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).
frequent cannabis use; cannabis dependence; young adults; qualitative research; life course approach; longitudinal study; education; employment
Cannabis is the most frequently abused illicit substance among adolescents and young adults. Genetic risk factors account for part of the variation in the development of Cannabis Dependence symptoms; however, no linkage studies have been performed for Cannabis Dependence symptoms. This study aimed to identify such loci.
324 sibling pairs from 192 families were assessed for Cannabis Dependence symptoms. Probands (13-19 years of age) were recruited from consecutive admissions to substance abuse treatment facilities. The siblings of the probands ranged in age from 12-25 years. A community-based sample of 4843 adolescents and young adults was utilized to define an age- and sex-corrected index of Cannabis Dependence vulnerability. DSM-IV Cannabis Dependence symptoms were assessed in youth and their family members with the Composite International Diagnostic Instrument -Substance Abuse Module. Siblings and parents were genotyped for 374 microsatellite markers distributed across the 22 autosomes (average inter-marker distance = 9.2 cM). Cannabis Dependence symptoms were analyzed using Merlin-regress, a regression-based method that is robust to sample selection.
Evidence for suggestive linkage was found on chromosome 3q21 near marker D3S1267 (LOD = 2.61), and on chromosome 9q34 near marker D9S1826 (LOD = 2.57).
This is the first reported linkage study of cannabis dependence symptoms. Other reports of linkage regions for illicit substance dependence have been reported near 3q21, suggesting that this region may contain a quantitative trait loci influencing cannabis dependence and other substance use disorders.
genetics; Cannabis; antisocial behavior; adolescence; linkage study
Background and Aims
Questions over the clinical significance of cannabis withdrawal have hindered its inclusion as a discrete cannabis induced psychiatric condition in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). This study aims to quantify functional impairment to normal daily activities from cannabis withdrawal, and looks at the factors predicting functional impairment. In addition the study tests the influence of functional impairment from cannabis withdrawal on cannabis use during and after an abstinence attempt.
Methods and Results
A volunteer sample of 49 non-treatment seeking cannabis users who met DSM-IV criteria for dependence provided daily withdrawal-related functional impairment scores during a one-week baseline phase and two weeks of monitored abstinence from cannabis with a one month follow up. Functional impairment from withdrawal symptoms was strongly associated with symptom severity (p = 0.0001). Participants with more severe cannabis dependence before the abstinence attempt reported greater functional impairment from cannabis withdrawal (p = 0.03). Relapse to cannabis use during the abstinence period was associated with greater functional impairment from a subset of withdrawal symptoms in high dependence users. Higher levels of functional impairment during the abstinence attempt predicted higher levels of cannabis use at one month follow up (p = 0.001).
Cannabis withdrawal is clinically significant because it is associated with functional impairment to normal daily activities, as well as relapse to cannabis use. Sample size in the relapse group was small and the use of a non-treatment seeking population requires findings to be replicated in clinical samples. Tailoring treatments to target withdrawal symptoms contributing to functional impairment during a quit attempt may improve treatment outcomes.
One in three young people use cannabis in Canada. Cannabis use can be associated with a variety of health problems which occur primarily among intensive/frequent users. Availability and effectiveness of conventional treatment for cannabis use is limited. While Brief Interventions (BIs) have been shown to result in short-term reductions of cannabis use risks or problems, few studies have assessed their longer-term effects. The present study examined 12-month follow-up outcomes for BIs in a cohort of young Canadian high-frequency cannabis users where select short-term effects (3 months) had previously been assessed and demonstrated.
N = 134 frequent cannabis users were recruited from among university students in Toronto, randomized to either an oral or a written cannabis BI, or corresponding health controls, and assessed in-person at baseline, 3-months, and 12-months. N = 72 (54 %) of the original sample were retained for follow-up analyses at 12-months where reductions in ‘deep inhalation/breathholding’ (Q = 13.1; p < .05) and ‘driving after cannabis use’ (Q = 9.3; p < .05) were observed in the experimental groups. Reductions for these indicators had been shown at 3-months in the experimental groups; these reductions were maintained over the year. Other indicators assessed remained overall stable in both experimental and control groups.
