report increased appetite, improved memory, enthusiasm, altered time perception, and increased musicality when high, while women were more likely than men to report loss of appetite and desire to clean when high. Men were more likely than women to report insomnia and vivid dreams during periods of withdrawal, while women were more likely than men to report nausea and anxiety as withdrawal symptoms. Sex differences in the conditions for which medical cannabis is used, and its efficacy, were trivial. Conclusions: These results may be used to focus research on biological and psychosocial mechanisms underlying cannabis-related sex differences, to inform clinicians treating individuals with cannabis use disorders, and to inform cannabis consumers, clinicians, and policymakers about the risks and benefits of cannabis for both sexes.

An MRI study of white matter tract integrity in regular cannabis users: effects of cannabis use and age.

PubMed

Jakabek, David; Yücel, Murat; Lorenzetti, Valentina; Solowij, Nadia

2016-10-01

Conflicting evidence exists on the effects of cannabis use on brain white matter integrity. The extant literature has exclusively focused on younger cannabis users, with no studies sampling older cannabis users. We recruited a sample with a broad age range to examine the integrity of major white matter tracts in association with cannabis use parameters and neurodevelopmental stage. Regular cannabis users (n = 56) and non-users (n = 20) with a mean age of 32 (range 18-55 years) underwent structural and diffusion MRI scans. White matter was examined using voxel-based statistics and via probabilistic tract reconstruction. The integrity of tracts was assessed using average fractional anisotropy, axial diffusivity and radial diffusivity. Diffusion measures were compared between users and non-users and as group-by-age interactions. Correlations between diffusion measures and age of onset, duration, frequency and dose of current cannabis use were examined. Cannabis users overall had lower fractional anisotropy than healthy non-users in the forceps minor tract only (p = .015, partial eta = 0.07), with no voxel-wise differences observed. Younger users showed predominantly reduced axial diffusivity, whereas older users had higher radial diffusivity in widespread tracts. Higher axial diffusivity was associated with duration of cannabis use in the cingulum angular bundle (beta = 5.00 × 10(-5), p = .003). Isolated higher AD in older cannabis users was also observed. The findings suggest that exogenous cannabinoids alter normal brain maturation, with differing effects at various neurodevelopmental stages of life. These age-related differences are posited to account for the disparate results described in the literature.

Statistics on Cannabis Users Skew Perceptions of Cannabis Use

PubMed Central

Burns, Rachel M.; Caulkins, Jonathan P.; Everingham, Susan S.; Kilmer, Beau

2013-01-01

Collecting information about the prevalence of cannabis use is necessary but not sufficient for understanding the size, dynamics, and outcomes associated with cannabis markets. This paper uses two data sets describing cannabis consumption in the United States and Europe to highlight (1) differences in inferences about sub-populations based on the measure used to quantify cannabis-related activity; (2) how different measures of cannabis-related activity can be used to more accurately describe trends in cannabis usage over time; and (3) the correlation between frequency of use in the past-month and average grams consumed per use-day. Key findings: focusing on days of use instead of prevalence shows substantially greater increases in U.S. cannabis use in recent years; however, the recent increase is mostly among adults, not youth. Relatively more rapid growth in use days also occurred among the college-educated and Hispanics. Further, data from a survey conducted in seven European countries show a strong positive correlation between frequency of use and quantity consumed per day of use, suggesting consumption is even more skewed toward the minority of heavy users than is suggested by days-of-use calculations. PMID:24223560

Association Between Use of Cannabis in Adolescence and Weight Change into Midlife

PubMed Central

Jin, Lexie Zhiyan; Rangan, Anna; Mehlsen, Jesper; Andersen, Lars Bo; Larsen, Sofus C.; Heitmann, Berit L.

2017-01-01

Cannabis use has been found to stimulate appetite and potentially promote weight gain via activation of the endocannabinoid system. Despite the fact that the onset of cannabis use is typically during adolescence, the association between adolescence cannabis use and long-term change in body weight is generally unknown. This study aims to examine the association between adolescence cannabis use and weight change to midlife, while accounting for the use of other substances. The study applied 20 to 22 years of follow-up data on 712 Danish adolescents aged between 15 and 19 years at baseline. Self-reported height and weight, cannabis, cigarette and alcohol use, socioeconomic status (SES) and physical activity levels were assessed in baseline surveys conducted in 1983 and 1985. The follow-up survey was conducted in 2005. In total 19.1% (n = 136) of adolescents reported having used/using cannabis. Weight gain between adolescence and midlife was not related to cannabis exposure during adolescence in either crude or adjusted models, and associations were not modified by baseline alcohol intake or smoking. However, cannabis use was significantly associated with cigarette smoking (p<0.001) and alcohol intake (p<0.001) and inversely associated with physical activity levels (p = 0.04). In conclusion, this study does not provide evidence of an association between adolescence cannabis use and weight change from adolescence to midlife. PMID:28060830

Association Between Use of Cannabis in Adolescence and Weight Change into Midlife.

PubMed

Jin, Lexie Zhiyan; Rangan, Anna; Mehlsen, Jesper; Andersen, Lars Bo; Larsen, Sofus C; Heitmann, Berit L

2017-01-01

Cannabis use has been found to stimulate appetite and potentially promote weight gain via activation of the endocannabinoid system. Despite the fact that the onset of cannabis use is typically during adolescence, the association between adolescence cannabis use and long-term change in body weight is generally unknown. This study aims to examine the association between adolescence cannabis use and weight change to midlife, while accounting for the use of other substances. The study applied 20 to 22 years of follow-up data on 712 Danish adolescents aged between 15 and 19 years at baseline. Self-reported height and weight, cannabis, cigarette and alcohol use, socioeconomic status (SES) and physical activity levels were assessed in baseline surveys conducted in 1983 and 1985. The follow-up survey was conducted in 2005. In total 19.1% (n = 136) of adolescents reported having used/using cannabis. Weight gain between adolescence and midlife was not related to cannabis exposure during adolescence in either crude or adjusted models, and associations were not modified by baseline alcohol intake or smoking. However, cannabis use was significantly associated with cigarette smoking (p<0.001) and alcohol intake (p<0.001) and inversely associated with physical activity levels (p = 0.04). In conclusion, this study does not provide evidence of an association between adolescence cannabis use and weight change from adolescence to midlife.

[Sociodemographic profiles, addictive and mental comorbidity in cannabis users in an outpatient specific setting].

PubMed

Guillem, E; Pelissolo, A; Vorspan, F; Bouchez-Arbabzadeh, S; Lépine, J-P

2009-06-01

In the 1990s, cannabis consumption in France increased considerably. So, in 10 years, the number of adolescents reporting regular cannabis use (10 or more times during the last 12 months) tripled. In 2004, an official program to address problems related to cannabis addiction was implemented. As part of this program, specific outpatient settings for cannabis use disorders were created. We present the sociodemographic characteristics, the prevalence of cannabis, alcohol and others psychoactive substances and the prevalence of mental disorders in 90 cannabis users seen at an outpatient specific setting for cannabis use disorders in the Lariboisière hospital (a university hospital in Paris). Twelve months prevalence of substance abuse and dependence, psychiatric diagnoses based on the DSM-IV and the Mini-International Neuropsychiatric Interview (MINI) results are described. The study population had the following characteristics: 67% male, mean age 27.5 (S.D.=8.4) years and 59% single or divorced. Approximately, two-thirds of the users (67%) were students or currently working and 32% were unemployed. Twenty-two percent of the cannabis users received unemployment, welfare or disability benefits and 11% declared no source of revenue. Most of the users (63%) decided on their own to seek care at the setting. Seventy-three percent of the subjects had seen a psychologist or a psychiatrist in the past, with or without relation to cannabis use. By far, most of the users were cannabis dependent (82%) and 9% cannabis abusers in the last 12 months according to DSM-IV criteria prior to their visit. Seven percent of the cannabis users had alcohol dependence and 7% were abusers. The 12 months prevalence of cocaine or ecstasy dependence was 2% and the prevalence of benzodiazepines, heroin or stimulants dependence 1%. The main substances used over lifetime were tobacco (99%); alcohol (96%); cocaine (41%); benzodiazepines and hypnotics (41%); ecstasy (40%) and heroin (23%). Four

Sleep impairment in ecstasy/polydrug and cannabis-only users.

PubMed

Fisk, John E; Montgomery, Catharine

2009-01-01

The present study investigated aspects of sleep quality in ecstasy and cannabis users. Two-hundred and twenty seven participants (117 ecstasy/polydrug users, 53 cannabis users and 57 drug naive participants) took part. The participants completed measures of daytime sleepiness, and indicators of sleep quality. The results demonstrated that ecstasy/polydrug users viewed themselves as being more evening types and having poorer sleep quality than cannabis users and drug naive participants. They were also more likely to have missed a night's sleep. The reported differences in sleep type may reflect ecstasy-related serotonergic dysfunction resulting in problems with shifting circadian rhythms.

Cannabis Users' Recommended Warnings for Packages of Legally Sold Cannabis: An Australia-Centered Study

PubMed Central

Malouff, John M.; Johnson, Caitlin E.; Rooke, Sally E.

2016-01-01

Abstract Introduction: Although cannabis use creates health risks, governments have recently been legalizing either medical use or leisure use. These governments can mandate health warnings on cannabis packages. Prior research examined recommended warnings of cannabis experts. The aim of this study was to obtain suggested cannabis health and safety warnings from cannabis users. Methods: We used a media release, Facebook postings, and announcements in university classes to seek individuals who had used cannabis at least once according to their own report. Using online data collection software that keeps participants anonymous, we asked the individuals to suggest a warning that governments could mandate on cannabis packages. Results: In total, 288 users suggested warnings. Categorizing the warnings into content categories led to six warning topics: (1) risk of harm to mental health and psychological functioning; (2) risk of operating machinery while under the influence; (3) short-term physical side effects; (4) responsible use; (5) long-term negative physical effects; and (6) dependence, addiction, or abuse. The user-suggested warnings overlapped with six expert-recommended warnings identified in prior survey research and included two content areas that did not feature in expert-recommended warnings: short-term physical side effects and the importance of responsible use. Conclusions: The results are consistent with prior findings that some youths perceive cannabis use as potentially harmful. The current findings provide possible new content for warnings on cannabis packages. PMID:28861495

Anxiety, depression and risk of cannabis use: Examining the internalising pathway to use among Chilean adolescents.

PubMed

Stapinski, Lexine A; Montgomery, Alan A; Araya, Ricardo

2016-09-01

Adolescents who experience internalising symptoms may be susceptible to the use of alcohol and other substances in an attempt to alleviate or cope with these symptoms. We examined the hypothesised internalising pathway from symptoms of depression, generalised anxiety, social anxiety and panic, to incidence and frequency of cannabis use 18 months later. Longitudinal cohort study of participants (n=2508; 45% female; mean age 14.5 years) recruited from the 9th grade at 22 low-income secondary schools in Santiago, Chile. Baseline internalising symptoms were assessed using the Beck Depression Inventory and the Revised Child Anxiety and Depression Scale. Frequency of cannabis was assessed at baseline, 6 month and 18 month follow-up. High rates of use were observed in this sample, with 40.3% reporting cannabis use at least once over the study period. Adjusted for baseline cannabis use, symptoms of depression, panic and generalised anxiety were associated with greater cannabis use frequency 18 months later. When all predictors were considered simultaneously, only generalised anxiety symptoms showed an independent association with subsequent cannabis use frequency (OR: 1.23, 95% CI: 1.08-1.41). Generalised anxiety symptoms were also associated with a 25% increased risk of transitioning from non-user to use of cannabis during the study (OR: 1.25, 95% CI: 1.09-1.44). Internalising symptoms, and in particular symptoms of generalised anxiety, increase risk of cannabis use during adolescence. Targeted interventions that promote adaptive anxiety management among high-risk adolescents may represent a promising strategy to prevent uptake of cannabis use during adolescence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Neuropsychological performance in long-term cannabis users.

PubMed

Pope, H G; Gruber, A J; Hudson, J I; Huestis, M A; Yurgelun-Todd, D

2001-10-01

Although cannabis is the most widely used illicit drug in the United States, its long-term cognitive effects remain inadequately studied. We recruited individuals aged 30 to 55 years in 3 groups: (1) 63 current heavy users who had smoked cannabis at least 5000 times in their lives and who were smoking daily at study entry; (2) 45 former heavy users who had also smoked at least 5000 times but fewer than 12 times in the last 3 months; and (3) 72 control subjects who had smoked no more than 50 times in their lives. Subjects underwent a 28-day washout from cannabis use, monitored by observed urine samples. On days 0, 1, 7, and 28, we administered a neuropsychological test battery to assess general intellectual function, abstraction ability, sustained attention, verbal fluency, and ability to learn and recall new verbal and visuospatial information. Test results were analyzed by repeated-measures regression analysis, adjusting for potentially confounding variables. At days 0, 1, and 7, current heavy users scored significantly below control subjects on recall of word lists, and this deficit was associated with users' urinary 11-nor-9-carboxy-Delta9-tetrahydrocannabinol concentrations at study entry. By day 28, however, there were virtually no significant differences among the groups on any of the test results, and no significant associations between cumulative lifetime cannabis use and test scores. Some cognitive deficits appear detectable at least 7 days after heavy cannabis use but appear reversible and related to recent cannabis exposure rather than irreversible and related to cumulative lifetime use.

A Meta-Analysis of Interventions to Reduce Adolescent Cannabis Use

ERIC Educational Resources Information Center

Bender, Kimberly; Tripodi, Stephen J.; Sarteschi, Christy; Vaughn, Michael G.

2011-01-01

Objective: This meta-analytic review assesses the effectiveness of substance abuse interventions to reduce adolescent cannabis use. Method: A systematic search identified 15 randomized controlled evaluations of interventions to reduce adolescent cannabis use published between 1960 and 2008. The primary outcome variables, frequency of cannabis use,…

The Co-Use of Tobacco and Cannabis among Adolescents over a 30-Year Period

ERIC Educational Resources Information Center

Webster, Lauren; Chaiton, Michael; Kirst, Maritt

2014-01-01

Background: This study explores the patterns of use and co-use of tobacco and cannabis among Ontario adolescents over 3 decades and if characteristics of co-users and single substance users have changed. Methods: Co-use trends for 1981-2011 were analyzed using the Centre for Addiction and Mental Health Ontario Student Drug Use and Health Survey,…

Frontal lobe dysfunction in long-term cannabis users.

PubMed

Lundqvist, T; Jönsson, S; Warkentin, S

2001-01-01

This study examined the neurophysiological effects of cannabis. Cerebral blood flow (CBF) was measured in 12 long-term cannabis users shortly after cessation of cannabis use (mean 1.6 days). The findings showed significantly lower mean hemispheric blood flow values and significantly lower frontal values in the cannabis subjects compared to normal controls. The results suggest that the functional level of the frontal lobes is affected by long-term cannabis use.

N-acetyl Aspartate Levels in Adolescents With Bipolar and/or Cannabis Use Disorders

PubMed Central

Bitter, Samantha M.; Weber, Wade A.; Chu, Wen-Jang; Adler, Caleb M.; Eliassen, James C.; Strakowski, Stephen M.; DelBello, Melissa P.

2014-01-01

Objective Bipolar and cannabis use disorders commonly co-occur during adolescence, and neurochemical studies may help clarify the pathophysiology underlying this co-occurrence. This study compared metabolite concentrations in the left ventral lateral prefrontal cortex among: adolescents with bipolar disorder (bipolar group; n=14), adolescents with a cannabis use disorder (cannabis use group, n=13), adolescents with cannabis use and bipolar disorders (bipolar and cannabis group, n=25), and healthy adolescents (healthy controls, n=15). We hypothesized that adolescents with bipolar disorder (with or without cannabis use disorder) would have decreased N-acetyl aspartate levels in the ventral lateral prefrontal cortex compared to the other groups, and that the bipolar and cannabis group would have the lowest N-acetyl aspartate levels of all groups. Methods N-acetyl aspartate concentrations in the left ventral lateral prefrontal cortex were obtained using Proton Magnetic Resonance Spectroscopy. Results Adolescents with bipolar disorder showed significantly lower left ventral lateral prefrontal cortex N-acetyl aspartate levels, but post-hoc analyses indicated that this was primarily due to increased N-acetyl aspartate levels in the cannabis group. The cannabis use disorder group had significantly higher N-acetyl aspartate levels compared to the bipolar disorder and the bipolar and cannabis groups (p=0.0002 and p=0.0002, respectively). Pearson correlations revealed a significant positive correlation between amount of cannabis used and N-acetyl aspartate concentrations. Conclusions Adolescents with cannabis use disorder showed higher levels of N-acetyl aspartate concentrations that were significantly positively associated with the amount of cannabis used; however, this finding was not present in adolescents with comorbid bipolar disorder. PMID:24729763

Sex differences in cannabis withdrawal symptoms among treatment-seeking cannabis users

PubMed Central

Herrmann, Evan S.; Weerts, Elise M.; Vandrey, Ryan

2015-01-01

Over 300,000 individuals enter treatment for cannabis use disorders (CUDs) in the U.S. annually. Cannabis withdrawal is associated with poor CUD treatment outcomes, but no prior studies have examined sex differences in withdrawal among treatment-seeking cannabis users. Treatment-seeking cannabis users (45 women and 91 men) completed a Marijuana Withdrawal Checklist (MWC) at treatment intake to retrospectively characterize withdrawal symptoms experienced during their most recent quit attempt. Composite Withdrawal Discomfort Scale (WDS) scores were calculated using the 14 items on the MWC that correspond to valid cannabis withdrawal symptoms described in DSM-5. Demographic and substance use characteristics, overall WDS scores, and scores on individual WDS symptoms were compared between women and men. Women had higher overall WDS scores than men, and women had higher scores than men on six individual symptoms in two domains, mood symptoms (irritability, restlessness, increased anger, violent outbursts) and gastrointestinal symptoms (nausea, stomach pain). Follow-up analyses isolating the incidence and severity of WDS symptoms demonstrated that women generally reported a higher number of individual withdrawal symptoms than men, and that they reported experiencing some symptoms as more severe. This is the first report to demonstrate that women seeking treatment for CUDs may experience more withdrawal then men during quit attempts. Prospective studies of sex differences in cannabis withdrawal are warranted. PMID:26461168

mHealth App for Cannabis Users: Satisfaction and Perceived Usefulness.

PubMed

Monney, Grégoire; Penzenstadler, Louise; Dupraz, Olivia; Etter, Jean-François; Khazaal, Yasser

2015-01-01

The aim of this study was to describe the characteristics of cannabis users and their levels of satisfaction with Stop-cannabis, an app intended for cannabis users who want to stop or reduce their cannabis use or prevent relapse. A cross-sectional online survey was administered to users of Stop-cannabis, a French-language app for iOS and Android devices. All app users were invited to participate in the survey via a message sent to the app. For hundred and eighty-two users answered the survey. The app was used daily by 348 of the participants (around 70%). More than 80% of participants (397) considered the app to have helped them "a little" or "a lot" to stop or reduce cannabis consumption. Most of the users' suggestions were related to the number or the quality of the messages sent by, or displayed in, the app. This pilot study supports the feasibility of such an app and its perceived usefulness. A self-selection bias, however, limits the conclusions of the study. The efficacy of the app should be evaluated in a randomized controlled trial.

Approach-bias predicts development of cannabis problem severity in heavy cannabis users: results from a prospective FMRI study.

PubMed

Cousijn, Janna; Goudriaan, Anna E; Ridderinkhof, K Richard; van den Brink, Wim; Veltman, Dick J; Wiers, Reinout W

2012-01-01

A potentially powerful predictor for the course of drug (ab)use is the approach-bias, that is, the pre-reflective tendency to approach rather than avoid drug-related stimuli. Here we investigated the neural underpinnings of cannabis approach and avoidance tendencies. By elucidating the predictive power of neural approach-bias activations for future cannabis use and problem severity, we aimed at identifying new intervention targets. Using functional Magnetic Resonance Imaging (fMRI), neural approach-bias activations were measured with a Stimulus Response Compatibility task (SRC) and compared between 33 heavy cannabis users and 36 matched controls. In addition, associations were examined between approach-bias activations and cannabis use and problem severity at baseline and at six-month follow-up. Approach-bias activations did not differ between heavy cannabis users and controls. However, within the group of heavy cannabis users, a positive relation was observed between total lifetime cannabis use and approach-bias activations in various fronto-limbic areas. Moreover, approach-bias activations in the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) independently predicted cannabis problem severity after six months over and beyond session-induced subjective measures of craving. Higher DLPFC/ACC activity during cannabis approach trials, but lower activity during cannabis avoidance trials were associated with decreases in cannabis problem severity. These findings suggest that cannabis users with deficient control over cannabis action tendencies are more likely to develop cannabis related problems. Moreover, the balance between cannabis approach and avoidance responses in the DLPFC and ACC may help identify individuals at-risk for cannabis use disorders and may be new targets for prevention and treatment.

Approach-Bias Predicts Development of Cannabis Problem Severity in Heavy Cannabis Users: Results from a Prospective FMRI Study

PubMed Central

Cousijn, Janna; Goudriaan, Anna E.; Ridderinkhof, K. Richard; van den Brink, Wim; Veltman, Dick J.; Wiers, Reinout W.

2012-01-01

A potentially powerful predictor for the course of drug (ab)use is the approach-bias, that is, the pre-reflective tendency to approach rather than avoid drug-related stimuli. Here we investigated the neural underpinnings of cannabis approach and avoidance tendencies. By elucidating the predictive power of neural approach-bias activations for future cannabis use and problem severity, we aimed at identifying new intervention targets. Using functional Magnetic Resonance Imaging (fMRI), neural approach-bias activations were measured with a Stimulus Response Compatibility task (SRC) and compared between 33 heavy cannabis users and 36 matched controls. In addition, associations were examined between approach-bias activations and cannabis use and problem severity at baseline and at six-month follow-up. Approach-bias activations did not differ between heavy cannabis users and controls. However, within the group of heavy cannabis users, a positive relation was observed between total lifetime cannabis use and approach-bias activations in various fronto-limbic areas. Moreover, approach-bias activations in the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) independently predicted cannabis problem severity after six months over and beyond session-induced subjective measures of craving. Higher DLPFC/ACC activity during cannabis approach trials, but lower activity during cannabis avoidance trials were associated with decreases in cannabis problem severity. These findings suggest that cannabis users with deficient control over cannabis action tendencies are more likely to develop cannabis related problems. Moreover, the balance between cannabis approach and avoidance responses in the DLPFC and ACC may help identify individuals at-risk for cannabis use disorders and may be new targets for prevention and treatment. PMID:22957019

Auditory mismatch negativity deficits in long-term heavy cannabis users.

PubMed

Roser, Patrik; Della, Beate; Norra, Christine; Uhl, Idun; Brüne, Martin; Juckel, Georg

2010-09-01

Mismatch negativity (MMN) is an auditory event-related potential indicating auditory sensory memory and information processing. The present study tested the hypothesis that chronic cannabis use is associated with deficient MMN generation. MMN was investigated in age- and gender-matched chronic cannabis users (n = 30) and nonuser controls (n = 30). The cannabis users were divided into two groups according to duration and quantity of cannabis consumption. The MMNs resulting from a pseudorandomized sequence of 2 × 900 auditory stimuli were recorded by 32-channel EEG. The standard stimuli were 1,000 Hz, 80 dB SPL and 90 ms duration. The deviant stimuli differed in duration (50 ms) or frequency (1,200 Hz). There were no significant differences in MMN values between cannabis users and nonuser controls in both deviance conditions. With regard to subgroups, reduced amplitudes of frequency MMN at frontal electrodes were found in long-term (≥8 years of use) and heavy (≥15 joints/week) users compared to short-term and light users. The results indicate that chronic cannabis use may cause a specific impairment of auditory information processing. In particular, duration and quantity of cannabis use could be identified as important factors of deficient MMN generation.

Daily Use, Especially of High-Potency Cannabis, Drives the Earlier Onset of Psychosis in Cannabis Users

PubMed Central

Di Forti, Marta; Sallis, Hannah; Allegri, Fabio; Trotta, Antonella; Ferraro, Laura; Stilo, Simona A.; Marconi, Arianna; La Cascia, Caterina; Reis Marques, Tiago; Pariante, Carmine; Dazzan, Paola; Mondelli, Valeria; Paparelli, Alessandra; Kolliakou, Anna; Prata, Diana; Gaughran, Fiona; David, Anthony S.; Morgan, Craig; Stahl, Daniel; Khondoker, Mizanur; MacCabe, James H.; Murray, Robin M.

2014-01-01

Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated. Methods: We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP. Results: Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16–1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11–1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06–1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users. Conclusions: Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users. PMID:24345517

Psychotic experiences are linked to cannabis use in adolescents in the community because of common underlying environmental risk factors.

PubMed

Shakoor, Sania; Zavos, Helena M S; McGuire, Philip; Cardno, Alastair G; Freeman, Daniel; Ronald, Angelica

2015-06-30

Cannabis users are more likely to have psychotic experiences (PEs). The degree to which these associations are driven by genetic or environmental influences in adolescence is unknown. This study estimated the genetic and environmental contributions to the relationship between cannabis use and PEs. Specific PEs were measured in a community-based twin sample (4830 16-year-old pairs) using self-reports and parent-reports. Adolescents reported on ever using cannabis. Multivariate liability threshold structural equation model-fitting was conducted. Cannabis use was significantly correlated with PEs. Modest heritability (37%), common environmental influences (55%) and unique environment (8%) were found for cannabis use. For PEs, modest heritability (27-54%), unique environmental influences (E=12-50%) and little common environmental influences (11-20%), with the exception of parent-rated Negative Symptoms (42%), were reported. Environmental influences explained all of the covariation between cannabis use and paranoia, cognitive disorganization and parent-rated negative symptoms (bivariate common environment=69-100%, bivariate unique environment=28-31%), whilst the relationship between cannabis use and hallucinations indicated familial influences. Cannabis use explains 2-5% of variance in positive, cognitive, and negative PEs. Cannabis use and psychotic experience co-occur due to environmental factors. Focus on specific environments may reveal why adolescent cannabis use and psychotic experiences tend to 'travel together'. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Psychotic experiences are linked to cannabis use in adolescents in the community because of common underlying environmental risk factors

PubMed Central

Shakoor, Sania; Zavos, Helena M.S.; McGuire, Philip; Cardno, Alastair G.; Freeman, Daniel; Ronald, Angelica

2015-01-01

Cannabis users are more likely to have psychotic experiences (PEs). The degree to which these associations are driven by genetic or environmental influences in adolescence is unknown. This study estimated the genetic and environmental contributions to the relationship between cannabis use and PEs. Specific PEs were measured in a community-based twin sample (4830 16-year-old pairs) using self-reports and parent-reports. Adolescents reported on ever using cannabis. Multivariate liability threshold structural equation model-fitting was conducted. Cannabis use was significantly correlated with PEs. Modest heritability (37%), common environmental influences (55%) and unique environment (8%) were found for cannabis use. For PEs, modest heritability (27–54%), unique environmental influences (E=12–50%) and little common environmental influences (11–20%), with the exception of parent-rated Negative Symptoms (42%), were reported. Environmental influences explained all of the covariation between cannabis use and paranoia, cognitive disorganization and parent-rated negative symptoms (bivariate common environment=69–100%, bivariate unique environment=28–31%), whilst the relationship between cannabis use and hallucinations indicated familial influences. Cannabis use explains 2–5% of variance in positive, cognitive, and negative PEs. Cannabis use and psychotic experience co-occur due to environmental factors. Focus on specific environments may reveal why adolescent cannabis use and psychotic experiences tend to ‘travel together’. PMID:25912376

Cigarette and cannabis use trajectories among adolescents in treatment for attention-deficit/hyperactivity disorder and substance use disorders.

PubMed

Gray, Kevin M; Riggs, Paula D; Min, Sung-Joon; Mikulich-Gilbertson, Susan K; Bandyopadhyay, Dipankar; Winhusen, Theresa

2011-09-01

Cigarette smoking is common in adolescents with attention-deficit/hyperactivity disorder (ADHD) and substance use disorders (SUD). However, little is known about the relationship between cigarette and cannabis use trajectories in the context of treatment for both ADHD and SUD. To address this research gap, we report collateral analyses from a 16-week randomized, controlled trial (n=303) of osmotic-release methylphenidate (OROS-MPH) in adolescents with ADHD concurrently receiving cognitive behavioral therapy (CBT) targeting non-nicotine SUD. Participants completed cigarette and cannabis use self-report at baseline and throughout treatment. Analyses were performed to explore the relationships between cigarette smoking, cannabis use, and other factors, such as medication treatment assignment (OROS-MPH versus placebo). Baseline (pre-treatment) cigarette smoking was positively correlated with cannabis use. Negligible decline in cigarette smoking during treatment for non-nicotine SUD was observed in both medication groups. Regular cigarette and cannabis users at baseline who reduced their cannabis use by >50% also reduced cigarette smoking (from 10.8±1.1 to 6.2±1.1 cigarettes per day). Findings highlight the challenging nature of concurrent cannabis and cigarette use in adolescents with ADHD, but demonstrate that changes in use of these substances during treatment may occur in parallel. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Cigarette and Cannabis Use Trajectories Among Adolescents in Treatment for Attention-Deficit/Hyperactivity Disorder and Substance Use Disorders

PubMed Central

Gray, Kevin M.; Riggs, Paula D.; Min, Sung-Joon; Mikulich-Gilbertson, Susan K.; Bandyopadhyay, Dipankar; Winhusen, Theresa

2011-01-01

Background Cigarette smoking is common in adolescents with attention-deficit/hyperactivity disorder (ADHD) and substance use disorders (SUD). However, little is known about the relationship between cigarette and cannabis use trajectories in the context of treatment for both ADHD and SUD. To address this research gap, we report collateral analyses from a 16-week randomized, controlled trial (n=303) of osmotic-release methylphenidate (OROS-MPH) in adolescents with ADHD concurrently receiving cognitive behavioral therapy (CBT) targeting non-nicotine SUD. Methods Participants completed cigarette and cannabis use self-report at baseline and throughout treatment. Analyses were performed to explore the relationships between cigarette smoking, cannabis use, and other factors, such as medication treatment assignment (OROS-MPH versus placebo). Results Baseline (pre-treatment) cigarette smoking was positively correlated with cannabis use. Negligible decline in cigarette smoking during treatment for non-nicotine SUD was observed in both medication groups. Regular cigarette and cannabis users at baseline who reduced their cannabis use by >50% also reduced cigarette smoking (from 10.8±1.1 to 6.2±1.1 cigarettes per day). Conclusions Findings highlight the challenging nature of concurrent cannabis and cigarette use in adolescents with ADHD, but demonstrate that changes in use of these substances during treatment may occur in parallel. PMID:21411243

The medicalisation of revolt: a sociological analysis of medical cannabis users.

PubMed

Pedersen, Willy; Sandberg, Sveinung

2013-01-01

In a qualitative study, we investigated the medical motives of 100 Norwegian cannabis users, none of whom had legal access to medical cannabis. Cannabis was used therapeutically for conditions such as multiple sclerosis, attention deficit hyperactivity disorder and rheumatism, as well as for quality of life conditions such as quality of sleep, relaxation and wellbeing. The borders between medical and recreational cannabis use were blurred. This article identifies strategies of medical cannabis users to gain social acceptance. Several respondents downplayed effects such as intoxication and euphoria. Others used the language of medicine and knowledge of current research in psychopharmacology. Cannabis was contrasted with the potential for abuse of prescription medicines. The medical cannabis movement has had little success in Norway. Medical professionals are unable to accept that users may be more knowledgeable than experts and medical users cannot discard the values of traditional cannabis culture. Calls for medical cannabis use are thus perceived as a gambit in attempts to have cannabis legalised. We argue that, despite having had little effect on health authorities, the medical cannabis movement may be having the unintended effect of medicalising cannabis use and using it as a cure for everyday problems. © 2012 The Authors. Sociology of Health & Illness © 2012 Foundation for the Sociology of Health & Illness/Blackwell Publishing Ltd.

Cannabis Problem Experiences Among Users of the Tobacco-Cannabis Combination Known As Blunts

PubMed Central

Fairman, Brian J.

2015-01-01

Background In most of the world, cannabis smokers mix loose tobacco inside a joint, pipe, spliff, or cone. More recently, a ‘blunt’ formulation combines these two drugs by inserting cannabis into a hollowed-out cigar. Epidemiological research linking simultaneous use of these two drugs and the development of cannabis use disorders (CUD) remains unclear. This study estimates associations linking blunt smoking with levels and subtypes of cannabis problems. Methods Cross-sectional data on 27,767 past-year cannabis users were analyzed from the US National Survey on Drug Use and Health (NSDUH) conducted from 2009–2012. Ten self-reported items of DSM-IV CUD features elicited a single latent trait of cannabis problem (CP) severity, which was then regressed on past-year blunt smoking and past-month blunt frequency measures within the context of a conceptual model. Differential item functioning (DIF) analysis evaluated potential bias in CP feature response by blunt smoking history. Results Past-year blunt smoking was associated with higher CP severity compared to cannabis users who did not smoke blunts. Days of blunt smoking in the past month also predicted higher CP severity than less frequent blunt use. Those smoking blunts experienced more subjectively felt tolerance and having spent more time obtaining or using cannabis, but were less likely to experience other problems, even at the same level of CP severity. Conclusions These findings suggest smoking blunts might promote the development of problematic cannabis use. Responses to cannabis problems differed by history of blunt smoking, possibly implicating an influence of tobacco on measurement of cannabis use disorders. PMID:25746234

Cannabis problem experiences among users of the tobacco-cannabis combination known as blunts.

PubMed

Fairman, Brian J

2015-05-01

In most of the world, cannabis smokers mix loose tobacco inside a joint, pipe, spliff, or cone. More recently, a 'blunt' formulation combines these two drugs by inserting cannabis into a hollowed-out cigar. Epidemiological research linking simultaneous use of these two drugs and the development of cannabis use disorders (CUD) remains unclear. This study estimates associations linking blunt smoking with levels and subtypes of cannabis problems. Cross-sectional data on 27,767 past-year cannabis users were analyzed from the US National Survey on Drug Use and Health (NSDUH) conducted from 2009 to 2012. Ten self-reported items of DSM-IV CUD features elicited a single latent trait of cannabis problem (CP) severity, which was then regressed on past-year blunt smoking and past-month blunt frequency measures within the context of a conceptual model. Differential item functioning (DIF) analysis evaluated potential bias in CP feature response by blunt smoking history. Past-year blunt smoking was associated with higher CP severity compared to cannabis users who did not smoke blunts. Days of blunt smoking in the past month also predicted higher CP severity than less frequent blunt use. Those smoking blunts experienced more subjectively felt tolerance and having spent more time obtaining or using cannabis, but were less likely to experience other problems, even at the same level of CP severity. These findings suggest smoking blunts might promote the development of problematic cannabis use. Responses to cannabis problems differed by history of blunt smoking, possibly implicating an influence of tobacco on measurement of cannabis use disorders. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Neuropsychological deficits in long-term frequent cannabis users.

PubMed

Messinis, Lambros; Kyprianidou, Anthoula; Malefaki, Sonia; Papathanasopoulos, Panagiotis

2006-03-14

The authors examined neuropsychological functioning in 20 long-term (LT), 20 shorter term (ST) heavy frequent cannabis users, and 24 controls after abstinence for > or =24 hours prior to testing. LT users performed significantly worse on verbal memory and psychomotor speed. LT and ST users had a higher proportion of deficits on verbal fluency, verbal memory, attention, and psychomotor speed. Specific cognitive domains appear to deteriorate with increasing years of heavy frequent cannabis use.

Altered attentional control strategies but spared executive functioning in chronic cannabis users.

PubMed

Nusbaum, Amy T; Whitney, Paul; Cuttler, Carrie; Spradlin, Alexander; Hinson, John M; McLaughlin, Ryan J

2017-12-01

Cannabis use has increased rapidly in recent decades. The increase in cannabis use makes it important to understand the potential influence of chronic use on attentional control and other executive functions (EFs). Because cannabis is often used to reduce stress, and because stress can constrain attentional control and EFs, the primary goal of this study was to determine the joint effect of acute stress and chronic cannabis use on specific EFs. Thirty-nine cannabis users and 40 non-users were assigned to either a stress or no stress version of the Maastricht Acute Stress Test. Participants then completed two cognitive tasks that involve EFs: (1) task switching, and (2) a novel Flexible Attentional Control Task. These two tasks provided assessments of vigilant attention, inhibitory control, top-down attentional control, and cognitive flexibility. Salivary cortisol was assessed throughout the study. Reaction time indices showed an interaction between stress and cannabis use on top-down attentional control (p=0.036, n p 2 =0.059). Follow-up tests showed that cannabis users relied less on top-down attentional control than did non-users in the no stress version. Despite not relying on top-down control, the cannabis users showed no overall performance deficits on the tasks. Chronic cannabis users performed cognitive tasks involving EFs as well as non-users while not employing cognitive control processes that are typical for such tasks. These results indicate alterations in cognitive processing in cannabis users, but such alterations do not necessarily lead to global performance deficits. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of cannabinoids in hair with self-reported cannabis consumption in heavy, light and non-cannabis users.

