Relapse in outpatient treatment for marijuana dependence

Long-term effects of THC exposure on reward learning and motivated behavior in adolescent and adult male rats

RATIONALE

The endocannabinoid system makes critical contributions to reward processing, motivation, and behavioral control. Repeated exposure to THC or other cannabinoid drugs can cause persistent adaptions in the endocannabinoid system and associated neural circuitry. It remains unclear how such treatments affect the way rewards are processed and pursued.

OBJECTIVE AND METHODS

We examined if repeated THC exposure (5 mg/kg/day for 14 days) during adolescence or adulthood led to long-term changes in rats' capacity to flexibly encode and use action-outcome associations for goal-directed decision making. Effects on hedonic feeding and progressive ratio responding were also assessed.

RESULTS

THC exposure had no effect on rats' ability to flexibly select actions following reward devaluation. However, instrumental contingency degradation learning, which involves avoiding an action that is unnecessary for reward delivery, was augmented in rats with a history of adult but not adolescent THC exposure. THC-exposed rats also displayed more vigorous instrumental behavior in this study, suggesting a motivational enhancement. A separate experiment found that while THC exposure had no effect on hedonic feeding behavior, it increased rats' willingness to work for food on a progressive ratio schedule, an effect that was more pronounced when THC was administered to adults. Adolescent and adult THC exposure had opposing effects on the CB1 receptor dependence of progressive ratio performance, decreasing and increasing sensitivity to rimonabant-induced behavioral suppression, respectively.

CONCLUSIONS

Our findings reveal that exposure to a translationally relevant THC exposure regimen induces long-lasting, age-dependent alterations in cognitive and motivational processes that regulate the pursuit of rewards.

The Relationship Between Behavioral Inhibition and Approach Motivation Systems (BIS/BAS) and Intrinsic Brain Network Connectivity in Adult Cannabis Users

Dampened behavioral inhibition and overactive behavioral approach motivation systems (i.e. BIS/BAS) are associated with cannabis use disorder (CUD), although the underlying neural mechanisms of these alterations have not yet been examined. The brain’s executive control network (ECN) plays a role in decision-making and is associated with BIS/BAS. In this study, we tested the hypothesis that altered ECN resting-state functional connectivity (rsFC) underlies dysfunctional behavioral inhibition and approach motivation in cannabis users. To that end, we collected resting-state functional magnetic resonance imaging scans in 86 cannabis using adults and 59 non-using adults to examine group differences in the relationship between ECN rsFC and BIS/BAS. Our results showed that BIS was positively correlated with left ECN rsFC in cannabis users, while it was positively correlated with right ECN rsFC in non-users. There was a trend-level moderation effect of group on the association between BIS/BAS and ECN rsFC, showing a weaker association in BIS/BAS and ECN rsFC in cannabis users compared to non-users. An exploratory mediation analysis found that the severity of CUD mediated the relationship between users’ BIS scores and left ECN rsFC. These findings suggest that cannabis use may lead to dysregulation in typical ECN functional organization related to BIS/BAS.

Ketamine-facilitated behavioral treatment for cannabis use disorder: A proof of concept study

BACKGROUND

Sub-anesthetic ketamine infusions may benefit a range of psychiatric conditions, including alcohol and cocaine use disorders. Currently, there are no effective pharmacological treatments for cannabis use disorder.

OBJECTIVES

The objective of this uncontrolled proof of concept trial was to test the feasibility, tolerability, and potential therapeutic effects of integrating ketamine infusions with a behavioral platform of motivational enhancement therapy and mindfulness-based relapse prevention in treating cannabis use disorder (CUD).

METHODS

Eight cannabis-dependent individuals (four female, four male) receiving motivational enhancement therapy and mindfulness-based relapse prevention behavioral treatments completed this single-blind outpatient 6-week study. Participants received either one or two infusions of ketamine (0.71 mg/kg [infusion 1]; 1.41 mg/kg [infusion 2] for non-responders) during the study. Participants self-reported cannabis use (Timeline Follow-Back) and underwent an assessment of confidence in abstaining from using cannabis (Drug-Taking Confidence Questionnaire) at predetermined time points throughout the study.