The results confirm findings from select other studies indicating the potential for longer-term and sustained risk reduction effects of BIs for cannabis use. While further research is needed on the long-term effects of BIs, these may be a valuable – and efficient – intervention tool in a public health approach to high-risk cannabis use.
Cannabis use; Frequent use; Young adults; Brief interventions; Prevention; Canada
The present study investigated the efficacy of nefazodone and bupropion-sustained release for treating cannabis dependence. A double blind, placebo controlled, piggy back design was employed to assess if nefazodone and bupropion-sustained release increased the probability of abstinence from cannabis and reduced the severity of cannabis dependence and cannabis withdrawal symptoms during a 13-week outpatient treatment program. One-hundred and six participants (M=32 years; Females n=25) were randomized to one of three medication conditions (nefazodone, bupropion-sustained release, or placebo) and participated in a weekly individually based coping skills therapy program. Results indicated a an increased probability of achieving abstinence over the course of treatment and a decrease in the severity of cannabis dependence and the withdrawal symptom of irritability. There were no significant effects demonstrated for nefazodone and bupropion-sustained release on cannabis use or cannabis withdrawal symptoms. The results indicate nefazodone and bupropion-sustained release may have limited efficacy in treating cannabis dependence.
Nefazodone; Bupropion; cannabis dependence; marijuana dependence
Cannabis is the most widely consumed illicit substance in America, with increasing rates of use. Some theorists tend to link frequency of use with cannabis dependence. Nevertheless, fewer than half of daily cannabis users meet DSM-IV-TR criteria for cannabis dependence. This study seeks to determine whether the negative aspects associated with cannabis use can be explained by a proxy measure of dependence instead of by frequency of use.
Over 2500 adult daily cannabis users completed an Internet survey consisting of measures of cannabis and other drug use, in addition to measures of commonly reported negative problems resulting from cannabis use. We compared those who met a proxy measure of DSM-IV-TR criteria for cannabis dependence (N = 1111) to those who did not meet the criteria (N = 1770). Cannabis dependent subjects consumed greater amounts of cannabis, alcohol, and a variety of other drugs. They also had lower levels of motivation, happiness, and satisfaction with life, with higher levels of depression and respiratory symptoms.
Although all of our subjects reported daily use, only those meeting proxy criteria for cannabis dependence reported significant associated problems. Our data suggest that dependence need not arise from daily use, but consuming larger amounts of cannabis and other drugs undoubtedly increases problems.
This study examined the treatment history and intention to seek treatment among 489 individuals interested in substance use disorder clinical trial participation. Opioid and cocaine users were more likely than cannabis users to report having received treatment for substance use in the past, and more likely than cannabis users to report planning to seek treatment for substance use before exposure to recruitment advertising. Free cost was the aspect of clinical trial participation that most influenced the decision to make an intake evaluation appointment for opioid-dependent patients as compared to cocaine and cannabis-dependent participants, and the availability of individual psychotherapy most influenced those who were cannabis-dependent. Cannabis-dependent individuals evaluated for clinical trial participation reported that recruitment advertising was an important factor in leading them to seek treatment. These results have implications for clinical trial recruitment as well as public health efforts directed at encouraging cannabis-dependent individuals to seek treatment.
Opioids; cannabis; cocaine; recruitment
Cannabis is the most frequently used illegal psychoactive substance in the world. There is a significant increase in the number of treatment admissions for cannabis use disorders in the past few years, and the majority of cannabis-dependent individuals who enter treatment have difficulty in achieving and maintaining abstinence. Thus, there is increased need for medications that can be used to treat this population. So far, no medication has been shown broadly and consistently effective; none has been approved by any national regulatory authority. Medications studied have included those that alleviate symptoms of cannabis withdrawal (e.g., dysphoric mood, irritability), those that directly affect endogenous cannabinoid receptor function, and those that have shown efficacy in treatment of other drugs of abuse or psychiatric conditions. Buspirone is the only medication to date that has shown efficacy for cannabis dependence in a controlled clinical trial. Results from controlled human laboratory studies and small open-label clinical trials suggest that dronabinol, the COMT inhibitor entacapone, and lithium may warrant further study. Recent pre-clinical studies suggest the potential of fatty acid amide hydrolase (FAAH) inhibitors such as URB597, endocannabinoid-metabolizing enzymes, and nicotinic alpha7 receptor antagonists such as methyllycaconitine (MLA). Controlled clinical trials are needed to evaluate the clinical efficacy of these medications and to validate the laboratory models being used to study candidate medications.