PubMed

Taylor, Michelle; Lees, Rosie; Henderson, Graeme; Lingford-Hughes, Anne; Macleod, John; Sullivan, John; Hickman, Matthew

2017-03-01

Biological tests of drug use can be used to inform clinical and legal decisions and hold potential to provide evidence for epidemiological studies where self-reported behaviour may be unavailable or unreliable. We test whether hair can be considered as a reliable marker of cannabis exposure. Hair samples were collected from 136 subjects who were self-reported heavy, light or non-users of cannabis and tested using GC-MS/MS. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for five cannabinoids (tetrahydrocannabinol [THC], THC-OH, THC-COOH, cannabinol and cannabidiol). Samples also were segmented in 1 cm sections representing 1 month exposure and the correlation between amount of cannabinoid detected and self-reported cannabis consumption tested. All five cannabinoids were detected. Seventy-seven percent of heavy users, 39% of light users and 0% of non-users tested positive for THC. The sensitivity of detection of THC was 0.77 (0.56-0.91) comparing heavy cannabis smokers with light and non-users, whereas the sensitivity of other cannabinoids generally was considerably lower. The positive and negative predictive value of detection of THC were 0.57 (0.39-0.74) and 0.91 (0.82-0.97), respectively. A correlation of 0.52 (P < 0.001) was observed between self-reported monthly cannabis use and THC. Hair analysis can be used as a qualitative indicator of heavy (daily or near daily) cannabis consumption within the past 3 months. However, this approach is unable to reliably detect light cannabis consumption or determine the quantity of cannabis used by the individual. [Taylor M, Lees R, Henderson G, Lingford-Hughes A, Macleod J, Sullivan J, Hickman M. Comparison of cannabinoids in hair with self-reported cannabis consumption in heavy, light and non-cannabis users. Drug Alcohol Rev 2017;36:220-226]. © 2016 The Authors Drug and Alcohol Review published by John Wiley & Sons Australia, Ltd on behalf of Australasian

Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users.

PubMed

Di Forti, Marta; Sallis, Hannah; Allegri, Fabio; Trotta, Antonella; Ferraro, Laura; Stilo, Simona A; Marconi, Arianna; La Cascia, Caterina; Reis Marques, Tiago; Pariante, Carmine; Dazzan, Paola; Mondelli, Valeria; Paparelli, Alessandra; Kolliakou, Anna; Prata, Diana; Gaughran, Fiona; David, Anthony S; Morgan, Craig; Stahl, Daniel; Khondoker, Mizanur; MacCabe, James H; Murray, Robin M

2014-11-01

Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated. We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP. Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16-1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11-1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06-1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users. Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users. © The Author 2013. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Cannabis and Alcohol Use, and the Developing Brain

PubMed Central

Meruelo, AD; Castro, N; Cota, CI; Tapert, SF

2017-01-01

Sex hormones and white (and grey) matter in the limbic system, cortex and other brain regions undergo changes during adolescence. Some of these changes include ongoing white matter myelination and sexually dimorphic features in grey and white matter. Adolescence is also a period of vulnerability when many are first exposed to alcohol and cannabis, which appear to influence the developing brain. Neuropsychological studies have provided considerable understanding of the effects of alcohol and cannabis on the brain. Advances in neuroimaging have allowed examination of neuroanatomic changes, metabolic and neurotransmitter activity, and neuronal activation during adolescent brain development and substance use. In this review, we examine major differences in brain development between users and non-users, and recent findings on the influence of cannabis and alcohol on the adolescent brain. We also discuss associations that appear to resolve following short-term abstinence, and attentional deficits that appear to persist. These findings can be useful in guiding earlier educational interventions for adolescents, and clarifying the neural sequelae of early alcohol and cannabis use to the general public. PMID:28223098

Cannabis-related hippocampal volumetric abnormalities specific to subregions in dependent users.

PubMed

Chye, Yann; Suo, Chao; Yücel, Murat; den Ouden, Lauren; Solowij, Nadia; Lorenzetti, Valentina

2017-07-01

Cannabis use is associated with neuroanatomical alterations in the hippocampus. While the hippocampus is composed of multiple subregions, their differential vulnerability to cannabis dependence remains unknown. The objective of the study is to investigate gray matter alteration in each of the hippocampal subregions (presubiculum, subiculum, cornu ammonis (CA) subfields CA1-4, and dentate gyrus (DG)) as associated with cannabis use and dependence. A total of 35 healthy controls (HC), 22 non-dependent (CB-nondep), and 39 dependent (CB-dep) cannabis users were recruited. We investigated group differences in hippocampal subregion volumes between HC, CB-nondep, and CB-dep users. We further explored the association between CB use variables (age of onset of regular use, monthly use, lifetime use) and hippocampal subregions in CB-nondep and CB-dep users separately. The CA1, CA2/3, CA4/DG, as well as total hippocampal gray matter were reduced in volume in CB-dep but not in CB-nondep users, relative to HC. The right CA2/3 and CA4/DG volumes were also negatively associated with lifetime cannabis use in CB-dep users. Our results suggest a regionally and dependence-specific influence of cannabis use on the hippocampus. Hippocampal alteration in cannabis users was specific to the CA and DG regions and confined to dependent users.

[Cannabis use among children and adolescents: impacts and consequences].

PubMed

Peyret, Emmanuelle; Delorme, Richard

2014-03-01

A health policy for the prevention and treatment of cannabis-related disorders is urgently needed in France, given the high prevalence of cannabis use among children and adolescents. Such a policy will require a better understanding of the endo-cannabinoid system and the impact of exogenous cannabinoids in this fragile population. The brain continues to undergo significant development until the age of about 25 years, and cannabis consumption by young people therefore carries specific risks of dependence (frequency and intensity), and of neuroanatomical, cognitive and emotional damage. This article summarizes the available data and offers a medical view of the risks and consequences of cannabis use by children and adolescents.

Sex differences in cannabis withdrawal symptoms among treatment-seeking cannabis users.

PubMed

Herrmann, Evan S; Weerts, Elise M; Vandrey, Ryan

2015-12-01

Over 300,000 individuals enter treatment for cannabis-use disorders (CUDs) in the United States annually. Cannabis withdrawal is associated with poor CUD-treatment outcomes, but no prior studies have examined sex differences in withdrawal among treatment-seeking cannabis users. Treatment-seeking cannabis users (45 women and 91 men) completed a Marijuana Withdrawal Checklist (Budney, Novy, & Hughes, 1999, Budney, Moore, Vandrey, & Hughes, 2003) at treatment intake to retrospectively characterize withdrawal symptoms experienced during their most recent quit attempt. Scores from the 14-item Composite Withdrawal Discomfort Scale (WDS), a subset of the Marijuana Withdrawal Checklist that corresponds to valid cannabis withdrawal symptoms described in the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; APA, 2013) were calculated. Demographic and substance-use characteristics, overall WDS scores, and scores on individual WDS symptoms were compared between women and men. Women had higher overall WDS scores than men, and women had higher scores than men on 6 individual symptoms in 2 domains, mood symptoms (i.e., irritability, restlessness, increased anger, violent outbursts), and gastrointestinal symptoms (i.e., nausea, stomach pain). Follow-up analyses isolating the incidence and severity of WDS symptoms demonstrated that women generally reported a higher number of individual withdrawal symptoms than men, and that they reported experiencing some symptoms as more severe. This is the first report to demonstrate that women seeking treatment for CUDs may experience more withdrawal then men during quit attempts. Prospective studies of sex differences in cannabis withdrawal are warranted. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Cannabis use and destructive periodontal diseases among adolescents.

PubMed

López, Rodrigo; Baelum, Vibeke

2009-03-01

The aim of this experiment was to investigate the association between cannabis use and destructive periodontal disease among adolescents. Data from a population screening examination carried out among Chilean high school students from the Province of Santiago were used to determine whether there was an association between the use of cannabis and signs of periodontal diseases as defined by (1) the presence of necrotizing ulcerative gingival (NUG) lesions or (2) the presence of clinical attachment loss (CAL) > or =3 mm. The cannabis exposures variables considered were "Ever use of cannabis" (yes/no) and "Regular use of cannabis" (yes/no). The associations were investigated using multiple logistic regression analyses adjusted for age, gender, paternal income, paternal education, frequency of tooth-brushing and time since last dental visit. Multiple logistic regression analyses showed that "Ever use of cannabis" was significantly negatively associated with the presence of NUG lesions (OR=0.47 [0.2;0.9]) among non-smokers only. No significant associations were observed between the presence of CAL > or =3 mm and cannabis use in either of the smoking groups. There was no evidence to suggest that the use of cannabis is positively associated with periodontal diseases in this adolescent population.

Deficits in learning and memory: parahippocampal hyperactivity and frontocortical hypoactivity in cannabis users.

PubMed

Nestor, Liam; Roberts, Gloria; Garavan, Hugh; Hester, Robert

2008-04-15

The consumption of cannabis has been linked to impairments in human learning and memory, as well as aspects of executive functioning. Cannabis-related impairments in learning and memory in chronic cannabis users, it has been argued, are caused by the effects of cannabis on hippocampal functioning. The current study involved two experiments. Experiment 1 compared 35 current users of cannabis and 38 well-matched controls on a face-name task, previously shown to activate the hippocampal region. Based on the results of experiment 1, experiment 2 used fMRI and a modified version of the face-name task, to examine cortical and (para)hippocampal activity during learning and recall in 14 current users of cannabis and 14 controls. Results of experiment 1 showed that cannabis users were significantly worse with respect to learning, short and long-term memory performance. Experiment 2 showed that despite non-significant differences in learning and memory performance, cannabis users had significantly lower levels of BOLD activity in the right superior temporal gyrus, right superior frontal gyrus, right middle frontal gyrus and left superior frontal gyrus compared to controls during learning. Results also showed that cannabis users had significantly higher BOLD activity in the right parahippocampal gyrus during learning. Hypoactivity in frontal and temporal cortices, and relative hyperactivity in the parahippocampus identify functional deficits and compensatory processes in cannabis users.

Cream of the Crop: Clinical Representativeness of Eligible and Ineligible Cannabis Users in Research.

PubMed

Rosen, Alexis S; Sodos, Louise M; Hirst, Rayna B; Vaughn, Dylan; Lorkiewicz, Sara A

2018-03-06

Experts have recommended criteria (Gonzalez et al., 2002) for recruiting pure chronic cannabis users (i.e., those without polysubstance use or psychiatric illness) when evaluating cannabis' non-acute effects on cognition. We sought to demonstrate the implications of using such criteria by examining characteristics of respondents who completed an eligibility screening for a parent study evaluating the cognitive effects of chronic cannabis use. Over a 3-year, 8-month period, 612 respondents from the community completed an eligibility screening based on recommendations in the cannabis literature. Using independent samples t-tests and chi-square tests, we examined whether qualified/eligible respondents (n = 219) differed from non-qualified/ineligible respondents (n = 393). Compared to ineligible cannabis users, eligible cannabis-using respondents were significantly younger, used cannabis more frequently, used alcohol less frequently, and were less likely to have a history of other drug use, a psychiatric diagnosis, or to have used psychiatric medication. Conclusions/Importance: Our findings indicate that eligible/pure cannabis users are not representative of typical cannabis users in the general community (i.e., ineligible users with polysubstance use and/or psychiatric diagnoses) who ultimately comprised the majority of our cannabis-using sample (65.2%). Thus, typical cannabis users may be more accurately characterized as polysubstance users, posing a number of challenges related to the generalizability of findings from studies utilizing pure samples of cannabis users. Recruiting samples of typical cannabis users will improve external validity in research. Furthermore, reporting comprehensive characteristics of such samples will enable consumers to gauge the applicability of study findings to populations of interest.

[Comorbidity in 207 cannabis users in a specific outpatient setting].

PubMed

Guillem, E; Arbabzadeh-Bouchez, S; Vorspan, F; Bellivier, F

2015-06-01

Health care seeking for a problematic use of cannabis is in progress in France. The aim is to assess the addictive and psychiatric comorbidity in cannabis users seen in the specific setting at the Lariboisière hospital. Two hundred and seven cannabis users were included from January 2004 to December 2009. Twelve-month and lifetime diagnosis of abuse and dependence (cannabis, alcohol, cocaine/crack) (DSM-IV), current and lifetime mood disorders, anxiety disorders, eating disorders and psychotic disorders were assessed (Mini-International Neuropsychiatric Interview). Logistic regression analyses identified adjusted odds ratios associated with the gender and the health care seeking (P=0.01). One hundred and forty-seven men (71%) and 60 women (29%), 29.3±8.6 years (15.2-51.6 years). Most of the outpatients ask for health care themselves (59.7%), whereas 19.4% are asked to seek health care by relatives (19.4%) or because of an academic, health or justice injunction (20.4%). In total, 49.3% of the outpatients are single, 35.7% are cohabitating, 9.3% are married and 6.3% are separated/divorced. About 20.4% of the outpatients are students, 35.7% have a professional activity, 19% are jobless, 2.4% are impaired, 0.5% are retired, at home and 12.1% do not have an official income. Twelve-month and lifetime prevalence of abuse/dependence are: cannabis (10.1/82.1% and 8.7/88.4%), alcohol (9.7/8.7% and 19.3/18.8%), cocaine/crack (2.4/3.4% and 4.8/11.6%). The mean duration of cannabis dependence for the current dependent users is 8.4±5.8 years. The mean number of "joints" during the last 6 months is 6±4.3, the mean amount of cannabis per week is 12.5±11.3g. About 51.3% of the dependent users report externalized and/or internalized disorders at school during childhood and adolescence. In total, 19.4% of the dependent users have a suicide attempt history and 18.9% have a psychiatric hospitalisation history, more frequently women (P<0.01 and P=0.02). About 73.8% have a

Cognitive, physical, and mental health outcomes between long-term cannabis and tobacco users.

PubMed

Lovell, M E; Bruno, R; Johnston, J; Matthews, A; McGregor, I; Allsop, D J; Lintzeris, N

2018-04-01

Cannabis intoxication adversely affects health, yet persistent effects following short-term abstinence in long-term cannabis users are unclear. This matched-subjects, cross-sectional study compared health outcomes of long-term cannabis and long-term tobacco-only users, relative to population norms. Nineteen long-term (mean 32.3years of use, mean age 55.7years), abstinent (mean 15h) cannabis users and 16 long-term tobacco users (mean 37.1years of use, mean age 52.9years), matched for age, educational attainment, and lifetime tobacco consumption, were compared on measures of learning and memory, response inhibition, information-processing, sustained attention, executive control, and mental and physical health. Cannabis users exhibited poorer overall learning and delayed recall and greater interference and forgetting than tobacco users, and exhibited poorer recall than norms. Inhibition and executive control were similar between groups, but cannabis users had slower reaction times during information processing and sustained attention tasks. Cannabis users had superior health satisfaction and psychological, somatic, and general health than tobacco users and had similar mental and physical health to norms whilst tobacco users had greater stress, role limitations from emotional problems, and poorer health satisfaction. Long-term cannabis users may exhibit deficits in some cognitive domains despite short-term abstinence and may therefore benefit from interventions to improve cognitive performance. Tobacco alone may contribute to adverse mental and physical health outcomes, which requires appropriate control in future studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Psychiatric effects of cannabis use.

PubMed

Tunving, K

1985-09-01

That cannabis use may provoke mental disturbances is well known to Scandinavian psychiatrists today. A review of the psychiatric aspects of cannabis use is given, and the clinical signs of 70 cases of cannabis psychoses collected in Sweden are described. The bluntness and "amotivation" following chronic cannabis use are discussed. Anxiety reactions, flashbacks, dysphoric reactions and an abstinence syndrome are all sequels of cannabis use. Three risk groups begin to emerge: a) Young teenage cannabis users who lose some of their capacity to learn complex functions and who flee from reality to a world of dreams. With its sedative effect, cannabis could modify such emotions as anger and anxiety and slow down the liberation process of adolescence. b) Heavy daily users, often persons who cannot cope with depression or their life circumstances. c) Psychiatric patients whose resistance to relapses into psychotic reactions might be diminished according to the psychotropic effects of cannabis.

Cannabis species and cannabinoid concentration preference among sleep-disturbed medicinal cannabis users.

PubMed

Belendiuk, Katherine A; Babson, Kimberly A; Vandrey, Ryan; Bonn-Miller, Marcel O

2015-11-01

Individuals report using cannabis for the promotion of sleep, and the effects of cannabis on sleep may vary by cannabis species. Little research has documented preferences for particular cannabis types or cannabinoid concentrations as a function of use for sleep disturbances. 163 adults purchasing medical cannabis for a physical or mental health condition at a cannabis dispensary were recruited. They provided self-report of (a) whether cannabis use was intended to help with sleep problems (e.g. insomnia, nightmares), (b) sleep quality (PSQI), (c) cannabis use (including preferred type), and (d) symptoms of DSM-5 cannabis dependence. 81 participants reported using cannabis for the management of insomnia and 14 participants reported using cannabis to reduce nightmares. Individuals using cannabis to manage nightmares preferred sativa to indica strains (Fisher's exact test (2) = 6.83, p < 0.05), and sativa users were less likely to endorse DSM-5 cannabis dependence compared with those who preferred indica strains (χ(2)(2) = 4.09, p < 0.05). Individuals with current insomnia (t(9) = 3.30, p < 0.01) and greater sleep latency (F(3,6) = 46.7, p < 0.001) were more likely to report using strains of cannabis with significantly higher concentrations of CBD. Individuals who reported at least weekly use of hypnotic medications used cannabis with lower THC concentrations compared to those who used sleep medications less frequently than weekly (t(17) = 2.40, p < 0.05). Associations between sleep characteristics and the type of cannabis used were observed in this convenience sample of individuals using cannabis for the management of sleep disturbances. Controlled prospective studies are needed to better characterize the impact that specific components of cannabis have on sleep. Copyright © 2015. Published by Elsevier Ltd.

Trajectories of Cannabis-Related Associative Memory among Vulnerable Adolescents: Psychometric and Longitudinal Evaluations

ERIC Educational Resources Information Center

Shono, Yusuke; Edwards, Michael C.; Ames, Susan L.; Stacy, Alan W.

2018-01-01

Indirect tests of memory associations relevant to cannabis have been shown to be useful in explaining and predicting adolescent cannabis use habits. This study sought to increase the understanding of adolescent cannabis-related associative memory and cannabis use behavior over time. A longitudinal sample of alternative high school students (N =…

Dopamine release in chronic cannabis users: a [11c]raclopride positron emission tomography study.

PubMed

Urban, Nina B L; Slifstein, Mark; Thompson, Judy L; Xu, Xiaoyan; Girgis, Ragy R; Raheja, Sonia; Haney, Margaret; Abi-Dargham, Anissa

2012-04-15

Low striatal dopamine 2/3 receptor (D(2/3)) availability and low ventrostriatal dopamine (DA) release have been observed in alcoholism and cocaine and heroin dependence. Less is known about the dopaminergic system in cannabis dependence. We assessed D(2/3) availability and DA release in abstinent cannabis users compared with control subjects and explored relationships to cannabis use history using [(11)C]raclopride positron emission tomography and an amphetamine challenge paradigm. Sixteen recently abstinent, psychiatrically healthy cannabis-using participants (27.3 ± 6.1 years, 1 woman, 15 men) and 16 matched control subjects (28.1 ± 6.7 years, 2 women, 14 men) completed two positron emission tomography scans, before and after injection of intravenous d-amphetamine (.3 mg/kg). Percent change in [(11)C]raclopride binding after amphetamine (change in nondisplaceable binding potential, ΔBP(ND)) in subregions of the striatum was compared between groups. Correlations with clinical parameters were examined. Cannabis users had an average consumption of 517 ± 465 estimated puffs per month, indicating mild to moderate cannabis dependence. Neither baseline BP(ND) nor ΔBP(ND) differed from control subjects in any region of interest, including ventral striatum. In cannabis-dependent subjects, earlier age of onset of use correlated with lower [ΔBP(ND)] in the associative striatum when controlling for current age. Unlike other addictions, cannabis dependence of mild to moderate severity is not associated with striatal DA alterations. However, earlier or longer duration of use is related to lower DA release in the associative striatum. These observations suggest a more harmful effect of use during adolescence; more research is needed to distinguish effects of chronicity versus onset. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Cannabis and alcohol use, and the developing brain.

PubMed

Meruelo, A D; Castro, N; Cota, C I; Tapert, S F

2017-05-15

Sex hormones and white (and grey) matter in the limbic system, cortex and other brain regions undergo changes during adolescence. Some of these changes include ongoing white matter myelination and sexually dimorphic features in grey and white matter. Adolescence is also a period of vulnerability when many are first exposed to alcohol and cannabis, which appear to influence the developing brain. Neuropsychological studies have provided considerable understanding of the effects of alcohol and cannabis on the brain. Advances in neuroimaging have allowed examination of neuroanatomic changes, metabolic and neurotransmitter activity, and neuronal activation during adolescent brain development and substance use. In this review, we examine major differences in brain development between users and non-users, and recent findings on the influence of cannabis and alcohol on the adolescent brain. We also discuss associations that appear to resolve following short-term abstinence, and attentional deficits that appear to persist. These findings can be useful in guiding earlier educational interventions for adolescents, and clarifying the neural sequelae of early alcohol and cannabis use to the general public. Copyright © 2017 Elsevier B.V. All rights reserved.

Abnormal medial prefrontal cortex activity in heavy cannabis users during conscious emotional evaluation.

PubMed

Wesley, Michael J; Lile, Joshua A; Hanlon, Colleen A; Porrino, Linda J

2016-03-01

Long-term heavy cannabis users (cannabis users) who are not acutely intoxicated have diminished subconscious neural responsiveness to affective stimuli. This study sought to determine if abnormal processing extends to the conscious evaluation of emotional stimuli. Functional magnetic resonance imaging (fMRI) was used to examine brain activity as cannabis users (N = 16) and non-cannabis-using controls (N = 17) evaluated and categorized standardized International Affective Picture System (IAPS) stimuli. Individual judgments were used to isolate activity during the evaluation of emotional (i.e., emotional evaluation) or neutral (i.e., neutral evaluation) stimuli. Within- and between-group analyses were performed. Both groups judged the same stimuli as emotional and had activations in visual, midbrain, and middle cingulate cortices during emotional evaluation, relative to neutral. Within-group analyses also revealed amygdalar and inferior frontal gyrus activations in controls, but not cannabis users, and medial prefrontal cortex (mPFC) deactivations in cannabis users, but not controls, during emotional evaluation, relative to neutral. Between-group comparisons found that mPFC activity during positive and negative evaluation was significantly hypoactive in cannabis users, relative to controls. Abnormal neural processing of affective content extends to the level of consciousness in cannabis users. The hypoactive mPFC responses observed resembles the attenuated mPFC responses found during increased non-affective cognitive load in prior research. These findings suggest that abnormal mPFC singling in cannabis users during emotional evaluation might be associated with increased non-affective cognitive load.

Who receives cannabis use offers: A general population study of adolescents.

PubMed

Burdzovic Andreas, Jasmina; Pape, Hilde

2015-11-01

Drug use is predicated on a combination of "willingness" and "opportunity". That is, independent of any desire to use drugs, a drug use opportunity is required; be it indirect (i.e., being in a drug-use setting) or direct (i.e., receiving a direct drug offer). However, whether some youth are more likely to encounter such direct drug use opportunities is not fully known. We examined whether certain characteristics placed adolescents at greater risk for being offered cannabis, after accounting for a number of demographic-, contextual-, interpersonal-, and personal-level risk factors. We utilized data from a Norwegian school survey (n=19,309) where the likelihood of receiving cannabis offer in the past year was estimated using logistic regression models. Substantive focus was on the individual and combined effects of personal (i.e., delinquency) and interpersonal (i.e., cannabis-using close friend) risk factors. Separate models were fit for middle- and high-school students. Delinquency was a significant risk factor for receiving cannabis offers, as was a cannabis-using best friend. In addition, peer cannabis use increased the risk of cannabis offers mostly for adolescents on the lower delinquency spectrum, but less so for highly delinquent adolescents. These interaction effects were primarily driven by the middle-school cohort. Cannabis offers were more likely to be extended to youth of certain high-risk profiles. Targeted prevention strategies can therefore be extended to a general profile of younger adolescents with externalizing problems and cannabis-using peers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Abnormal Medial Prefrontal Cortex Activity in Heavy Cannabis Users During Conscious Emotional Evaluation

PubMed Central

Lile, Joshua A.; Hanlon, Colleen A.; Porrino, Linda J.

2015-01-01

Rationale Long-term heavy cannabis users (cannabis users) who are not acutely intoxicated have diminished subconscious neural responsiveness to affective stimuli. Objective This study sought to determine if abnormal processing extends to the conscious evaluation of emotional stimuli. Methods Functional Magnetic Resonance Imaging (fMRI) was used to examine brain activity as cannabis users (N=16) and non-cannabis using controls (N=17) evaluated and categorized standardized International Affective Picture System (IAPS) stimuli. Individual judgments were used to isolate activity during the evaluation of emotional (i.e., emotional evaluation) or neutral (i.e., neutral evaluation) stimuli. Within- and between-group analyses were performed. Results Both groups judged the same stimuli as emotional and had activations in visual, midbrain, and middle cingulate cortices during emotional evaluation, relative to neutral. Within-group analyses also revealed amygdalar and inferior frontal gyrus activations in controls, but not cannabis users, and medial prefrontal cortex (mPFC) deactivations in cannabis users, but not controls, during emotional evaluation, relative to neutral. Between-group comparisons found that mPFC activity during positive and negative evaluation was significantly hypoactive in cannabis users, relative to controls. Conclusions Abnormal neural processing of affective content extends to the level of consciousness in cannabis users. The hypoactive mPFC responses observed resembles the attenuated mPFC responses found during increased non-affective cognitive load in prior research. These findings suggest that abnormal mPFC singling in cannabis users during emotional evaluation might be associated with increased non-affective cognitive load. PMID:26690589

New Zealand Health Survey 2012/13: characteristics of medicinal cannabis users.

PubMed

Pledger, Megan; Martin, Greg; Cumming, Jacqueline

2016-04-22

To explore the characteristics of medicinal and non-medicinal cannabis users, and the conditions that were treated with cannabis. The data comes from the New Zealand Health Survey 2012/2013, which sampled 13,009 people, aged 15+ years, living in private or non-private dwellings in New Zealand. Participants self-reported cannabis use and were put into groups: 1) non-users; 2) ex-users; 3) last year users-non-medicinal; 4) last-year users-medicinal. Prevalence was reported for the major demographic subgroups; sex, age and ethnicity. Regression models were then used to find associations between demographic characteristics and cannabis use for groups 3 and 4. About five percent (4.6%, 95% CI 4.1-5.1) of those aged 15+ report using cannabis medicinally. This use was associated with being male, younger, less well-educated and relatively poor. While Māori have the highest prevalence of medicinal use, European NZ/Others make up 67.9% (95% CI 62.7-72.6) of medicinal users. Reported medicinal use was associated with reported conditions that were typically hard to manage: pain, anxiety/nerves and depression. Medicinal users were more likely to report chronic pain and pain interfering, moderately or more, with housework and other work.

Prolonged Cannabidiol Treatment Effects on Hippocampal Subfield Volumes in Current Cannabis Users.

PubMed

Beale, Camilla; Broyd, Samantha J; Chye, Yann; Suo, Chao; Schira, Mark; Galettis, Peter; Martin, Jennifer H; Yücel, Murat; Solowij, Nadia

2018-01-01

Introduction: Chronic cannabis use is associated with neuroanatomical alterations in the hippocampus. While adverse impacts of cannabis use are generally attributed to Δ 9 -tetrahydrocannabinol, emerging naturalistic evidence suggests cannabidiol (CBD) is neuroprotective and may ameliorate brain harms associated with cannabis use, including protection from hippocampal volume loss. This study examined whether prolonged administration of CBD to regular cannabis users within the community could reverse or reduce the characteristic hippocampal harms associated with chronic cannabis use. Materials and Methods: Eighteen regular cannabis users participated in an ∼10-week open-label pragmatic trial involving daily oral administration of 200 mg CBD, with no change to their ongoing cannabis use requested. Participants were assessed at baseline and post-CBD treatment using structural magnetic resonance imaging. Automated longitudinal hippocampal segmentation was performed to assess volumetric change over the whole hippocampus and within 12 subfields. Results: No change was observed in left or right hippocampus as a whole. However, left subicular complex (parasubiculum, presubiculum, and subiculum) volume significantly increased from baseline to post-treatment ( p =0.017 uncorrected) by 1.58% (Cohen's d =0.63; 2.83% in parasubiculum). Heavy cannabis users demonstrated marked growth in the left subicular complex, predominantly within the presubiculum, and right cornu ammonis (CA)1 compared to lighter users. Associations between greater right subicular complex and total hippocampal volume and higher plasma CBD concentration were evident, particularly in heavy users. Conclusions: Our findings suggest a restorative effect of CBD on the subicular and CA1 subfields in current cannabis users, especially those with greater lifetime exposure to cannabis. While replication is required in a larger, placebo-controlled trial, these findings support a protective role of CBD against

Prolonged Cannabidiol Treatment Effects on Hippocampal Subfield Volumes in Current Cannabis Users

PubMed Central

Beale, Camilla; Broyd, Samantha J.; Chye, Yann; Suo, Chao; Schira, Mark; Galettis, Peter; Martin, Jennifer H.; Yücel, Murat; Solowij, Nadia

2018-01-01

Abstract Introduction: Chronic cannabis use is associated with neuroanatomical alterations in the hippocampus. While adverse impacts of cannabis use are generally attributed to Δ9-tetrahydrocannabinol, emerging naturalistic evidence suggests cannabidiol (CBD) is neuroprotective and may ameliorate brain harms associated with cannabis use, including protection from hippocampal volume loss. This study examined whether prolonged administration of CBD to regular cannabis users within the community could reverse or reduce the characteristic hippocampal harms associated with chronic cannabis use. Materials and Methods: Eighteen regular cannabis users participated in an ∼10-week open-label pragmatic trial involving daily oral administration of 200 mg CBD, with no change to their ongoing cannabis use requested. Participants were assessed at baseline and post-CBD treatment using structural magnetic resonance imaging. Automated longitudinal hippocampal segmentation was performed to assess volumetric change over the whole hippocampus and within 12 subfields. Results: No change was observed in left or right hippocampus as a whole. However, left subicular complex (parasubiculum, presubiculum, and subiculum) volume significantly increased from baseline to post-treatment (p=0.017 uncorrected) by 1.58% (Cohen's d=0.63; 2.83% in parasubiculum). Heavy cannabis users demonstrated marked growth in the left subicular complex, predominantly within the presubiculum, and right cornu ammonis (CA)1 compared to lighter users. Associations between greater right subicular complex and total hippocampal volume and higher plasma CBD concentration were evident, particularly in heavy users. Conclusions: Our findings suggest a restorative effect of CBD on the subicular and CA1 subfields in current cannabis users, especially those with greater lifetime exposure to cannabis. While replication is required in a larger, placebo-controlled trial, these findings support a protective role of CBD against

Tobacco may mask poorer episodic memory among young adult cannabis users.

PubMed

Schuster, Randi M; Crane, Natania A; Mermelstein, Robin; Gonzalez, Raul

2015-09-01

Co-occurring cannabis and tobacco use has become increasingly prevalent among young adults, but it is not clear how tobacco use may alter the neurocognitive profile typically observed among cannabis users. Although there is substantial evidence citing cannabis and tobacco's individual effect on episodic memory and related brain structures, few studies have examined the effect of combined cannabis and tobacco use on memory. This investigation examined relationships between amount of past year cannabis and tobacco use on 4 different indices of episodic memory among a sample of young adults who identified cannabis as their drug of choice. Results indicated that more cannabis use was linked with poorer initial acquisition, total learning, and delayed recall on the Hopkins Verbal Learning Test-Revised, but only among cannabis users who sporadically smoked cigarettes in the past year. Conversely, the amount of past year cannabis use was not associated with episodic memory performance among individuals who more consistently smoked cigarettes in the past year. These differences could not be explained by several relevant potential confounds. These findings provide important insight into a potential mechanism (i.e., attenuation of cognitive decrements) that might reinforce use of both substances and hamper cessation attempts among cannabis users who also smoke cigarettes. Ongoing and future research will help to better understand how co-use of cannabis and tobacco affects memory during acute intoxication and abstinence and the stability of these associations over time. (c) 2015 APA, all rights reserved).

Psychosis following traumatic brain injury and cannabis use in late adolescence.

PubMed

Rabner, Jonathan; Gottlieb, Sarah; Lazdowsky, Lori; LeBel, Alyssa

2016-03-01

Both cannabis and traumatic brain injury (TBI) pose risks on the developing brain, including a potential increased vulnerability for developing psychosis. Recent reports detail an upward trend in both adolescent cannabis use and the concentration of THC, the most potent psychoactive component in cannabis. Similarly, it is estimated that 1.7 million Americans incur a TBI each year. Previously trivialized as a minor nuisance, attitudes towards TBIs are changing as researchers and the public recognize TBIs' possible long-lasting sequelae. Two cases are presented of adolescent patients with histories of TBI and self-reported heavy, recreational cannabis use who developed symptoms of psychosis. Similar neuronal signaling pathways involved in cannabis ingestion and TBI recovery, specifically CB1 receptors of the endocannabinoid system, as well as the allostatic load model provide context for the two presented cases. Given the cases and theories presented, we believe that cannabis use may act as a neurological stressor and risk factor for psychosis outweighing its possible benefits as a therapeutic solution for pain in late adolescent and young adult populations. The presented cases provide further support for the compounded risk of developing psychosis following TBI and cannabis use. © American Academy of Addiction Psychiatry.

Postoperative Shivering Among Cannabis Users at a Public Hospital in Trinidad, West Indies.

PubMed

Sankar-Maharaj, Sasha; Chen, Deryk; Hariharan, Seetharaman

2018-02-01

Postoperative shivering has been anecdotally observed to be frequent and severe in Cannabis smokers following general anesthesia in the Caribbean. The aim of this study was to compare the frequency and intensity of postoperative shivering in Cannabis users versus non-users. A prospective, cross-sectional, observational design was used. Demographic data were obtained. Patients were grouped into Cannabis users and non-users. All patients received standardized general anesthesia and were administered warmed fluids intraoperatively. Ambient room temperatures and clinical data were recorded. Patients' core body temperature was recorded at 10-minute intervals both in the operating room and the post-anesthesia care unit (PACU). Postoperatively an independent observer assessed the patients who had shivering using a scoring system ranging from 0 to 3. Treatment for shivering and post-treatment shivering scores were also recorded. Fifty-five patients were studied, of which 71% were male. There were 25 (45%) Cannabis users, of which 50% smoked < 5 joints per week, and 35% smoked >10 joints per week; 30 (55%) patients were non-users. The overall incidence of postoperative shivering was 36%; 16% had a shivering score of '3', 13% had '2' and 7% had a score of '1'. The incidence of postoperative shivering among Cannabis users was 40% while it was 33.3% in non-users. Also, 90% of Cannabis users had shivering scores of 2 and 3, compared to 70% of non-users. There was a higher incidence and intensity of shivering in Cannabis smokers, although the study could not establish a statistically significant difference in the frequency and severity of shivering between Cannabis users and non-users. Copyright © 2016 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.

Neuropsychological sex differences associated with age of initiated use among young adult cannabis users.

PubMed

Crane, Natania A; Schuster, Randi Melissa; Mermelstein, Robin J; Gonzalez, Raul

2015-01-01

Earlier initiation of cannabis use is associated with poorer neuropsychological functioning across several domains. Given well-documented sex differences in neuromaturation during adolescence, initiation of cannabis use during this time may affect neuropsychological functioning differently for males and females. In the current study, we examined sex differences in the relationship between age of initiated cannabis use and neuropsychological performance after controlling for amount of lifetime cannabis use in 44 male and 25 female young adult cannabis users. We found that an earlier age of initiated use was related to poorer episodic memory, especially immediate recall, in females, but not in males. On the other hand, we found that, surprisingly, an earlier age of initiated use was associated with better decision making overall. However, exploratory analyses found sex-specific factors associated with decision making and age of initiated use, specifically that attention-deficit/hyperactivity disorder (ADHD) symptoms in females may drive the relationship between an earlier age of initiated use and better decision making. Further, an earlier age of initiated use was associated with less education, a lower IQ, and fewer years of mother's education for females, but more lifetime cannabis use for males. Taken together, our findings suggest there are sex differences in the associations between age of initiated cannabis use and neuropsychological functioning. The current study provides preliminary evidence that males and females may have different neuropsychological vulnerabilities that place them at risk for initiating cannabis use and continued cannabis use, highlighting the importance of examining the impact of cannabis on neuropsychological functioning separately for males and females.

Risky cannabis use is associated with alexithymia, frontal lobe dysfunction, and impulsivity in young adult cannabis users.