RESULTS

Ketamine infusions were well-tolerated and there were no adverse events. Frequency of cannabis use decreased significantly from baseline (B = 5.1, s.e = 0.7) to the week following the first infusion (B = 0.8, s.e = 0.412), and remained reduced at the end of the study (B = 0.5, s.e = 0.3). Participants' confidence in their ability to abstain from cannabis in potentially triggering situations increased significantly from baseline to the end of study.

CONCLUSIONS

These findings suggest that combining ketamine with behavioral therapy is feasible,tolerable, and potentially helpful, in treating cannabis-dependent individuals.

Review of Medicinal Use of Cannabis Derivatives and the Societal Impact of Legalization

Background:

In recent past, there has been a rush to legalize marijuana along with a lot of support for its medicinal uses. This review intends to discuss the medicinal uses of marijuana and its adverse effects based on the current available evidence. Furthermore, it discusses the impact of legalization of marijuana.

Methodology:

This was a narrative review for which a thorough literature search was conducted on the Medline and PubMed databases. A detailed search of the Internet to find relevant information on webpages was also performed.

Results:

High-quality evidence for the majority of medical indications of marijuana remains investigational. Most of the available literature compares it against placebos. Postlegalization usage of marijuana has increased.

Conclusion:

It would be prudent to wait for studies which prove beyond doubt the advantages of marijuana over the existing drugs and also outweigh its side effects and addiction potential. Moreover, further legalization of marijuana should only be considered after evaluating its effects at places where it is already legally available.

Integrated cognitive behavioral therapy for comorbid cannabis use and anxiety disorders: A pilot randomized controlled trial

Cannabis use disorder (CUD) is the most common illicit substance use disorder and individuals with CUD have high rates of comorbid anxiety disorders. Comorbidity between CUD and anxiety disorders is of public health relevance given that although motivation enhancement therapy (MET) combined with cognitive-behavioral therapy (CBT) is an efficacious intervention for CUD, outcomes are worse for patients with elevated anxiety. The current study tested the acceptability and efficacy of the integration of a transdiagnostic anxiety CBT (i.e., treatment of patients with any anxiety disorder) with MET-CBT (integrated cannabis and anxiety reduction treatment, or ICART) for CUD compared to MET-CBT alone. Treatment-seeking cannabis users (56.4% male, M_age = 23.2, 63.3% non-Hispanic White) with CUD and at least one comorbid anxiety disorder were randomly assigned to ICART (n = 27) or MET-CBT (n = 28). Patients in the ICART condition attended significantly more treatment sessions than those in the MET-CBT condition. Patients in the ICART condition were more likely to be abstinent post-treatment than those in MET-CBT. Further, treatment produced decreases in cannabis use and related problems. Notably, therapy type did not moderate the impact of treatment on frequency of use and related problems. Together, these data suggest that ICART may be at least as efficacious as a gold-standard psychosocial CUD treatment, MET-CBT, for a difficult-to-treat subpopulation of cannabis users.

A Model of Δ9-Tetrahydrocannabinol Self-administration and Reinstatement That Alters Synaptic Plasticity in Nucleus Accumbens

BACKGROUND

Cannabis is the most widely used illicit drug, but knowledge of the neurological consequences of cannabis use is deficient. Two primary components of cannabis are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). We established a THC+CBD model of self-administration and reinstated drug seeking to determine if, similar to other addictive drugs, cannabis produces enduring synaptic changes in nucleus accumbens core (NAcore) thought to contribute vulnerability to drug reinstatement.

METHODS

Sprague Dawley rats were trained to self-administer THC+CBD (n = 165) or were used as vehicle self-administering control animals (n = 24). Reinstatement was initiated by context, cues, drug priming, and stress (yohimbine injection). Enduring neuroadaptations produced by THC+CBD self-administration were assayed using four measures: dendritic spine morphology, long-term depression, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid/N-methyl-D-aspartate ratios, and behavioral pharmacology.

RESULTS

We described a novel rodent model of cannabis relapse involving intravenous THC+CBD self-administration and drug seeking induced by conditioned context, cues, and stress. Cued reinstatement of THC+CBD seeking depended on a sequence of events implicated in relapse to other addictive drugs, as reinstatement was prevented by daily treatment with N-acetylcysteine or acute intra-NAcore pretreatment with a neuronal nitric oxide synthase or matrix metalloprotease-9 inhibitor, all of which normalize impaired glutamate homeostasis. The capacity to induce N-methyl-D-aspartate long-term depression in NAcore medium spiny neurons was abolished and dendritic spine density was reduced, but alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid/N-methyl-D-aspartate ratio was unaltered in THC+CBD-trained animals, akin to opioids, but not to psychostimulants.