Cannabis; withdrawal; dependence; pharmacotherapy; treatment
There are no FDA-approved pharmacotherapies for cannabis dependence. Cannabis is the most widely used illicit drug in the world, and patients seeking treatment for primary cannabis dependence represent 25% of all substance use admissions. We conducted a phase IIa proof-of-concept pilot study to examine the safety and efficacy of a calcium channel/GABA modulating drug, gabapentin, for the treatment of cannabis dependence. A 12-week, randomized, double-blind, placebo-controlled clinical trial was conducted in 50 unpaid treatment-seeking male and female outpatients, aged 18–65 years, diagnosed with current cannabis dependence. Subjects received either gabapentin (1200 mg/day) or matched placebo. Manual-guided, abstinence-oriented individual counseling was provided weekly to all participants. Cannabis use was measured by weekly urine toxicology and by self-report using the Timeline Followback Interview. Cannabis withdrawal symptoms were assessed using the Marijuana Withdrawal Checklist. Executive function was measured using subtests from the Delis–Kaplan Executive Function System. Relative to placebo, gabapentin significantly reduced cannabis use as measured both by urine toxicology (p=0.001) and by the Timeline Followback Interview (p=0.004), and significantly decreased withdrawal symptoms as measured by the Marijuana Withdrawal Checklist (p<0.001). Gabapentin was also associated with significantly greater improvement in overall performance on tests of executive function (p=0.029). This POC pilot study provides preliminary support for the safety and efficacy of gabapentin for treatment of cannabis dependence that merits further study, and provides an alternative conceptual framework for treatment of addiction aimed at restoring homeostasis in brain stress systems that are dysregulated in drug dependence and withdrawal.
cannabis dependence; marijuana withdrawal; executive function; gabapentin; addiction treatment; randomized controlled trial; addiction & substance abuse; GABA; clinical pharmacology/clinical trials; psychopharmacology; cannabis dependence; marijuana withdrawal; executive function; gabapentin; addiction treatment; controlled trial
Cannabis can produce and/or exacerbate psychotic symptoms in vulnerable individuals. Early exposure to cannabis, particularly in combination with genetic factors, increases the risk of a subsequent, primary, psychotic disorder. Because paranoia is a common feature of stimulant abuse and cocaine dependent individuals frequently endorse a history of cannabis abuse, we examined whether early cannabis exposure, in conjunction with polymorphic variation in the catechol-O-methyl transferase gene (COMT Val158Met), influences the risk for cocaine-induced paranoia (CIP).
Cannabis-use history was obtained in 1140 cocaine-dependent individuals from a family-based (affected sibling pair) study using the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA). Logistic regression and generalized estimating equations analyses were used to examine the role of adolescent-onset cannabis use (≤ 15 yrs of age) on CIP risk, both controlling for previously implicated CIP risk factors and familial relationships, and considering potential interactions with COMT Val158Met genotype.
Cocaine-dependent individuals who endorsed CIP had significantly higher rates of adolescent-onset cannabis use than those without CIP (62.2% vs. 50.2%; χ2 = 15.2, df = 1, p < 0.0001), a finding that remained after controlling for sibling correlations and other risk factors. There were no effects of COMT genotype or genotype by early cannabis onset interactions. A modest (OR = 1.4) and nearly significant (p = 0.053) effect of CIP status in probands on CIP status in siblings was also noted.