PubMed

Lyvers, Michael; Jamieson, Reuben; Thorberg, Fred Arne

2013-01-01

Risky or problematic alcohol use by young adults has been found to be associated with factors such as alexithymia, frontal lobe dysfunction, reward sensitivity, and impulsivity. One interpretation is that these factors reflect inherent traits that predispose to risky substance use in general, a notion examined in the present study. Alexithymia, everyday frontal lobe functioning, sensitivity to reward and punishment, and impulsivity were examined in 138 young adult cannabis users who were divided into Low Risk (n = 99) and Risky (n = 39) users according to their Cannabis Use Disorder Identification Test (CUDIT) scores. Risky cannabis use was significantly positively associated with alexithymia, multiple signs of frontal lobe dysfunction in everyday life, and impulsivity. A broader pattern of dysfunction was indicated for risky cannabis use than for risky alcohol use in this sample. Findings are interpreted as likely reflecting not only inherent traits that predispose to risky substance use in general, but also perhaps residual effects of recent heavy cannabis use in the Risky user group. Longitudinal research is needed to disentangle these competing possibilities.

COMT val158met and 5-HTTLPR Genetic Polymorphisms Moderate Executive Control in Cannabis Users

PubMed Central

Verdejo-García, Antonio; Beatriz Fagundo, Ana; Cuenca, Aida; Rodriguez, Joan; Cuyás, Elisabet; Langohr, Klaus; de Sola Llopis, Susana; Civit, Ester; Farré, Magí; Peña-Casanova, Jordi; de la Torre, Rafael

2013-01-01

The adverse effects of cannabis use on executive functions are still controversial, fostering the need for novel biomarkers able to unveil individual differences in the cognitive impact of cannabis consumption. Two common genetic polymorphisms have been linked to the neuroadaptive impact of Δ9-tetrahydrocannabinol (THC) exposure and to executive functions in animals: the catechol-O-methyltransferase (COMT) gene val158met polymorphism and the SLC6A4 gene 5-HTTLPR polymorphism. We aimed to test if these polymorphisms moderate the harmful effects of cannabis use on executive function in young cannabis users. We recruited 144 participants: 86 cannabis users and 58 non-drug user controls. Both groups were genotyped and matched for genetic makeup, sex, age, education, and IQ. We used a computerized neuropsychological battery to assess different aspects of executive functions: sustained attention (CANTAB Rapid Visual Information Processing Test, RVIP), working memory (N-back), monitoring/shifting (CANTAB ID/ED set shifting), planning (CANTAB Stockings of Cambridge, SOC), and decision-making (Iowa Gambling Task, IGT). We used general linear model-based analyses to test performance differences between cannabis users and controls as a function of genotypes. We found that: (i) daily cannabis use is not associated with executive function deficits; and (ii) COMT val158met and 5-HTTLPR polymorphisms moderate the link between cannabis use and executive performance. Cannabis users carrying the COMT val/val genotype exhibited lower accuracy of sustained attention, associated with a more strict response bias, than val/val non-users. Cannabis users carrying the COMT val allele also committed more monitoring/shifting errors than cannabis users carrying the met/met genotype. Finally, cannabis users carrying the 5-HTTLPR s/s genotype had worse IGT performance than s/s non-users. COMT and SLC6A4 genes moderate the impact of cannabis use on executive functions. PMID:23449176

Cannabis withdrawal is common among treatment-seeking adolescents with cannabis dependence and major depression, and is associated with rapid relapse to dependence.

PubMed

Cornelius, Jack R; Chung, Tammy; Martin, Christopher; Wood, D Scott; Clark, Duncan B

2008-11-01

Recently, reports have suggested that cannabis withdrawal occurs commonly in adults with cannabis dependence, though it is unclear whether this extends to those with comorbid depression or to comorbid adolescents. We hypothesized that cannabis withdrawal would be common among our sample of comorbid adolescents and young adults, and that the presence of cannabis withdrawal symptoms would be associated with a self-reported past history of rapid reinstatement of cannabis dependence symptoms (rapid relapse). The participants in this study included 170 adolescents and young adults, including 104 with cannabis dependence, 32 with cannabis abuse, and 34 with cannabis use without dependence or abuse. All of these subjects demonstrated current depressive symptoms and cannabis use, and most demonstrated current DSM-IV major depressive disorder and current comorbid cannabis dependence. These subjects had presented for treatment for either of two double-blind, placebo-controlled trials involving fluoxetine. Cannabis withdrawal was the most commonly reported cannabis dependence criterion among the 104 subjects in our sample with cannabis dependence, being noted in 92% of subjects, using a two-symptom cutoff for determination of cannabis withdrawal. The most common withdrawal symptoms among those with cannabis dependence were craving (82%), irritability (76%), restlessness (58%), anxiety (55%), and depression (52%). Cannabis withdrawal symptoms (in the N=170 sample) were reported to have been associated with rapid reinstatement of cannabis dependence symptoms (rapid relapse). These findings suggest that cannabis withdrawal should be included as a diagnosis in the upcoming DSM-V, and should be listed in the upcoming criteria list for the DSM-V diagnostic category of cannabis dependence.

Attributes of long-term heavy cannabis users: a case-control study.

PubMed

Gruber, A J; Pope, H G; Hudson, J I; Yurgelun-Todd, D

2003-11-01

Although cannabis is the most widely used illicit drug in the United States, few recent American studies have examined the attributes of long-term heavy cannabis users. Using a case-control design, we obtained psychological and demographic measures on 108 individuals, age 30-55, who had smoked cannabis a mean of 18000 times and a minimum of 5000 times in their lives. We compared these heavy users to 72 age-matched control subjects who had smoked at least once, but no more than 50 times in their lives. We found no significant differences between the two groups on reported levels of income and education in their families of origin. However, the heavy users themselves reported significantly lower educational attainment (P < 0.001) and income (P = 0.003) than the controls, even after adjustment for a large number of potentially confounding variables. When asked to rate the subjective effects of cannabis on their cognition, memory, career, social life, physical health and mental health, large majorities of heavy users (66-90%) reported a 'negative effect'. On several measures of quality of life, heavy users also reported significantly lower levels of satisfaction than controls. Both objective and self-report measures suggest numerous negative features associated with long-term heavy cannabis use. Thus, it seems important to understand why heavy users continue to smoke regularly for years, despite acknowledging these negative effects. Such an understanding may guide the development of strategies to treat cannabis dependence.

Spatial working memory in heavy cannabis users: a functional magnetic resonance imaging study.

PubMed

Kanayama, Gen; Rogowska, Jadwiga; Pope, Harrison G; Gruber, Staci A; Yurgelun-Todd, Deborah A

2004-11-01

Many neuropsychological studies have documented deficits in working memory among recent heavy cannabis users. However, little is known about the effects of cannabis on brain activity. We assessed brain function among recent heavy cannabis users while they performed a working memory task. Functional magnetic resonance imaging was used to examine brain activity in 12 long-term heavy cannabis users, 6-36 h after last use, and in 10 control subjects while they performed a spatial working memory task. Regional brain activation was analyzed and compared using statistical parametric mapping techniques. Compared with controls, cannabis users exhibited increased activation of brain regions typically used for spatial working memory tasks (such as prefrontal cortex and anterior cingulate). Users also recruited additional regions not typically used for spatial working memory (such as regions in the basal ganglia). These findings remained essentially unchanged when re-analyzed using subjects' ages as a covariate. Brain activation showed little or no significant correlation with subjects' years of education, verbal IQ, lifetime episodes of cannabis use, or urinary cannabinoid levels at the time of scanning. Recent cannabis users displayed greater and more widespread brain activation than normal subjects when attempting to perform a spatial working memory task. This observation suggests that recent cannabis users may experience subtle neurophysiological deficits, and that they compensate for these deficits by "working harder"-calling upon additional brain regions to meet the demands of the task.

High School Students’ Use of Electronic Cigarettes to Vaporize Cannabis

PubMed Central

Kong, Grace; Camenga, Deepa R.; Cavallo, Dana A.; Krishnan-Sarin, Suchitra

2015-01-01

BACKGROUND AND OBJECTIVES: Electronic cigarette (e-cigarette) use is increasing rapidly among high school (HS) students. Of concern, e-cigarettes can be used to vaporize cannabis, although use rates among adolescents are unknown. We evaluated lifetime rates of using e-cigarettes to vaporize cannabis among all lifetime e-cigarette users (27.9%), all lifetime cannabis users (29.2%), and lifetime users of both e-cigarettes and cannabis (18.8%); common means of vaporizing cannabis including hash oil, wax infused with Δ-9-tetrahydrocannabinol (THC), and dried cannabis; and demographic predictors of using e-cigarettes to vaporize cannabis. METHODS: In the spring of 2014, 3847 Connecticut HS students completed an anonymous survey assessing e-cigarette and cannabis use. RESULTS: Vaporizing cannabis using e-cigarettes was common among lifetime e-cigarette users, lifetime cannabis users, and lifetime dual users (e-cigarette 18.0%, cannabis 18.4%, dual users 26.5%). Students reported using e-cigarettes to vaporize hash oil (e-cigarette 15.4%, cannabis 15.5%, dual users 22.9%) and wax infused with THC (e-cigarette 10.0%, cannabis 10.2%, dual users 14.8%) and using portable electronic vaporizers to vaporize dried cannabis leaves (e-cigarette 19.6%, lifetime cannabis 23.1%, lifetime dual users 29.1%). Binary logistic regression indicated that male students (odds ratio [OR] = 2.05), younger students (OR = 0.64), lifetime e-cigarette users (OR = 5.27), and lifetime cannabis users (OR = 40.89) were most likely to vaporize cannabis using e-cigarettes. Rates also differed by HS attended. CONCLUSIONS: Rates of vaporizing cannabis using e-cigarettes were high. These findings raise concerns about the lack of e-cigarette regulations and the potential use of e-cigarettes for purposes other than vaping nicotine. PMID:26347431

Telling true from false: cannabis users show increased susceptibility to false memories.

PubMed

Riba, J; Valle, M; Sampedro, F; Rodríguez-Pujadas, A; Martínez-Horta, S; Kulisevsky, J; Rodríguez-Fornells, A

2015-06-01

Previous studies on the neurocognitive impact of cannabis use have found working and declarative memory deficits that tend to normalize with abstinence. An unexplored aspect of cognitive function in chronic cannabis users is the ability to distinguish between veridical and illusory memories, a crucial aspect of reality monitoring that relies on adequate memory function and cognitive control. Using functional magnetic resonance imaging, we show that abstinent cannabis users have an increased susceptibility to false memories, failing to identify lure stimuli as events that never occurred. In addition to impaired performance, cannabis users display reduced activation in areas associated with memory processing within the lateral and medial temporal lobe (MTL), and in parietal and frontal brain regions involved in attention and performance monitoring. Furthermore, cannabis consumption was inversely correlated with MTL activity, suggesting that the drug is especially detrimental to the episodic aspects of memory. These findings indicate that cannabis users have an increased susceptibility to memory distortions even when abstinent and drug-free, suggesting a long-lasting compromise of memory and cognitive control mechanisms involved in reality monitoring.

Depression symptoms associated with cannabis dependence in an adolescent American Indian community sample.

PubMed

Gilder, David A; Ehlers, Cindy L

2012-01-01

Depression and substance use disorders, including cannabis dependence, arise during adolescence, are frequently comorbid, and represent major health burdens in the general US population. Yet little is known about the association of depression symptoms with cannabis and other substance use and use disorders in Native American adolescents. To investigate the comorbidity of cannabis use and depression symptoms in Native American adolescents. This study used the Children's Semi-Structured Assessment for the Genetics of Alcoholism (Adolescent Version) to obtain lifetime DSM-III-R diagnoses from a community sample of 202 (98 boys, 104 girls) American Indian adolescents living on contiguous reservations. Thirteen percent of boys and 38% of girls had a lifetime DSM-III-R major depression disorder (MDD) independent of substance use. Fifteen percent of boys and 41% of girls had a major depression episode (MDE) either coincident with or independent of cannabis use. MDE and several individual depression symptoms were significantly associated with cannabis dependence in boys but not in girls. The median ages of onset of MDE were the same in the boys and girls who had experienced both depression and cannabis use. These findings suggest that the association of depression with cannabis dependence is more significant in boys than girls in this population of adolescents. Understanding comorbidity between depression and cannabis use is important in order to disentangle the etiological relationship between the two and also for designing more effective treatment and prevention strategies, particularly in Native Americans who are at high risk for both disorders. Copyright © American Academy of Addiction Psychiatry.

Adolescent exposure to cannabis as a risk factor for psychiatric disorders.

PubMed

Rubino, Tiziana; Zamberletti, Erica; Parolaro, Daniela

2012-01-01

Adolescence represents a critical period for brain development and the endocannabinoid system plays a crucial role in the regulation of neuronal refinement during this period. Cannabis is the most consumed drug among adolescent people and its heavy use may affect maturational refinement by disrupting the regulatory role of the endocannabinoid system. In animals, adolescent cannabinoid exposure has been reported to cause long-term impairment in specific components of learning and memory and to differentially affect emotional reactivity with milder effects on anxiety behaviour and more pronounced effects on depression-like behaviour. Moreover, adolescent exposure to cannabinoids might represent a risk factor for developing psychotic-like symptoms at adulthood. Also epidemiological studies suggest that heavy adolescent cannabis use may increase the risk of cognitive abnormalities, psychotic illness, mood disorders and other illicit substance use later in life. In conclusion, the available data point to the hypothesis that heavy cannabis use in adolescence could increase the risk of developing psychiatric disorders, especially in people who already have a vulnerability to develop a psychiatric syndrome. Only few papers have investigated the neurobiological substrates of this vulnerability, thus further studies are needed to clarify the molecular mechanisms underlying the effect of cannabis on the adolescent brain.

Different psychological effects of cannabis use in adolescents at genetic high risk for schizophrenia and with attention deficit/hyperactivity disorder (ADHD).

PubMed

Hollis, Chris; Groom, Madeleine J; Das, Debasis; Calton, Tim; Bates, Alan T; Andrews, Hayley K; Jackson, Georgina M; Liddle, Peter F

2008-10-01

Controversy exists regarding whether young people at risk for schizophrenia are at increased risk of adverse mental effects of cannabis use. We examined cannabis use and mental health functioning in three groups of young people aged 14-21; 36 non-psychotic siblings of adolescents with schizophrenia (genetic high risk group), 25 adolescents with attention deficit hyperactivity disorder (ADHD) and 72 healthy controls. The groups were sub-divided into 'users' and 'non-users' of cannabis based on how often they had used cannabis previously. Mental health functioning was quantified by creating a composite index derived from scores on the Schizotypal Personality Questionnaire (SPQ), Strengths and Difficulties Questionnaire (SDQ) and Global Assessment of Function (GAF). A significant positive association between cannabis use and mental health disturbance was confined to young people at genetic high risk for schizophrenia. To determine whether the relationship was specific to particular dimensions of mental health function, a second composite index was created based on scores from the SPQ Disorganisation and SDQ hyperactivity-inattention sub-scales. Again, there was a significant positive association between cannabis use and factor scores which was specific to the genetic high risk group. There was a trend for this association to be negative in the ADHD group (p=0.07). The findings support the view that young people at genetic high risk for schizophrenia are particularly vulnerable to mental health problems associated with cannabis use. Further research is needed to investigate the basis of relationships between cannabis and mental health in genetically vulnerable individuals.

Cannabis use disorders are comparatively prevalent among nonwhite racial/ethnic groups and adolescents: a national study.

PubMed

Wu, Li-Tzy; Brady, Kathleen T; Mannelli, Paolo; Killeen, Therese K

2014-03-01

The racial/ethnic composition of the US population is shifting, with the nonwhite population growing faster than whites. We examined cannabis use disorder (CUD) prevalences and correlates in seven racial/ethnic groups. We included cannabis use (CU) prevalence as a comparison. Data were from the 2005-2011 National Surveys on Drug Use and Health (N = 394,400). Substance use among respondents aged ≥12 years was assessed by computer-assisted, self-interviewing methods. The following were included as control variables: age, sex, family income, government assistance, county type, residential stability, major depressive episode history, arrest history, nicotine dependence, alcohol disorder, and survey year. Past-year CU prevalence increased significantly from 10.45% in 2005 to 11.41-11.54% during 2009-2011. Compared with whites, mixed-race individuals had higher odds of CU; Asian Americans and Hispanics had lower odds of CU. There were no significant yearly changes in CUD prevalence in the sample during 2005-2011 (1.58-1.73%). Compared with whites, individuals who were mixed-race, black, and Native American had higher odds of CUD; Asian Americans had lower odds. In aggregate, 15.35% of past-year cannabis users met criteria for a CUD in the 12-month period. Past-year cannabis users who were black, Native American, Hispanic, or Asian American had higher odds of CUD than white users. In each racial/ethnic group, adolescent cannabis users generally showed greater odds of CUD than adult users. Behavioral health indicators (major depressive episode, arrest history, nicotine dependence, alcohol disorder) were associated with CU and CUD. In conclusion, CUD disproportionally affects nonwhite groups and youth. Copyright © 2013 Elsevier Ltd. All rights reserved.

Adverse Effects of Cannabis on Adolescent Brain Development: A Longitudinal Study

PubMed Central

Camchong, Jazmin; Lim, Kelvin O; Kumra, Sanjiv

2017-01-01

Abstract Cannabis is widely perceived as a safe recreational drug and its use is increasing in youth. It is important to understand the implications of cannabis use during childhood and adolescence on brain development. This is the first longitudinal study that compared resting functional connectivity of frontally mediated networks between 43 healthy controls (HCs; 20 females; age M = 16.5 ± 2.7) and 22 treatment-seeking adolescents with cannabis use disorder (CUD; 8 females; age M = 17.6 ± 2.4). Increases in resting functional connectivity between caudal anterior cingulate cortex (ACC) and superior frontal gyrus across time were found in HC, but not in CUD. CUD showed a decrease in functional connectivity between caudal ACC and dorsolateral and orbitofrontal cortices across time. Lower functional connectivity between caudal ACC cortex and orbitofrontal cortex at baseline predicted higher amounts of cannabis use during the following 18 months. Finally, high amounts of cannabis use during the 18-month interval predicted lower intelligence quotient and slower cognitive function measured at follow-up. These data provide compelling longitudinal evidence suggesting that repeated exposure to cannabis during adolescence may have detrimental effects on brain resting functional connectivity, intelligence, and cognitive function. PMID:26912785

Distress intolerance moderation of motivated attention to cannabis and negative stimuli after induced stress among cannabis users: an ERP study.

PubMed

Macatee, Richard J; Okey, Sarah A; Albanese, Brian J; Schmidt, Norman B; Cougle, Jesse R

2018-05-07

Prevalence of cannabis use is increasing, but many regular users do not develop cannabis use disorder (CUD); thus, CUD risk identification among current users is vital for targeted intervention development. Existing data suggest that high distress intolerance (DI), an individual difference reflective of the ability to tolerate negative affect, may be linked to CUD, but no studies have tested possible neurophysiological mechanisms. Increased motivated attentional processing of cannabis and negative emotional stimuli as indexed by neurophysiology [i.e. the late positive potential (LPP)], particularly during acute stress, may contribute to CUD among high DI users. Frequent cannabis users with high (n = 61) and low DI (n = 44) viewed cannabis, negative, and matched neutral images during electroencephalography (EEG) recording before and after a laboratory stressor. Cannabis cue-elicited modulation of the 1000- to 3000-milliseconds LPP was larger in high DI users at post-stressor only, although the effect was only robust in the 1000- to 2000-milliseconds window. Further, modulation magnitude in the high DI group covaried with stress-relief craving and some CUD indices in the 400- to 1000-milliseconds and 1000- to 3000-milliseconds windows, respectively. No significant effects of DI on negative stimuli-elicited LPP modulation were found, although inverse associations with some CUD indices were observed. Finally, exploratory analyses revealed some evidence for DI moderation of the relation between subjective stressor reactivity and negative stimuli-elicited LPP modulation such that greater stressor reactivity was associated with blunted versus enhanced modulation in the high and low DI groups, respectively. Negative and cannabis stimuli-elicited LPP modulation appear to index distinct, CUD-relevant neural processes in high DI cannabis users. © 2018 Society for the Study of Addiction.

Sizing the cannabis market: a demand-side and user-specific approach in seven European countries.

PubMed

van Laar, Margriet; Frijns, Tom; Trautmann, Franz; Lombi, Linda

2013-06-01

Demand-based estimates of total cannabis consumption rarely consider differences among different user types and variation across countries. To describe cannabis consumption patterns and estimate annual consumption for different user types across EU Member States, a web survey in Bulgaria, Czech Republic, Italy, the Netherlands, Portugal, Sweden and United Kingdom (England & Wales) collected data on cannabis use patterns from 3,922 persons who had consumed cannabis at least once in the past year. They were classified into four groups based on their number of use days in the past 12 months: infrequent users or chippers (<11 days), occasional users (11-50 days), regular users (51-250 days) and intensive users (>250 days). User type specific data on typical amounts consumed were matched with data on numbers of users per user type estimated from existing population surveys, taking differences in mode of consumption, age and gender into account. Estimates were supplemented with data from populations of problem users to compensate for under coverage. Results showed remarkably consistent differences among user groups across countries. Both the average number of units consumed per typical use day and the average amount of cannabis consumed per unit increased across user types of increasing frequency of use. In all countries except Portugal, intensive users formed the smallest group of cannabis users but were responsible for the largest part of total annual cannabis consumption. Annual cannabis consumption varied across countries but confidence intervals were wide. Results are compared with previous estimates and discussed in the context of improving estimation methods.

Swiss Adolescents' and Adults' Perceptions of Cannabis Use: A Qualitative Study

ERIC Educational Resources Information Center

Menghrajani, P.; Klaue, K.; Dubois-Arber, F.; Michaud, P.-A.

2005-01-01

Few studies have attempted to investigate the nature of adolescents and adults conceptions and perceptions of cannabis use. Our objectives were to explore adolescent and adult perception of use and misuse of cannabis, and their opinions and beliefs about the current legal context and preventive strategies. We used focus group discussions with four…

Episodic foresight deficits in regular, but not recreational, cannabis users.

PubMed

Mercuri, Kimberly; Terrett, Gill; Henry, Julie D; Curran, H Valerie; Elliott, Morgan; Rendell, Peter G

2018-06-01

Cannabis use is associated with a range of neurocognitive deficits, including impaired episodic memory. However, no study to date has assessed whether these difficulties extend to episodic foresight, a core component of which is the ability to mentally travel into one's personal future. This is a particularly surprising omission given that episodic memory is considered to be critical to engage episodic foresight. In the present study, we provide the first test of how episodic foresight is affected in the context of differing levels of cannabis use, and the degree to which performance on a measure of this construct is related to episodic memory. Fifty-seven regular cannabis users (23 recreational, 34 regular) and 57 controls were assessed using an adapted version of the Autobiographical Interview. The results showed that regular-users exhibited greater impairment of episodic foresight and episodic memory than both recreational-users and cannabis-naïve controls. These data therefore show for the first time that cannabis-related disruption of cognitive functioning extends to the capacity for episodic foresight, and they are discussed in relation to their potential implications for functional outcomes in this group.

Patterns of cannabis use during adolescence and their association with harmful substance use behaviour: findings from a UK birth cohort

PubMed Central

Collin, Simon M; Munafò, Marcus R; MacLeod, John; Hickman, Matthew; Heron, Jon

2017-01-01

Background Evidence on the role of cannabis as a gateway drug is inconsistent. We characterise patterns of cannabis use among UK teenagers aged 13–18 years, and assess their influence on problematic substance use at age 21 years. Methods We used longitudinal latent class analysis to derive trajectories of cannabis use from self-report measures in a UK birth cohort. We investigated (1) factors associated with latent class membership and (2) whether latent class membership predicted subsequent nicotine dependence, harmful alcohol use and recent use of other illicit drugs at age 21 years. Results 5315 adolescents had three or more measures of cannabis use from age 13 to 18 years. Cannabis use patterns were captured as four latent classes corresponding to ‘non-users’ (80.1%), ‘late-onset occasional’ (14.2%), ‘early-onset occasional’ (2.3%) and ‘regular’ users (3.4%). Sex, mother's substance use, and child's tobacco use, alcohol consumption and conduct problems were strongly associated with cannabis use. At age 21 years, compared with the non-user class, late-onset occasional, early-onset occasional and regular cannabis user classes had higher odds of nicotine dependence (OR=3.5, 95% CI 0.7 to 17.9; OR=12.1, 95% CI 1.0 to 150.3; and OR=37.2, 95% CI 9.5 to 144.8, respectively); harmful alcohol consumption (OR=2.6, 95% CI 1.5 to 4.3; OR=5.0, 95% CI 2.1 to 12.1; and OR=2.6, 95% CI 1.0 to 7.1, respectively); and other illicit drug use (OR=22.7, 95% CI 11.3 to 45.7; OR=15.9, 95% CI 3.9 to 64.4; and OR=47.9, 95% CI 47.9 to 337.0, respectively). Conclusions One-fifth of the adolescents in our sample followed a pattern of occasional or regular cannabis use, and these young people were more likely to progress to harmful substance use behaviours in early adulthood. PMID:28592420

Patterns of cannabis use during adolescence and their association with harmful substance use behaviour: findings from a UK birth cohort.

PubMed

Taylor, Michelle; Collin, Simon M; Munafò, Marcus R; MacLeod, John; Hickman, Matthew; Heron, Jon

2017-08-01

Evidence on the role of cannabis as a gateway drug is inconsistent. We characterise patterns of cannabis use among UK teenagers aged 13-18 years, and assess their influence on problematic substance use at age 21 years. We used longitudinal latent class analysis to derive trajectories of cannabis use from self-report measures in a UK birth cohort. We investigated (1) factors associated with latent class membership and (2) whether latent class membership predicted subsequent nicotine dependence, harmful alcohol use and recent use of other illicit drugs at age 21 years. 5315 adolescents had three or more measures of cannabis use from age 13 to 18 years. Cannabis use patterns were captured as four latent classes corresponding to 'non-users' (80.1%), 'late-onset occasional' (14.2%), 'early-onset occasional' (2.3%) and 'regular' users (3.4%). Sex, mother's substance use, and child's tobacco use, alcohol consumption and conduct problems were strongly associated with cannabis use. At age 21 years, compared with the non-user class, late-onset occasional, early-onset occasional and regular cannabis user classes had higher odds of nicotine dependence (OR=3.5, 95% CI 0.7 to 17.9; OR=12.1, 95% CI 1.0 to 150.3; and OR=37.2, 95% CI 9.5 to 144.8, respectively); harmful alcohol consumption (OR=2.6, 95% CI 1.5 to 4.3; OR=5.0, 95% CI 2.1 to 12.1; and OR=2.6, 95% CI 1.0 to 7.1, respectively); and other illicit drug use (OR=22.7, 95% CI 11.3 to 45.7; OR=15.9, 95% CI 3.9 to 64.4; and OR=47.9, 95% CI 47.9 to 337.0, respectively). One-fifth of the adolescents in our sample followed a pattern of occasional or regular cannabis use, and these young people were more likely to progress to harmful substance use behaviours in early adulthood. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Performance of Young Adult Cannabis Users on Neurocognitive Measures of Impulsive Behavior and their Relationship to Symptoms of Cannabis Use Disorders

PubMed Central

Gonzalez, Raul; Schuster, Randi Melissa; Mermelstein, Robin J.; Vassileva, Jasmin; Martin, Eileen M.; Diviak, Kathleen R.

2012-01-01

Recent studies suggest that abstinent cannabis users show deficits on neurocognitive laboratory tasks of impulsive behavior. But results are mixed and less is known on the performance of non-treatment seeking, young adult cannabis users. Importantly, relationships between performance on measures of impulsive behavior and symptoms of cannabis addiction remain relatively unexplored. We compared young adult current cannabis users (CU, n = 65) and non-using controls (NU, n = 65) on several laboratory measures of impulsive behavior, as well as on a measure of episodic memory commonly impacted by cannabis use. The CU group performed more poorly than the NU group on the Hopkins Verbal Learning Test-Revised Total Immediate Recall and Delayed Recall. No significant differences were observed on the measures of impulsive behavior (i.e., Iowa Gambling Task [IGT], Go-Stop Task, Monetary Choice Questionnaire, Balloon Analogue Risk Task). We examined relationships between neurocognitive performance and symptoms of cannabis use disorder symptoms (DSM-IV CUD) among the CU group, which revealed that poorer IGT performance was associated with more symptoms of DSM-IV CUD. Our results show poorer memory performance among young adult cannabis users relative to healthy controls, but no differences on measures of impulsive behavior. However, performance on a specific type of impulsive behavior (i.e., poorer decision-making) was associated with more cannabis use disorder symptoms. These results provide preliminary evidence to suggest that decision-making deficits may be more strongly associated with problems experienced from cannabis use, rather than solely being a consequence of cannabis use, per se. PMID:22882144

Differential responses to cannabis potency: a typology of users based on self-reported consumption behaviour.

PubMed

Korf, Dirk J; Benschop, Annemieke; Wouters, Marije

2007-05-01

To determine whether a classification of cannabis users into different types can help to clarify the relationship between cannabis potency and consumption behaviour, harmful physical effects and psychological dependency. A field sample of 388 respondents was recruited who had smoked cannabis at least once in the past month. They were contacted and interviewed in 28 cannabis coffee shops located in five Dutch cities. Data were collected with an assisted self-completion questionnaire. Cluster analysis was performed using the k-means method. Various ways were observed in which cannabis users in natural settings adjusted their intake to the potency of the drug. Cluster analysis identified three broad types of cannabis users. The strongest high type was the youngest, consumed the highest monthly dose, inhaled higher-potency cannabis more deeply, and scored highest on psychological cannabis dependency. The consistent high type preferred milder cannabis, consumed the lowest monthly dose, and compensated for stronger cannabis by inhaling less deeply and smoking less. The steady quantity type was the oldest, usually smoked alone, consumed an intermediate monthly dose, and did not tend to adjust the depth of inhalation to the potency of the cannabis. The results suggest that this typology might also reflect three successive stages in the careers of continuing cannabis users. Laboratory studies to assess the effects of higher THC concentrations on external and internal exposure to cannabis should allow for the possibility that the types of users studied can affect the results.

Early Cannabis Use, Polygenic Risk Score for Schizophrenia and Brain Maturation in Adolescence.

PubMed

French, Leon; Gray, Courtney; Leonard, Gabriel; Perron, Michel; Pike, G Bruce; Richer, Louis; Séguin, Jean R; Veillette, Suzanne; Evans, C John; Artiges, Eric; Banaschewski, Tobias; Bokde, Arun W L; Bromberg, Uli; Bruehl, Ruediger; Buchel, Christian; Cattrell, Anna; Conrod, Patricia J; Flor, Herta; Frouin, Vincent; Gallinat, Jurgen; Garavan, Hugh; Gowland, Penny; Heinz, Andreas; Lemaitre, Herve; Martinot, Jean-Luc; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Pangelinan, Melissa Marie; Poustka, Luise; Rietschel, Marcella; Smolka, Michael N; Walter, Henrik; Whelan, Robert; Timpson, Nic J; Schumann, Gunter; Smith, George Davey; Pausova, Zdenka; Paus, Tomáš

2015-10-01

Cannabis use during adolescence is known to increase the risk for schizophrenia in men. Sex differences in the dynamics of brain maturation during adolescence may be of particular importance with regard to vulnerability of the male brain to cannabis exposure. To evaluate whether the association between cannabis use and cortical maturation in adolescents is moderated by a polygenic risk score for schizophrenia. Observation of 3 population-based samples included initial analysis in 1024 adolescents of both sexes from the Canadian Saguenay Youth Study (SYS) and follow-up in 426 adolescents of both sexes from the IMAGEN Study from 8 European cities and 504 male youth from the Avon Longitudinal Study of Parents and Children (ALSPAC) based in England. A total of 1577 participants (aged 12-21 years; 899 [57.0%] male) had (1) information about cannabis use; (2) imaging studies of the brain; and (3) a polygenic risk score for schizophrenia across 108 genetic loci identified by the Psychiatric Genomics Consortium. Data analysis was performed from March 1 through December 31, 2014. Cortical thickness derived from T1-weighted magnetic resonance images. Linear regression tests were used to assess the relationships between cannabis use, cortical thickness, and risk score. Across the 3 samples of 1574 participants, a negative association was observed between cannabis use in early adolescence and cortical thickness in male participants with a high polygenic risk score. This observation was not the case for low-risk male participants or for the low- or high-risk female participants. Thus, in SYS male participants, cannabis use interacted with risk score vis-à-vis cortical thickness (P = .009); higher scores were associated with lower thickness only in males who used cannabis. Similarly, in the IMAGEN male participants, cannabis use interacted with increased risk score vis-à-vis a change in decreasing cortical thickness from 14.5 to 18.5 years of age (t137 = -2.36; P�

Early Cannabis Use, Polygenic Risk Score for Schizophrenia, and Brain Maturation in Adolescence

PubMed Central

French, Leon; Gray, Courtney; Leonard, Gabriel; Perron, Michel; Pike, G. Bruce; Richer, Louis; Séguin, Jean R.; Veillette, Suzanne; Evans, C. John; Artiges, Eric; Banaschewski, Tobias; Bokde, Arun W. L.; Bromberg, Uli; Bruehl, Ruediger; Buchel, Christian; Cattrell, Anna; Conrod, Patricia J.; Flor, Herta; Frouin, Vincent; Gallinat, Jurgen; Garavan, Hugh; Gowland, Penny; Heinz, Andreas; Lemaitre, Herve; Martinot, Jean-Luc; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Pangelinan, Melissa Marie; Poustka, Luise; Rietschel, Marcella; Smolka, Michael N.; Walter, Henrik; Whelan, Robert; Timpson, Nic J.; Schumann, Gunter; Smith, George Davey; Pausova, Zdenka; Paus, Tomáš

2016-01-01

IMPORTANCE Cannabis use during adolescence is known to increase the risk for schizophrenia in men. Sex differences in the dynamics of brain maturation during adolescence may be of particular importance with regard to vulnerability of the male brain to cannabis exposure. OBJECTIVE To evaluate whether the association between cannabis use and cortical maturation in adolescents is moderated by a polygenic risk score for schizophrenia. DESIGN, SETTING, AND PARTICIPANTS Observation of 3 population-based samples included initial analysis in 1024 adolescents of both sexes from the Canadian Saguenay Youth Study (SYS) and follow-up in 426 adolescents of both sexes from the IMAGEN Study from 8 European cities and 504 male youth from the Avon Longitudinal Study of Parents and Children (ALSPAC) based in England. A total of 1577 participants (aged 12–21 years; 899 [57.0%] male) had (1) information about cannabis use; (2) imaging studies of the brain; and (3) a polygenic risk score for schizophrenia across 108 genetic loci identified by the Psychiatric Genomics Consortium. Data analysis was performed from March 1 through December 31, 2014. MAIN OUTCOMES AND MEASURES Cortical thickness derived from T1-weighted magnetic resonance images. Linear regression tests were used to assess the relationships between cannabis use, cortical thickness, and risk score. RESULTS Across the 3 samples of 1574 participants, a negative association was observed between cannabis use in early adolescence and cortical thickness in male participants with a high polygenic risk score. This observation was not the case for low-risk male participants or for the low- or high-risk female participants. Thus, in SYS male participants, cannabis use interacted with risk score vis-à-vis cortical thickness (P = .009); higher scores were associated with lower thickness only in males who used cannabis. Similarly, in the IMAGEN male participants, cannabis use interacted with increased risk score vis-à-vis a change in

A Cross-Sectional Survey of Medical Cannabis Users: Patterns of Use and Perceived Efficacy.

PubMed

Sexton, Michelle; Cuttler, Carrie; Finnell, John S; Mischley, Laurie K

2016-01-01

Background: The political climate around Cannabis as a medicine is rapidly changing. Legislators are adopting policies regarding appropriate medical applications, while the paucity of research may make policy decisions around conditions for which Cannabis is an effective medicine difficult. Methods: An anonymous online survey was developed to query medical Cannabis users about the conditions they use Cannabis to treat, their use patterns, perception of efficacy, and physical and mental health. Participants were recruited through social media and Cannabis dispensaries in Washington State. Results: A total of 1429 participants identified as medical Cannabis users. The most frequently reported conditions for which they used Cannabis were pain (61.2%), anxiety (58.1%), depression (50.3%), headache/migraine (35.5%), nausea (27.4%), and muscle spasticity (18.4%). On average, participants reported an 86% reduction in symptoms as a result of Cannabis use; 59.8% of medical users reported using Cannabis as an alternative to pharmaceutical prescriptions. Global health scores were on par with the general population for mental health and physical health. Conclusions: While patient-reported outcomes favor strong efficacy for a broad range of symptoms, many medical users are using Cannabis without physician supervision and for conditions for which there is no formal research to support the use of Cannabis (e.g., depression and anxiety). Future research and public policy should attempt to reduce the incongruence between approved and actual use.