CONCLUSIONS

We report enduring consequences of THC+CBD use on critical relapse circuitry and synaptic physiology in NAcore following rat self-administration and provide the first report of cue- and stress-induced reinstatement with this model.

Among whom is cigarette smoking declining in the United States? The impact of cannabis use status, 2002-2015

OBJECTIVES

To 1) estimate changes in the prevalence of daily and non-daily cigarette smoking among current (past 30-day) daily, non-daily, and non-cannabis users in the United States (U.S.) population; 2) examine time trends in current (past 30-day) cigarette smoking in daily, non-daily, and non-cannabis users ages 12+ from 2002 to 2015.

METHODS

Data collected annually from the 2002 to 2015 National Survey on Drug Use and Health (NSDUH) were employed. Linear time trends of daily and non-daily cigarette smoking were assessed using logistic regression with year as the predictor.

RESULTS

In 2015, the prevalence of current (past 30-day) cigarette smoking was highest among daily (54.57%), followed by non-daily (40.17%) and non-cannabis users (15.06%). The prevalence of non-daily cigarette smoking increased among daily cannabis users from 2002 to 2015, whereas non-daily cigarette smoking declined among non-daily cannabis users and non-cannabis users from 2002 to 2015. Daily cigarette smoking declined among both cannabis users and non-users; the most rapid decline was observed among daily cannabis users, followed by non-daily and then by non-cannabis users. However, the relative magnitude of the change in prevalence of daily cigarette smoking was similar across the three cannabis groups.

CONCLUSIONS

Despite ongoing declines in cigarette smoking in the U.S., non-daily cigarette smoking is increasing among current cannabis users, a growing proportion of the U.S.

POPULATION

Daily and non-daily cigarette smoking continue to decline among those who do not use cannabis. Efforts to further tobacco control should consider novel co-use-oriented intervention strategies and outreach for the increasing population of cannabis users.

Nondaily Cigarette Smoking Is Increasing Among People With Common Mental Health and Substance Use Problems in the United States: Data From Representative Samples of US Adults, 2005-2014

OBJECTIVE

The current study estimated trends in the prevalence of daily and nondaily cigarette smoking among United States adults with any common mental health or substance use problem (MHSUP), compared to US adults without MHSUP, from 2005 to 2014.

METHODS

Data were drawn from the years 2005 to 2014 from the public use data files for the annually conducted National Survey on Drug Use and Health. Linear time trends of current, daily, and nondaily cigarette smoking among adults (age 18 years and older) with and without MHSUP were assessed using logistic regression models with continuous year as the predictor.

RESULTS

In 2014, the prevalence of current cigarette smoking among those with MHSUP was more than twice that of those without MHSUP. Nondaily cigarette smoking increased significantly from 2005 to 2014 among those with MHSUP (P = .001) in contrast to a decline in nondaily cigarette smoking among those without MHSUP (P < .01). The rate of change differed significantly (P < .001). Daily cigarette smoking declined significantly from 2005 to 2014 among those with and without MHSUP (P values < .001).

CONCLUSIONS

The prevalence of nondaily cigarette smoking is increasing among US adults with common mental health and substance use problems, while it continues to decline among those without these vulnerabilities. The disparity in prevalence of daily cigarette smoking between those with and without MHSUP remains substantial. Conclusions about how to reach the tobacco endgame may need to be reconsidered to develop targeted tobacco control public health approaches that address common MHSUP.

Trends in Daily Cannabis Use Among Cigarette Smokers: United States, 2002-2014

OBJECTIVES

To estimate changes in the prevalence of daily cannabis use among current, former, and never cigarette smokers from 2002 to 2014 in the United States.

METHODS

The National Survey on Drug Use and Health is a nationally representative cross-sectional study conducted annually among persons aged 12 years and older in the United States.