Adolescent-onset cannabis use increases the risk of CIP in cocaine dependent individuals. COMT genotype and its interaction with early cannabis exposure did not emerge as significant predictors of CIP. In addition, trait vulnerability to CIP may also be familial in nature.
cocaine; paranoia; cannabis; adolescent
This article reviews established and emerging treatment options for cannabis dependence. Cannabis dependence poses some distinct challenges for treatment providers. The evolving sociocultural context of cannabis use for medical purposes, policy liberalization, and societal normalization has contributed to decreased perceived risk and increased acceptability of use. Simultaneously, the comparatively lower “severity” of cannabis-associated consequences makes it more difficult for some users to recognize the impact of their use and establish an enduring commitment to change. As a result, many treatment seekers are reluctant to accept traditional abstinence-based goals.
Among treatment providers, consensus has not been established about the value of non-abstinence goals, such as moderation and harm reduction. Notwithstanding these challenges, the high prevalence of cannabis dependence, its strong association with co-morbid mental health problems, and the difficulty of achieving cannabis cessation ensure that many psychiatrists will face patients with cannabis dependence. While no pharmacotherapy has been approved for cannabis dependence, a number of promising approaches are in development. Psychotherapy studies are establishing a number of evidence-based models and techniques in the treatment resources for patients in need.
Cannabis; Marijuana; Endocannabinoids; Dependence; Withdrawal; Treatment; Therapy
Naltrexone is a theoretically promising alternative to agonist substitution treatment for opioid dependence, but its effectiveness has been severely limited by poor adherence. This study examined, in an independent sample, a previously observed association between moderate cannabis use and improved retention in naltrexone treatment. Opioid dependent patients (N = 63), admitted for inpatient detoxification and induction onto oral naltrexone, and randomized into a six-month trial of intensive behavioral therapy (Behavioral Naltrexone Therapy) versus a control behavioral therapy (Compliance Enhancement), were classified into three levels of cannabis use during treatment based on biweekly urine toxicology: abstinent (0% cannabis positive urine samples); intermittent use (1% to 79% cannabis positive samples); and consistent use (80% or greater cannabis positive samples). Intermittent cannabis users showed superior retention in naltrexone treatment (median days retained = 133; mean = 112.8, SE = 17.5), compared to abstinent (median = 35; mean = 47.3, SE = 9.2) or consistent users (median = 35; mean = 68.3, SE = 14.1) (log rank = 12.2, df = 2, p = .002). The effect remained significant in a Cox model after adjustment for baseline level of heroin use and during treatment level of cocaine use. Intermittent cannabis use was also associated with greater adherence to naltrexone pill-taking. Treatment interacted with cannabis use level, such that intensive behavioral therapy appeared to moderate the adverse prognosis in the consistent cannabis use group. The association between moderate cannabis use and improved retention on naltrexone treatment was replicated. Experimental studies are needed to directly test the hypothesis that cannabinoid agonists exert a beneficial pharmacological effect on naltrexone maintenance and to understand the mechanism.
Although cannabis is the most widely abused illicit drug, little is known about the prevalence of cannabis withdrawal, its factor structure, clinical validity and psychiatric correlates in the general population.
National Epidemiologic Survey on Alcohol and Related Conditions participants were assessed with structured in-person interviews covering substance history, DSM-IV Axis I and II disorders, and withdrawal symptoms after cessation of use. Of these, 2,613 had been frequent cannabis users (≥3 times/week), and a cannabis-only subset (N=1,119) never binge-drank or used other drugs ≥3 times/week.
In the full sample and subset, 44.3% (se 1.19) and 44.2% (se 1.75), respectively, experienced ≥2 cannabis withdrawal symptoms, while 34.4% (se 1.21) and 34.1% (se 1.76), respectively, experienced ≥3 symptoms. The symptoms formed two factors, one characterized by weakness, hypersomnia, and psychomotor retardation, and the second by anxiety, restlessness, depression, insomnia. Both symptom types were associated with significant distress/impairment (p<.01), substance use to relieve/avoid cannabis withdrawal symptoms (p<.01), and quantity of cannabis use (among the cannabis-only users p<.05). Panic (p<.01) and personality disorders (p<.01) associated with anxiety symptoms in both samples, family history of drug problems with weakness symptoms in the subset (p=.01), and depression with both sets of symptoms in the subset (p<.05).