Mismatch Negativity and P50 Sensory Gating in Abstinent Former Cannabis Users

PubMed Central

Broyd, Samantha J.; Greenwood, Lisa-marie; van Hell, Hendrika H.; Croft, Rodney J.; Coyle, Hannah; Lee-Bates, Ben; Todd, Juanita; Johnstone, Stuart J.; Michie, Patricia T.; Solowij, Nadia

2016-01-01

Prolonged heavy exposure to cannabis is associated with impaired cognition and brain functional and structural alterations. We recently reported attenuated mismatch negativity (MMN) and altered P50 sensory gating in chronic cannabis users. This study investigated the extent of brain functional recovery (indexed by MMN and P50) in chronic users after cessation of use. Eighteen ex-users (median 13.5 years prior regular use; median 3.5 years abstinence) and 18 nonusers completed (1) a multifeature oddball task with duration, frequency, and intensity deviants and (2) a P50 paired-click paradigm. Trend level smaller duration MMN amplitude and larger P50 ratios (indicative of poorer sensory gating) were observed in ex-users compared to controls. Poorer P50 gating correlated with prior duration of cannabis use. Duration of abstinence was positively correlated with duration MMN amplitude, even after controlling for age and duration of cannabis use. Impaired sensory gating and attenuated MMN amplitude tended to persist in ex-users after prolonged cessation of use, suggesting a lack of full recovery. An association with prolonged duration of prior cannabis use may indicate persistent cannabis-related alterations to P50 sensory gating. Greater reductions in MMN amplitude with increasing abstinence (positive correlation) may be related to either self-medication or an accelerated aging process. PMID:27019754

Are changes in drinking related to changes in cannabis use among Swedish adolescents? A time-series analysis for the period 1989-2016.

PubMed

Gripe, Isabella; Danielsson, Anna-Karin; Ramstedt, Mats

2018-04-21

To examine if changes in alcohol consumption are associated with changes in cannabis use among Swedish adolescents in a period of diverging trends, and to investigate if cannabis and alcohol act as complements or substitutes. Data comprise a nationally representative annual school survey of alcohol and drug habits among Swedish 9th-grade students (aged 15-16 years) covering years 1989-2016 (n = 149 603). Alcohol and cannabis use were measured concurrently and alcohol consumption was measured in litres of 100% alcohol per year. Frequency of cannabis use was transformed into a mean using category mid-points. Autoregressive integrated moving average (ARIMA) time-series analysis was used to estimate the association between cannabis and alcohol use. To elucidate changes in the association during the study period, two subperiods (2000-16 and 1989-99) were analysed. There was a positive and statistically significant association between changes in alcohol consumption and changes in frequency of cannabis use among cannabis users for the period 1989-2016. A 1-litre increase in mean alcohol consumption was associated with a 0.28 increase in frequency of cannabis use (P = 0.010). The corresponding increase for the period 1989-99 was 0.52 (P = 0.003). When restricting the analysis to 2000-16, the association was not statistically significant (P = 0.735). When analysing all adolescents we found no statistically significant association between changes in alcohol consumption and changes in frequency of cannabis use. From 1989 to 2016 there appears to be a positive association between alcohol and cannabis consumption among Swedish adolescents who use cannabis. This association seems to have become weaker over time, suggesting that alcohol and cannabis are neither substitutes nor complements among Swedish adolescents and that the recent decline in youth drinking is not associated with the increase in frequency of cannabis use. © 2018 Society for the Study of Addiction.

Poorer frontolimbic white matter integrity is associated with chronic cannabis use, FAAH genotype, and increased depressive and apathy symptoms in adolescents and young adults.

PubMed

Shollenbarger, Skyler G; Price, Jenessa; Wieser, Jon; Lisdahl, Krista

2015-01-01

The heaviest period of cannabis use coincides with ongoing white matter (WM) maturation. Further, cannabis-related changes may be moderated by FAAH genotype (rs324420). We examined the association between cannabis use and FAAH genotype on frontolimbic WM integrity in adolescents and emerging adults. We then tested whether observed WM abnormalities were linked with depressive or apathy symptoms. Participants included 37 cannabis users and 37 healthy controls (33 female; ages 18-25). Multiple regressions examined the independent and interactive effects of variables on WM integrity. Regular cannabis users demonstrated reduced WM integrity in the bilateral uncinate fasciculus (UNC) (MD, right: p = .009 and left: p = .009; FA, right: p = .04 and left: p = .03) and forceps minor (fMinor) (MD, p = .03) compared to healthy controls. Marginally reduced WM integrity in the cannabis users was found in the left anterior thalamic radiation (ATR) (FA, p = .08). Cannabis group ∗ FAAH genotype interaction predicted WM integrity in bilateral ATR (FA, right: p = .05 and left: p = .001) and fMinor (FA, p = .02). In cannabis users, poorer WM integrity was correlated with increased symptoms of depression and apathy in bilateral ATR and UNC. Consistent with prior findings, cannabis use was associated with reduced frontolimbic WM integrity. WM integrity was also moderated by FAAH genotype, in that cannabis-using FAAH C/C carriers and A carrying controls had reduced WM integrity compared to control C/C carriers. Observed frontolimbic white matter abnormalities were linked with increased depressive and apathy symptoms in the cannabis users.

Poorer frontolimbic white matter integrity is associated with chronic cannabis use, FAAH genotype, and increased depressive and apathy symptoms in adolescents and young adults

PubMed Central

Shollenbarger, Skyler G.; Price, Jenessa; Wieser, Jon; Lisdahl, Krista

2015-01-01

Background The heaviest period of cannabis use coincides with ongoing white matter (WM) maturation. Further, cannabis-related changes may be moderated by FAAH genotype (rs324420). We examined the association between cannabis use and FAAH genotype on frontolimbic WM integrity in adolescents and emerging adults. We then tested whether observed WM abnormalities were linked with depressive or apathy symptoms. Methods Participants included 37 cannabis users and 37 healthy controls (33 female; ages 18–25). Multiple regressions examined the independent and interactive effects of variables on WM integrity. Results Regular cannabis users demonstrated reduced WM integrity in the bilateral uncinate fasciculus (UNC) (MD, right: p = .009 and left: p = .009; FA, right: p = .04 and left: p = .03) and forceps minor (fMinor) (MD, p = .03) compared to healthy controls. Marginally reduced WM integrity in the cannabis users was found in the left anterior thalamic radiation (ATR) (FA, p = .08). Cannabis group ∗ FAAH genotype interaction predicted WM integrity in bilateral ATR (FA, right: p = .05 and left: p = .001) and fMinor (FA, p = .02). In cannabis users, poorer WM integrity was correlated with increased symptoms of depression and apathy in bilateral ATR and UNC. Conclusions Consistent with prior findings, cannabis use was associated with reduced frontolimbic WM integrity. WM integrity was also moderated by FAAH genotype, in that cannabis-using FAAH C/C carriers and A carrying controls had reduced WM integrity compared to control C/C carriers. Observed frontolimbic white matter abnormalities were linked with increased depressive and apathy symptoms in the cannabis users. PMID:26106535

fMRI study of neural sensitization to hedonic stimuli in long‐term, daily cannabis users

PubMed Central

Dunlop, Joseph; Ketcherside, Ariel; Baine, Jessica; Rhinehardt, Tyler; Kuhn, Brittany; DeWitt, Sam; Alvi, Talha

2016-01-01

Abstract Although there is emergent evidence illustrating neural sensitivity to cannabis cues in cannabis users, the specificity of this effect to cannabis cues as opposed to a generalized hyper‐sensitivity to hedonic stimuli has not yet been directly tested. Using fMRI, we presented 53 daily, long‐term cannabis users and 68 non‐using controls visual and tactile cues for cannabis, a natural reward, and, a sensory‐perceptual control object to evaluate brain response to hedonic stimuli in cannabis users. The results showed an interaction between group and reward type such that the users had greater response during cannabis cues relative to natural reward cues (i.e., fruit) in the orbitofrontal cortex, striatum, anterior cingulate gyrus, and ventral tegmental area compared to non‐users (cluster‐threshold z = 2.3, P < 0.05). In the users, there were positive brain‐behavior correlations between neural response to cannabis cues in fronto‐striatal‐temporal regions and subjective craving, marijuana‐related problems, withdrawal symptoms, and levels of THC metabolites (cluster‐threshold z = 2.3, P < 0.05). These findings demonstrate hyper‐responsivity, and, specificity of brain response to cannabis cues in long‐term cannabis users that are above that of response to natural reward cues. These observations are concordant with incentive sensitization models suggesting sensitization of mesocorticolimbic regions and disruption of natural reward processes following drug use. Although the cross‐sectional nature of this study does not provide information on causality, the positive correlations between neural response and indicators of cannabis use (i.e., THC levels) suggest that alterations in the reward system are, in part, related to cannabis use. Hum Brain Mapp 37:3431–3443, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:27168331

fMRI study of neural sensitization to hedonic stimuli in long-term, daily cannabis users.

PubMed

Filbey, Francesca M; Dunlop, Joseph; Ketcherside, Ariel; Baine, Jessica; Rhinehardt, Tyler; Kuhn, Brittany; DeWitt, Sam; Alvi, Talha

2016-10-01

Although there is emergent evidence illustrating neural sensitivity to cannabis cues in cannabis users, the specificity of this effect to cannabis cues as opposed to a generalized hyper-sensitivity to hedonic stimuli has not yet been directly tested. Using fMRI, we presented 53 daily, long-term cannabis users and 68 non-using controls visual and tactile cues for cannabis, a natural reward, and, a sensory-perceptual control object to evaluate brain response to hedonic stimuli in cannabis users. The results showed an interaction between group and reward type such that the users had greater response during cannabis cues relative to natural reward cues (i.e., fruit) in the orbitofrontal cortex, striatum, anterior cingulate gyrus, and ventral tegmental area compared to non-users (cluster-threshold z = 2.3, P < 0.05). In the users, there were positive brain-behavior correlations between neural response to cannabis cues in fronto-striatal-temporal regions and subjective craving, marijuana-related problems, withdrawal symptoms, and levels of THC metabolites (cluster-threshold z = 2.3, P < 0.05). These findings demonstrate hyper-responsivity, and, specificity of brain response to cannabis cues in long-term cannabis users that are above that of response to natural reward cues. These observations are concordant with incentive sensitization models suggesting sensitization of mesocorticolimbic regions and disruption of natural reward processes following drug use. Although the cross-sectional nature of this study does not provide information on causality, the positive correlations between neural response and indicators of cannabis use (i.e., THC levels) suggest that alterations in the reward system are, in part, related to cannabis use. Hum Brain Mapp 37:3431-3443, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Recent-onset schizophrenia and adolescent cannabis use: MRI evidence for structural hyperconnectivity?

PubMed

Peters, Bart D; de Haan, Lieuwe; Vlieger, Erik-Jan; Majoie, Charles B; den Heeten, Gerard J; Linszen, Don H

2009-01-01

There is growing evidence that brain white matter abnormalities are implicated in the pathophysiology of schizophrenia. Cannabis use is an independent risk factor for schizophrenia.We tested the hypothesis that cannabis use during early adolescence is associated with white matter abnormalities in schizophrenia patients. Thirtyfive male recent-onset schizophrenia patients, with and without a history of cannabis use before age 17, and twenty-one matched healthy comparison men without illicit drug use were assessed with diffusion tensor imaging (DTI).White matter regions of interest were examined in co-registered DTI images. Compared to controls, patients with cannabis use before age 17 showed increased directional coherence in the bilateral uncinate fasciculus, anterior internal capsule and frontal white matter. These abnormalities were absent in patients without cannabis use before age 17. The abnormalities were not related to lifetime doses of cannabis or other illicit drugs.We could not exclude confounding effects of other illicit drugs. Recent-onset schizophrenia patients with start of cannabis use during early adolescence use may represent a subgroup of schizophrenia patients with increased white matter directional coherence, which may reflect structural hyperconnectivity. This is in contrast with most DTI studies in schizophrenia, which have produced evidence for hypoconnectivity. Further studies are necessary to assess the effect of adolescent cannabis and other illicit drug use on brain white matter in schizophrenia.

Characterizing smoking topography of cannabis in heavy users

PubMed Central

Stitzer, Maxine L.; Vandrey, Ryan

2013-01-01

Rationale Little is known about the smoking topography characteristics of heavy cannabis users. Such measures may be able to predict cannabis use-related outcomes and could be used to validate self-reported measures of cannabis use. Objectives The current study was conducted to measure cannabis smoking topography characteristics during periods of ad libitum use and to correlate topography assessments with measures of self-reported cannabis use, withdrawal and craving during abstinence, and cognitive task performance. Methods Participants (N=20) completed an inpatient study in which they alternated between periods of ad libitum cannabis use and abstinence. Measures of self-reported cannabis use, smoking topography, craving, withdrawal, and sleep measures were collected. Results Participants smoked with greater intensity (e.g., greater volume, longer duration) on initial cigarette puffs with a steady decline on subsequent puffs. Smoking characteristics were significantly correlated with severity of withdrawal, notably sleep quality and architecture, and craving during abstinence, suggesting dose-related effects of cannabis use on these outcomes. Smoking characteristics generally were not significantly associated with cognitive performance. Smoking topography measures were significantly correlated with self-reported measures of cannabis use, indicating validity of these assessments, but topography measures were more sensitive than self-report in predicting cannabis-related outcomes. Conclusions A dose–effect relationship between cannabis consumption and outcomes believed to be clinically important was observed. With additional research, smoking topography assessments may become a useful clinical tool. PMID:21922170

Are IQ and educational outcomes in teenagers related to their cannabis use? A prospective cohort study

PubMed Central

Mokrysz, C; Landy, R; Gage, SH; Munafò, MR; Roiser, JP; Curran, HV

2016-01-01

There is much debate about the impact of adolescent cannabis use on intellectual and educational outcomes. We investigated associations between adolescent cannabis use and IQ and educational attainment in a sample of 2235 teenagers from the Avon Longitudinal Study of Parents and Children. By the age of 15, 24% reported having tried cannabis at least once. A series of nested linear regressions was employed, adjusted hierarchically by pre-exposure ability and potential confounds (e.g. cigarette and alcohol use, childhood mental-health symptoms and behavioural problems), to test the relationships between cumulative cannabis use and IQ at the age of 15 and educational performance at the age of 16. After full adjustment, those who had used cannabis ⩾50 times did not differ from never-users on either IQ or educational performance. Adjusting for group differences in cigarette smoking dramatically attenuated the associations between cannabis use and both outcomes, and further analyses demonstrated robust associations between cigarette use and educational outcomes, even with cannabis users excluded. These findings suggest that adolescent cannabis use is not associated with IQ or educational performance once adjustment is made for potential confounds, in particular adolescent cigarette use. Modest cannabis use in teenagers may have less cognitive impact than epidemiological surveys of older cohorts have previously suggested. PMID:26739345

Effects of cannabis on the adolescent brain.

PubMed

Jacobus, Joanna; Tapert, Susan F

2014-01-01

This article reviews neuroimaging, neurocognitive, and preclinical findings on the effects of cannabis on the adolescent brain. Marijuana is the second most widely used intoxicant in adolescence, and teens who engage in heavy marijuana use often show disadvantages in neurocognitive performance, macrostructural and microstructural brain development, and alterations in brain functioning. It remains unclear whether such disadvantages reflect pre-existing differences that lead to increased substances use and further changes in brain architecture and behavioral outcomes. Future work should focus on prospective investigations to help disentangle dose-dependent effects from pre-existing effects, and to better understand the interactive relationships with other commonly abused substances (e.g., alcohol) to better understand the role of regular cannabis use on neurodevelopmental trajectories.

Effects of Cannabis on the Adolescent Brain

PubMed Central

Jacobus, Joanna; Tapert, Susan F.

2014-01-01

This article reviews neuroimaging, neurocognitive, and preclinical findings on the effects of cannabis on the adolescent brain. Marijuana is the second most widely used intoxicant in adolescence, and teens who engage in heavy marijuana use often show disadvantages in neurocognitive performance, macrostructural and microstructural brain development, and alterations in brain functioning. It remains unclear whether such disadvantages reflect pre-existing differences that lead to increased substances use and further changes in brain architecture and behavioral outcomes. Future work should focus on prospective investigations to help disentangle dose-dependent effects from pre-existing effects, and to better understand the interactive relationships with other commonly abused substances (e.g., alcohol) to better understand the role of regular cannabis use on neurodevelopmental trajectories. PMID:23829363

A Cross-Sectional Survey of Medical Cannabis Users: Patterns of Use and Perceived Efficacy

PubMed Central

Sexton, Michelle; Cuttler, Carrie; Finnell, John S.; Mischley, Laurie K.

2016-01-01

Abstract Background: The political climate around Cannabis as a medicine is rapidly changing. Legislators are adopting policies regarding appropriate medical applications, while the paucity of research may make policy decisions around conditions for which Cannabis is an effective medicine difficult. Methods: An anonymous online survey was developed to query medical Cannabis users about the conditions they use Cannabis to treat, their use patterns, perception of efficacy, and physical and mental health. Participants were recruited through social media and Cannabis dispensaries in Washington State. Results: A total of 1429 participants identified as medical Cannabis users. The most frequently reported conditions for which they used Cannabis were pain (61.2%), anxiety (58.1%), depression (50.3%), headache/migraine (35.5%), nausea (27.4%), and muscle spasticity (18.4%). On average, participants reported an 86% reduction in symptoms as a result of Cannabis use; 59.8% of medical users reported using Cannabis as an alternative to pharmaceutical prescriptions. Global health scores were on par with the general population for mental health and physical health. Conclusions: While patient-reported outcomes favor strong efficacy for a broad range of symptoms, many medical users are using Cannabis without physician supervision and for conditions for which there is no formal research to support the use of Cannabis (e.g., depression and anxiety). Future research and public policy should attempt to reduce the incongruence between approved and actual use. PMID:28861489

Cannabis and Ecstasy/ MDMA: empirical measures of creativity in recreational users.

PubMed

Jones, Katy A; Blagrove, M; Parrott, A C

2009-12-01

This study investigated the associations between chronic cannabis and Ecstasy/MDMA use and one objective and two subjective measure of creativity. Fifteen abstinent Ecstasy users, 15 abstinent cannabis users, and 15 nondrug-user controls, completed three measures of creativity: the Consequences behavioral test of creativity, self-assessed performance on the Consequences test, and Gough's Trait Self-Report Creative Adjective Checklist. The Consequences test involved five scenarios where possible consequences had to be devised; scoring was conducted by the standard blind rating (by two independent judges) for "remoteness" and "rarity," and by a frequency and rarity of responses method. Cannabis users had significantly more "rare-creative" responses than controls (Tukey, p < 0.05); this effect remained significant with gender as a covariate. There were no significant differences between the groups on the number of standard scoring "remote-creative" ideas or for fluency of responses. On self-rated creativity, there was a significant ANOVA group difference (p < 0.05), with Ecstasy users tending to rate their answers as more creative than controls (Tukey comparison; p = 0.058, two-tailed). Ecstasy users did not differ from controls on the behavioral measures of creativity, although there was a borderline trend for self-assessment of greater creativity. Cannabis users produced significantly more "rare-creative" responses, but did not rate themselves as more creative.

Le cannabis et les enfants et adolescents canadiens

PubMed Central

Grant, Christina N; Bélanger, Richard E

2017-01-01

Résumé L’usage du cannabis, la drogue illicite la plus consommée dans le monde, est fréquent chez les adolescents canadiens. La consommation de cannabis à l’adolescence peut provoquer des modifications fonctionnelles et structurelles du cerveau en développement et induire une atteinte cérébrale. Dans ce groupe d’âge, la consommation de marijuana s’associe fortement à la dépendance au cannabis et à d’autres troubles de l’usage d’une substance, à l’adoption et au maintien du tabagisme, à l’augmentation des troubles de santé mentale, y compris la dépression, l’anxiété et la psychose, à une perturbation du développement neurologique et à un déclin cognitif ainsi qu’à une diminution de la performance scolaire et des réalisations au cours de la vie. Le taux de soins médicaux aigus et d’hospitalisations chez les jeunes enfants qui ont consommé involontairement du cannabis est en hausse. Compte tenu du débat en cours sur la réglementation du cannabis au Canada, l’examen attentif des preuves de ses effets sur la santé et la mise en place de mécanismes de protection deviennent des priorités absolues en santé publique.

Predictors of Adult E-Cigarette Users Vaporizing Cannabis Using E-Cigarettes and Vape-Pens.

PubMed

Morean, Meghan E; Lipshie, Noah; Josephson, Margo; Foster, Dawn

2017-07-03

Given limited extant research, we assessed the use of portable, battery-powered cannabis vaporizers by adult e-cigarette users. 522 adult vapers completed an online survey. Demographics; lifetime and past-month cannabis vaporization via e-cigarettes/vape-pens; preferences for hash oil, D-9-tetrahydrocannabinol (THC) wax, or dried buds; and cannabis vaporization beliefs and motives were examined. Demographics, age of e-cigarette onset, e-cigarette use frequency, state-level legal status of cannabis, cannabis vaping beliefs/motives, and impulsivity were examined as predictors of lifetime cannabis vaporization, past-month cannabis vaporization, and cannabis vaping frequency. E-cigarette users reported lifetime (17.8%) and past-month (11.5%) cannabis vaporization. Vapers preferred hash oil (LT/PM 45.5/47.5%), THC wax (15.2/32.2%), and dried buds (39.4/35.6%). Motivations to vape cannabis included: it tastes better (39.3/37.9%), is healthier (42.9/39.7%), is easier to conceal/hide (35.7/46.6%), does not smell as strong (42.9/39.7%), is more convenient (42.9/27.6%), and produces a stronger/better high (58.1/40.7%) than smoking cannabis. Lifetime and past-month cannabis vaporization, respectively, were associated with initiating e-cigarette use at an earlier age (odds ratio (OR) = 0.09/0.88), being impulsive (OR = 2.25/3.23), having poor self-control (OR = 2.23/1.85), and vaporizing cannabis because it is easier to conceal/hide (OR = 2.45/2.48) or is more convenient than smoking cannabis (OR = 5.02/2.83). Frequency of vaping cannabis was associated with heavier e-cigarette use (η p 2 = 0.10) and impulsivity (η p 2 = 0.09). Adult e-cigarette users are vaporizing cannabis using e-cigarettes/vape-pens. Efforts to curb cannabis vaporization may benefit from targeting impulsivity in users and regulating device features that facilitate or promote convenient, inconspicuous cannabis use.

Functional Connectivity in Brain Networks Underlying Cognitive Control in Chronic Cannabis Users

PubMed Central

Harding, Ian H; Solowij, Nadia; Harrison, Ben J; Takagi, Michael; Lorenzetti, Valentina; Lubman, Dan I; Seal, Marc L; Pantelis, Christos; Yücel, Murat

2012-01-01

The long-term effect of regular cannabis use on brain function underlying cognitive control remains equivocal. Cognitive control abilities are thought to have a major role in everyday functioning, and their dysfunction has been implicated in the maintenance of maladaptive drug-taking patterns. In this study, the Multi-Source Interference Task was employed alongside functional magnetic resonance imaging and psychophysiological interaction methods to investigate functional interactions between brain regions underlying cognitive control. Current cannabis users with a history of greater than 10 years of daily or near-daily cannabis smoking (n=21) were compared with age, gender, and IQ-matched non-using controls (n=21). No differences in behavioral performance or magnitude of task-related brain activations were evident between the groups. However, greater connectivity between the prefrontal cortex and the occipitoparietal cortex was evident in cannabis users, as compared with controls, as cognitive control demands increased. The magnitude of this connectivity was positively associated with age of onset and lifetime exposure to cannabis. These findings suggest that brain regions responsible for coordinating behavioral control have an increased influence on the direction and switching of attention in cannabis users, and that these changes may have a compensatory role in mitigating cannabis-related impairments in cognitive control or perceptual processes. PMID:22534625

Adverse Effects of Cannabis on Adolescent Brain Development: A Longitudinal Study.

PubMed

Camchong, Jazmin; Lim, Kelvin O; Kumra, Sanjiv

2017-03-01

Cannabis is widely perceived as a safe recreational drug and its use is increasing in youth. It is important to understand the implications of cannabis use during childhood and adolescence on brain development. This is the first longitudinal study that compared resting functional connectivity of frontally mediated networks between 43 healthy controls (HCs; 20 females; age M = 16.5 ± 2.7) and 22 treatment-seeking adolescents with cannabis use disorder (CUD; 8 females; age M = 17.6 ± 2.4). Increases in resting functional connectivity between caudal anterior cingulate cortex (ACC) and superior frontal gyrus across time were found in HC, but not in CUD. CUD showed a decrease in functional connectivity between caudal ACC and dorsolateral and orbitofrontal cortices across time. Lower functional connectivity between caudal ACC cortex and orbitofrontal cortex at baseline predicted higher amounts of cannabis use during the following 18 months. Finally, high amounts of cannabis use during the 18-month interval predicted lower intelligence quotient and slower cognitive function measured at follow-up. These data provide compelling longitudinal evidence suggesting that repeated exposure to cannabis during adolescence may have detrimental effects on brain resting functional connectivity, intelligence, and cognitive function. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Cannabis craving in response to laboratory-induced social stress among racially diverse cannabis users: The impact of social anxiety disorder

PubMed Central

Buckner, Julia D; Zvolensky, Michael J; Ecker, Anthony H; Jeffries, Emily R

2016-01-01

Social anxiety disorder appears to be a risk factor for cannabis-related problems. Although it is presumed that increases in cannabis craving during elevated social anxiety reflect an intent to cope with greater negative affectivity, it is unclear whether increases in physiological arousal during social stress are related to cannabis craving, especially among those with social anxiety disorder. Similarly, no studies have assessed motivational reasons for cannabis use during elevated social stress. Thus, the current study tested whether increases in state social anxiety (measured subjectively and via physiological arousal) were related to greater cannabis craving among 126 current cannabis users (88.9% with cannabis use disorder, 31.7% with social anxiety disorder, 54.0% non-Hispanic Caucasian) randomly assigned to either a social interaction or reading task. As predicted, cannabis users in the social interaction condition reported greater cannabis craving than those in the reading condition. This effect was particularly evident among those with social anxiety disorder. Although physiological arousal did not moderate the relationship between condition and craving, coping motives were the most common reasons cited for wanting to use cannabis and were reported more among those in the social interaction task. These experimental results uniquely add to a growing literature suggesting the importance of elevated state social anxiety (especially among those with social anxiety disorder) in cannabis use vulnerability processes. PMID:26839322

Cannabis craving in response to laboratory-induced social stress among racially diverse cannabis users: The impact of social anxiety disorder.

PubMed

Buckner, Julia D; Zvolensky, Michael J; Ecker, Anthony H; Jeffries, Emily R

2016-04-01

Social anxiety disorder appears to be a risk factor for cannabis-related problems. Although it is presumed that increases in cannabis craving during elevated social anxiety reflect an intent to cope with greater negative affectivity, it is unclear whether increases in physiological arousal during social stress are related to cannabis craving, especially among those with social anxiety disorder. Similarly, no studies have assessed motivational reasons for cannabis use during elevated social stress. Thus, the current study tested whether increases in state social anxiety (measured subjectively and via physiological arousal) were related to greater cannabis craving among 126 current cannabis users (88.9% with cannabis use disorder, 31.7% with social anxiety disorder, 54.0% non-Hispanic Caucasian) randomly assigned to either a social interaction or reading task. As predicted, cannabis users in the social interaction condition reported greater cannabis craving than those in the reading condition. This effect was particularly evident among those with social anxiety disorder. Although physiological arousal did not moderate the relationship between condition and craving, coping motives were the most common reasons cited for wanting to use cannabis and were reported more among those in the social interaction task. These experimental results uniquely add to a growing literature suggesting the importance of elevated state social anxiety (especially among those with social anxiety disorder) in cannabis use vulnerability processes. © The Author(s) 2016.

Considering Cannabis: The Effects of Regular Cannabis Use on Neurocognition in Adolescents and Young Adults

PubMed Central

Lisdahl, Krista M.; Wright, Natasha E.; Kirchner-Medina, Christopher; Maple, Kristin E.; Shollenbarger, Skyler

2014-01-01

Thirty-six percent of high school seniors have used cannabis in the past year, and an alarming 6.5% smoked cannabis daily, up from 2.4% in 1993 (Johnston et al., 2013). Adolescents and emerging adults are undergoing significant neurodevelopment and animal studies suggest they may be particularly vulnerable to negative drug effects. In this review, we will provide a detailed overview of studies outlining the effects of regular (at least weekly) cannabis use on neurocognition, including studies outlining cognitive, structural and functional findings. We will also explore the public health impact of this research. PMID:25013751

Are IQ and educational outcomes in teenagers related to their cannabis use? A prospective cohort study.

PubMed

Mokrysz, C; Landy, R; Gage, S H; Munafò, M R; Roiser, J P; Curran, H V

2016-02-01

There is much debate about the impact of adolescent cannabis use on intellectual and educational outcomes. We investigated associations between adolescent cannabis use and IQ and educational attainment in a sample of 2235 teenagers from the Avon Longitudinal Study of Parents and Children. By the age of 15, 24% reported having tried cannabis at least once. A series of nested linear regressions was employed, adjusted hierarchically by pre-exposure ability and potential confounds (e.g. cigarette and alcohol use, childhood mental-health symptoms and behavioural problems), to test the relationships between cumulative cannabis use and IQ at the age of 15 and educational performance at the age of 16. After full adjustment, those who had used cannabis ⩾ 50 times did not differ from never-users on either IQ or educational performance. Adjusting for group differences in cigarette smoking dramatically attenuated the associations between cannabis use and both outcomes, and further analyses demonstrated robust associations between cigarette use and educational outcomes, even with cannabis users excluded. These findings suggest that adolescent cannabis use is not associated with IQ or educational performance once adjustment is made for potential confounds, in particular adolescent cigarette use. Modest cannabis use in teenagers may have less cognitive impact than epidemiological surveys of older cohorts have previously suggested. © The Author(s) 2016.

Alterations of monetary reward and punishment processing in chronic cannabis users: an FMRI study.

PubMed

Enzi, Björn; Lissek, Silke; Edel, Marc-Andreas; Tegenthoff, Martin; Nicolas, Volkmar; Scherbaum, Norbert; Juckel, Georg; Roser, Patrik

2015-01-01

Alterations in reward and punishment processing have been reported in adults suffering from long-term cannabis use. However, previous findings regarding the chronic effects of cannabis on reward and punishment processing have been inconsistent. In the present study, we used functional magnetic resonance imaging (fMRI) to reveal the neural correlates of reward and punishment processing in long-term cannabis users (n = 15) and in healthy control subjects (n = 15) with no history of drug abuse. For this purpose, we used the well-established Monetary Incentive Delay (MID) task, a reliable experimental paradigm that allows the differentiation between anticipatory and consummatory aspects of reward and punishment processing. Regarding the gain anticipation period, no significant group differences were observed. In the left caudate and the left inferior frontal gyrus, cannabis users were - in contrast to healthy controls - not able to differentiate between the conditions feedback of reward and control. In addition, cannabis users showed stronger activations in the left caudate and the bilateral inferior frontal gyrus following feedback of no punishment as compared to healthy controls. We interpreted these deficits in dorsal striatal functioning as altered stimulus-reward or action-contingent learning in cannabis users. In addition, the enhanced lateral prefrontal activation in cannabis users that is related to non-punishing feedback may reflect a deficit in emotion regulation or cognitive reappraisal in these subjects.

Executive attention impairment in adolescents with schizophrenia who have used cannabis.

PubMed

Epstein, Katherine A; Kumra, Sanjiv

2014-08-01

Repeated exposure to cannabis in nonpsychotic adolescents is associated with impairments in executive control of attention, similar to those observed in young adults with first-episode schizophrenia. To assess the impact of recurrent exposure to cannabis on cognitive function, this study characterized attention performance in both nonpsychotic adolescents and adolescents with early-onset schizophrenia (EOS). The Attention Network Test, a standard procedure that estimates the functional state of neural networks controlling the efficiency of three different attentional behaviors (alerting, orienting, and executive attention), was administered to four groups of participants: (1) adolescents with EOS and comorbid cannabis use disorder (EOS+CUD; n=18), (2) "Pure" schizophrenia (EOS; n=34), (3) "Pure" cannabis use disorder (CUD; n=29), and (4) Healthy controls (HC; n=53). Task performance was examined with a 2×2 design (EOS+ versus EOS- and CUD+ versus CUD-) using multivariate analysis of covariance. Correlative analyses were conducted between executive attention performance and measures of surface area in the right anterior cingulate cortex. A significant EOS×CUD interaction was observed. In the executive attention network, adolescents with EOS+CUD showed reduced efficiency relative to adolescents with pure EOS, whereas no group differences were found between adolescents with pure CUD and HC. Less efficient executive attention was significantly associated with smaller surface area in the right caudal anterior cingulate cortex in EOS+CUD. These preliminary data suggest that the presence of CUD has a moderating effect on attentional performance in adolescents with schizophrenia compared to nonpsychotic adolescents. These deficits could have a role in difficulties with self-regulation and predisposition to substance misuse in this patient group. The anatomic substrate of this cognitive deficit may be related to surface area in the right caudal anterior cingulate cortex

Contribution of cannabis and MDMA ("ecstasy") to cognitive changes in long-term polydrug users.

PubMed

Dafters, Richard Ian; Hoshi, Rosa; Talbot, Annie Claire

2004-05-01

Establishing whether cognitive changes follow long-term use of MDMA ("ecstasy") in humans has been difficult because of possible confounds with other drug use, particularly cannabis. Convincing evidence may be only obtained using experimental designs that account for such confounds. In the present study, cognitive/behavioural measures were used to investigate whether long-term MDMA use or long-term cannabis use is responsible for the changes sometimes observed in recreational MDMA users. Tests of attention and memory were administered to subjects who used both MDMA and cannabis, cannabis only, or neither drug. The main finding was that cannabis users, whether or not they also used MDMA, showed significantly impaired memory function on word free-recall and on immediate and delayed story recall compared to non-users. The findings highlight the importance of controlling for other drug use (particularly cannabis) when investigating persistent effects of MDMA in humans.

Working Memory Training for Adolescents with Cannabis Use Disorders: A Randomized Controlled Trial

ERIC Educational Resources Information Center

Sweeney, Mary M.; Rass, Olga; DiClemente, Cara; Schacht, Rebecca L.; Vo, Hoa T.; Fishman, Marc J.; Leoutsakos, Jeannie-Marie S.; Mintzer, Miriam Z.; Johnson, Matthew W.

2018-01-01

Adolescent cannabis use is associated with working memory impairment. The present randomized controlled trial assigned adolescents ages 14 to 21 enrolled in cannabis use treatment to receive either working memory training (experimental group) or a control training (control group) as an adjunctive treatment. Cognitive function, drug use, and other…

Police crackdowns, structural violence and impact on the well-being of street cannabis users in a Nigerian city.

PubMed

Nelson, Ediomo-Ubong

2018-04-01

There is abundant literature on the impact of law enforcement on cannabis markets, but scant literature on the effects of law enforcement on cannabis users. This study undertook a qualitative exploration of police crackdowns as a form of structural violence and examined their impact on the well-being of street cannabis users in a Nigerian city. The study was qualitative and descriptive. It was carried out in Uyo, southern Nigeria. Ninety-seven (97) frequent cannabis users (78 males and 19 females) took part. They were aged between 21 and 34 years and recruited from 11 cannabis hot-points in the city. Data were collected through in-depth, individual interviews, conducted over six-months. Data analysis was thematic and data-driven, involving identifying themes, assigning codes, revising codes and verification by independent qualitative methodology experts. Police crackdowns are commonly experienced by street cannabis users. These do not reduce cannabis use, but displace cannabis markets. Crackdowns are associated with police brutality, confiscation of funds, drugs and belongings, stigma and discrimination, arrest and incarceration, which impacts negatively on the health, livelihoods and well-being of cannabis users. Cannabis users try to escape arrest by running from police, disposing of cannabis, disguising themselves and, when caught, bribing officers to secure release. Crackdowns constitute a form of structural violence in the everyday life of cannabis users, and have negative effects on their health and social and economic well-being. Cannabis use should be decriminalized de facto and arrested users directed to treatment and skills training programmes. Treatment and social services for users should be expanded and legal aid interventions should be mounted to support users in addressing discriminatory practices and human rights violations. Copyright © 2018 Elsevier B.V. All rights reserved.

Dopamine release in chronic cannabis users: a [11C]raclopride Positron Emission Tomography study

PubMed Central

Urban, Nina B.L.; Slifstein, Mark; Thompson, Judy L.; Xu, Xiaoyan; Girgis, Ragy R.; Raheja, Sonia; Haney, Margaret; Abi-Dargham, Anissa

2012-01-01

Introduction Low striatal dopamine 2/3 receptor (D2/3) availability and low ventrostriatal (VST) dopamine (DA) release have been observed in alcoholism, cocaine and heroin dependence. Less is known about the dopaminergic system in cannabis dependence. We assessed D2/3 availability and DA release in abstinent cannabis users compared to controls and explored relationships to parameters of cannabis use history, using [11C]raclopride Positron Emission Tomography (PET) and an amphetamine challenge paradigm. Methods 16 recently abstinent, medically and psychiatrically healthy cannabis-using participants (CD, 27.3 ± 6.1 years, 1 female, 15 males) and 16 matched controls (HC, 28.1 ± 6.7 years, 2 females, 14 males) completed two PET scans, before and after injection of i.v. d-amphetamine (0.3 mg/kg). Percent change in [11C]raclopride binding after amphetamine (ΔBPND) in subregions of the striatum was compared between groups. Correlations with clinical parameters were examined. Results Cannabis dependent participants had an average consumption of 517± 465 estimated puffs per month, indicating overall mild to moderate cannabis dependence. Neither baseline BPND nor ΔBPND differed from controls in any ROI, including VST. In CD, earlier age of onset of use correlated with lower [ΔBPND] in the associative striatum (AST) when controlling for current age. Conclusions Unlike other addictions, cannabis dependence of mild to moderate severity is not associated with striatal DA alterations. However, earlier use, or longer duration of use, is related to lower DA release in the AST. These observations suggest a more harmful effect of use during adolescence; more research is needed to distinguish effects of chronicity versus onset. PMID:22290115

Heavy cannabis users at elevated risk of stroke: evidence from a general population survey.