RESULTS

Daily cannabis use occurs nearly exclusively among nondaily and daily cigarette smokers compared with former and never smokers (8.03%, 9.01%, 2.79%, 1.05%, respectively). Daily cannabis use increased over the past decade among both nondaily (8.03% [2014] vs 2.85% [2002]; linear trend P < .001) and daily smokers (9.01% [2014]; 4.92% [2002]; linear trend P < .001). Daily cannabis use increased most rapidly among former cigarette smokers (2.79% [2014] vs 0.98% [2002]; linear trend P < .001).

CONCLUSIONS

Daily cannabis use occurs predominantly among cigarette smokers in the United States. Daily cannabis use increased among current, former, and never smokers over the past decade, with particularly rapid increases among youth and female cigarette smokers. Future research is needed to monitor the observed increase in daily cannabis use, especially among youths and adults who smoke cigarettes.

Social cognitive predictors of treatment outcome in cannabis dependence

BACKGROUND

Drug-related outcomes expectancies and refusal self-efficacy are core components of Social Cognitive Theory. Both predict treatment outcome in alcohol use disorders. Few studies have reported expectancies and refusal self-efficacy in cannabis dependence. None have examined both, although both constructs are key targets in Cognitive-Behavioural Therapy (CBT). This study tests the predictive role of expectancies and refusal self-efficacy in treatment outcome for cannabis dependence.

DESIGN

Outpatients completed a comprehensive assessment when commencing cannabis treatment and predictors of treatment outcome were tested.

SETTING

A university hospital alcohol and drug outpatient clinic.

PARTICIPANTS

221 cannabis-dependent patients participated in a 6-week CBT program where the goal was abstinence.

MEASUREMENTS

Cannabis Expectancy Questionnaire and Cannabis Refusal Self-Efficacy Questionnaire, cannabis dependence severity [Severity of Dependence Scale], psychological distress [General Health Questionnaire] at baseline; the timeline follow-back procedure at baseline and each session.

FINDINGS

Patients reporting lower confidence in their ability to resist cannabis during high negative affect (emotional relief refusal self-efficacy) had a lower likelihood of abstinence (p=0.004), more days of use (p<0.001), and larger amount used (p<0.001). Negative cannabis expectancies predicted greater likelihood of abstinence (p=0.024). Higher positive expectancies were associated with lower emotional relief self-efficacy, mediating its association with outcome (p<0.001).

CONCLUSIONS

Emotional relief refusal self-efficacy and negative expectancies are predictive of better treatment outcomes for cannabis dependence. Positive expectancies may indirectly predict poorer outcome because of a negative association with self-efficacy, but this conclusion remains tentative as directionality could not be established.

Abstinence at Successful Discharge in Publicly Funded Addiction Health Services

Abstinence at successful discharge in substance use disorder treatment is important to reducing relapse rates and increasing long-term recovery from substance use disorders. However, few studies have examined abstinence as an essential component of successful discharge. This study examined rates and correlates of reported abstinence (nonuse of drugs 30 days prior to successful discharge) among clients attending publicly funded treatment in Los Angeles County, California. Finding show that only 36% of clients who were successfully discharged reported abstinence. Black clients were less likely than non-Hispanic Whites to report abstinence at successful discharge. Clients in methadone treatment programs were less likely than outpatient clients to report abstinence, whereas clients referred to treatment through the legal system (Proposition 36) were more likely to report abstinence compared to self-referred clients. Findings underscore the importance of systematic assessment of abstinence in determining successful discharge and provide a basis for further examination of strategies to improve abstinence and reduce relapse.

Evidence-based Treatment Options in Cannabis Dependency

BACKGROUND

Now that the consumption of natural and synthetic cannabinoids is becoming more widespread, the specific treatment of cannabis-related disturbances is an increasingly important matter. There are many therapeutic options, and it is not always clear which ones are evidence-based and appropriate for use in a given clinical situation.

METHODS

This review is based on reports of pertinent randomized and controlled trials (RCTs) that were retrieved by a selective search in the PubMed and Cochrane databases.