Cannabis withdrawal was prevalent and clinically significant among a representative sample of frequent cannabis users. Similar results in the subset without polysubstance abuse confirmed the specificity of symptoms to cannabis. Cannabis withdrawal should be added to DSM-V and the etiology and treatment implications of cannabis withdrawal symptoms investigated.
cannabis; marijuana; withdrawal; general population; DSM-V
While most individuals initiate their use of tobacco prior to onset of cannabis use, recent reports have identified a smaller subset of youth who report onset of cannabis use prior to tobacco use. In this study, we characterize patterns of cannabis and tobacco use (tobacco but not cannabis, cannabis but not tobacco or both) and compare the factors associated with onset of tobacco before cannabis and cannabis before tobacco.
Data on 1812 offspring aged 12–32 years, drawn from two related offspring of Vietnam Era twin studies, were used. Individuals were divided into tobacco but not cannabis (T), cannabis but not tobacco (C) and users of both substances (CT). Those who used both could be further classified by the timing of onset of tobacco and cannabis use. Multinomial logistic regression was used to characterize the groups using socio-demographic and psychiatric covariates. Furthermore, data on parental smoking and drug use was used to identify whether certain groups represented greater genetic or environmental vulnerability.
22% (n=398) reported T, 3% (n=55) reported C and 44% reported CT (n=801). Of the 801 CT individuals, 72.8% (n=583), 9.9% (n=77) and 17.3% (n=139) reported onset of tobacco before cannabis, cannabis before tobacco and onsets at the same age. C users were as likely as CT users to report peer drug use and psychopathology, such as conduct problems while CT was associated with increased tobacco use relative to T. Onset of tobacco prior to cannabis, when compared onset of cannabis before tobacco or reporting initiation at the same age was associated with greater cigarettes smoked per day, however no distinct factors distinguished the group with onset of cannabis before tobacco from those with initiation at the same age.
A small subset of individuals report cannabis without tobacco use. Of those who use both cannabis and tobacco, a small group report cannabis use prior to tobacco use. Follow-up analyses that chart the trajectories of these individuals will be required to delineate their course of substance involvement.
Cannabis; Tobacco; Reverse Gateways
Risk for substance use disorder is frequently transmitted across generations due to significant heritability.
This longitudinal study tests the hypothesis that initial exposure to cannabis in youths having high transmissible risk is a signal event promoting development of cannabis use disorder (CUD).
At age 22, 412 men were classified into three groups: (1) lifetime CUD, (2) cannabis use without CUD, and (3) no lifetime cannabis use. Transmissible risk, quantified on a continuous scale using the previously validated transmissible liability index (TLI), along with cannabis use and CUD were documented at 10–12, 12–14, 16, 19, and 22 years of age.
The CUD group scored higher on the TLI before they began cannabis use compared to the other two groups. In addition, a progressive increase in TLI severity was evinced by the CUD group beginning at the time of initiation of cannabis use whereas cannabis users who did not subsequently develop CUD exhibited a decline in transmissible risk following first exposure.
Initial use of cannabis potentiates development of CUD in youths who are at high transmissible risk but is inconsequential in youths having low risk. The practical ramifications of these results for prevention are discussed.
Transmissible Liability; Addiction; Cannabis use disorder; Longitudinal modeling
Background: Population-based surveys demonstrate cannabis users are more likely to use both illicit and licit substances, compared with non-cannabis users. Few studies have examined the substance use profiles of cannabis users referred for treatment. Co-existing mental health symptoms and underlying cannabis-related beliefs associated with these profiles remains unexplored.
Methods: Comprehensive drug use and dependence severity (Severity of Dependence Scale-Cannabis) data were collected on a sample of 826 cannabis users referred for treatment. Patients completed the General Health Questionnaire, Cannabis Expectancy Questionnaire, Cannabis Refusal Self-Efficacy Questionnaire, and Positive Symptoms and Manic-Excitement subscales of the Brief Psychiatric Rating Scale. Latent class analysis was performed on last month use of drugs to identify patterns of multiple drug use. Mental health comorbidity and cannabis beliefs were examined by identified drug use pattern.