PubMed

Hemachandra, Dilini; McKetin, Rebecca; Cherbuin, Nicolas; Anstey, Kaarin J

2016-06-01

Case reports and hospital-based case-control studies suggest that cannabis use may increase the risk of stroke. We examined the risk of non-fatal stroke or transient ischemic attack (TIA) among cannabis users in the general community. A general population survey of Australians aged 20-24 years (n=2,383), 40-44 years (n=2,525) and 60-64 years (n=2,547) was used to determine the odds of lifetime stroke or TIA among participants who had smoked cannabis in the past year while adjusting for other stroke risk factors. There were 153 stroke/TIA cases (2.1%). After adjusting for age cohort, past year cannabis users (n=1,043) had 3.3 times the rate of stroke/TIA (95% CI 1.8-6.3, p<0.001). The incidence rate ratio (IRR) reduced to 2.3 after adjustment for covariates related to stroke, including tobacco smoking (95% CI 1.1-4.5). Elevated stroke/TIA was specific to participants who used cannabis weekly or more often (IRR 4.7, 95% CI 2.1-10.7) with no elevation among participants who used cannabis less often. Heavy cannabis users in the general community have a higher rate of non-fatal stroke or transient ischemic attack than non-cannabis users. © 2015 Public Health Association of Australia.

Cannabis use and neurocognitive functioning in a non-clinical sample of users.

PubMed

Thames, April D; Arbid, Natalie; Sayegh, Philip

2014-05-01

With the recent debates over marijuana legalization and increases in use, it is critical to examine its role in cognition. While many studies generally support the adverse acute effects of cannabis on neurocognition, the non-acute effects remain less clear. The current study used a cross-sectional design to examine relationships between recent and past cannabis use on neurocognitive functioning in a non-clinical adult sample. One hundred and fifty-eight participants were recruited through fliers distributed around local college campuses and the community. All participants completed the Brief Drug Use History Form, the Structured Clinical Interview for DSM-IV Disorders, and neurocognitive assessment, and underwent urine toxicology screening. Participants consisted of recent users (n=68), past users (n=41), and non-users (n=49). Recent users demonstrated significantly (p<.05) worse performance than non-users across cognitive domains of attention/working memory (M=42.4, SD=16.1 vs. M=50.5, SD=10.2), information processing speed (M=44.3, SD=7.3 vs. M=52.1, SD=11.0), and executive functioning (M=43.6, SD=13.4 vs. M=48.6, SD=7.2). There were no statistically significant differences between recent users and past users on neurocognitive performance. Frequency of cannabis use in the last 4 weeks was negatively associated with global neurocognitive performance and all individual cognitive domains. Similarly, amount of daily cannabis use was negatively associated with global neurocognitive performance and individual cognitive domains. Our results support the widespread adverse effects of cannabis use on neurocognitive functioning. Although some of these adverse effects appear to attenuate with abstinence, past users' neurocognitive functioning was consistently lower than non-users. Copyright © 2014 Elsevier Ltd. All rights reserved.

Buying cannabis in 'coffee shops'.

PubMed

Monshouwer, Karin; Van Laar, Margriet; Vollebergh, Wilma A

2011-03-01

The key objective of Dutch cannabis policy is to prevent and limit the risks of cannabis consumption for users, their direct environment and society ('harm reduction'). This paper will focus on the tolerated sale of cannabis in 'coffee shops'. We give a brief overview of Dutch policy on coffee shops, its history and recent developments. Furthermore, we present epidemiological data that may be indicative of the effects of the coffee shop policy on cannabis and other drug use. Dutch coffee shop policy has become more restrictive in recent years and the number of coffee shops has decreased. Cannabis prevalence rates in the adult population are somewhat below the European average; the rate is relatively high among adolescents; and age of first use appears to be low. On a European level, the use of hard drugs in both the Dutch adult and adolescent population is average to low (except for ecstasy among adults). International comparisons do not suggest a strong, upward effect of the coffee shop system on levels of cannabis use, although prevalence rates among Dutch adolescents give rise to concern. Furthermore, the coffee shop system appears to be successful in separating the hard and soft drugs markets. Nevertheless, in recent years, issues concerning the involvement of organised crime and the public nuisance related to drug tourism have given rise to several restrictive measures on the local level and have sparked a political debate on the reform of Dutch drug policy. © 2011 Trimbos Institute.

Adverse health effects of non-medical cannabis use.

PubMed

Hall, Wayne; Degenhardt, Louisa

2009-10-17

For over two decades, cannabis, commonly known as marijuana, has been the most widely used illicit drug by young people in high-income countries, and has recently become popular on a global scale. Epidemiological research during the past 10 years suggests that regular use of cannabis during adolescence and into adulthood can have adverse effects. Epidemiological, clinical, and laboratory studies have established an association between cannabis use and adverse outcomes. We focus on adverse health effects of greatest potential public health interest-that is, those that are most likely to occur and to affect a large number of cannabis users. The most probable adverse effects include a dependence syndrome, increased risk of motor vehicle crashes, impaired respiratory function, cardiovascular disease, and adverse effects of regular use on adolescent psychosocial development and mental health.

Environmental Cues and Attempts to Change in Daily Cannabis Users: An Intensive Longitudinal Study

PubMed Central

Hughes, John R.; Naud, Shelly; Budney, Alan J.; Fingar, James R.; Callas, Peter W.

2016-01-01

Introduction We tested whether environmental cues prompt or inhibit quit or reduction attempts among heavy cannabis users. Methods We recruited 196 daily cannabis users who intended to stop or reduce at some point in the next 3 months. Users called an Interactive Voice Response system daily over 3 months to report on cues that might prompt an attempt to quit or reduce (e.g., a request to stop), cues that might inhibit a quit/reduction attempt (e.g., someone offering cannabis), cannabis use, and attempts to stop or reduce cannabis. No treatment was provided. Results Our major findings were a) cost and health/psychological problems were the most common prompting cues, and seeing others use and being offered cannabis were the most common inhibiting cues, b) the number of different types of prompting cues prospectively predicted an increase in attempts to change in a dose-related manner, c) more proximal cues appeared to be more strongly related to change, d) requests to stop or reduce, and physical or psychological problems from cannabis, best predicted change attempts, and e) inhibiting cues did not consistently predict the probability of an attempt to change. Conclusion These preliminary results suggest several environmental cues prompt attempts to change cannabis use. Thus, interventions to increase the frequency of these cues, and specifically requests to stop or reduce cannabis use, and reinforcing concerns about health and mental adverse events from cannabis use may increase cannabis reduction or cessation. PMID:26872879

Environmental cues and attempts to change in daily cannabis users: An intensive longitudinal study.

PubMed

Hughes, John R; Naud, Shelly; Budney, Alan J; Fingar, James R; Callas, Peter W

2016-04-01

We tested whether environmental cues prompt or inhibit quit or reduction attempts among heavy cannabis users. We recruited 196 daily cannabis users who intended to stop or reduce at some point in the next 3 months. Users called an Interactive Voice Response system daily over 3 months to report on cues that might prompt an attempt to quit or reduce (e.g., a request to stop), cues that might inhibit a quit/reduction attempt (e.g., someone offering cannabis), cannabis use, and attempts to stop or reduce cannabis. No treatment was provided. Our major findings were (a) cost and health/psychological problems were the most common prompting cues, and seeing others use and being offered cannabis were the most common inhibiting cues, (b) the number of different types of prompting cues prospectively predicted an increase in attempts to change in a dose-related manner, (c) more proximal cues appeared to be more strongly related to change, (d) requests to stop or reduce, and physical or psychological problems from cannabis, best predicted change attempts, and (e) inhibiting cues did not consistently predict the probability of an attempt to change. These preliminary results suggest several environmental cues prompt attempts to change cannabis use. Thus, interventions to increase the frequency of these cues, and specifically requests to stop or reduce cannabis use, and reinforcing concerns about health and mental adverse events from cannabis use, may increase cannabis reduction or cessation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Reliability and validity of the Marijuana Motives Measure among young adult frequent cannabis users and associations with cannabis dependence.

PubMed

Benschop, Annemieke; Liebregts, Nienke; van der Pol, Peggy; Schaap, Rick; Buisman, Renate; van Laar, Margriet; van den Brink, Wim; de Graaf, Ron; Korf, Dirk J

2015-01-01

The Marijuana Motives Measure (MMM) has so far been examined mainly in student populations, often with relatively limited involvement in cannabis use. This study evaluated the factor structure of the MMM in a demographically mixed sample of 600 young adult (18-30 years) frequent (≥ 3 days per week) cannabis users in the Netherlands. Analysis confirmed a five-factor solution, denoting coping, enhancement, social, conformity and expansion motives. Additionally, the original MMM was extended with two items (boredom and habit), which formed a distinct, internally consistent sixth factor labelled routine motives. In a multivariable logistic regression analysis, coping and routine motives showed significant associations with 12-month DSM-IV cannabis dependence. The results suggest general reliability and validity of the MMM in a heterogeneous population of experienced cannabis users. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mechanisms underlying the lifetime co-occurrence of tobacco and cannabis use in adolescent and young adult twins

PubMed Central

Agrawal, Arpana; Silberg, Judy L.; Lynskey, Michael T.; Maes, Hermine H.; Eaves, Lindon J.

2009-01-01

Using twins assessed during adolescence (Virginia Twin Study of Adolescent Behavioral Development: 8–17 years) and followed up in early adulthood (Young Adult Follow-Up, 18–27 years), we tested 13 genetically informative models of co-occurrence, adapted for the inclusion of covariates. Models were fit, in Mx, to data at both assessments allowing for a comparison of the mechanisms that underlie the lifetime co-occurrence of cannabis and tobacco use in adolescence and early adulthood. Both cannabis and tobacco use were influenced by additive genetic (38–81%) and non-shared environmental factors with the possible role of non-shared environment in the adolescent assessment only. Causation models, where liability to use cannabis exerted a causal influence on the liability to use tobacco fit the adolescent data best, while the reverse causation model (tobacco causes cannabis) fit the early adult data best. Both causation models (cannabis to tobacco and tobacco to cannabis) and the correlated liabilities model fit data from the adolescent and young adult assessments well. Genetic correlations (0.59–0.74) were moderate. Therefore, the relationship between cannabis and tobacco use is fairly similar during adolescence and early adulthood with reciprocal influences across the two psychoactive substances. However, our study could not exclude the possibility that ‘gateways’ and ‘reverse gateways’, particularly within a genetic context, exist, such that predisposition to using one substance (cannabis or tobacco) modifies predisposition to using the other. Given the high addictive potential of nicotine and the ubiquitous nature of cannabis use, this is a public health concern worthy of considerable attention. PMID:20047801

Antecedents and consequences of cannabis use among racially diverse cannabis users: an analysis from Ecological Momentary Assessment.

PubMed

Buckner, Julia D; Zvolensky, Michael J; Crosby, Ross D; Wonderlich, Stephen A; Ecker, Anthony H; Richter, Ashley

2015-02-01

Cannabis remains the most commonly used illicit substance and use rates are rising. Notably, the prevalence of cannabis use disorders (CUD) nearly equals that of other illicit substance use disorders combined. Thus, the present study aimed to identify cognitive, affective, and situational predictors and consequences of ad-lib cannabis use in a racially diverse sample. The sample consisted of 93 current cannabis users (34.4% female; 57.1% non-Hispanic Caucasian), 87.1% of whom evinced a current CUD. Ecological Momentary Assessment was used to collect frequent ratings of cannabis withdrawal, craving, affect, cannabis use motives, and peer cannabis use over two weeks. Mixed effects linear models examined within- and between-day correlates and consequences of cannabis use. Withdrawal and craving were higher on cannabis use days than non-use days. Withdrawal, craving, and positive and negative affect were higher immediately prior to cannabis use compared to non-use episodes. Withdrawal and craving were higher among those who subsequently used cannabis than those who did not. Cannabis use resulted in less subsequent withdrawal, craving, and negative affect. Enhancement and coping motives were the most common reasons cited for use. Withdrawal and negative affect were related to using cannabis for coping motives and social motives. Participants were most likely to use cannabis if others were using, and withdrawal and craving were greater in social situations when others were using. Data support the contention that cannabis withdrawal and craving and affect and peer use play important roles in the maintenance of cannabis use. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Electrophysiological evidence of early attentional bias to drug-related pictures in chronic cannabis users.

PubMed

Asmaro, Deyar; Carolan, Patrick L; Liotti, Mario

2014-01-01

Behavioral and electrophysiological correlates of attentional bias to cannabis-related cues were investigated in a marijuana dependent group and a non-user group employing a drug Stroop task in which cannabis-related, negative and neutral images were presented. Behaviorally, cannabis users were less accurate during drug-containing blocks than non-users. Electrophysiologically, in chronic marijuana-users, an early positive ERP enhancement over left frontal scalp (EAP, 200-350ms) was present in response to drug-containing blocks relative to negative blocks. This effect was absent in the non-user group. Furthermore, drug-containing blocks gave rise to enhanced voltage of a posterior P300 (300-400ms), and a posterior sustained slow wave (LPP, 400-700ms) relative to negative blocks. However, such effects were similar between cannabis users and non-users. Brain source imaging in cannabis users revealed a generator for the EAP effect to drug stimuli in left ventromedial prefrontal cortex/medial orbitofrontal cortex, a region active in fMRI studies of drug cue-reactivity and a target of the core dopaminergic mesolimbic pathway involved in the processing of substances of abuse. This study identifies the timing and brain localization of an ERP correlate of early attentional capture to drug-related pictures in chronic marijuana users. The EAP to drug cues may identify a new electrophysiological marker with clinical implications for predicting abstinence versus relapse or to evaluate treatment interventions. © 2013.

Rapid elimination of Carboxy-THC in a cohort of chronic cannabis users.

PubMed

Lewis, John; Molnar, Anna; Allsop, David; Copeland, Jan; Fu, Shanlin

2016-01-01

Urinary 11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid (Carboxy-THC) concentrations, normalised to creatinine output, have been demonstrated to be a useful tool in the interpretation of the results of a series of urine tests for cannabis. These tests, often termed historical data, can be used to identify potential chronic cannabis users who may present occupational health and safety risks within the workplace. Conversely, the data can also be used to support employee claims of previous regular, rather than recent, cannabis use. This study aimed at examining the mean elimination of Carboxy-THC in 37 chronic users undergoing voluntary abstinence over a 2-week period. Urine specimens were collected prior to the study and after 1 and 2 weeks of abstinence. Carboxy-THC levels in urine were measured by gas chromatography-mass spectrometry (GC-MS) following alkaline hydrolysis, organic solvent extraction and derivatisation to form its pentafluoropropionic derivative. The creatinine-normalised Carboxy-THC concentrations declined rapidly over the 2 weeks of abstinence period and the majority of chronic cannabis users (73%) reduced their urinary Carboxy-THC levels to below the 15-μg/L confirmatory cutoff within that time. The study further highlights the value of historical urinary Carboxy-THC data as a means of identifying potential occupational health and safety risks among chronic cannabis users.

The effects of concurrent cannabis use among ecstasy users: neuroprotective or neurotoxic?

PubMed

Fisk, John E; Montgomery, Catharine; Wareing, Michelle; Murphy, Philip N

2006-08-01

The research evidence regarding the potential effects of ecstasy suggests that it may be neurotoxic and that its use is associated with cognitive impairment. In recent years evidence has emerged suggesting that cannabinoids, the active ingredients in cannabis, can be neuroprotective under certain conditions. Given that many ecstasy users also consume cannabis at the same time, the possibility emerges that these individuals might be less susceptible to ecstasy-related impairment. The present paper reanalyses the data from a number of previous studies, contrasting the performance of those individuals who generally consume cannabis and ecstasy at the same time with those who generally consume ecstasy on its own. The two ecstasy-using groups are compared with non-ecstasy users on a range of measures including processing speed, random letter generation, verbal and visuo-spatial working memory span, reasoning and associative learning. The two ecstasy user groups did not differ significantly from each other on any of the measures. Both user groups were significantly worse than non-ecstasy users on measures of associative learning, verbal and visuo-spatial working memory and reasoning. The results suggest that consuming cannabis at the same time as ecstasy does not reduce the likelihood of cognitive impairment.

Demographic trends among older cannabis users in the United States, 2006–13

PubMed Central

Han, Benjamin H.; Sherman, Scott; Mauro, Pia M.; Martins, Silvia S.; Rotenberg, James; Palamar, Joseph J.

2017-01-01

Background and Aims The ageing US population is providing an unprecedented population of older adults who use recreational drugs. We aimed to estimate the trends in the prevalence of past-year use of cannabis, describe the patterns and attitudes and determine correlates of cannabis use by adults age 50 years and older. Design Secondary analysis of the National Survey on Drug Use and Health survey from 2006 to 2013, a cross-sectional survey given to a nationally representative probability sample of populations living in US households. Setting USA. Participants A total of 47 140 survey respondents aged ≥ 50 years. Measures Estimates and trends of past-year use of cannabis. Findings The prevalence of past-year cannabis use among adults aged ≥ 50 increased significantly from 2006/07 to 2012/13, with a 57.8% relative increase for adults aged 50–64 (linear trend P < 0.001) and a 250% relative increase for those aged ≥ 65 (linear trend P = 0.002). When combining data from 2006 to 2013, 6.9% of older cannabis users met criteria for cannabis abuse or dependence, and the majority of the sample reported perceiving no risk or slight risk associated with monthly cannabis use (85.3%) or weekly use (79%). Past-year users were more likely to be younger, male, non-Hispanic, not have multiple chronic conditions and use tobacco, alcohol or other drugs compared with non-past-year cannabis users. Conclusions The prevalence of cannabis use has increased significantly in recent years among US adults aged ≥ 50 years. PMID:27767235

Alterations of Monetary Reward and Punishment Processing in Chronic Cannabis Users: An fMRI Study

PubMed Central

Enzi, Björn; Lissek, Silke; Edel, Marc-Andreas; Tegenthoff, Martin; Nicolas, Volkmar; Scherbaum, Norbert; Juckel, Georg; Roser, Patrik

2015-01-01

Alterations in reward and punishment processing have been reported in adults suffering from long-term cannabis use. However, previous findings regarding the chronic effects of cannabis on reward and punishment processing have been inconsistent. In the present study, we used functional magnetic resonance imaging (fMRI) to reveal the neural correlates of reward and punishment processing in long-term cannabis users (n = 15) and in healthy control subjects (n = 15) with no history of drug abuse. For this purpose, we used the well-established Monetary Incentive Delay (MID) task, a reliable experimental paradigm that allows the differentiation between anticipatory and consummatory aspects of reward and punishment processing. Regarding the gain anticipation period, no significant group differences were observed. In the left caudate and the left inferior frontal gyrus, cannabis users were – in contrast to healthy controls – not able to differentiate between the conditions feedback of reward and control. In addition, cannabis users showed stronger activations in the left caudate and the bilateral inferior frontal gyrus following feedback of no punishment as compared to healthy controls. We interpreted these deficits in dorsal striatal functioning as altered stimulus-reward or action-contingent learning in cannabis users. In addition, the enhanced lateral prefrontal activation in cannabis users that is related to non-punishing feedback may reflect a deficit in emotion regulation or cognitive reappraisal in these subjects. PMID:25799565

Nonmedical prescription pain reliever and alcohol consumption among cannabis users

PubMed Central

Novak, Scott P.; Peiper, Nicholas C.; Zarkin, Gary A.

2016-01-01

Background This study examined poly-drug use involving the use of cannabis with nonmedical prescription pain reliever use (NMPR) and alcohol use. Methods Computer-assisted survey data from the National Survey on Drug Use and Health were examined. The NSDUH is an annual, cross-sectional survey of non-institutionalized citizens in the United States (ages 12+). Replicate analyses were conducted using the 2013 and 2003 survey waves. Results Higher levels of cannabis use were consistently associated with more frequent consumption of prescription pain relievers, with findings replicating in both 2013 and 2003. While the prevalence of dual users declined from 2003 (2.5%) to 2013 (2.3%), the average number of days used among dual users increased by an average of 20 days over that period. These changes largely occurred among those aged 35 or older, males, whites, and non-illicit drug users. Past-year marijuana use increased by 16% (10.8–12.6%, p-value < .001) whereas NMPR decreased by 15% (4.9–4.2%, p-value < .001). The largest changes occurred after 2011. Persons using the most cannabis generally had higher levels of alcohol use relative to those using the least amount of cannabis. There was a significant increase in the prevalence of dual use between 2003 (10.2%) and 2013 (11.6%), while the prevalence of past-year alcohol use remained relatively stable. Conclusions Clinical efforts and public health interventions should consider the possible co-ingestion of cannabis with NMPR and alcohol, as concomitant use may portend negative health effects in the short and long-term. PMID:26748409

Expected impacts of the Cannabis Infringement Notice scheme in Western Australia on regular users and their involvement in the cannabis market.

PubMed

Chanteloup, Francoise; Lenton, Simon; Fetherston, James; Barratt, Monica J

2005-07-01

The effect on the cannabis market is one area of interest in the evaluation of the new 'prohibition with civil penalties' scheme for minor cannabis offences in WA. One goal of the scheme is to reduce the proportion of cannabis consumed that is supplied by large-scale suppliers that may also supply other drugs. As part of the pre-change phase of the evaluation, 100 regular (at least weekly) cannabis users were given a qualitative and quantitative interview covering knowledge and attitudes towards cannabis law, personal cannabis use, market factors, experience with the justice system and impact of legislative change. Some 85% of those who commented identified the changes as having little impact on their cannabis use. Some 89% of the 70 who intended to cultivate cannabis once the CIN scheme was introduced suggested they would grow cannabis within the two non-hydroponic plant-limit eligible for an infringement notice under the new law. Only 15% believed an increase in self-supply would undermine the large scale suppliers of cannabis in the market and allow some cannabis users to distance themselves from its unsavoury aspects. Only 11% said they would enter, or re-enter, the cannabis market as sellers as a result of the scheme introduction. Most respondents who commented believed that the impact of the legislative changes on the cannabis market would be negligible. The extent to which this happens will be addressed in the post-change phase of this research. Part of the challenge in assessing the impact of the CIN scheme on the cannabis market is that it is distinctly heterogeneous.

Negative affectivity as a mechanism underlying perceived distress tolerance and cannabis use problems, barriers to cessation, and self-efficacy for quitting among urban cannabis users.

PubMed

Manning, Kara; Paulus, Daniel J; Hogan, Julianna B D; Buckner, Julia D; Farris, Samantha G; Zvolensky, Michael J

2018-03-01

Cannabis use rates continue to rise in the United States and currently cannabis is among the most widely used substances in the world. Cannabis use is associated with several mental health problems, low educational attainment, low income, and underemployment. The current study explored the tendency to experience negative affect (negative affectivity) as a factor accounting for the association between perceived distress tolerance and problems related to the use of cannabis. Participants included 203 urban adult daily cannabis users (29.2% female, M=37.7years, 63% African American). Results indicated that there was a significant indirect effect of distress tolerance via negative affectivity in terms of cannabis use problems (b=-0.58, 95%CI [-1.14, -0.21]), cannabis withdrawal (b=-0.65, 95%CI [-1.36, -0.21]), self-efficacy for quitting (b=-0.83, 95%CI [-1.85, -0.22]), and perceived barriers for cannabis cessation (b=-0.71, 95%CI [-1.51, -0.24]). The present data provide novel empirical evidence suggesting negative affectivity may help explain the relation between perceived distress tolerance and an array of clinically significant cannabis use processes. Intervention programming for daily cannabis users may benefit from targeting negative affectivity to facilitate change in cannabis use processes among users who tend to perceive that they are less capable of tolerating distress. Copyright © 2017 Elsevier Ltd. All rights reserved.

Don't Judge a Book by its Cover: Examiner Expectancy Effects Predict Neuropsychological Performance for Individuals Judged as Chronic Cannabis Users.

PubMed

Sodos, Louise M; Hirst, Rayna B; Watson, Jessica; Vaughn, Dylan

2018-01-12

The experimenter expectancy effect confound remains largely unexplored in neuropsychological research and has never been investigated among cannabis users. This study investigated whether examiner expectancies of cannabis user status affected examinees' neuropsychological performance. Participants included 41 cannabis users and 20 non-users. Before testing, examiners who were blind to participant user status privately rated whether they believed the examinee was a cannabis user or non-user. Examiners then administered a battery of neuropsychological and performance validity measures. Multiple regression analyses compared performance between examinees judged as cannabis users (n = 37) and those judged as non-users (n = 24). Examiners' judgments of cannabis users were 75% accurate; judgments of non-users were at chance. After controlling for age, gender, and actual user status, examiner judgments of cannabis user status predicted performance on two measures (California Verbal Learning Test-II, and Trail Making Test B; p < .05), as individuals judged as cannabis users obtained lower scores than those judged as non-users. Examiners' judgments of cannabis user status predicted performance even after controlling for actual user status, indicating vulnerability to examiner expectancy effects. These findings have important implications for both research and clinical settings, as scores may partially reflect examiners' expectations regarding cannabis effects rather than participants' cognitive abilities. These results demonstrate the need for expectancy effect research in the neuropsychological assessment of all populations, not just cannabis users. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Striatal D(2)/D(3) receptor availability is inversely correlated with cannabis consumption in chronic marijuana users.

PubMed

Albrecht, Daniel S; Skosnik, Patrick D; Vollmer, Jennifer M; Brumbaugh, Margaret S; Perry, Kevin M; Mock, Bruce H; Zheng, Qi-Huang; Federici, Lauren A; Patton, Elizabeth A; Herring, Christine M; Yoder, Karmen K

2013-02-01

Although the incidence of cannabis abuse/dependence in Americans is rising, the neurobiology of cannabis addiction is not well understood. Imaging studies have demonstrated deficits in striatal D(2)/D(3) receptor availability in several substance-dependent populations. However, this has not been studied in currently using chronic cannabis users. The purpose of this study was to compare striatal D(2)/D(3) receptor availability between currently using chronic cannabis users and healthy controls. Eighteen right-handed males age 18-34 were studied. Ten subjects were chronic cannabis users; eight were demographically matched controls. Subjects underwent a [(11)C]raclopride (RAC) PET scan. Striatal RAC binding potential (BP(ND)) was calculated on a voxel-wise basis. Prior to scanning, urine samples were obtained from cannabis users for quantification of urine Δ-9-tetrahydrocannabinol (THC) and THC metabolites (11-nor-Δ-9-THC-9-carboxylic acid; THC-COOH and 11-hydroxy-THC;OH-THC). There were no differences in D(2)/D(3) receptor availability between cannabis users and controls. Voxel-wise analyses revealed that RAC BP(ND) values were negatively associated with both urine levels of cannabis metabolites and self-report of recent cannabis consumption. In this sample, current cannabis use was not associated with deficits in striatal D(2)/D(3) receptor availability. There was an inverse relationship between chronic cannabis use and striatal RAC BP(ND). Additional studies are needed to identify the neurochemical consequences of chronic cannabis use on the dopamine system. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Increased ventral striatal BOLD activity during non-drug reward anticipation in cannabis users.

PubMed

Nestor, Liam; Hester, Robert; Garavan, Hugh

2010-01-01

Despite an increased understanding of the pharmacology and long-term cognitive effects of cannabis in humans, there has been no research to date examining its chronic effects upon reward processing in the brain. Motivational theories regarding long-term drug use posit contrasting predictions with respect to how drug users are likely to process non-drug incentives. The reward deficiency syndrome (RDS) of addiction posits that there are deficits in dopamine (DA) motivational circuitry for non-drug rewards, such that only drugs of abuse are capable of normalizing DA in the ventral striatum (VS). Alternatively, the opponent process theory (OPT) holds that in individuals prone to drug use, there exists some form of mesolimbic hyperactivity, in which there is a bias towards reward-centred behaviour concomitant with impulsivity. The current study examined BOLD responses during reward and loss anticipation and their outcome deliveries in 14 chronic cannabis users and 14 drug-naive controls during a monetary incentive delay (MID) task. Despite no significant behavioural differences between the two groups, cannabis users had significantly more right VS BOLD activity during reward anticipation. Correlation analyses demonstrated that this right VS BOLD response was significantly correlated with life-time use and reported life-time cannabis joints consumed. No correlations between cannabis abstinence and BOLD responses were observed. We also observed a number of group differences following outcome deliveries, most notably hypoactivity in the left insula cortex in response to loss and loss avoidance outcome notifications in the cannabis group. These results may suggest hypersensitivity during instrumental response anticipation for non-drug rewards and a hyposensitivity to loss outcomes in chronic cannabis users; the implications of which are discussed with respect to the potentially sensitizing effects of cannabis for other rewards.

Functional MRI of inhibitory processing in abstinent adolescent marijuana users.

PubMed

Tapert, Susan F; Schweinsburg, Alecia D; Drummond, Sean P A; Paulus, Martin P; Brown, Sandra A; Yang, Tony T; Frank, Lawrence R

2007-10-01

Marijuana intoxication appears to impair response inhibition, but it is unclear if impaired inhibition and associated brain abnormalities persist after prolonged abstinence among adolescent users. We hypothesized that brain activation during a go/no-go task would show persistent abnormalities in adolescent marijuana users after 28 days of abstinence. Adolescents with (n = 16) and without (n = 17) histories of marijuana use were compared on blood oxygen level dependent (BOLD) response to a go/no-go task during functional magnetic resonance imaging (fMRI) after 28 days of monitored abstinence. Participants had no neurological problems or Axis I diagnoses other than cannabis abuse/dependence. Marijuana users did not differ from non-users on task performance but showed more BOLD response than non-users during inhibition trials in right dorsolateral prefrontal, bilateral medial frontal, bilateral inferior and superior parietal lobules, and right occipital gyri, as well as during "go" trials in right prefrontal, insular, and parietal cortices (p < 0.05, clusters > 943 microl). Differences remained significant even after controlling for lifetime and recent alcohol use. Adolescent marijuana users relative to non-users showed increased brain processing effort during an inhibition task in the presence of similar task performance, even after 28 days of abstinence. Thus, increased brain processing effort to achieve inhibition may predate the onset of regular use or result from it. Future investigations will need to determine whether increased brain processing effort is associated with risk to use.

Family Stressors and Adolescent Cannabis Use: A Pathway to Problem Use.

ERIC Educational Resources Information Center

Butters, Jennifer E.

2002-01-01

Estimates the direct impact of family stressors on the progression to problem cannabis use among adolescents in Ontario. Results suggest that family stressors have direct and indirect effects increasing the probability of cannabis use outcomes. The implications of these more complex associations between factors believed to influence adolescent…

Cannabis use, attitudes, and legal status in the U.S.: A review.

PubMed

Carliner, Hannah; Brown, Qiana L; Sarvet, Aaron L; Hasin, Deborah S

2017-11-01

Cannabis is widely used among adolescents and adults. In the U.S., marijuana laws have been changing, and Americans increasingly favor legalizing cannabis for medical and recreational uses. While some can use cannabis without harm, others experience adverse consequences. The objective of this review is to summarize information on the legal status of cannabis, perceptions regarding cannabis, prevalence and time trends in use and related adverse consequences, and evidence on the relationship of state medical (MML) and recreational (RML) marijuana laws to use and attitudes. Twenty-nine states now have MMLs, and eight of these have RMLs. Since the early 2000s, adult and adolescent perception of cannabis use as risky has decreased. Over the same time, the prevalence of adolescent cannabis use has changed little. However, adult cannabis use, disorders, and related consequences have increased. Multiple nationally representative studies indicate that MMLs have had little effect on cannabis use among adolescents. However, while MML effects have been less studied in adults, available evidence suggests that MMLs increase use and cannabis use disorders in adults. While data are not yet available to evaluate the effect of RMLs, they are likely to lower price, increase availability, and thereby increase cannabis use. More permissive marijuana laws may accomplish social justice aims (e.g., reduce racial disparities in law enforcement) and generate tax revenues. However, such laws may increase cannabis-related adverse health and psychosocial consequences by increasing the population of users. Dissemination of balanced information about the potential health harms of cannabis use is needed. Copyright © 2017. Published by Elsevier Inc.

Discriminating the effects of Cannabis sativa and Cannabis indica: a web survey of medical cannabis users.

PubMed

Pearce, Daniel D; Mitsouras, Katherine; Irizarry, Kristopher J

2014-10-01

To evaluate the opinions of medical cannabis (MC) users on the effects of Cannabis indica vs. those of Cannabis sativa on conditions and symptoms through an online survey. Survey of 95 non-randomly assigned MC users. A two-sided chi-square test followed by Bonferroni post hoc multiple comparison and Fisher exact test were used to determine correlations. The Cronbach α was used to determine internal consistency. Announcements on 13 MC websites with links to SurveyMonkey.com. Self-identified MC users. Web survey. Species effects were compared regarding health symptoms, conditions, purpose, route, and trust in product label. Trust in the purity, the route of administration, or the purpose (recreational vs. medicinal) did not differ between the two species. A preference for C. indica was statistically significant for pain management (p=0.001), helping with sedation (p=0.015), and sleep (p<0.001). C. sativa was preferred for euphoria (p<0.001) and enhancing energy (p=0.022). The conditions reaching statistical significance for C. indica preference were: nonmigraine headaches (p=0.042), glaucoma (p=0.036), neuropathy (p=0.024), spasticity (p=0.048), seizures (p=0.031), insomnia (p<0.001), and joint pain (p=0.048). For C. sativa, no conditions reached significance. The MC websites' descriptions of effects that agreed with the survey results are listed. Some conditions had very few respondents. The internal consistency/reliability (Cronbach α) was adequate for the condition scale but not for the symptom survey. In this anonymous Web survey, which had limitations, the two species had different effect associations on symptoms and conditions, possibly because of ingredient differences. Future surveys and subsequent prospective definitive trials are needed to confirm the findings.

Evaluation of herbal cannabis characteristics by medical users: a randomized trial

PubMed Central

Ware, Mark A; Ducruet, Thierry; Robinson, Ann R

2006-01-01

Background Cannabis, in herbal form, is widely used as self-medication by patients with diseases such as HIV/AIDS and multiple sclerosis suffering from symptoms including pain, muscle spasticity, stress and insomnia. Valid clinical studies of herbal cannabis require a product which is acceptable to patients in order to maximize adherence to study protocols. Methods We conducted a randomized controlled crossover trial of 4 different herbal cannabis preparations among 8 experienced and authorized cannabis users with chronic pain. Preparations were varied with respect to grind size, THC content and humidity. Subjects received each preparation on a separate day and prepared the drug in their usual way in a dedicated and licensed clinical facility. They were asked to evaluate the products based on appearance (smell, colour, humidity, grind size, ease of preparation and overall appearance) and smoking characteristics (burn rate, hotness, harshness and taste). Five-point Likert scores were assigned to each characteristic. Scores were compared between preparations using ANOVA. Results Seven subjects completed the study, and the product with highest THC content (12%), highest humidity (14%) and largest grind size (10 mm) was rated highest overall. Significant differences were noted between preparations on overall appearance and colour (p = 0.003). Discussion While the small size of the study precludes broad conclusions, the study shows that medical cannabis users can appreciate differences in herbal product. A more acceptable cannabis product may increase recruitment and retention in clinical studies of medical cannabis. PMID:17101054

Progress toward pharmacotherapies for cannabis-use disorder: an evidence-based review

PubMed Central

Copeland, Jan; Pokorski, Izabella

2016-01-01

Cannabis is the most widely used and variably regulated drug in the world, with increasing trends of use being reported in the US, Australia, Asia, and Africa. Evidence has shown a decrease in the age of commencement of cannabis use in some developed countries and a prolongation of risk of initiation to cannabis use beyond adolescence among more recent users. Cannabis use is associated with numerous health risks and long-term morbidity, as well as risk of developing cannabis-use disorders. Cannabis users infrequently seek professional treatment, and normally do so after a decade of use. Cannabis-use disorders are currently treated using a selection of psychosocial interventions. Severity of withdrawal is a factor that increases the risk of relapse, and is the target of pharmacotherapy studies. Currently, there is no approved pharmacotherapy for cannabis-use disorders. A number of approaches have been examined, and trials are continuing to find a safe and effective medication with little abuse liability. PMID:27217809

Feasibility of Momentary Sampling Assessment of Cannabis Use in Adolescents and Young Adults

ERIC Educational Resources Information Center

Black, Shimrit K.; de Moor, Carl; Kendall, Ashley D.; Shrier, Lydia A.

2014-01-01

This study examines the feasibility of recruiting and retaining adolescents and young adults with frequent cannabis use for a 2-week momentary sampling study of cannabis use. Participants responded to random signals on a handheld computer with reports of their use. Participants also initiated reports pre- and post-cannabis use. Participants had…

Believability of Messages about Cannabis, Cocaine and Heroin among Never-Triers, Trier-Rejecters and Current Users of Cannabis

ERIC Educational Resources Information Center

Jones, Sandra C.; Rossiter, John R.