RESULTS

Cognitive behavior therapy (CBT) combined with other techniques has been found to have a moderate to large effect (Cohen's d = 0.53-0.9) on the amount of cannabis consumed as well as on the level of psychosocial functioning or the dependence syndrome. Systemic multidimensional family therapy (MDFT) has been found beneficial for younger adolescents who consume large amounts of cannabis and have psychiatric comorbidities. Short-term interventions with motivational talk therapy have been found effective for patients with or without an initial desire to achieve cannabis abstinence. All of these psychotherapeutic interventions are effective at evidence level Ia. The administration of gabapentin had a weak effect (d = 0.26) on the quantity consumed and on abstinence (evidence level Ib). Withdrawal symptoms can be alleviated with cannabinoid-receptor antagonists (d = 0.223 and 0.481) (evidence level Ib). On the other hand, there is evidence that serotonergic antidepressants can worsen withdrawal manifestations and increase the likelihood of relapse.

CONCLUSION

Psychotherapeutic techniques remain the foundation of treatment for cannabis dependence. No drug has yet been approved for the treatment of cannabis dependence because of the lack of scientific evidence. The rates of abstinence that are currently achieved, even with psychotherapy, are still only moderate. Further clinical studies are needed for the evaluation of combinations of various treatments that can meet the needs of individual patients.

Continuous Abstinence During Early Alcohol Treatment is Significantly Associated with Positive Treatment Outcomes, Independent of Duration of Abstinence

AIMS

Neither the predictive value of early continuous abstinence in alcohol use disorder (AUD) or the point at which this effect may emerge has been evaluated. This analysis of the Combined Pharmacotherapies and Behavioral Interventions (COMBINE) clinical trial evaluated whether abstinence early in treatment was a predictor of longer term abstinence.

METHODS

Participants who stated a goal of total abstinence (N = 954) were dichotomized into Early Abstainer vs. Nonabstainers and were compared on a variety of drinking outcome measures that are frequently used in clinical trial evaluations of alcohol treatment strategies, as a function of duration of early continuous abstinence.

RESULTS

Significant differences existed for every outcome. Early Abstinence was significantly associated with fewer drinks per drinking day, number of drinking and number of heavy drinking days, and longer time to first drinking and first heavy drinking day. Effects were evident within the first week. The magnitude of all effects increased as the duration of early abstinence (1-4 weeks) increased, though the size of increase varied across the outcomes.

CONCLUSIONS

These data provide evidence that drinking at the beginning of alcohol treatment is significantly and robustly associated with drinking throughout and at the end of a clinical trial treatment for AUD. Early drinking may be a useful early index to identify whether patients are responding positively to a treatment strategy, and provides a useful method for tailoring treatment to patients that is consistent with a personalized medicine approach.

The natural history of substance use disorders

PURPOSE OF REVIEW

Illicit drugs, alcohol, and tobacco use disorders contribute substantially to the global burden of disease. Knowledge about the major elements of the natural history of substance use disorders (incidence, remission, persistence, and relapse) is crucial to a broader understanding of the course and outcomes of substance use disorders.

RECENT FINDINGS

Prospective cohort studies in nonclinical samples indicate that externalizing psychopathology in earlier life, including early disordered substance use, delinquency, and personality disorders, are related to substance use disorders later in life and chronic course. Externalizing psychopathology may be initiated by early adverse experiences, for example, childhood maltreatment and stressful life events. After controlling for confounders, 'age at first use' as a causal factor for alcohol use disorder later in life and the 'drug substitution' hypothesis are not supported in general population data.

SUMMARY

Future research should focus on elaborating the causal framework that leads to the development and persistence of severe substance use disorders, with an emphasis on identifying modifiable factors for intervention by policy makers or health professionals. More research is needed on the natural history of substance use disorders in low-income and middle-income countries.

Psychological and psychosocial interventions for cannabis cessation in adults: a systematic review short report

BACKGROUND

Cannabis is the most commonly used illicit drug worldwide. Cannabis dependence is a recognised psychiatric diagnosis, often diagnosed via the Diagnostic and Statistical Manual of Mental Disorders criteria and the International Classification of Diseases, 10th Revision. Cannabis use is associated with an increased risk of medical and psychological problems. This systematic review evaluates the use of a wide variety of psychological and psychosocial interventions, such as motivational interviewing (MI), cognitive-behavioural therapy (CBT) and contingency management.

OBJECTIVE

To systematically review the clinical effectiveness of psychological and psychosocial interventions for cannabis cessation in adults who use cannabis regularly.