Results: A three-class solution provided the best fit to the data: (1) cannabis and tobacco users (n = 176), (2) cannabis, tobacco, and alcohol users (n = 498), and (3) wide-ranging substance users (n = 132). Wide-ranging substance users (3) reported higher levels of cannabis dependence severity, negative cannabis expectancies, lower opportunistic, and emotional relief self-efficacy, higher levels of depression and anxiety and higher manic-excitement and positive psychotic symptoms.
Conclusion: In a sample of cannabis users referred for treatment, wide-ranging substance use was associated with elevated risk on measures of cannabis dependence, co-morbid psychopathology, and dysfunctional cannabis cognitions. These findings have implications for cognitive-behavioral assessment and treatment.
cannabis; latent class; drugs; comorbidity; expectancy; self-efficacy; treatment seeking
Cannabis withdrawal can be a negative reinforcer for relapse, but little is known about its association with demographic characteristics.
Evaluate the association of demographic characteristics with the experience of cannabis withdrawal.
Retrospective self-report of a “serious” cannabis quit attempt without formal treatment in a convenience sample of 104 non-treatment-seeking, adult cannabis smokers (mean age 35 years, 52% white, 78% male) with no other current substance use disorder (except tobacco) or chronic health problems. Reasons for quitting, coping strategies to help quit, and 18 specific withdrawal symptoms were assessed by questionaire.
Among withdrawal symptoms, only anxiety, increased sex drive, and craving showed significant associations with age, race, or sex. Women were more likely than men to report a physical withdrawal symptom (OR = 3.2, 95% CI = .99–10.4, p = .05), especially upset stomach. There were few significant demographic associations with coping strategies or reasons for quitting.
Conclusions and Scientific Significance
This small study suggests that there are few robust associations between demographic characteristics and cannabis withdrawal. Future studies with larger samples are needed. Attention to physical withdrawal symptoms in women may help promote abstinence.
Age; cannabis; marijuana; quitting; race; relapse; sex; withdrawal
Cannabis consumption is central to diagnosis of DSM-IV cannabis abuse and dependence; yet, most research on cannabis disorders has focused just on diagnosis or criteria. The present study examines the ability of a frequency and quantity measure of cannabis use as well as cannabis abuse and dependence criteria to discriminate between individuals across the cannabis use disorder continuum.
A representative sample of USA adults in 2001–2002 (N=43,093) were queried about past year frequency of cannabis use and each DSM-IV cannabis abuse and dependence criterion. Factor analysis and item response theory (IRT) models were used to define the relationship between observed responses and the underlying unobserved latent trait (cannabis use disorder severity).
Factor analyses demonstrated a good fit for a one factor model both with and without the cannabis use criterion and no differential criterion functioning was demonstrated across sex. The IRT model including the cannabis use criterion had discriminatory power comparable to the model without the cannabis use criterion and exceeded the informational value of the model without the cannabis use criterion in mild and moderate ranges of the severity continuum.
Factor and IRT analyses disprove the validity of the DSM-IV abuse and dependence distinction: A single dimension represented the criteria rather than the two implied by the separate abuse/dependence categories. IRT models identified some dependence criteria to be among the mildest and some abuse criteria to be among the most severe —results inconsistent with the interpretation of DSM-IV cannabis abuse as a milder disorder or prodrome of cannabis dependence. The consumption criterion defined the mild end of the cannabis use disorder continuum and its excellent psychometric properties strongly supported its inclusion as a DSM -V criterion for cannabis use disorders. Additional work is needed to identify candidate consumption criteria across all drugs that apply to the milder end of the severity continuum while also improving overall model performance and clinical diagnostic utility.
Cannabis use disorders; IRT analysis; Cannabis use
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.
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.
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.
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.
Approach avoidance task; approach-bias; cannabis; cannabis use disorder; craving; dependence
To determine whether cannabinoid-positive urine specimens in heroin-dependent outpatients predict other drug use or impairments in psychosocial functioning, and whether such outcomes are better predicted by cannabis-use disorders than by cannabis use itself.
Retrospective analyses of three clinical trials; each included a behavioral intervention (contingency management) for cocaine or heroin use during methadone maintenance. Trials lasted 25–29 weeks; follow-up evaluations occurred 3, 6, and 12 months posttreatment. For the present analyses, data were pooled across trials where appropriate.