2004-01-01

This paper examines the believability of strong warnings about the negative consequences of drug use among young adults in Australia who have never tried, currently use, or have tried and rejected cannabis. It finds that the strong warnings about cannabis are generally believed by never-triers. The same warnings are perceived by current users as…

Cannabis use in children and adolescents with first episode psychosis: influence on psychopathology and short-term outcome (CAFEPS study).

PubMed

Baeza, Immaculada; Graell, Montserrat; Moreno, Dolores; Castro-Fornieles, Josefina; Parellada, Mara; González-Pinto, Ana; Payá, Beatriz; Soutullo, César; de la Serna, Elena; Arango, Celso

2009-09-01

To know the prevalence of substance use and its relationship with psychopathology at onset and after six months in children and adolescents with first episode psychosis (FEP). 110 FEP patients, aged 9-17, were assessed for substance use, and with the Positive and Negative Syndrome Scale (PANSS) and other psychopathological and general functioning scales at baseline and after a six-month follow-up. Patients' substance use at baseline was: tobacco (30.9%), cannabis (29.1%), alcohol (21.8%), cocaine (8.2%), amphetamines (2.7%), LSD (1.8%) and opiates (0.90%). Six months later, there was a decrease in patients' use of cannabis (p=0.004) and other drugs, except tobacco. Patients were divided, according to their baseline cannabis use, into 32 cannabis users (CU) and 78 non-cannabis users (NCU). CU were older (p=0.002) and had higher PANSS positive scores (p=0.002) and lower PANSS negative (p<0.001), PANSS general (p=0.002) and PANSS total (p=0.007) scores than NCU. At six months, CU had significantly lower PANSS positive (p=0.010), negative (p=0.0001), general (p=0.002) and total (p=0.002) scores than NCU. When we divided CU at six months into previous CU (n=16) and current CU (n=15), previous CU had the best outcome, NCU the worst and current CU had an intermediate profile. Cannabis use may be related to higher positive symptom scores for FEP patients, with greater improvement after six months for those who cease using cannabis.

Nonmedical prescription pain reliever and alcohol consumption among cannabis users.

PubMed

Novak, Scott P; Peiper, Nicholas C; Zarkin, Gary A

2016-02-01

This study examined poly-drug use involving the use of cannabis with nonmedical prescription pain reliever use (NMPR) and alcohol use. Computer-assisted survey data from the National Survey on Drug Use and Health were examined. The NSDUH is an annual, cross-sectional survey of non-institutionalized citizens in the United States (ages 12+). Replicate analyses were conducted using the 2013 and 2003 survey waves. Higher levels of cannabis use were consistently associated with more frequent consumption of prescription pain relievers, with findings replicating in both 2013 and 2003. While the prevalence of dual users declined from 2003 (2.5%) to 2013 (2.3%), the average number of days used among dual users increased by an average of 20 days over that period. These changes largely occurred among those aged 35 or older, males, whites, and non-illicit drug users. Past-year marijuana use increased by 16% (10.8-12.6%, p-value<.001) whereas NMPR decreased by 15% (4.9-4.2%, p-value<.001). The largest changes occurred after 2011. Persons using the most cannabis generally had higher levels of alcohol use relative to those using the least amount of cannabis. There was a significant increase in the prevalence of dual use between 2003 (10.2%) and 2013 (11.6%), while the prevalence of past-year alcohol use remained relatively stable. Clinical efforts and public health interventions should consider the possible co-ingestion of cannabis with NMPR and alcohol, as concomitant use may portend negative health effects in the short and long-term. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Comparing adult cannabis treatment-seekers enrolled in a clinical trial with national samples of cannabis users in the United States

PubMed Central

McClure, Erin A.; King, Jacqueline S.; Wahle, Aimee; Matthews, Abigail G.; Sonne, Susan C.; Lofwall, Michelle R.; McRae-Clark, Aimee L.; Ghitza, Udi E.; Martinez, Melissa; Cloud, Kasie; Virk, Harvir S.; Gray, Kevin M.

2017-01-01

Background Cannabis use rates are increasing among adults in the United States (US) while the perception of harm is declining. This may result in an increased prevalence of cannabis use disorder and the need for more clinical trials to evaluate efficacious treatment strategies. Clinical trials are the gold standard for evaluating treatment, yet study samples are rarely representative of the target population. This finding has not yet been established for cannabis treatment trials. This study compared demographic and cannabis use characteristics of a cannabis cessation clinical trial sample (run through National Drug Abuse Treatment Clinical Trials Network) with three nationally representative datasets from the US; 1) National Survey on Drug Use and Health, 2) National Epidemiologic Survey on Alcohol and Related Conditions-III, and 3) Treatment Episodes Data Set – Admissions. Methods Comparisons were made between the clinical trial sample and appropriate cannabis using sub-samples from the national datasets, and propensity scores were calculated to determine the degree of similarity between samples. Results Results showed that the clinical trial sample was significantly different from all three national datasets, with the clinical trial sample having greater representation among older adults, African Americans, Hispanic/Latinos, adults with more education, non-tobacco users, and daily and almost daily cannabis users. Conclusions These results are consistent with previous studies of other substance use disorder populations and extend sample representation issues to a cannabis use disorder population. This illustrates the need to ensure representative samples within cannabis treatment clinical trials to improve the generalizability of promising findings. PMID:28511033

Comparing adult cannabis treatment-seekers enrolled in a clinical trial with national samples of cannabis users in the United States.

PubMed

McClure, Erin A; King, Jacqueline S; Wahle, Aimee; Matthews, Abigail G; Sonne, Susan C; Lofwall, Michelle R; McRae-Clark, Aimee L; Ghitza, Udi E; Martinez, Melissa; Cloud, Kasie; Virk, Harvir S; Gray, Kevin M

2017-07-01

Cannabis use rates are increasing among adults in the United States (US) while the perception of harm is declining. This may result in an increased prevalence of cannabis use disorder and the need for more clinical trials to evaluate efficacious treatment strategies. Clinical trials are the gold standard for evaluating treatment, yet study samples are rarely representative of the target population. This finding has not yet been established for cannabis treatment trials. This study compared demographic and cannabis use characteristics of a cannabis cessation clinical trial sample (run through National Drug Abuse Treatment Clinical Trials Network) with three nationally representative datasets from the US; 1) National Survey on Drug Use and Health, 2) National Epidemiologic Survey on Alcohol and Related Conditions-III, and 3) Treatment: Episodes Data Set - Admissions. Comparisons were made between the clinical trial sample and appropriate cannabis using sub-samples from the national datasets, and propensity scores were calculated to determine the degree of similarity between samples. showed that the clinical trial sample was significantly different from all three national datasets, with the clinical trial sample having greater representation among older adults, African Americans, Hispanic/Latinos, adults with more education, non-tobacco users, and daily and almost daily cannabis users. These results are consistent with previous studies of other substance use disorder populations and extend sample representation issues to a cannabis use disorder population. This illustrates the need to ensure representative samples within cannabis treatment clinical trials to improve the generalizability of promising findings. Copyright © 2017 Elsevier B.V. All rights reserved.

Individual and country-level effects of cannabis-related perceptions on cannabis use. A multilevel study among adolescents in 32 European countries.

PubMed

Piontek, Daniela; Kraus, Ludwig; Bjarnason, Thoroddur; Demetrovics, Zsolt; Ramstedt, Mats

2013-04-01

The present article investigated individual and aggregated effects of cannabis-related perceptions and other cannabis-related indicators on 12-month cannabis use prevalence and frequency among 15-16 year olds using multilevel analysis across 32 European countries. Data on cannabis use, perceptions of availability, risks and friends' use as well as socio-demographic characteristics were taken from the 2007 European School Survey Project on Alcohol and Other Drugs. At the country level, aggregated measures of the perceptions were used. Data on cannabis price and 12-month cannabis use prevalence in the total population were taken from the World Drug Report. The analytical sample comprised 86,107 students (82.5% of the overall 2007 international database). Strong and persistent individual-level effects were identified for perceived availability, perceived harm, and the number of cannabis using friends. The effects on cannabis use prevalence and frequency were more pronounced than country-level effects. At the country level, aggregated perceived peer consumption and population prevalence were significant predictors, whereas price was not found to be related to both outcome variables. The association between perceived friends' use and cannabis use was moderated by aggregated perceived availability. Proximal influences related to the immediate social situation seem to be more strongly associated with cannabis use than do distal influences related to social contexts, emphasizing the importance of personal attitudes and perceptions in substance use behavior. Prevention programs may focus on informing adolescents about the potential risks of cannabis and on correcting misperceptions of social norms. Policy measures may target on reducing visibility of drug use. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Characteristics and problems of 600 adolescent cannabis abusers in outpatient treatment.

PubMed

Tims, Frank M; Dennis, Michael L; Hamilton, Nancy; J Buchan, Betty; Diamond, Guy; Funk, Rod; Brantley, Laura B

2002-12-01

Risk factors among adolescent substance abusers have been shown to correlate with substance use severity. Characteristics related to severity, such as demographic and family factors, peer influences, psychiatric co-morbidity and HIV risk behaviors, are examined for a sample of adolescent cannabis users entering treatment. These data are from a clinical trial study utilizing blocked random assignment of clients to one of five treatment conditions. The study targeted adolescents entering outpatient treatment for primarily cannabis abuse or dependence. Treatment and research facilities in four metropolitan areas of the US were used to recruit study participants. Treatment was delivered in outpatient drug-free settings. Participants were 600 clients, ages 12-18, admitted to outpatient substance abuse treatment programs for cannabis problems, 96% with DSM-IV diagnoses of substance abuse or dependence, with the remaining 4% having at least one symptom of dependence plus significant problems indicating need for treatment. The Global Appraisal of Individual Needs (GAIN) was used to collect the information presented in this paper. The GAIN incorporates DSM-IV criteria for substance use disorders, conduct disorder and attention deficit hyperactivity disorder, as well as dimensional (scale) measures for physical and mental health. All participants reported at least one symptom of substance use disorders, and 46% met the DSM-IV criteria for substance dependence, while 50% met criteria for a diagnosis of abuse. Only 20% of the participants perceived any need for help with problems associated with their drug or alcohol use. Clients participating in the study typically presented multiple problems at treatment entry, most often including conduct disorder, attention deficit hyperactivity disorder (ADHD), internal (mental) distress, and physical health distress. The co-occurrence of conduct disorder and ADHD was found in 30% of the sample. Clients meeting criteria for substance

Approach to cannabis use disorder in primary care

PubMed Central

Turner, Suzanne D.; Spithoff, Sheryl; Kahan, Meldon

2014-01-01

Objective To review the clinical features and complications of at-risk cannabis use and cannabis use disorder, and to outline an office-based protocol for screening, identifying, and managing this disorder. Sources of information PubMed was searched for controlled trials, observational studies, and reviews on cannabis use among adolescents and young adults; cannabis-related medical and psychiatric harms; cannabis use disorder and its treatment; and lower-risk cannabis use guidelines. Main message Physicians should ask all patients about cannabis use. They should ask adolescents and young adults and those at highest risk of cannabis-related harms (those with concurrent psychiatric or substance use disorders) more frequently. Physicians should also ask about cannabis use in patients who have problems that could be caused by cannabis, such as mood disorders, psychosis, and respiratory symptoms. In patients who report cannabis use, physicians should inquire about frequency and amount, tolerance and withdrawal symptoms, attempts to reduce use, and cannabis-related harms. Lower-risk cannabis users smoke, inhale, or ingest cannabis occasionally without evidence of school, work, or social dysfunction; those with problematic use often use cannabis daily or almost daily, have difficulty reducing their use, and have impaired school, work, or social functioning. Physicians should offer all patients with problematic use brief advice and counseling, focusing on the health effects of cannabis and setting a goal of abstinence (some higher-risk groups should not use cannabis at all) or reduced use, and they should provide practical strategies to reduce cannabis use. Physicians should incorporate simple motivational interviewing techniques into the counseling sessions. They should refer those patients who are unable to reduce use or who are experiencing harms from cannabis use to specialized care, while ensuring those patients remain connected to primary care. As well, physicians

Adolescent substance use and educational attainment: An integrative data analysis comparing cannabis and alcohol from three Australasian cohorts.

PubMed

Silins, Edmund; Fergusson, David M; Patton, George C; Horwood, L John; Olsson, Craig A; Hutchinson, Delyse M; Degenhardt, Louisa; Tait, Robert J; Borschmann, Rohan; Coffey, Carolyn; Toumbourou, John W; Najman, Jake M; Mattick, Richard P

2015-11-01

The relative contributions of cannabis and alcohol use to educational outcomes are unclear. We examined the extent to which adolescent cannabis or alcohol use predicts educational attainment in emerging adulthood. Participant-level data were integrated from three longitudinal studies from Australia and New Zealand (Australian Temperament Project, Christchurch Health and Development Study, and Victorian Adolescent Health Cohort Study). The number of participants varied by analysis (N=2179-3678) and were assessed on multiple occasions between ages 13 and 25. We described the association between frequency of cannabis or alcohol use prior to age 17 and high school non-completion, university non-enrolment, and degree non-attainment by age 25. Two other measures of alcohol use in adolescence were also examined. After covariate adjustment using a propensity score approach, adolescent cannabis use (weekly+) was associated with 1½ to two-fold increases in the odds of high school non-completion (OR=1.60, 95% CI=1.09-2.35), university non-enrolment (OR=1.51, 95% CI=1.06-2.13), and degree non-attainment (OR=1.96, 95% CI=1.36-2.81). In contrast, adjusted associations for all measures of adolescent alcohol use were inconsistent and weaker. Attributable risk estimates indicated adolescent cannabis use accounted for a greater proportion of the overall rate of non-progression with formal education than adolescent alcohol use. Findings are important to the debate about the relative harms of cannabis and alcohol use. Adolescent cannabis use is a better marker of lower educational attainment than adolescent alcohol use and identifies an important target population for preventive intervention. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Prevalence of Cannabis Use Disorder and Associated Factors among Cannabis Young Adult Users at Shashemene Town, Oromia Region, Ethiopia, 2016

PubMed Central

Tullu, Mikiyas; Azale, Telake; Solomon, Haddis; Habtamu, Yodit

2018-01-01

Introduction Cannabis users are at high risk of developing cannabis use disorder which is a problematic pattern of cannabis use leading to clinically significant impairment or distress. Objective To assess the magnitude of cannabis use disorder and associated factors among young adults using cannabis at Shashemene Town, Oromia Region, Ethiopia. Methods A cross-sectional study was conducted at Shashemene Town, from May to June 2016. Young adults aged 18–25 who use cannabis and are permanent residents of Shashemene were included in the study. Using single proportion formula, 423 participants were selected using exponential discriminative snow ball sampling. Result This study revealed that the magnitude of cannabis use disorder was 42.2%. The most contributing factors that remained to be statistically significant with cannabis use disorder were common mental disorder (AOR = 2.125, 95% CI: 1.218, 3.708), current cigarette smoking (AOR = 6.118, 95% CI: 2.13, 17.575), and current use of shisha (AOR = 4.313, 95% CI: 2.427, 7.664). Conclusion The magnitude of cannabis use disorder among young adults using cannabis was high. PMID:29670893

Cannabis and adolescents: Exploring the substance misuse treatment provider experience in a climate of legalization.

PubMed

Sobesky, Matthew; Gorgens, Kim

2016-07-01

Understanding consumer attitudes toward drugs is vital for the design and implementation of effective substance misuse prevention and treatment programs. Research that enhances our understanding of these perceptions is of the utmost importance in the climate of cannabis legalization. While there is a body of literature focused on the perceptions of drug use among adolescents, less attention has been paid to the experiences of health care professionals who serve this vulnerable population. Research aimed at better understanding the experiences of professionals may improve cannabis misuse prevention efforts and inform policy decisions as cannabis moves closer to legalization nationwide. The present study applied a grounded theory qualitative methodology to interview 11 adolescent substance misuse treatment providers. Each participant had at least two years of clinical practice in Colorado before January 1, 2014, when cannabis became available for recreational sale. Extensive analysis of data obtained from participant interviews, yielded seven core concepts related to cannabis use and decriminalization: normalizing, increasing access, rising addiction potential, link to opioids and other drugs, complicating substance treatment, diversity issues, and responding to change. According to participants, legalization has contributed to the continuing normalization of cannabis, validation of its consumption, and greater access to a host of new and more potent THC products by adolescents. Providers attributed these attitudinal changes to heavier use of both cannabis and other drugs and increased resistance to treatment efforts and interventions. These results support the need to expand access to a wider range of substance misuse treatment options for adolescents and to further our understanding of the impact on this population of the cannabis laws. Copyright © 2016 Elsevier B.V. All rights reserved.

Utilizing Big Data and Twitter to Discover Emergent Online Communities of Cannabis Users

PubMed Central

Baumgartner, Peter; Peiper, Nicholas

2017-01-01

Large shifts in medical, recreational, and illicit cannabis consumption in the United States have implications for personalizing treatment and prevention programs to a wide variety of populations. As such, considerable research has investigated clinical presentations of cannabis users in clinical and population-based samples. Studies leveraging big data, social media, and social network analysis have emerged as a promising mechanism to generate timely insights that can inform treatment and prevention research. This study extends a novel method called stochastic block modeling to derive communities of cannabis consumers as part of a complex social network on Twitter. A set of examples illustrate how this method can ascertain candidate samples of medical, recreational, and illicit cannabis users. Implications for research planning, intervention design, and public health surveillance are discussed. PMID:28615950

[Multidimensional family therapy and cognitive behavioral therapy in adolescents with a cannabis use disorder: a randomised controlled study].

PubMed

Hendriks, V M; van der Schee, E; Blanken, P

2013-01-01

More and more adolescents with cannabis problems are seeking treatment at addiction clinics. There is an urgent need for new types of treatment in this field. To evaluate the effectiveness of multidimensional family therapy (MDFT) and cognitive behavioral therapy (CBT) in adolescents with a cannabis use disorder. One hundred and nine adolescents were randomly assigned to outpatient MDFT or CBT. Both types of therapy groups had a planned treatment course lasting 5 to 6 months. After 12 months the two groups were compared in terms of changes in cannabis use and in terms of secondary outcome measures, including delinquency. Adolescents in both treatment groups showed significant and relevant reductions in cannabis use and delinquency over 12 months. Although the MDFT treatment lasted longer and was more intensive than the CBT treatment, there was no difference in the key outcome measures of the treatments. Secondary analyses indicated that older adolescents and those without comorbid psychiatric problems derived considerably more benefit from CBT, whereas younger adolescents and those with comorbid psychiatric problems benefited much more from MDFT. MDFT and CBT are equally effective in reducing cannabis use and delinquent behavior in adolescents with a cannabis use disorder. Age and comorbid psychiatric problems turned out to be important moderators of the treatment results of MDFT and CBT and could therefore be used as a starting point for matching adolescent substance abusers to the most appropriate type of treatment.

Predicting later problematic cannabis use from psychopathological symptoms during childhood and adolescence: Results of a 25-year longitudinal study.

PubMed

Zohsel, Katrin; Baldus, Christiane; Schmidt, Martin H; Esser, Günter; Banaschewski, Tobias; Thomasius, Rainer; Laucht, Manfred

2016-06-01

Cannabis is the most commonly used illegal substance among adolescents and young adults. Problematic cannabis use is often associated with comorbid psychopathological problems. The purpose of the current study was to elucidate the underlying developmental processes connecting externalizing and internalizing psychopathology in childhood and adolescence with problematic cannabis use in young adulthood. Data were drawn from the Mannheim Study of Children at Risk, an ongoing epidemiological cohort study from birth to adulthood. For n=307 participants, symptom scores of conduct/oppositional defiant disorder, attention problems, hyperactivity/impulsivity, and internalizing disorders were available for the periods of childhood (4.5-11 years) and adolescence (15 years). At age 25 years, problematic cannabis use was assessed via clinical interview and a self-rating questionnaire. At age 25 years, problematic cannabis use was identified in n=28 participants (9.1%). Childhood conduct/oppositional behavior problems were predictive of problematic cannabis use during young adulthood when comorbid symptoms were controlled for. No such effect was found for childhood attention, hyperactivity/impulsivity or internalizing problems. With respect to psychopathological symptoms during adolescence, only attention problems were significantly related to later problematic cannabis use when controlling for comorbidity. The current study highlights the role of conduct/oppositional behavior problems during childhood and attention problems during adolescence in later problematic cannabis use. It sheds more light on the developmental sequence of childhood and adolescence psychopathology and young adult cannabis use, which is a prerequisite for effective prevention approaches. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dose-dependent effects of cannabis on the neural correlates of error monitoring in frequent cannabis users.

PubMed

Kowal, Mikael A; van Steenbergen, Henk; Colzato, Lorenza S; Hazekamp, Arno; van der Wee, Nic J A; Manai, Meriem; Durieux, Jeffrey; Hommel, Bernhard

2015-11-01

Cannabis has been suggested to impair the capacity to recognize discrepancies between expected and executed actions. However, there is a lack of conclusive evidence regarding the acute impact of cannabis on the neural correlates of error monitoring. In order to contribute to the available knowledge, we used a randomized, double-blind, between-groups design to investigate the impact of administration of a low (5.5 mg THC) or high (22 mg THC) dose of vaporized cannabis vs. placebo on the amplitudes of the error-related negativity (ERN) and error positivity (Pe) in the context of the Flanker task, in a group of frequent cannabis users (required to use cannabis minimally 4 times a week, for at least 2 years). Subjects in the high dose group (n=18) demonstrated a significantly diminished ERN in comparison to the placebo condition (n=19), whereas a reduced Pe amplitude was observed in both the high and low dose (n=18) conditions, as compared to placebo. The results suggest that a high dose of cannabis may affect the neural correlates of both the conscious (late), as well as the initial automatic processes involved in error monitoring, while a low dose of cannabis might impact only the conscious (late) processing of errors. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Diffusion abnormalities in adolescents and young adults with a history of heavy cannabis use.

PubMed

Ashtari, Manzar; Cervellione, Kelly; Cottone, John; Ardekani, Babak A; Sevy, Serge; Kumra, Sanjiv

2009-01-01

There is growing evidence that adolescence is a key period for neuronal maturation. Despite the high prevalence of marijuana use among adolescents and young adults in the United States and internationally, very little is known about its impact on the developing brain. Based on neuroimaging literature on normal brain developmental during adolescence, we hypothesized that individuals with heavy cannabis use (HCU) would have brain structure abnormalities in similar brain regions that undergo development during late adolescence, particularly the fronto-temporal connection. Fourteen young adult males in residential treatment for cannabis dependence and 14 age-matched healthy male control subjects were recruited. Patients had a history of HCU throughout adolescence; 5 had concurrent alcohol abuse. Subjects underwent structural and diffusion tensor magnetic resonance imaging. White matter integrity was compared between subject groups using voxelwise and fiber tractography analysis. Voxelwise and tractography analyses revealed that adolescents with HCU had reduced fractional anisotropy, increased radial diffusivity, and increased trace in the homologous areas known to be involved in ongoing development during late adolescence, particularly in the fronto-temporal connection via arcuate fasciculus. Our results support the hypothesis that heavy cannabis use during adolescence may affect the trajectory of normal brain maturation. Due to concurrent alcohol consumption in five HCU subjects, conclusions from this study should be considered preliminary, as the DTI findings reported here may be reflective of the combination of alcohol and marijuana use. Further research in larger samples, longitudinal in nature, and controlling for alcohol consumption is needed to better understand the pathophysiology of the effect of cannabis on the developing brain.

Potential protective effects of cannabidiol on neuroanatomical alterations in cannabis users and psychosis: a critical review.

PubMed

Hermann, Derik; Schneider, Miriam

2012-01-01

Cannabis use and the development of schizophrenic psychoses share a variety of similarities. Both start during late adolescence; go along with neuropsychological deficits, reduced activity, motivation deficits, and hallucinations suggesting impairment of similar brain structures. In cannabis heavy users diminished regional gray and white matter volume was reported. Similar alterations were observed in the large literature addressing structural abnormalities in schizophrenia. Furthermore, in cannabis using schizophrenic patients, these brain alterations were especially pronounced. Close relatives of schizophrenic patients showed greater cannabis-associated brain tissue loss than non-relatives indicating a genetically mediated particular sensitivity to brain tissue loss. Possible mechanisms for the induction of structural brain alterations are here discussed including impairments of neurogenesis, disturbance of endocannabinoids and diminished neuroplasticity. Especially direct THC effects (or via endocannabinoids) may mediate diminished glutamatergic neurotransmission usually driving neuroplasticity. Correspondingly, alterations of the kynurenic acid blocking NMDA receptors may contribute to brain structure alterations. However, different cannabis compounds may exert opposite effects on the neuroanatomical changes underlying psychosis. In particular, cannabidiol (CBD) was shown to prevent THC associated hippocampal volume loss in a small pilot study. This finding is further supported by several animal experiments supporting neuroprotective properties of CBD mainly via anti-oxidative effects, CB2 receptors or adenosine receptors. We will discuss here the mechanisms by which CBD may reduce brain volume loss, including antagonism of THC, interactions with endocannabinoids, and mechanisms that specifically underlie antipsychotic properties of CBD.

Processing dynamic facial affect in frequent cannabis-users: evidence of deficits in the speed of identifying emotional expressions.

PubMed

Platt, Bradley; Kamboj, Sunjeev; Morgan, Celia J A; Curran, H Valerie

2010-11-01

While heavy cannabis-users seem to show various cognitive impairments, it remains unclear whether they also experience significant deficits in affective functioning. Evidence of such deficits may contribute to our understanding of the interpersonal difficulties in cannabis-users, and the link between cannabis-use and psychological disorders (Moore et al., 2007). Emotion recognition performance of heavy cannabis-users and non-using controls was compared. A measure of emotion recognition was used in which participants identified facial expressions as they changed from neutral (open-mouth) to gradually more intense expressions of sadness, neutral, anger or happiness (open or closed mouth). Reaction times and accuracy were recorded as the facial expressions changed. Participants also completed measures of 'theory of mind,' depression and impulsivity. Cannabis-users were significantly slower than controls at identifying all three emotional expressions. There was no difference between groups in identifying facial expressions changing from open-mouth neutral expressions to closed-mouth neutral expressions suggesting that differences in emotion recognition were not due to a general slowing of reaction times. Cannabis-users were also significantly more liberal in their response criterion for recognising sadness. Heavy cannabis-use may be associated with affect recognition deficits. In particular, a greater intensity of emotion expression was required before identification of positive and negative emotions. This was found using stimuli which simulated dynamic changes in emotion expression, and in turn, suggests that cannabis-users may experience generalised problems in decoding basic emotions during social interactions. The implications of these findings are discussed for vulnerability to psychological and interpersonal difficulties in cannabis-users. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Cannabis Withdrawal Among Detained Adolescents: Exploring the Impact of Nicotine and Race.

PubMed

Soenksen, Shayna; Stein, L A R; Brown, Joanna D; Stengel, JoAnn R; Rossi, Joseph S; Lebeau, Rebecca

2015-04-01

Rates of marijuana use among detained youths are exceptionally high. Research suggests a cannabis withdrawal syndrome is valid and clinically significant; however, these studies have mostly been conducted in highly controlled laboratory settings with treatment-seeking, White adults. The present study analyzed archival data to explore the magnitude of cannabis withdrawal symptoms within a diverse sample of detained adolescents while controlling for tobacco use and investigating the impact of race on symptom reports. Adolescents recruited from a juvenile correctional facility (N=93) completed a background questionnaire and the Marijuana Withdrawal Checklist. Analyses revealed a significant main effect for level of tobacco use on severity of irritability, and for level of marijuana use on severity of craving to smoke marijuana and strange/wild dreams. Furthermore, a significant main effect for race was found with Black adolescents reporting lower withdrawal discomfort scores and experiencing less severe depressed mood, difficulty sleeping, nervousness/anxiety, and strange/wild dreams. Although exploratory, these findings may have significant clinical implications for providers in juvenile detention facilities, allowing the execution of proper medical and/or behavioral interventions to assist adolescents presenting with problematic cannabis and/or tobacco withdrawal.

A Contingency Management Method for 30-Days Abstinence in Non-Treatment Seeking Young Adult Cannabis Users*

PubMed Central

Schuster, Randi Melissa; Hanly, Ailish; Gilman, Jodi; Budney, Alan; Vandrey, Ryan; Evins, A. Eden

2016-01-01

Background Rates of young adult cannabis use are rising, perceived harm is at its historical nadir, and most users do not want to quit. Most studies evaluating effects of cannabis use in young adults are cross-sectional, limiting causal inference. A method to reliably induce abstinence periods in cannabis users would allow assessment of the effects of abstinence and resumption of use on a variety of outcomes in a within subjects, repeated measure design. Methods We examined the efficacy and feasibility of a voucher-based contingency management procedure for incentivizing one month of continuous cannabis abstinence among young adults who reported at least weekly cannabis use, volunteered to participate in a laboratory study, and did not express desire to discontinue cannabis use long-term. Continuous cannabis abstinence was reinforced with an escalating incentive schedule, and self-report of abstinence was confirmed by frequent quantitative assays of urine cannabis metabolite (THCCOOH) concentration. New cannabis use during the abstinence period was determined using an established algorithm of change in creatinine-adjusted cannabis metabolite concentration between study visits. Results Thirty-eight young adults, aged 18–25, enrolled and 34 (89.5%) attained biochemically confirmed 30-day abstinence. Among those who attained abstinence, 93.9% resumed regular use within two-weeks of incentive discontinuation. Conclusion Findings support the feasibility and efficacy of contingency management to elicit short-term, continuous cannabis abstinence among young adult, non-treatment-seeking, regular cannabis users. Further work should test the effectiveness of this CM procedure for cannabis abstinence periods longer than one month, which may be required to evaluate some effects of abstinence. PMID:27590742

A contingency management method for 30-days abstinence in non-treatment seeking young adult cannabis users.

PubMed

Schuster, Randi Melissa; Hanly, Ailish; Gilman, Jodi; Budney, Alan; Vandrey, Ryan; Evins, A Eden

2016-10-01

Rates of young adult cannabis use are rising, perceived harm is at its historical nadir, and most users do not want to quit. Most studies evaluating effects of cannabis use in young adults are cross-sectional, limiting causal inference. A method to reliably induce abstinence periods in cannabis users would allow assessment of the effects of abstinence and resumption of use on a variety of outcomes in a within-subjects, repeated measures design. We examined the efficacy and feasibility of a voucher-based contingency management procedure for incentivizing one month of continuous cannabis abstinence among young adults who reported at least weekly cannabis use, volunteered to participate in a laboratory study, and did not express a desire to discontinue cannabis use long-term. Continuous cannabis abstinence was reinforced with an escalating incentive schedule, and self-report of abstinence was confirmed by frequent quantitative assays of urine cannabis metabolite (THCCOOH) concentration. New cannabis use during the abstinence period was determined using an established algorithm of change in creatinine-adjusted cannabis metabolite concentrations between study visits. Thirty-eight young adults, aged 18-25 years, enrolled and 34 (89.5%) attained biochemically confirmed 30-day abstinence. Among those who attained abstinence, 93.9% resumed regular use within two-weeks of incentive discontinuation. Findings support the feasibility and efficacy of contingency management to elicit short-term, continuous cannabis abstinence among young adult, non-treatment seeking, regular cannabis users. Further work should test the effectiveness of this contingency management procedure for cannabis abstinence in periods longer than one month, which may be required to evaluate some effects of abstinence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The Role of Study and Work in Cannabis Use and Dependence Trajectories among Young Adult Frequent Cannabis Users

PubMed Central

Liebregts, Nienke; van der Pol, Peggy; Van Laar, Margriet; de Graaf, Ron; van den Brink, Wim; Korf, Dirk J.

2013-01-01

Life course theory considers events in study and work as potential turning points in deviance, including illicit drug use. This qualitative study explores the role of occupational life in cannabis use and dependence in young adults. Two and three years after the initial structured interview, 47 at baseline frequent cannabis users were interviewed in-depth about the dynamics underlying changes in their cannabis use and dependence. Overall, cannabis use and dependence declined, including interviewees who quit using cannabis completely, in particular with students, both during their study and after they got employed. Life course theory appeared to be a useful framework to explore how and why occupational life is related to cannabis use and dependence over time. Our study showed that life events in this realm are rather common in young adults and can have a strong impact on cannabis use. While sometimes changes in use are temporary, turning points can evolve from changes in educational and employment situations; an effect that seems to be related to the consequences of these changes in terms of amount of leisure time and agency (i.e., feelings of being in control). PMID:23950748

The effects of multitasking on psychological stress reactivity in recreational users of cannabis and MDMA.

PubMed

Wetherell, Mark A; Atherton, Katie; Grainger, Jessica; Brosnan, Robert; Scholey, Andrew B

2012-03-01

Cannabis and 3,4-methylenedioxymethamphetamine (MDMA) use is associated with psychobiological and neurocognitive deficits. Assessments of the latter typically include tests of memory and everyday cognitive functioning. However, to date, little attention has been paid to effects of drug use on psychological stress reactivity. We report three studies examining the effects of recreational use of cannabis and MDMA on mood and psychological responses to multitasking using a cognitively demanding laboratory stressor that provides an analogue for everyday situations involving responses to multiple stimuli. The effects of the multitasking framework on mood and perceived workload were assessed in cannabis (N=25), younger (N=18) and older (N=20) MDMA users and compared with non-target drug controls. Compared with respective control groups, cannabis users became less alert and content, and both MDMA groups became less calm following acute stress. Unexpectedly, the stressor increased ratings of calm in cannabis users. Users also scored higher than their controls with respect to ratings of resources needed to complete the multitasking framework. These findings show, for the first time, that recreational use of cannabis and MDMA, beyond the period of intoxication, can negatively influence psychological responses to a multitasking stressor, and this may have implications for real-life situations which place high demands on cognitive resources. Copyright © 2012 John Wiley & Sons, Ltd.

Moderation of the effect of adolescent-onset cannabis use on adult psychosis by a functional polymorphism in the catechol-O-methyltransferase gene: longitudinal evidence of a gene X environment interaction.

PubMed

Caspi, Avshalom; Moffitt, Terrie E; Cannon, Mary; McClay, Joseph; Murray, Robin; Harrington, HonaLee; Taylor, Alan; Arseneault, Louise; Williams, Ben; Braithwaite, Antony; Poulton, Richie; Craig, Ian W

2005-05-15

Recent evidence documents that cannabis use by young people is a modest statistical risk factor for psychotic symptoms in adulthood, such as hallucinations and delusions, as well as clinically significant schizophrenia. The vast majority of cannabis users do not develop psychosis, however, prompting us to hypothesize that some people are genetically vulnerable to the deleterious effects of cannabis. In a longitudinal study of a representative birth cohort followed to adulthood, we tested why cannabis use is associated with the emergence of psychosis in a minority of users, but not in others. A functional polymorphism in the catechol-O-methyltransferase (COMT) gene moderated the influence of adolescent cannabis use on developing adult psychosis. Carriers of the COMT valine158 allele were most likely to exhibit psychotic symptoms and to develop schizophreniform disorder if they used cannabis. Cannabis use had no such adverse influence on individuals with two copies of the methionine allele. These findings provide evidence of a gene x environment interaction and suggest that a role of some susceptibility genes is to influence vulnerability to environmental pathogens.

If cannabis caused schizophrenia--how many cannabis users may need to be prevented in order to prevent one case of schizophrenia? England and Wales calculations.

PubMed

Hickman, Matt; Vickerman, Peter; Macleod, John; Lewis, Glyn; Zammit, Stan; Kirkbride, James; Jones, Peter

2009-11-01

We consider how many cannabis users may need to be prevented in order to prevent one case of schizophrenia or psychosis [defined as number needed to prevent (NNP)]. Calculation for England and Wales using best available estimates of: incidence of schizophrenia; rates of heavy and light cannabis use; and risk that cannabis causes schizophrenia. In men the annual mean NNP for heavy cannabis and schizophrenia ranged from 2800 [90% confidence interval (CI) 2018-4530] in those aged 20-24 years to 4700 (90% CI 3114-8416) in those aged 35-39. In women, mean NNP for heavy cannabis use and schizophrenia ranged from 5470 (90% CI 3640-9839) in those aged 25-29 to 10 870 (90% CI 6786-22 732) in 35-39-year-olds. Equivalent mean NNP for heavy cannabis use and psychosis were lower, from 1360 (90% CI 1007-2124) in men aged 20-24 and 2480 (90% CI 1408-3518) in women aged 16-19. The mean and median number of light cannabis users that would need to be prevented in order to prevent one case of schizophrenia or psychosis per year are four to five times greater than among heavy users. The number of young people who need to be exposed to an intervention to generate NNP and prevent one case of schizophrenia will be even larger. The public health importance of preventing cannabis to reduce schizophrenia or psychosis remains uncertain. More attention should be given to testing the hypothesis that cannabis is related causally to psychotic outcomes, and to considering what strategies will be the most effective in reducing heavy cannabis use among young people.

[Epidemiological news in cannabis].

PubMed

Beck, François; Guignard, Romain; Richard, Jean-Baptiste

2013-12-01

Cannabis is by far the most common illicit drug in France. Among 15-64 years, 32.1% have already experienced it and 8.4% declare they have used it at least once during the past twelve months. In Europe, France is one of the countries with the highest prevalence. Males are markedly more often cannabis users than females and this gender gap tends to increase with the level of use. During the last two decades, the part of the population having tried cannabis did not stop increasing, under the influence of a generalization of the cannabis experience among young people. However, cannabis last year prevalence is rather stable since 2000. Cannabis lifetime use is very rare at the beginning of middle school (1.5% in sixth grade at age 11) but increases in the following years (11% of the pupils of the eighth grade, 24% of the pupils of the ninth grade). Cannabis use at a younger age is related to subsequent onset of cannabis related problems. Adolescent and young adults from high socioeconomic status (SES) more often try cannabis than young people from lower SES. However, cannabis regular use is associated with bad school results, truancy and early school leaving, and with a lower SES. Young people from high SES indeed dispose of greater sociocultural resources to master and regulate their consumption and are more often conscious of their interest not to be tipped over in problematic use.

Item Response Theory Analysis of DSM-IV Cannabis Abuse and Dependence Criteria in Adolescents

ERIC Educational Resources Information Center

Hartman, Christie A.; Gelhorn, Heather; Crowley, Thomas J.; Sakai, Joseph T.; Stallings, Michael; Young, Susan E.; Rhee, Soo Hyun; Corley, Robin; Hewitt, John K.; Hopfer, Christian J.

2008-01-01

A study to examine the DSM-IV criteria for cannabis abuse and dependence among adolescents is conducted. Results conclude that abuse and dependence criteria were not found to affect the different levels of severity in cannabis use.

Comparing Medical and Recreational Cannabis Users on Socio-Demographic, Substance and Medication Use, and Health and Disability Characteristics.

PubMed

Goulet-Stock, Sybil; Rueda, Sergio; Vafaei, Afshin; Ialomiteanu, Anca; Manthey, Jakob; Rehm, Jürgen; Fischer, Benedikt

2017-01-01

While recreational cannabis use is common, medical cannabis programs have proliferated across North America, including a federal program in Canada. Few comparisons of medical and recreational cannabis users (RCUs) exist; this study compared these groups on key characteristics. Data came from a community-recruited sample of formally approved medical cannabis users (MCUs; n = 53), and a sub-sample of recreational cannabis users (RCUs; n = 169) from a representative adult survey in Ontario (Canada). Samples were telephone-surveyed on identical measures, including select socio-demographic, substance and medication use, and health and disability measures. Based on initial bivariate comparisons, multivariate logistical regression with a progressive adjustment approach was performed to assess independent predictors of group status. In bivariate analyses, older age, lower household income, lower alcohol use, higher cocaine, prescription opioid, depression and anxiety medication use, and lower health and disability status were significantly associated with medical cannabis use. In the multivariate analysis, final model, household income, alcohol use, and disability levels were associated with medical cannabis use. Conclusions/Scientific Significance: Compared to RCUs, medical users appear to be mainly characterized by factors negatively influencing their overall health status. Future studies should investigate the actual impact and net benefits of medical cannabis use on these health problems. © 2017 S. Karger AG, Basel.

Psychotic-like experiences with cannabis use predict cannabis cessation and desire to quit: a cannabis discontinuation hypothesis.

PubMed

Sami, Musa; Notley, Caitlin; Kouimtsidis, Christos; Lynskey, Michael; Bhattacharyya, Sagnik

2018-03-23

Evidence suggests that cannabis-induced psychotic-like experiences may be a marker of psychosis proneness. The effect of such experiences on cannabis use has not systematically been examined. We undertook a mixed-methods online survey of 1231 cannabis users (including 926 continued users) using the Cannabis Experiences Questionnaire. We examined the effect of psychotic-like and pleasurable experiences on cessation of cannabis and intention to quit. Socio-demographic variables, cannabis use parameters and substance misuse history were included as covariates. Free-text data explored subjective reasons for changes in use. Cessation of cannabis use was associated with greater psychotic-like experiences [p < 0.001, Exp(B) 1.262, 95% confidence interval (CI) 1.179-1.351], whilst continued cannabis users were more likely to report pleasurable experiences [p < 0.001, Exp(B) 0.717, 95% CI 0.662-0.776]. Intention to quit cannabis in continued users was associated with greater psychotic-like experiences [p < 0.003, Exp(B) 1.131, 95% CI 1.044-1.225], whilst intention to not quit was significantly associated with increased pleasurable experiences [p < 0.015, Exp(B) 0.892, 95% CI 0.814-0.978]. Whereas former users clearly ascribed cessation to negative experiences, continued users who expressed intention to quit less readily ascribed the intention to negative experiences. Elucidation of psychotic-like experiences may form the basis of a therapeutic intervention for those who wish to quit. Cessation in those with cannabis-induced psychotomimetic experiences may offset the risk for the development of a psychotic disorder, in this higher risk group.

Functional connectivity alterations in brain networks relevant to self-awareness in chronic cannabis users.

PubMed

Pujol, Jesus; Blanco-Hinojo, Laura; Batalla, Albert; López-Solà, Marina; Harrison, Ben J; Soriano-Mas, Carles; Crippa, Jose A; Fagundo, Ana B; Deus, Joan; de la Torre, Rafael; Nogué, Santiago; Farré, Magí; Torrens, Marta; Martín-Santos, Rocío

2014-04-01

Recreational drugs are generally used to intentionally alter conscious experience. Long-lasting cannabis users frequently seek this effect as a means to relieve negative affect states. As with conventional anxiolytic drugs, however, changes in subjective feelings may be associated with memory impairment. We have tested whether the use of cannabis, as a psychoactive compound, is associated with alterations in spontaneous activity in brain networks relevant to self-awareness, and whether such potential changes are related to perceived anxiety and memory performance. Functional connectivity was assessed in the Default and Insula networks during resting state using fMRI in 28 heavy cannabis users and 29 control subjects. Imaging assessments were conducted during cannabis use in the unintoxicated state and repeated after one month of controlled abstinence. Cannabis users showed increased functional connectivity in the core of the Default and Insula networks and selective enhancement of functional anticorrelation between both. Reduced functional connectivity was observed in areas overlapping with other brain networks. Observed alterations were associated with behavioral measurements in a direction suggesting anxiety score reduction and interference with memory performance. Alterations were also related to the amount of cannabis used and partially persisted after one month of abstinence. Chronic cannabis use was associated with significant effects on the tuning and coupling of brain networks relevant to self-awareness, which in turn are integrated into brain systems supporting the storage of personal experience and motivated behavior. The results suggest potential mechanisms for recreational drugs to interfere with higher-order network interactions generating conscious experience. Copyright © 2014 Elsevier Ltd. All rights reserved.

Non-Dependent and Dependent Daily Cannabis Users Differ in Mental Health but Not Prospective Memory Ability

PubMed Central

Braidwood, Ruth; Mansell, Samantha; Waldron, Jon; Rendell, Peter G.; Kamboj, Sunjeev K.; Curran, H. Valerie

2018-01-01

Research suggests that daily cannabis users have impaired memory for past events, but it is not clear whether they are also impaired in prospective memory (PM) for future events. The present study examined PM in daily cannabis users who were either dependent (n = 18) or non-dependent (n = 18), and compared them with non-using controls (n = 18). The effect of future event simulation (FES) on PM performance was also examined. Participants were matched across groups on age, gender, and highest level of education. The virtual week (VW) was used to objectively assess PM abilities, both at baseline and following FES. Other measures used were: cannabis use variables, immediate and delayed prose recall, phonemic and category fluency, spot-the-word test (premorbid intelligence), Beck Depression Inventory, Beck Anxiety Inventory, and a measure of schizotypy (Oxford-Liverpool Inventory of Feelings and Experiences: unusual experiences subscale). No group differences were found in PM performance on the VW, and FES did not improve PM performance in any group. Dependent cannabis users scored higher on depression, anxiety, and schizotypy than both other groups with non-dependent cannabis users scoring at a similar level to controls. There were no group differences in alcohol use. Findings suggest that when carefully matched on baseline variables, and not differing in premorbid IQ or alcohol use, young, near-daily cannabis users do not differ from non-using controls in PM performance. PMID:29636705

Chronic cannabis users show altered neurophysiological functioning on Stroop task conflict resolution.

PubMed

Battisti, Robert A; Roodenrys, Steven; Johnstone, Stuart J; Pesa, Nicole; Hermens, Daniel F; Solowij, Nadia

2010-12-01

Chronic cannabis use has been related to deficits in cognition (particularly memory) and the normal functioning of brain structures sensitive to cannabinoids. There is increasing evidence that conflict monitoring and resolution processes (i.e. the ability to detect and respond to change) may be affected. This study examined the ability to inhibit an automatic reading response in order to activate a more difficult naming response (i.e. conflict resolution) in a variant of the discrete trial Stroop colour-naming task. Event-related brain potentials to neutral, congruent and incongruent trials were compared between 21 cannabis users (mean 16.4 years of near daily use) in the unintoxicated state and 19 non-using controls. Cannabis users showed increased errors on colour-incongruent trials (e.g. "RED" printed in blue ink) but no performance differences from controls on colour congruent (e.g. "RED" printed in red ink) or neutral trials (e.g. "*****" printed in green ink). Poorer incongruent trial performance was predicted by an earlier age of onset of regular cannabis use. Users showed altered expression of a late sustained potential related to conflict resolution, evident by opposite patterns of activity between trial types at midline and central sites, and altered relationships between neurophysiological and behavioural outcome measures not evident in the control group. These findings indicate that chronic use of cannabis may impair the brain's ability to respond optimally in the presence of events that require conflict resolution and hold implications for the ability to refrain from substance misuse and/or maintain substance abstention behaviours.

Characteristics of Synthetic Cannabinoid and Cannabis Users Admitted to a Psychiatric Hospital: A Comparative Study.

PubMed

Shalit, Nadav; Barzilay, Ran; Shoval, Gal; Shlosberg, Dan; Mor, Nofar; Zweigenhaft, Nofar; Weizman, Abraham; Krivoy, Amir

2016-08-01

Psychotic and affective exacerbations associated with synthetic cannabinoid (SC) use are becoming an emerging concern in psychiatric hospitals. However, data are lacking regarding whether clinical manifestations of SC use differ from those associated with cannabis use. Our aim was to explore the unique profile of SC users admitted to a mental health center in terms of demographic, clinical, and physiologic variables in comparison to cannabis users. We retrieved retrospective data of patients admitted to a mental health center between October 2007 and May 2014 who self-reported recent use of SC (n = 60) and patients who were cannabis users (positive carboxy-tetrahydrocannabinol urine test at admission) without a history of SC use (n = 163). Clinical measures included hospitalization length, number of previous hospitalizations, Positive and Negative Syndrome Scale (PANSS) scores, psychiatric status at admission, and relevant physiologic and laboratory parameters. Hospitalized SC users were younger than hospitalized cannabis users (n = 163) (30.46 ± 7.83 years versus 34.67 ± 10.07 years, U₂₂₃ = 3,781.5, P = .009, respectively). SC patients had longer hospitalizations compared to cannabis users (43.45 ± 54.02 days versus 22.91 ± 31.36 days, U₂₁₉ = 5,701.5, P = .005, respectively), had more previous hospitalizations (3.73 ± 5.05 versus 1.98 ± 5.12, U₂₂₃ = 6,284, P < .001, respectively), and were more likely to be hospitalized by criminal court order (36.7% [n = 22] versus 19.9% [n = 32], χ²₂ = 7.136, P = .028, respectively). SC patients presented with a more severe clinical picture manifested by higher total PANSS scores (82.53 ± 23.05 versus 69.98 ± 19.94, t₉₁ = -2.696, P = .008) in a subset of patients with PANSS scores assessed within a week from admission (n = 30 in the SC group and n = 63 in the cannabis group). No differences were found in physiologic or laboratory measures on admission between the SC and cannabis groups. Patients

Longitudinal changes in white matter microstructure after heavy cannabis use

PubMed Central

Becker, Mary P.; Collins, Paul F.; Lim, Kelvin O.; Muetzel, R.L.; Luciana, M.

2015-01-01

Diffusion tensor imaging (DTI) studies of cannabis users report alterations in brain white matter microstructure, primarily based on cross-sectional research, and etiology of the alterations remains unclear. We report findings from longitudinal voxelwise analyses of DTI data collected at baseline and at a 2-year follow-up on 23 young adult (18-20 years old at baseline) regular cannabis users and 23 age-, sex-, and IQ-matched non-using controls with limited substance use histories. Onset of cannabis use was prior to age 17. Cannabis users displayed reduced longitudinal growth in fractional anisotropy in the central and parietal regions of the right and left superior longitudinal fasciculus, in white matter adjacent to the left superior frontal gyrus, in the left corticospinal tract, and in the right anterior thalamic radiation lateral to the genu of the corpus callosum, along with less longitudinal reduction of radial diffusion in the right central/posterior superior longitudinal fasciculus, corticospinal tract, and posterior cingulum. Greater amounts of cannabis use were correlated with reduced longitudinal growth in FA as was relatively impaired performance on a measure of verbal learning. These findings suggest that continued heavy cannabis use during adolescence and young adulthood alters ongoing development of white matter microstructure, contributing to functional impairment. PMID:26602958

A prospective study of the substance use and mental health outcomes of young adult former and current cannabis users.

PubMed

Silins, Edmund; Swift, Wendy; Slade, Tim; Toson, Barbara; Rodgers, Bryan; Hutchinson, Delyse M

2017-09-01

The extent to which young adult former cannabis users fare better than infrequent users is unclear. We investigated the association between cannabis use status at age 23 and substance use and mental health outcomes at age 27. Data were from the 20+ year cohort of the PATH Through Life Study. Lifetime cannabis users (n = 1410) at age 23 were classified as former/occasional/regular users. Multivariable logistic regression was used to estimate the association between cannabis use status at age 23 and six outcomes assessed at age 27. Compared with occasional cannabis users: (i) former users had odds of subsequent tobacco use [odds ratio (OR) = 0.67, 95% confidence interval (CI) 0.52-0.85], illicit drug use (cannabis, OR = 0.22, 95% CI 0.17-0.28; other illicit drugs, OR = 0.29, 95% CI 0.22-0.39) and mental health impairment (OR = 0.71, 95% CI 0.55-0.92) that were 29-78% lower; and (ii) regular users had odds of subsequent frequent alcohol use (OR = 2.34, 95% CI 0.67-1.34), tobacco use (OR = 3.67, 95% CI 2.54-5.30), cannabis use (OR = 11.73, 95% CI 6.81-20.21) and dependence symptoms (OR = 12.60, 95% CI 8.38-18.94), and other illicit drug use (OR = 2.95, 95% CI 2.07-4.21) that were 2-13 times greater. Associations attenuated after covariate adjustment, and most remained significant. Clear associations exist between cannabis use status in young adulthood and subsequent mental health and substance use. While early intervention remains important to prevent regular cannabis use and the associated harms, experimentation with cannabis use in the years leading into young adulthood may not necessarily determine an immutable pathway to mental health problems and illicit substance use. [Silins E, Swift W, Slade T, Toson B, Rodgers B, Hutchinson DM. A prospective study of the substance use and mental health outcomes of young adult former and current cannabis users. Drug Alcohol Rev 2017;00:000-000]. © 2017 Australasian Professional Society on Alcohol and other

Psychosocial correlates of adolescent cannabis use: data from the Italian subsample of the second International Self-Reported Delinquency study.

PubMed

Maniglio, Roberto; Innamorati, Marco

2014-01-01

To provide a comprehensive picture of the whole spectrum of psychosocial factors potentially associated with adolescent cannabis use, bivariate and multivariate analyses were used to assess a variety of social, demographic, psychological, and behavioral correlates of last-month cannabis use and age of first use among 6,838 students. Results showed that only family problems, alcohol and/or other drug use/misuse, deviant behavior, and victimization were independently associated with either recent cannabis use or early onset of cannabis use when multiple, interacting factors were considered. Certain family and behavioral factors might be more important than other psychosocial correlates of adolescent cannabis use.

Cannabis policies and user practices: market separation, price, potency, and accessibility in Amsterdam and San Francisco.

PubMed

Reinarman, Craig

2009-01-01

This paper explores user perceptions and practices in contrasting legal-policy milieux-Amsterdam (de facto decriminalization) and San Francisco (de jure criminalization) on four policy issues: sources of cannabis and separation of markets for it and other drugs; user perceptions of effects of price on consumption; effects of potency on consumption; and perceived risk of arrest and accessibility of cannabis. Questions on these issues were added to surveys on career use patterns amongst representative samples of experienced cannabis users using comparable methods. Most San Francisco respondents obtained cannabis through friends who knew dealers, whereas most Amsterdam respondents obtained it from regulated shops. Only one in seven Amsterdam respondents but half the San Francisco respondents could obtain other drugs from their cannabis sources. Majorities under both systems had never found cannabis "too expensive." Amsterdam respondents preferred milder cannabis whilst San Francisco respondents preferred stronger; majorities in both cities reported self-titrating with potent cannabis. Risk and fear of arrest were higher in San Francisco, but most in both cities perceived arrest as unlikely. Estimated search times were somewhat longer in San Francisco, but a majority reported being able to access it within half a day. There is substantial separation of markets in the Dutch system. Policies designed to increase cannabis prices appear unlikely to impact consumption. Decriminalization was associated with a preference for milder cannabis, but under both policy regimes most respondents self-titrated when using more potent strains. Criminalization was associated with somewhat higher risk and fear of arrest and somewhat longer search times, but these did not appear to significantly impede access for most respondents.

[Drinking motivates, depending on the use of tobacco and cannabis among adolescents].

PubMed

Dzielska, Anna

2014-01-01

Alcohol, tobacco and marijuana are the most common drugs used by adolescents. There is evidence of co-occurrence of alcohol use by young people with taking other problem behaviors, little is known about the causes of drinking depending on the type and severity of different substances use. Aim of the study is to find differences in the structure and the rank of drinking motives among people who smoke cigarettes or use marijuana. The study was carried out on a nationwide sample of 1411 in mean age 17.7 years (53.3% girls) as a part of next series of HBSC study (Health Behaviour in School aged Children) conducted in 2010 .To investigate reasons for alcohol use, research instrument DMQ-R (Drinking Motives Questionnaire-Revised) was used. Questions about currently tobacco smoking and marijuana or, hashish use during last year were also asked. One-way ANOVA with post-hoc test Scheffe were used for analysis. Results: The highest means were noticed in the dimension of social motives and they differed significantly due to smoking (F (2, 1170) = 35.76, p <0.001) and marijuana use (F (2, 1.139) = 30.73, p <0.001). Regular smokers have obtained lower mean (M = 61.2, SD = 25.2) than frequently marijuana users (M = 65.9, SD = 25.1). Conformity motives were the weakest motives of drinking among tobacco or marijuana users. Significant differences due to the type and frequency of substance use occurred only in the groups were taking into account tobacco smoking, (F (2,1176)= 4.25, p <0.05). Differences of the levels of motivation to deal with problems (coping motives) were obtained due to tobacco smoking (F (2,1172) = 44.20, p <0.001) and marijuana use (F (2, 1143) = 9.18, p <0.001). Regular smokers were more pointed on the negative intrinsic motivation (M = 38.1, SD = 29.4) than marijuana users (M = 33.5, SD = 29.6). Means in terms of motivation for enhancement also differed in the groups taking into account tobacco smoking (F (2,1174) = 30.63, p <0.001) and cannabis use (F(2

Is cannabis neurotoxic for the healthy brain? A meta-analytical review of structural brain alterations in non-psychotic users.

PubMed

Rocchetti, Matteo; Crescini, Alessandra; Borgwardt, Stefan; Caverzasi, Edgardo; Politi, Pierluigi; Atakan, Zerrin; Fusar-Poli, Paolo

2013-11-01

Despite growing research in the field of cannabis imaging, mostly in those with a psychotic illness, the possible neurotoxic effects of smoked cannabis on the healthy brain have yet to be fully understood. There appears to be a need to evaluate the existing imaging data on the neuroanatomical effects of cannabis use on non-psychotic populations. We conducted a meta-analytical review to estimate the putative neurotoxic effect of cannabis in non-psychotic subjects who were using or not using cannabis. We specifically tested the hypothesis that cannabis use can alter grey and white matter in non-psychotic subjects. Our systematic literature search uncovered 14 studies meeting the inclusion criteria for the meta-analysis. The overall database comprised 362 users and 365 non-users. At the level of the individual studies there is limited and contrasting evidence supporting a cannabis-related alteration on the white and grey matter structures of non-psychotic cannabis users. However, our meta-analysis showed a consistent smaller hippocampus in users as compared to non-users. Heterogeneity across study designs, image acquisition, small sample sizes and limited availability of regions of interest to be included in the meta-analysis may undermine the core findings of this study. Our results suggest that in the healthy brain, chronic and long-term cannabis exposure may exert significant effects in brain areas enriched with cannabinoid receptors, such as the hippocampus, which could be related to a neurotoxic action. © 2013 The Authors. Psychiatry and Clinical Neurosciences © 2013 Japanese Society of Psychiatry and Neurology.

[Cognitive abnormalities and cannabis use].

PubMed

Solowij, Nadia; Pesa, Nicole

2010-05-01

Evidence that cannabis use impairs cognitive function in humans has been accumulating in recent decades. The purpose of this overview is to update knowledge in this area with new findings from the most recent literature. Literature searches were conducted using the Web of Science database up to February 2010. The terms searched were: "cannabi*" or "marijuana", and "cogniti*" or "memory" or "attention" or "executive function", and human studies were reviewed preferentially over the animal literature. Cannabis use impairs memory, attention, inhibitory control, executive functions and decision making, both during the period of acute intoxication and beyond, persisting for hours, days, weeks or more after the last use of cannabis. Pharmacological challenge studies in humans are elucidating the nature and neural substrates of cognitive changes associated with various cannabinoids. Long-term or heavy cannabis use appears to result in longer-lasting cognitive abnormalities and possibly structural brain alterations. Greater adverse cognitive effects are associated with cannabis use commencing in early adolescence. The endogenous cannabinoid system is involved in regulatory neural mechanisms that modulate processes underlying a range of cognitive functions that are impaired by cannabis. Deficits in human users most likely therefore reflect neuroadaptations and altered functioning of the endogenous cannabinoid system.

The impact of early-onset cannabis use on functional brain correlates of working memory.

PubMed

Becker, Benjamin; Wagner, Daniel; Gouzoulis-Mayfrank, Euphrosyne; Spuentrup, Elmar; Daumann, Jörg

2010-08-16

Cannabis is the most commonly used illicit drug. Prevalence rates are particularly high among adolescents. Neuropsychological studies have identified cannabis-associated memory deficits, particularly linked to an early onset of use. However, it remains unclear, whether the age of onset accounts for altered cortical activation patterns usually observed in cannabis users. Functional magnetic resonance imaging was used to examine cortical activation during verbal working memory challenge in (1) early-onset (onset before the age of sixteen; n=26) and (2) late-onset cannabis users (age at onset at least sixteen; n=17). Early-onset users showed increased activation in the left superior parietal lobe. Correlational analyses confirmed the association between an earlier start of use and increased activity. Contrariwise neither cumulative dose, frequency nor time since last use was significantly associated with cortical activity. Our findings suggest that an early start of cannabis use is associated with increased cortical activation in adult cannabis users, possibly reflecting suboptimal cortical efficiency during cognitive challenge. The maturing brain might be more vulnerable to the harmful effects of cannabis use. However, due to a lack of a non-using control group we cannot exclude alternative interpretations. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Orbitofrontal and caudate volumes in cannabis users: a multi-site mega-analysis comparing dependent versus non-dependent users.

PubMed

Chye, Yann; Solowij, Nadia; Suo, Chao; Batalla, Albert; Cousijn, Janna; Goudriaan, Anna E; Martin-Santos, Rocio; Whittle, Sarah; Lorenzetti, Valentina; Yücel, Murat

2017-07-01

Cannabis (CB) use and dependence are associated with regionally specific alterations to brain circuitry and substantial psychosocial impairment. The objective of this study was to investigate the association between CB use and dependence, and the volumes of brain regions critically involved in goal-directed learning and behaviour-the orbitofrontal cortex (OFC) and caudate. In the largest multi-site structural imaging study of CB users vs healthy controls (HC), 140 CB users and 121 HC were recruited from four research sites. Group differences in OFC and caudate volumes were investigated between HC and CB users and between 70 dependent (CB-dep) and 50 non-dependent (CB-nondep) users. The relationship between quantity of CB use and age of onset of use and caudate and OFC volumes was explored. CB users (consisting of CB-dep and CB-nondep) did not significantly differ from HC in OFC or caudate volume. CB-dep compared to CB-nondep users exhibited significantly smaller volume in the medial and the lateral OFC. Lateral OFC volume was particularly smaller in CB-dep females, and reduced volume in the CB-dep group was associated with higher monthly cannabis dosage. Smaller medial OFC volume may be driven by CB dependence-related mechanisms, while smaller lateral OFC volume may be due to ongoing exposure to cannabinoid compounds. The results highlight a distinction between cannabis use and dependence and warrant examination of gender-specific effects in studies of CB dependence.

Social Skills as Precursors of Cannabis Use in Young Adolescents: A Trails Study

ERIC Educational Resources Information Center

Griffith-Lendering, Merel F. H.; Huijbregts, Stephan C. J.; Huizink, Anja C.; Ormel, Hans; Verhulst, Frank C.; Vollebergh, Wilma A. M.; Swaab, Hanna

2011-01-01

Social skills (cooperation, assertion, and self-control) were assessed by teachers for a longitudinal cohort of (pre)adolescents, with measurements at average ages 11.1 (baseline) and 16.3 years (follow-up). Prospective associations with participants' self-reported use of cannabis, (age of) onset of cannabis use, and frequency of use at follow-up…

Personality Characteristics of Adolescents with Hallucinogen, Methamphetamine, and Cannabis Dependence: A Comparative Study

ERIC Educational Resources Information Center

Palmer, Glen A.; Daiss, Doyle D.

2005-01-01

A comparison of personality factors on scales of the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A) was conducted with a sample of adolescents referred to a residential substance abuse treatment program. A total of sixty adolescents identified with hallucinogen (n = 20), cannabis (n = 20), or methamphetamine (n = 20) as their drug…

To what extent does adding tobacco to cannabis expose young users to nicotine?

PubMed

Bélanger, Richard E; Marclay, François; Berchtold, André; Saugy, Martial; Cornuz, Jacques; Suris, Joan-Carles

2013-11-01

To determine if mulling, the process of adding tobacco to cannabis for its consumption, exposes young cannabis users to significant levels of nicotine. This observational study performed in 2009-2010 among Swiss youths aged 16-25 years involved the completion of a self-administrated questionnaire and the collection of a urine sample on the same day. Measures of urinary cotinine were blindly performed using liquid chromatography coupled-mass spectrometry. A total of 197 eligible participants were divided in 3 groups based on their consumption profile in the past 5 days: 70 abstainers (ABS) not having used cigarettes or cannabis, 57 cannabis users adding tobacco to the cannabis they smoke (MUL) but not having smoked cigarettes, and 70 cigarette smokers (CIG) not having smoked cannabis. Exposure to nicotine was at its lowest among ABS with a mean (SE) cotinine level of 3.2 (1.4) ng/ml compared, respectively, with 214.6 (43.8) and 397.9 (57.4) for MUL and CIG (p < .001). While consumption profile appeared as the only significant factor of influence when examining nicotine exposure from the ABS and MUL participants on multivariate analysis, it did not result in substantial differences among MUL and CIG groups. Urinary cotinine levels found among MUL are high enough to indicate a significant exposure to nicotine originating from the mulling process. In line with our results, health professionals should pay attention to mulling as it is likely to influence cannabis and cigarette use as well as the efficacy of cessation interventions.

Adverse effects of cannabis.

PubMed

2011-01-01

Cannabis, Cannabis sativa L., is used to produce a resin that contains high levels of cannabinoids, particularly delta9-tetrahydrocannabinol (THC), which are psychoactive substances. Although cannabis use is illegal in France and in many other countries, it is widely used for its relaxing or euphoric effects, especially by adolescents and young adults. What are the adverse effects of cannabis on health? During consumption? And in the long term? Does cannabis predispose users to the development of psychotic disorders? To answer these questions, we reviewed the available evidence using the standard Prescrire methodology. The long-term adverse effects of cannabis are difficult to evaluate. Since and associated substances, with or without the user's knowledge. Tobacco and alcohol consumption, and particular lifestyles and behaviours are often associated with cannabis use. Some traits predispose individuals to the use of psychoactive substances in general. The effects of cannabis are dosedependent.The most frequently report-ed adverse effects are mental slowness, impaired reaction times, and sometimes accentuation of anxiety. Serious psychological disorders have been reported with high levels of intoxication. The relationship between poor school performance and early, regular, and frequent cannabis use seems to be a vicious circle, in which each sustains the other. Many studies have focused on the long-term effects of cannabis on memory, but their results have been inconclusive. There do not * About fifteen longitudinal cohort studies that examined the influence of cannabis on depressive thoughts or suicidal ideation have yielded conflicting results and are inconclusive. Several longitudinal cohort studies have shown a statistical association between psychotic illness and self-reported cannabis use. However, the results are difficult to interpret due to methodological problems, particularly the unknown reliability of self-reported data. It has not been possible to

Parietal lobe volume deficits in adolescents with schizophrenia and adolescents with cannabis use disorders.

PubMed

Kumra, Sanjiv; Robinson, Paul; Tambyraja, Rabindra; Jensen, Daniel; Schimunek, Caroline; Houri, Alaa; Reis, Tiffany; Lim, Kelvin

2012-02-01

In early-onset schizophrenia (EOS), the earliest structural brain volumetric abnormalities appear in the parietal cortices. Early exposure to cannabis may represent an environmental risk factor for developing schizophrenia. This study characterized cerebral cortical gray matter structure in adolescents in regions of interest (ROIs) that have been implicated in EOS and cannabis use disorders (CUD). T1-weighted magnetic resonance images were acquired from adolescents with EOS (n = 35), CUD (n = 16), EOS + CUD (n = 13), and healthy controls (HC) (n = 51). Using FreeSurfer, brain volume was examined within frontal, temporal, parietal and subcortical ROIs by a 2 (EOS versus no EOS) × 2 (CUD versus no CUD) design using multivariate analysis of covariance. In ROIs in which volumetric differences were identified, additional analyses of cortical thickness and surface area were conducted. A significant EOS-by-CUD interaction was observed. In the left superior parietal region, both "pure" EOS and "pure" CUD had smaller gray matter volumes that were associated with lower surface area compared with HC. A similar alteration was observed in the comorbid group compared with HC, but there was no additive volumetric deficit found in the comorbid group compared with the separate groups. In the left thalamus, the comorbid group had smaller gray matter volumes compared with the CUD and HC groups. These preliminary data indicate that the presence of a CUD may moderate the relationship between EOS and cerebral cortical gray matter structure in the left superior parietal lobe. Future research will follow this cohort over adolescence to further examine the impact of cannabis use on neurodevelopment.

Cannabis and tolerance: acute drug impairment as a function of cannabis use history

PubMed Central

Ramaekers, J. G.; van Wel, J. H.; Spronk, D. B.; Toennes, S. W.; Kuypers, K. P. C.; Theunissen, E. L.; Verkes, R. J.

2016-01-01

Cannabis use history as predictor of neurocognitive response to cannabis intoxication remains subject to scientific and policy debates. The present study assessed the influence of cannabis on neurocognition in cannabis users whose cannabis use history ranged from infrequent to daily use. Drug users (N = 122) received acute doses of cannabis (300 μg/kg THC), cocaine HCl (300 mg) and placebo. Cocaine served as active control for demonstrating neurocognitive test sensitivity. Executive function, impulse control, attention, psychomotor function and subjective intoxication were significantly worse after cannabis administration relative to placebo. Cocaine improved psychomotor function and attention, impaired impulse control and increased feelings of intoxication. Acute effects of cannabis and cocaine on neurocognitive performance were similar across cannabis users irrespective of their cannabis use history. Absence of tolerance implies that that frequent cannabis use and intoxication can be expected to interfere with neurocognitive performance in many daily environments such as school, work or traffic. PMID:27225696

Cannabis and tolerance: acute drug impairment as a function of cannabis use history.

PubMed

Ramaekers, J G; van Wel, J H; Spronk, D B; Toennes, S W; Kuypers, K P C; Theunissen, E L; Verkes, R J

2016-05-26

Cannabis use history as predictor of neurocognitive response to cannabis intoxication remains subject to scientific and policy debates. The present study assessed the influence of cannabis on neurocognition in cannabis users whose cannabis use history ranged from infrequent to daily use. Drug users (N = 122) received acute doses of cannabis (300 μg/kg THC), cocaine HCl (300 mg) and placebo. Cocaine served as active control for demonstrating neurocognitive test sensitivity. Executive function, impulse control, attention, psychomotor function and subjective intoxication were significantly worse after cannabis administration relative to placebo. Cocaine improved psychomotor function and attention, impaired impulse control and increased feelings of intoxication. Acute effects of cannabis and cocaine on neurocognitive performance were similar across cannabis users irrespective of their cannabis use history. Absence of tolerance implies that that frequent cannabis use and intoxication can be expected to interfere with neurocognitive performance in many daily environments such as school, work or traffic.

Legal substance use and the development of a DSM-IV cannabis use disorder during adolescence: the TRAILS study.

PubMed

Prince van Leeuwen, Andrea; Creemers, Hanneke E; Verhulst, Frank C; Vollebergh, Wilma A M; Ormel, Johan; van Oort, Floor; Huizink, Anja C

2014-02-01

To examine whether early onset of tobacco or alcohol use, and continued use of tobacco or alcohol in early adolescence, are related to a higher likelihood of developing a cannabis use disorder during adolescence. Data were used from four consecutive assessment waves of the TRacking Adolescents' Individual Lives Survey (TRAILS), a general Dutch population study. TRAILS is an ongoing longitudinal study that will follow the same group of adolescents from the ages of 10 to 24 years. The sample consisted of 1108 (58% female) adolescents (mean ages at the four assessment waves are 11.09, 13.56, 16.27 and 19.05 years, respectively) Cannabis use disorders were assessed using the Composite International Diagnostic Interview 3.0 (CIDI). Adolescent tobacco and alcohol use were assessed using self-report questionnaires. Early-onset tobacco use [odds ratio (OR) = 1.82, confidence interval (CI) = 1.05-3.14, P < 0.05], but not early-onset alcohol use (OR = 1.33, CI = 0.84-2.12, P > 0.05), was associated with a higher likelihood of developing a cannabis use disorder. Similarly, adolescents who reported continued use of tobacco (OR = 2.47, CI = 1.02-5.98, P < 0.05), but not continued use of alcohol (OR = 1.71, CI = 0.87-3.38, P > 0.05), were more likely to develop a cannabis use disorder. Early-onset and continued tobacco use appear to predict the development of a cannabis use disorder in adolescence, whereas early onset and continued alcohol use do not. © 2013 Society for the Study of Addiction.

Cannabis Users Show Enhanced Expression of CB1-5HT2A Receptor Heteromers in Olfactory Neuroepithelium Cells.

PubMed

Galindo, Liliana; Moreno, Estefanía; López-Armenta, Fernando; Guinart, Daniel; Cuenca-Royo, Aida; Izquierdo-Serra, Mercè; Xicota, Laura; Fernandez, Cristina; Menoyo, Esther; Fernández-Fernández, José M; Benítez-King, Gloria; Canela, Enric I; Casadó, Vicent; Pérez, Víctor; de la Torre, Rafael; Robledo, Patricia

2018-01-02

Cannabinoid CB1 receptors (CB 1 R) and serotonergic 2A receptors (5HT 2A R) form heteromers in the brain of mice where they mediate the cognitive deficits produced by delta-9-tetrahydrocannabinol. However, it is still unknown whether the expression of this heterodimer is modulated by chronic cannabis use in humans. In this study, we investigated the expression levels and functionality of CB 1 R-5HT 2A R heteromers in human olfactory neuroepithelium (ON) cells of cannabis users and control subjects, and determined their molecular characteristics through adenylate cyclase and the ERK 1/2 pathway signaling studies. We also assessed whether heteromer expression levels correlated with cannabis consumption and cognitive performance in neuropsychological tests. ON cells from controls and cannabis users expressed neuronal markers such as βIII-tubulin and nestin, displayed similar expression levels of genes related to cellular self-renewal, stem cell differentiation, and generation of neural crest cells, and showed comparable Na + currents in patch clamp recordings. Interestingly, CB 1 R-5HT 2A R heteromer expression was significantly increased in cannabis users and positively correlated with the amount of cannabis consumed, and negatively with age of onset of cannabis use. In addition, a negative correlation was found between heteromer expression levels and attention and working memory performance in cannabis users and control subjects. Our findings suggest that cannabis consumption regulates the formation of CB 1 R-5HT 2A R heteromers, and may have a key role in cognitive processing. These heterodimers could be potential new targets to develop treatment alternatives for cognitive impairments.

Schizophrenia and cannabis use.

PubMed

Kumra, Sanjiv

2007-01-01

Genetic predisposition and environmental risk factors are thought to play a role in the pathophysiology of schizophrenia. Exposure to cannabis is one environmental factor that's being studied for its possible link to development of schizophrenia in adolescents. This article presents evidence that supports the hypothesis that repeated cannabis use could interfere with the development of frontal white matter in some adolescents and may exacerbate anatomic pathology in those with schizophrenia. This putative mechanism may explain the deficits in working memory and worsening in the severity of clinical symptoms in adolescents with schizophrenia who use cannabis.