Urban outpatient methadone clinic.
408 polydrug abusers meeting methadone-maintenance criteria.
Participants were categorized as nonusers, occasional users, or frequent users of cannabis based on thrice-weekly qualitative urinalyses. Cannabis-use disorders were assessed with the Diagnostic Interview Schedule III-R. Outcome measures included proportion of cocaine- and opiate-positive urines and the Addiction Severity Index (at intake and follow-ups).
Cannabis use was not associated with retention, use of cocaine or heroin, or any other outcome measure during or after treatment. Our analyses had a power of .95 to detect an r2 of .11 between cannabis use and heroin or cocaine use; the r2 we detected was less than .03 and nonsignificant. A previous finding that cannabis use predicted lapse to heroin use in heroin-abstinent patients did not replicate in our sample. However, cannabis-use disorders were weakly associated with psychosocial problems at posttreatment follow-up.
Cannabinoid-positive urines need not be a major focus of clinical attention during treatment for opiate dependence, unless patients report symptoms of cannabis-use disorders.
cannabis; methadone maintenance; treatment outcome
Cannabis dependence is a significant public health problem. Because there are
no approved medications for this condition, treatment must rely on
behavioral approaches empirically complemented by such lifestyle change as
To examine the effects of moderate aerobic exercise on cannabis craving and
use in cannabis dependent adults under normal living conditions.
Participants attended 10 supervised 30-min treadmill exercise sessions
standardized using heart rate (HR) monitoring (60–70% HR
reserve) over 2 weeks. Exercise sessions were conducted by exercise
physiologists under medical oversight.
Sedentary or minimally active non-treatment seeking cannabis-dependent adults
(n = 12, age 25±3 years, 8 females) met criteria
for primary cannabis dependence using the Substance Abuse module of the
Structured Clinical Interview for DSM-IV (SCID).
Self-reported drug use was assessed for 1-week before, during, and 2-weeks
after the study. Participants viewed visual cannabis cues before and after
exercise in conjunction with assessment of subjective cannabis craving using
the Marijuana Craving Questionnaire (MCQ-SF).
Daily cannabis use within the run-in period was 5.9 joints per day
(SD = 3.1, range 1.8–10.9). Average cannabis use
levels within the exercise (2.8 joints, SD = 1.6, range
0.9–5.4) and follow-up (4.1 joints, SD = 2.5,
range 1.1–9.5) periods were lower than during the run-in period (both
P<.005). Average MCQ factor scores for the pre- and post-exercise craving
assessments were reduced for compulsivity (P = .006),
emotionality (P = .002), expectancy (P
= .002), and purposefulness (P
The findings of this pilot study warrant larger, adequately powered
controlled trials to test the efficacy of prescribed moderate aerobic
exercise as a component of cannabis dependence treatment. The
neurobiological mechanisms that account for these beneficial effects on
cannabis use may lead to understanding of the physical and emotional
underpinnings of cannabis dependence and recovery from this disorder.
Cannabis use disorders have been recently identified as a relevant clinical issue: a subset of cannabis smokers seeks treatment for their cannabis use, yet few succeed in maintaining long-term abstinence. The rewarding and positive reinforcing effects of the primary psychoactive component of smoked cannabis, delta-9-tetrahydrocannabinol (THC) are mediated by the cannabinoid CB1 receptor. The CB1 receptor has also been shown to mediate cannabinoid dependence and expression of withdrawal upon cessation of drug administration, a phenomenon verified across species. This paper will review findings implicating the CB1 receptor in the behavioural effects of exogenous cannabinoids with a focus on cannabinoid dependence and reinforcement, factors that contribute to the maintenance of chronic cannabis smoking despite negative consequences. Opioidergic modulation of these effects is also discussed.
This study compared the acute phase (12-week) efficacy of fluoxetine versus placebo for the treatment of the depressive symptoms and the cannabis use of adolescents and young adults with comorbid major depression (MDD) and an cannabis use disorder (CUD)(cannabis dependence or cannabis abuse). We hypothesized that fluoxetine would demonstrate efficacy versus placebo for the treatment of the depressive symptoms and the cannabis use of adolescents and young adults with comorbid MDD/CUD.