The consequences of chronic cannabis smoking in vulnerable adolescents.

PubMed

Iede, Montaha Al; Nunn, Kenneth; Milne, Bronwyn; Fitzgerald, Dominic A

2017-09-01

Cannabis, like the mythic shape-shifter, presents in various guises, morphing with the perspective and context of the observer. Arguments about cannabis are confused by a myriad of debates-medical, social, ethical and political-as if a single conceptual umbrella can capture the variety and granularity of marijuana-related issues. This paper responds to marijuana use as it is commonly practised by youth in Australia. It has little to say about synthetic cannabinoids, specific medicinal cannabinoids, or medicinal properties of marijuana. We address those adolescents genetically and environmentally vulnerable to mental illness, with specific emphasis on indigenous and neurodevelopmentally impaired young people who show patterns of usage and response very different to adults and more resilient members of the population. Specifically, the practice of mixing tobacco with marijuana by aboriginal youth, and the resultant coalition of dependencies, will likely presage a rise in pulmonary and central nervous system pathology over the coming decades. Aboriginal youth begin using earlier, persist longer, and take greater quantities of cannabis than non-indigenous youth. This paper recommends practical interventions to reduce the multiple health consequences of chronic cannabis use in young people, especially indigenous young people. Copyright © 2016. Published by Elsevier Ltd.

Parietal Lobe Volume Deficits in Adolescents with Schizophrenia and Adolescents with Cannabis Use Disorders

ERIC Educational Resources Information Center

Kumra, Sanjiv; Robinson, Paul; Tambyraja, Rabindra; Jensen, Daniel; Schimunek, Caroline; Houri, Alaa; Reis, Tiffany; Lim, Kelvin

2012-01-01

Objective: In early-onset schizophrenia (EOS), the earliest structural brain volumetric abnormalities appear in the parietal cortices. Early exposure to cannabis may represent an environmental risk factor for developing schizophrenia. This study characterized cerebral cortical gray matter structure in adolescents in regions of interest (ROIs) that…

The role of depressive symptoms in treatment of adolescent cannabis use disorder with N-Acetylcysteine.

PubMed

Tomko, Rachel L; Gilmore, Amanda K; Gray, Kevin M

2018-05-21

Relative to adults, adolescents are at greater risk of developing a cannabis use disorder (CUD) and risk may be exacerbated by co-occurring depressive symptoms. N-Acetylcysteine (NAC), an over-the-counter antioxidant, is thought to normalize glutamate transmission. Oxidative stress and glutamate transmission are disrupted in both depression and CUD. Thus, NAC may be particularly effective at promoting cannabis abstinence among adolescents with elevated depressive symptoms. Secondary analyses were conducted using a sub-sample of adolescents with CUD (N = 74) who participated in an 8-week randomized placebo-controlled clinical trial examining the efficacy of NAC for cannabis cessation. It was hypothesized that NAC would reduce severity of depressive symptoms, and that decreases depressive symptom severity would mediate decreases in positive weekly urine cannabinoid tests (11-nor-9-carboxy-Δ9-tetrahydrocannabinol). Additionally, it was expected that adolescents with greater severity of baseline depressive symptoms would be more likely to become abstinent when assigned NAC relative to placebo. Results from linear mixed models and generalized estimating equations did not suggest that NAC reduced severity of depressive symptoms, and the hypothesis that NAC's effect on cannabis cessation would be mediated by reduced depressive symptoms was not supported. However, an interaction between treatment condition and baseline severity of depressive symptoms as a predictor of weekly urine cannabinoid tests was significant, suggesting that NAC was more effective at promoting abstinence among adolescents with heightened baseline depressive symptoms. These secondary findings, though preliminary, suggest a need for further examination of the role of depressive symptoms in treatment of adolescent CUD with NAC. Copyright © 2018. Published by Elsevier Ltd.

Cannabis cue reactivity and craving among never, infrequent and heavy cannabis users.

PubMed

Henry, Erika A; Kaye, Jesse T; Bryan, Angela D; Hutchison, Kent E; Ito, Tiffany A

2014-04-01

Substance cue reactivity is theorized as having a significant role in addiction processes, promoting compulsive patterns of drug-seeking and drug-taking behavior. However, research extending this phenomenon to cannabis has been limited. To that end, the goal of the current work was to examine the relationship between cannabis cue reactivity and craving in a sample of 353 participants varying in self-reported cannabis use. Participants completed a visual oddball task whereby neutral, exercise, and cannabis cue images were presented, and a neutral auditory oddball task while event-related brain potentials (ERPs) were recorded. Consistent with past research, greater cannabis use was associated with greater reactivity to cannabis images, as reflected in the P300 component of the ERP, but not to neutral auditory oddball cues. The latter indicates the specificity of cue reactivity differences as a function of substance-related cues and not generalized cue reactivity. Additionally, cannabis cue reactivity was significantly related to self-reported cannabis craving as well as problems associated with cannabis use. Implications for cannabis use and addiction more generally are discussed.

Cannabis Cue Reactivity and Craving Among Never, Infrequent and Heavy Cannabis Users

PubMed Central

Henry, Erika A; Kaye, Jesse T; Bryan, Angela D; Hutchison, Kent E; Ito, Tiffany A

2014-01-01

Substance cue reactivity is theorized as having a significant role in addiction processes, promoting compulsive patterns of drug-seeking and drug-taking behavior. However, research extending this phenomenon to cannabis has been limited. To that end, the goal of the current work was to examine the relationship between cannabis cue reactivity and craving in a sample of 353 participants varying in self-reported cannabis use. Participants completed a visual oddball task whereby neutral, exercise, and cannabis cue images were presented, and a neutral auditory oddball task while event-related brain potentials (ERPs) were recorded. Consistent with past research, greater cannabis use was associated with greater reactivity to cannabis images, as reflected in the P300 component of the ERP, but not to neutral auditory oddball cues. The latter indicates the specificity of cue reactivity differences as a function of substance-related cues and not generalized cue reactivity. Additionally, cannabis cue reactivity was significantly related to self-reported cannabis craving as well as problems associated with cannabis use. Implications for cannabis use and addiction more generally are discussed. PMID:24264815

Larger Gray Matter Volume in the Basal Ganglia of Heavy Cannabis Users Detected by Voxel-Based Morphometry and Subcortical Volumetric Analysis.

PubMed

Moreno-Alcázar, Ana; Gonzalvo, Begoña; Canales-Rodríguez, Erick J; Blanco, Laura; Bachiller, Diana; Romaguera, Anna; Monté-Rubio, Gemma C; Roncero, Carlos; McKenna, Peter J; Pomarol-Clotet, Edith

2018-01-01

Background: Structural imaging studies of cannabis users have found evidence of both cortical and subcortical volume reductions, especially in cannabinoid receptor-rich regions such as the hippocampus and amygdala. However, the findings have not been consistent. In the present study, we examined a sample of adult heavy cannabis users without other substance abuse to determine whether long-term use is associated with brain structural changes, especially in the subcortical regions. Method: We compared the gray matter volume of 14 long-term, heavy cannabis users with non-using controls. To provide robust findings, we conducted two separate studies using two different MRI techniques. Each study used the same sample of cannabis users and a different control group, respectively. Both control groups were independent of each other. First, whole-brain voxel-based morphometry (VBM) was used to compare the cannabis users against 28 matched controls (HC1 group). Second, a volumetric analysis of subcortical regions was performed to assess differences between the cannabis users and a sample of 100 matched controls (HC2 group) obtained from a local database of healthy volunteers. Results: The VBM study revealed that, compared to the control group HC1, the cannabis users did not show cortical differences nor smaller volume in any subcortical structure but showed a cluster ( p < 0.001) of larger GM volume in the basal ganglia, involving the caudate, putamen, pallidum, and nucleus accumbens, bilaterally. The subcortical volumetric analysis revealed that, compared to the control group HC2, the cannabis users showed significantly larger volumes in the putamen ( p = 0.001) and pallidum ( p = 0.0015). Subtle trends, only significant at the uncorrected level, were also found in the caudate ( p = 0.05) and nucleus accumbens ( p = 0.047). Conclusions: This study does not support previous findings of hippocampal and/or amygdala structural changes in long-term, heavy cannabis users. It does

Therapeutic Effects of Prolonged Cannabidiol Treatment on Psychological Symptoms and Cognitive Function in Regular Cannabis Users: A Pragmatic Open-Label Clinical Trial.

PubMed

Solowij, Nadia; Broyd, Samantha J; Beale, Camilla; Prick, Julie-Anne; Greenwood, Lisa-Marie; van Hell, Hendrika; Suo, Chao; Galettis, Peter; Pai, Nagesh; Fu, Shanlin; Croft, Rodney J; Martin, Jennifer H; Yücel, Murat

2018-01-01

Introduction: Chronic cannabis use has been associated with impaired cognition and elevated psychological symptoms, particularly psychotic-like experiences. While Δ 9 -tetrahydrocannabinol (THC) is thought to be primarily responsible for these deleterious effects, cannabidiol (CBD) is purported to have antipsychotic properties and to ameliorate cognitive, symptomatic, and brain harms in cannabis users. However, this has never been tested in a prolonged administration trial in otherwise healthy cannabis users. Here, we report the first study of prolonged CBD administration to a community sample of regular cannabis users in a pragmatic trial investigating potential restorative effects of CBD on psychological symptoms and cognition. Materials and Methods: Twenty frequent cannabis users (16 male, median age 25 years) underwent a 10-week open-label trial of 200 mg of daily oral CBD treatment, while continuing to use cannabis as usual. The majority of participants were daily cannabis users who had used cannabis for several years (median 5.5 years of regular use). Participants underwent psychological and cognitive assessments at baseline (BL) and post-treatment (PT) and were monitored weekly throughout the trial. Results: CBD was well tolerated with no reported side effects; however, participants retrospectively reported reduced euphoria when smoking cannabis. No impairments to cognition were found, nor were there deleterious effects on psychological function. Importantly, participants reported significantly fewer depressive and psychotic-like symptoms at PT relative to BL, and exhibited improvements in attentional switching, verbal learning, and memory. Increased plasma CBD concentrations were associated with improvements in attentional control and beneficial changes in psychological symptoms. Greater benefits were observed in dependent than in nondependent cannabis users. Conclusions: Prolonged CBD treatment appears to have promising therapeutic effects for improving

Therapeutic Effects of Prolonged Cannabidiol Treatment on Psychological Symptoms and Cognitive Function in Regular Cannabis Users: A Pragmatic Open-Label Clinical Trial

PubMed Central

Solowij, Nadia; Broyd, Samantha J.; Beale, Camilla; Prick, Julie-Anne; Greenwood, Lisa-marie; van Hell, Hendrika; Suo, Chao; Galettis, Peter; Pai, Nagesh; Fu, Shanlin; Croft, Rodney J.; Martin, Jennifer H.; Yücel, Murat

2018-01-01

Abstract Introduction: Chronic cannabis use has been associated with impaired cognition and elevated psychological symptoms, particularly psychotic-like experiences. While Δ9-tetrahydrocannabinol (THC) is thought to be primarily responsible for these deleterious effects, cannabidiol (CBD) is purported to have antipsychotic properties and to ameliorate cognitive, symptomatic, and brain harms in cannabis users. However, this has never been tested in a prolonged administration trial in otherwise healthy cannabis users. Here, we report the first study of prolonged CBD administration to a community sample of regular cannabis users in a pragmatic trial investigating potential restorative effects of CBD on psychological symptoms and cognition. Materials and Methods: Twenty frequent cannabis users (16 male, median age 25 years) underwent a 10-week open-label trial of 200 mg of daily oral CBD treatment, while continuing to use cannabis as usual. The majority of participants were daily cannabis users who had used cannabis for several years (median 5.5 years of regular use). Participants underwent psychological and cognitive assessments at baseline (BL) and post-treatment (PT) and were monitored weekly throughout the trial. Results: CBD was well tolerated with no reported side effects; however, participants retrospectively reported reduced euphoria when smoking cannabis. No impairments to cognition were found, nor were there deleterious effects on psychological function. Importantly, participants reported significantly fewer depressive and psychotic-like symptoms at PT relative to BL, and exhibited improvements in attentional switching, verbal learning, and memory. Increased plasma CBD concentrations were associated with improvements in attentional control and beneficial changes in psychological symptoms. Greater benefits were observed in dependent than in nondependent cannabis users. Conclusions: Prolonged CBD treatment appears to have promising therapeutic effects for

The hazards of bad sleep-Sleep duration and quality as predictors of adolescent alcohol and cannabis use.

PubMed

Mike, Thomas B; Shaw, Daniel S; Forbes, Erika E; Sitnick, Stephanie L; Hasler, Brant P

2016-11-01

Although an association between adolescent sleep and substance use is supported by the literature, few studies have characterized the longitudinal relationship between early adolescent sleep and subsequent substance use. The current study examined the prospective association between the duration and quality of sleep at age 11 and alcohol and cannabis use throughout adolescence. The present study, drawn from a cohort of 310 boys taking part in a longitudinal study in Western Pennsylvania, includes 186 boys whose mothers completed the Child Sleep Questionnaire; sleep duration and quality at age 11 were calculated based on these reports. At ages 20 and 22, participants were interviewed regarding lifetime alcohol and cannabis use. Cox proportional hazard analysis was used to determine the association between sleep and substance use. After accounting for race, socioeconomic status, neighborhood danger, active distraction, internalizing problems, and externalizing problems, both the duration and quality of sleep at age 11 were associated with multiple earlier substance use outcomes. Specifically, less sleep was associated with earlier use, intoxication, and repeated use of both alcohol and cannabis. Lower sleep quality was associated with earlier alcohol use, intoxication, and repeated use. Additionally, lower sleep quality was associated with earlier cannabis intoxication and repeated use, but not first use. Both sleep duration and sleep quality in early adolescence may have implications for the development of alcohol and cannabis use throughout adolescence. Further studies to understand the mechanisms linking sleep and substance use are warranted. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Risks associated with the non-medicinal use of cannabis.

PubMed

Hoch, Eva; Bonnetn, Udo; Thomasius, Rainer; Ganzer, Florian; Havemann-Reinecke, Ursula; Preuss, Ulrich W

2015-04-17

Cannabis is the most commonly consumed illicit drug around the world; in Germany, about 4.5% of all adults use it each year. Intense cannabis use is associated with health risks. Evidence-based treatments are available for health problems caused by cannabis use. Selective literature review based on a search of the PubMed database, with special emphasis on systematic reviews, meta-analyses, cohort studies, randomized controlled trials (RCTs), case-control studies, and treatment guidelines. The delta-9-tetrahydrocannabinol content of cannabis products is rising around the world as a result of plant breeding, while cannabidiol, in contrast, is often no longer detectable. Various medical conditions can arise acutely after cannabis use, depending on the user's age, dose, frequency, mode and situation of use, and individual disposition; these include panic attacks, psychotic symptoms, deficient attention, impaired concentration, motor incoordination, and nausea. In particular, intense use of high doses of cannabis over many years, and the initiation of cannabis use in adolescence, can be associated with substance dependence (DSM-5; ICD-10), specific withdrawal symptoms, cognitive impairment, affective disorders, psychosis, anxiety disorders, and physical disease outside the brain (mainly respiratory and cardiovascular conditions). At present, the most effective way to treat cannabis dependence involves a combination of motivational encouragement, cognitive behavioral therapy, and contingency management (level 1a evidence). For adolescents, family therapy is also recommended (level 1a evidence). No pharmacological treatments can be recommended to date, as evidence for their efficacy is lacking. Further research is needed to elucidate the causal relationships between intense cannabis use and potential damage to physical and mental health. Health problems due to cannabis use can be effectively treated.

Cannabis use and adult ADHD symptoms.

PubMed

Fergusson, David M; Boden, Joseph M

2008-05-01

The present study examined the associations between cannabis use in adolescence and young adulthood and self-reported adult attention deficit/hyperactivity disorder (ADHD) symptoms in adulthood. A 25-year prospective longitudinal study of the health, development, and adjustment of a birth cohort of 1265 New Zealand children. Measures included assessments of adolescent and young adult cannabis use and ADHD symptoms at age 25, measures of childhood socioeconomic disadvantage, family adversity, childhood and early adolescent behavioural adjustment and cognitive ability, and adolescent and young adult other drug use. Cannabis use by age 25 was significantly (p<.0001) associated with increasing self-reported adult ADHD symptoms at age 25. Adjustment of the association for potentially confounding factors from childhood and early adolescence reduced the magnitude of the association, but it remained statistically significant (p<.0001). However, control for the mediating effects of other drug use in adolescence and early adulthood reduced the association between cannabis use and adult ADHD symptoms to statistical non-significance (p>.20). The current study suggested that the association between cannabis use and adult ADHD symptoms was mediated by other substance use that was associated with cannabis use. The results suggest that cannabis use leads to other drug use, which in turn leads to increased ADHD symptoms. However, it should be noted that the potential influence of such factors as genetic predispositions may still be unaccounted for.

Cannabis Use in Psychiatrie Patients.

PubMed

Chaudhury, S; Sudarsanan, S; Salujha, S K; Srivastava, K

2005-02-01

Cannabis abuse has been associated with psychiatric disorders. The pattern of cannabis use and incidence of cannabis dependence and cannabis psychosis among 471 consecutive patients admitted to a tertiary care psychiatric center was investigated. Cannabis use was reported by 67 (14.23%) patients of whom 42 (8.92%) were occasional users, 18 (3.82%) were classified as frequent users while 7 (1.49%) fulfilled criteria for cannabis dependence. 3 (0.64%) patients showed symptoms which were characteristic of cannabis psychosis. Among the 67 cannabis users, 56 (83.58%) had their first exposure to cannabis before entering service at 13-19 years of age. The remaining 14 (16.09%) began consuming cannabis 1-5 years after joining service. The reasons given for using cannabis were curiosity about its effects 32 (47.76%), peer pressure 17 (25.37%) or traditional use during festivals 18 (26.87%).

Adolescent brain maturation, the endogenous cannabinoid system and the neurobiology of cannabis-induced schizophrenia.

PubMed

Bossong, Matthijs G; Niesink, Raymond J M

2010-11-01

Cannabis use during adolescence increases the risk of developing psychotic disorders later in life. However, the neurobiological processes underlying this relationship are unknown. This review reports the results of a literature search comprising various neurobiological disciplines, ultimately converging into a model that might explain the neurobiology of cannabis-induced schizophrenia. The article briefly reviews current insights into brain development during adolescence. In particular, the role of the excitatory neurotransmitter glutamate in experience-dependent maturation of specific cortical circuitries is examined. The review also covers recent hypotheses regarding disturbances in strengthening and pruning of synaptic connections in the prefrontal cortex, and the link with latent psychotic disorders. In the present model, cannabis-induced schizophrenia is considered to be a distortion of normal late postnatal brain maturation. Distortion of glutamatergic transmission during critical periods may disturb prefrontal neurocircuitry in specific brain areas. Our model postulates that adolescent exposure to Δ9-tetrahydrocannabinol (THC), the primary psychoactive substance in cannabis, transiently disturbs physiological control of the endogenous cannabinoid system over glutamate and GABA release. As a result, THC may adversely affect adolescent experience-dependent maturation of neural circuitries within prefrontal cortical areas. Depending on dose, exact time window and duration of exposure, this may ultimately lead to the development of psychosis or schizophrenia. The proposed model provides testable hypotheses which can be addressed in future studies, including animal experiments, reanalysis of existing epidemiological data, and prospective epidemiological studies in which the role of the dose-time-effect relationship should be central. Copyright © 2010 Elsevier Ltd. All rights reserved.

User characteristics and effect profile of Butane Hash Oil: An extremely high-potency cannabis concentrate.

PubMed

Chan, Gary C K; Hall, Wayne; Freeman, Tom P; Ferris, Jason; Kelly, Adrian B; Winstock, Adam

2017-09-01

Recent reports suggest an increase in use of extremely potent cannabis concentrates such as Butane Hash Oil (BHO) in some developed countries. The aims of this study were to examine the characteristics of BHO users and the effect profiles of BHO. Anonymous online survey in over 20 countries in 2014 and 2015. Participants aged 18 years or older were recruited through onward promotion and online social networks. The overall sample size was 181,870. In this sample, 46% (N=83,867) reported using some form of cannabis in the past year, and 3% reported BHO use (n=5922). Participants reported their use of 7 types of cannabis in the past 12 months, the source of their cannabis, reasons for use, use of other illegal substances, and lifetime diagnosis for depression, anxiety and psychosis. Participants were asked to rate subjective effects of BHO and high potency herbal cannabis. Participants who reported a lifetime diagnosis of depression (OR=1.15, p=0.003), anxiety (OR=1.72, p<0.001), and a larger number of substance use (OR=1.29, p<0.001) were more likely to use BHO than only using high potency herbal cannabis. BHO users also reported stronger negative effects and less positive effects when using BHO than high potency herbal cannabis (p<0.001) CONCLUSION: Mental health problems and other illicit drug use were associated with use of BHO. BHO was reported to have stronger negative and weaker positive effects than high potency herbal cannabis. Copyright © 2017. Published by Elsevier B.V.

A survey of synthetic cannabinoid consumption by current cannabis users.

PubMed

Gunderson, Erik W; Haughey, Heather M; Ait-Daoud, Nassima; Joshi, Amruta S; Hart, Carl L

2014-01-01

Despite growing concern about the increased rates of synthetic cannabinoid (SC) use and their effects, only limited data are available that addresses these issues. This study assessed the extent of SC product use and reported effects among a cohort of adult marijuana and tobacco users. A brief telephone interview was conducted with individuals who had given permission to be contacted for future research while screening for a cannabis/nicotine dependence medication development study (NCT01204723). Respondents (N = 42; 88% participation rate) were primarily young adults, male, racially diverse, and high school graduates. Nearly all currently smoked tobacco and cannabis, with 86% smoking cannabis on 5 or more days per week. Nearly all (91%) were familiar with SC products, half (50%) reported smoking SC products previously, and a substantial minority (24%) reported current use (i.e., past month). Despite a federal ban on 5 common SCs, which went into effect on March 1, 2011, a number of respondents reported continued SC product use. Common reasons reported for use included, but were not limited to, seeking a new "high" similar to that produced by marijuana and avoiding drug use detection via a positive urine screen. The primary side effects were trouble thinking clearly, headache, dry mouth, and anxiety. No significant differences were found between synthetic cannabinoid product users (ever or current) and nonusers by demographics or other characteristics. Among current marijuana and tobacco users, SC product consumption was common and persisted despite a federal ban. The primary reasons for the use of SC-containing products seem to be to evade drug detection and to experience a marijuana-like high.

WHY NOT POT?: A Review of the Brain-based Risks of Cannabis.

PubMed

MacDonald, Kai; Pappas, Katherine

2016-01-01

In this review, we provide a historical perspective on marijuana, and survey contemporary research investigating its potential negative effects on the brain. We discuss the evidence regarding cannabis dependence, driving under the influence of cannabis, underachievement, inducing (or worsening) certain psychiatric conditions, and the potential for progression to use of more dangerous drugs-summarized by the acronym DDUMB, a cognitive tool that may help healthcare providers in their risk/benefit discussions with patients who use cannabis. We also review and discuss the impact of marijuana use on target populations, including adolescents (who are at increased risk of harm); heavy users; and people suffering from-or at high risk of- mental illness. While cannabis presents certain subjective, healthrelated, and pecuniary benefits to users, growers, and other entities, it is also associated with several brainbased risks. Understanding these risks aids clinicians and their patients in making informed and balanced decisions regarding the initiation or continuance of marijuana use.

Predicting onset of cannabis use in early adolescence: the interrelation between high-intensity pleasure and disruptive behavior. The TRAILS Study.

PubMed

Creemers, Hanneke E; van Lier, Pol A C; Vollebergh, Wilma A M; Ormel, Johan; Verhulst, Frank C; Huizink, Anja C

2009-11-01

Increased knowledge about the mechanisms by which some individuals are at risk for early onset of cannabis use might contribute to the improvement of prevention efforts. We focus on the roles of early-adolescent high-intensity pleasure, disruptive behavior, and their interplay in the prediction of onset of cannabis use 2 years later. Data from 81% (n = 1,804) of the participants (51.9% girls) of the Tracking Adolescents' Individual Lives Survey (TRAILS), a prospective general population study in the north of The Netherlands, were analyzed. Measures included parent-reported high-intensity pleasure, and parent- and self-reported general disruptive behavior, attention-deficit hyperactivity, oppositional problems, and conduct problems (Child Behavior Checklist/6-18 and Youth Self-Report) at ages 10-12. Onset of cannabis use was assessed at age 12-14 by means of self-reports. Analyses were carried out in Mplus. Early adolescent high-intensity pleasure and disruptive behavior, mainly conduct problems and to some extent attention-deficit hyperactivity, predicted the onset of cannabis use in adolescence. Although we found some mediation by general disruptive behavior, conduct problems, and attention-deficit hyperactivity, the contribution of high-intensity pleasure in predicting the onset of cannabis use was found to be mainly independent from disruptive behavior. The unique contribution of both high-intensity pleasure and disruptive behavior points in the direction of different pathways toward onset of cannabis use.

Cannabis use in young people: the risk for schizophrenia.

PubMed

Casadio, Paola; Fernandes, Cathy; Murray, Robin M; Di Forti, Marta

2011-08-01

Cannabis is one of the most commonly used illicit drugs, and despite the widely held belief that it is a safe drug, its long-term use has potentially harmful consequences. To date, the research on the impact of its use has largely been epidemiological in nature and has consistently found that cannabis use is associated with schizophrenia outcomes later in life, even after controlling for several confounding factors. While the majority of users can continue their use without adverse effects, it is clear from studies of psychosis that some individuals are more vulnerable to its effects than others. In addiction, evidence from both epidemiological and animal studies indicates that cannabis use during adolescence carries particular risk. Further studies are warranted given the increase in the concentration of the main active ingredient (Δ(9)-tetrahydrocannabinol) in street preparations of cannabis and a decreasing age of first-time exposure to cannabis. Copyright © 2011 Elsevier Ltd. All rights reserved.

ABCB1 C3435T polymorphism is associated with tetrahydrocannabinol blood levels in heavy cannabis users.

PubMed

Kebir, Oussama; Lafaye, Genevieve; Blecha, Lisa; Chaumette, Boris; Mouaffak, Fayçal; Laqueille, Xavier; Benyamina, Amine

2018-04-01

ABCB1 polymorphisms are known to modify drug pharmacokinetics but have yet to be studied for their role in generating and maintaining cannabis dependence. The objective of this study is to determine if ABCB1 C3435T (rs1045642) polymorphism may modulate Δ9-Tetrahydrocannabinol (THC) blood levels in a sample of heavy cannabis users. The study sample includes 39 Caucasian individuals, recruited in two French addictology centres, with isolated cannabis dependence and heavy use (defined as ≥ 7 joints per week). Each underwent clinical evaluation, cannabis blood metabolite dosage (THC, 11-OH-THC, and THC-COOH) and genotyping of ABCB1 C3435T polymorphism. In this population (males: 74.4%, average age 29.5 +/- 9), average cannabis use was 21 joints per week (median 12; range 7 - 80). T carriers (TT/CT) had significantly lower plasma THC levels (ng/ml) versus non T carriers (8 vs 15.70, significant), controlling for level of weekly use, 11-OH-THC and THC-COOH levels. Our results show that ABCB1 C3435T polymorphism may modulate serum THC levels in chronic heavy cannabis users. The exact mechanisms and roles that this may play in cannabis dependence genesis and evolution remain to be elucidated. These results should be controlled in a replication study using a larger population. Copyright © 2017 Elsevier B.V. All rights reserved.

Cannabis and social welfare assistance: a longitudinal study.

PubMed

Pedersen, Willy

2011-09-01

To investigate associations between cannabis use and subsequent receipt of social welfare assistance. The Young in Norway Longitudinal Study. A population-based Norwegian sample (n = 2606) was followed-up from adolescence to late 20s. Self-report data were merged with data from national registers. Data were extracted on the use of alcohol, tobacco and cannabis and other illegal substances. Information was also retrieved on socio-demographic and family factors, academic achievement, conduct problems and mental health. National registers provided data on social welfare assistance, educational level and crime statistics. We observed prospective bivariate associations between increasing levels of cannabis use and subsequent social welfare assistance (P < 0.0001). The associations were reduced after adjusting for a range of potentially confounding factors, but remained significant. Frequent cannabis users were at highly increased risk for subsequently receiving social welfare assistance. At 28 years, those with 50+ times cannabis use during the previous 12 months and had an odds ratio of 9.3 (95% confidence interval: 4.3-20.1) for receiving social welfare assistance in the following 2-year span. Users of cannabis also had longer periods of receiving social welfare assistance than others (P < 0.0001) and were less likely to leave the welfare assistance system (P < 0.0001). In Norway the use of cannabis is linked with subsequent receipt of social welfare assistance whether the consequences are related to use of the substance per se, or to cultural factors and the illegal status of the cannabis. Future research should attempt to understand the interactions of factors behind these associations. © 2011 The Author, Addiction © 2011 Society for the Study of Addiction.

Orbitofrontal volumes in early adolescence predict initiation of cannabis use: a 4-year longitudinal and prospective study.

PubMed

Cheetham, Ali; Allen, Nicholas B; Whittle, Sarah; Simmons, Julian G; Yücel, Murat; Lubman, Dan I

2012-04-15

There is growing evidence that long-term, heavy cannabis use is associated with alterations in regional brain volumes. Although these changes are frequently attributed to the neurotoxic effects of cannabis, it is possible that some abnormalities might predate use and represent markers of vulnerability. To date, no studies have examined whether structural brain abnormalities are present before the onset of cannabis use. This study aims to determine whether adolescents who have initiated cannabis use early (i.e., before age 17 years) show premorbid structural abnormalities in the amygdala, hippocampus, orbitofrontal cortex, and anterior cingulate cortex. Participants (n = 121) were recruited from primary schools in Melbourne, Australia, as part of a larger study examining adolescent emotional development. Participants underwent structural magnetic resonance imaging at age 12 years and were assessed for cannabis use 4 years later, at age 16 years. At the follow-up assessment, 28 participants had commenced using cannabis (16 female subjects [57%]), and 93 had not (43 female subjects [46%]). Smaller orbitofrontal cortex volumes at age 12 years predicted initiation of cannabis use by age 16 years. The volumes of other regions (amygdala, hippocampus, and anterior cingulate cortex) did not predict later cannabis use. These findings suggest that structural abnormalities in the orbitofrontal cortex might contribute to risk for cannabis exposure. Although the results have important implications for understanding neurobiological predictors of cannabis use, further research is needed to understand their relationship with heavier patterns of use in adulthood as well as later abuse of other substances. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Regular cannabis and alcohol use is associated with resting-state time course power spectra in incarcerated adolescents.

PubMed

Thijssen, Sandra; Rashid, Barnaly; Gopal, Shruti; Nyalakanti, Prashanth; Calhoun, Vince D; Kiehl, Kent A

2017-09-01

Cannabis and alcohol are believed to have widespread effects on the brain. Although adolescents are at increased risk for substance use, the adolescent brain may also be particularly vulnerable to the effects of drug exposure due to its rapid maturation. Here, we examined the association between cannabis and alcohol use duration and resting-state functional connectivity in a large sample of male juvenile delinquents. The present sample was drawn from the Southwest Advanced Neuroimaging Cohort, Youth sample, and from a youth detention facility in Wisconsin. All participants were scanned at the maximum-security facilities using The Mind Research Network's 1.5T Avanto SQ Mobile MRI scanner. Information on cannabis and alcohol regular use duration was collected using self-report. Resting-state networks were computed using group independent component analysis in 201 participants. Associations with cannabis and alcohol use were assessed using Mancova analyses controlling for age, IQ, smoking and psychopathy scores in the complete case sample of 180 male juvenile delinquents. No associations between alcohol or cannabis use and network spatial maps were found. Longer cannabis use was associated with decreased low frequency power of the default mode network, the executive control networks (ECNs), and several sensory networks, and with decreased functional network connectivity. Duration of alcohol use was associated with decreased low frequency power of the right frontoparietal network, salience network, dorsal attention network, and several sensory networks. Our findings suggest that adolescent cannabis and alcohol use are associated with widespread differences in resting-state time course power spectra, which may persist even after abstinence. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimating the economic value of British Columbia's domestic cannabis market: implications for provincial cannabis policy.

PubMed

Werb, Dan; Nosyk, Bohdan; Kerr, Thomas; Fischer, Benedikt; Montaner, Julio; Wood, Evan

2012-11-01

British Columbia (BC), Canada, is home to a large illegal cannabis industry that is known to contribute to substantial organized crime concerns. Although debates have emerged regarding the potential benefits of a legally regulated market to address a range of drug policy-related social problems, the value of the local (i.e., domestically consumed) cannabis market has not been characterized. Monte Carlo simulation methods were used to generate a median value and 95% credibility interval for retail expenditure estimates of the domestic cannabis market in BC. Model parameter estimates were obtained for the number of cannabis users, the frequency of cannabis use, the quantity of cannabis used, and the price of cannabis from government surveillance data and studies of BC cannabis users. The median annual estimated retail expenditure on cannabis by British Columbians was $407 million (95% Credibility Interval [CI]: $169-948 million). Daily users accounted for the bulk of the cannabis revenue, with a median estimated expenditure of approximately $357 million (95% CI: $149-845 million), followed by weekly users ($44 million, 95% CI: $18-90 million), and monthly users ($6 million, 95% CI: $3-12 million). When under-reporting of cannabis use was adjusted for, the estimated retail expenditure ranged from $443 million (95% CI: $185-1 billion) to $564 million (95% CI: $236-1.3 billion). Based on local consumption patterns, conservative estimates suggest that BC's domestic illegal cannabis trade is worth hundreds of millions of dollars annually. Given the value of this market and the failure and harms of law enforcement efforts to control the cannabis market, policymakers should consider regulatory alternatives. Copyright © 2012 Elsevier B.V. All rights reserved.

Cannabis Use Patterns and Motives: A Comparison of Younger, Middle-Aged, and Older Medical Cannabis Dispensary Patients

PubMed Central

Haug, Nancy A.; Padula, Claudia B.; Sottile, James E.; Vandrey, Ryan; Heinz, Adrienne J.; Bonn-Miller, Marcel O.

2017-01-01

Introduction Medical cannabis is increasingly being used for a variety of health conditions as more states implement legislation permitting medical use of cannabis. Little is known about medical cannabis use patterns and motives among adults across the lifespan. Methods The present study examined data collected at a medical cannabis dispensary in San Francisco, California. Participants included 217 medical cannabis patients who were grouped into age-defined cohorts (younger: 18–30, middle-aged: 31–50, and older: 51–72). The age groups were compared on several measures of cannabis use, motives and medical conditions using one-way ANOVAs, chi-square tests and linear regression analyses. Results All three age groups had similar frequency of cannabis use over the past month; however, the quantity of cannabis used and rates of problematic cannabis use were higher among younger users relative to middle-aged and older adults. The association between age and problematic cannabis use was moderated by age of regular use initiation such that earlier age of regular cannabis use onset was associated with more problematic use in the younger users, but not among older users. Middle-aged adults were more likely to report using medical cannabis for insomnia, while older adults were more likely to use medical cannabis for chronic medical problems such as cancer, glaucoma and HIV/AIDS. Younger participants reported cannabis use when bored at a greater rate than middle-aged and older adults. Conclusions Findings suggest that there is an age-related risk for problematic cannabis use among medical cannabis users, such that younger users should be monitored for cannabis use patterns that may lead to deleterious consequences. PMID:28340421

Cannabis use patterns and motives: A comparison of younger, middle-aged, and older medical cannabis dispensary patients.

PubMed

Haug, Nancy A; Padula, Claudia B; Sottile, James E; Vandrey, Ryan; Heinz, Adrienne J; Bonn-Miller, Marcel O

2017-09-01

Medical cannabis is increasingly being used for a variety of health conditions as more states implement legislation permitting medical use of cannabis. Little is known about medical cannabis use patterns and motives among adults across the lifespan. The present study examined data collected at a medical cannabis dispensary in San Francisco, California. Participants included 217 medical cannabis patients who were grouped into age-defined cohorts (younger: 18-30, middle-aged: 31-50, and older: 51-72). The age groups were compared on several measures of cannabis use, motives and medical conditions using one-way ANOVAs, chi-square tests and linear regression analyses. All three age groups had similar frequency of cannabis use over the past month; however, the quantity of cannabis used and rates of problematic cannabis use were higher among younger users relative to middle-aged and older adults. The association between age and problematic cannabis use was moderated by age of regular use initiation such that earlier age of regular cannabis use onset was associated with more problematic use in the younger users, but not among older users. Middle-aged adults were more likely to report using medical cannabis for insomnia, while older adults were more likely to use medical cannabis for chronic medical problems such as cancer, glaucoma and HIV/AIDS. Younger participants reported cannabis use when bored at a greater rate than middle-aged and older adults. Findings suggest that there is an age-related risk for problematic cannabis use among medical cannabis users, such that younger users should be monitored for cannabis use patterns that may lead to deleterious consequences. Copyright © 2017 Elsevier Ltd. All rights reserved.