We conducted the first double-blind placebo-controlled study of fluoxetine in adolescents and young adults with comorbid MDD/CUD. All participants in both treatment groups also received manual-based cognitive behavioral therapy (CBT) and motivation enhancement therapy (MET) during the 12-week course of the study.
Fluoxetine was well tolerated in this treatment population. No significant group-by-time interactions were noted for any depression-related or cannabis-use related outcome variable over the 12-week study. Subjects in both the fluoxetine group and the placebo group showed significant within-group improvement in depressive symptoms and in number of DSM diagnostic criteria for a CUD. Large magnitude decreases in depressive symptoms were noted in both treatment groups, and end-of-study levels of depressive symptoms were low in both treatment groups.
Fluoxetine did not demonstrate greater efficacy than placebo for treating either the depressive symptoms or the cannabis-related symptoms of our study sample of comorbid adolescents and young adults. The lack of a significant between-group difference in these symptoms may reflect limited medication efficacy, or may result from efficacy of the CBT/MET psychotherapy or from limited sample size.
Cannabis Use Disorder; Major Depressive Disorder; Fluoxetine; Cognitive Behavioral Therapy; Motivation Enhancement Therapy
Evidence suggests that cannabis users are at increased risk for cigarette smoking – if so, this may potentially be the single most alarming public health challenge posed by cannabis use. We examine whether cannabis use prior to age 17 is associated with an increased likelihood of DSM-IV nicotine dependence and the extent to which genetic and environmental factors contribute to this association.
A population-based cohort of 24–36 year old Australian male and female twins (N=6,257, 286 and 229 discordant pairs) was used. The cotwin-control method, with twin pairs discordant for early cannabis use, was used to examine whether after controlling for genetic and familial environmental background, there was evidence for an additional influence of early cannabis use on DSM-IV nicotine dependence. Bivariate genetic models were fitted to the full dataset to quantify the genetic correlation between early cannabis use and nicotine dependence.
The early cannabis-using twin was about twice as likely to report nicotine dependence, when compared to their co-twin who had experimented with cigarettes but never used cannabis. Even when analyses were restricted to cannabis users, earlier age cannabis use onset conferred greater risk (1.7) for nicotine dependence than did later onset. This association was largely governed by common genetic liability to early cannabis use and nicotine dependence as demonstrated by genetic correlations of 0.41–0.52.
Early-onset cannabis users are at increased risk for nicotine dependence but this risk is largely attributable to common genetic vulnerability. There is no evidence for a causal relationship between cannabis use and nicotine dependence.
cannabis; nicotine dependence; discordant twins; Mx; twin modeling; genetic
Cannabis is the most widely used illicit drug. Acute cannabis administration increases blood pressure and heart rate and tolerance develops to these effects with heavy use. A valid and reliable withdrawal syndrome occurs in most daily users, but few studies have assessed the cardiovascular effects of withdrawal. The objective of this report is to describe unexpected changes in cardiovascular function during brief periods of supervised cannabis use and abstinence in daily cannabis users.
A within-subjects ABAC crossover study in which inpatient volunteers smoked cannabis ad-libitum (A), and abstained from cannabis (B/C). Vital signs were obtained three times daily during eleven inpatient days for thirteen daily cannabis users (11 Male, 8 African American).
Blood pressure increased significantly during periods of cannabis abstinence compared with periods of cannabis use. The magnitude of increase was substantial in a subset (N=6) of participants, with mean increases of up to 22.8mmHg systolic and 12.3mmHg diastolic blood pressure observed. Heart rate also increased during abstinence when measures collected during periods of acute intoxication were excluded, but the magnitude of effect was not clinically significant.
Abrupt cessation of heavy cannabis use may cause clinically significant increases in blood pressure in a subset of users. Blood pressure should be monitored among those attempting to reduce or quit frequent cannabis use, particularly those with preexisting hypertension. The time course of this effect is currently unknown and requires further study.
Cannabis; Marijuana; Blood Pressure; Hypertension; Withdrawal