DATA SOURCES

Studies were identified via searches of 11 databases [MEDLINE, EMBASE, Cochrane Controlled Trials Register, Health Technology Assessment (HTA) database, Database of Abstracts of Reviews of Effects, Cochrane Database of Systematic Reviews, NHS Economic Evaluation Database, PsycINFO, Web of Science Conference Proceedings Citation Index, ClinicalTrials.gov and metaRegister of Current Controlled Trials] from inception to February 2014, searching of existing reviews and reference tracking.

METHODS

Randomised controlled trials (RCTs) assessing psychological or psychosocial interventions in a community setting were eligible. Risk of bias was assessed using adapted Cochrane criteria and narrative synthesis was undertaken. Outcomes included change in cannabis use, severity of cannabis dependence, motivation to change and intervention adherence.

RESULTS

The review included 33 RCTs conducted in various countries (mostly the USA and Australia). General population studies: 26 studies assessed the general population of cannabis users. Across six studies, CBT (4-14 sessions) significantly improved outcomes (cannabis use, severity of dependence, cannabis problems) compared with wait list post treatment, maintained at 9 months in the one study with later follow-up. Studies of briefer MI or motivational enhancement therapy (MET) (one or two sessions) gave mixed results, with some improvements over wait list, while some comparisons were not significant. Four studies comparing CBT (6-14 sessions) with MI/MET (1-4 sessions) also gave mixed results: longer courses of CBT provided some improvements over MI. In one small study, supportive-expressive dynamic psychotherapy (16 sessions) gave significant improvements over one-session MI. Courses of other types of therapy (social support group, case management) gave similar improvements to CBT based on limited data. Limited data indicated that telephone- or internet-based interventions might be effective. Contingency management (vouchers for abstinence) gave promising results in the short term; however, at later follow-ups, vouchers in combination with CBT gave better results than vouchers or CBT alone. Psychiatric population studies: seven studies assessed psychiatric populations (schizophrenia, psychosis, bipolar disorder or major depression). CBT appeared to have little effect over treatment as usual (TAU) based on four small studies with design limitations (both groups received TAU and patients were referred). Other studies reported no significant difference between types of 10-session therapy.

LIMITATIONS

Included studies were heterogeneous, covering a wide range of interventions, comparators, populations and outcomes. The majority were considered at high risk of bias. Effect sizes were reported in different formats across studies and outcomes.

CONCLUSIONS

Based on the available evidence, courses of CBT and (to a lesser extent) one or two sessions of MI improved outcomes in a self-selected population of cannabis users. There was some evidence that contingency management enhanced long-term outcomes in combination with CBT. Results of CBT for cannabis cessation in psychiatric populations were less promising, but may have been affected by provision of TAU in both groups and the referred populations. Future research should focus on the number of CBT/MI sessions required and potential clinical effectiveness and cost-effectiveness of shorter interventions. CBT plus contingency management and mutual aid therapies warrant further study. Studies should consider potential effects of recruitment methods and include inactive control groups and long-term follow-up. TAU arms in psychiatric population studies should aim not to confound the study intervention.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014008952.

FUNDING

The National Institute for Health Research HTA programme.

Marijuana dependence: not just smoke and mirrors

Marijuana (Cannabis sativa) is the most commonly used illicit drug worldwide as well as in the Unites States. Prolonged use of marijuana or repeated administration of its primary psychoactive constituent, Δ9-tetrahydrocannabinol (THC), can lead to physical dependence in humans and laboratory animals. The changes that occur with repeated cannabis use include alterations in behavioral, physiological, and biochemical responses. A variety of withdrawal responses occur in cannabis-dependent individuals: anger, aggression, irritability, anxiety and nervousness, decreased appetite or weight loss, restlessness, and sleep difficulties with strange dreams. But the long half-life and other pharmacokinetic properties of THC result in delayed expression of withdrawal symptoms, and because of the lack of contiguity between drug cessation and withdrawal responses the latter are not readily recognized as a clinically relevant syndrome. Over the past 30 years, a substantial body of clinical and laboratory animal research has emerged supporting the assertion that chronic exposure to cannabinoids produces physical dependence and may contribute to drug maintenance in cannabis-dependent individuals. However, no medications are approved to treat cannabis dependence and withdrawal. In this review, we describe preclinical and clinical research that supports the existence of a cannabinoid withdrawal syndrome. In addition, we review research evaluating potential pharmacotherapies (e.g., THC, a variety of antidepressant drugs, and lithium) to reduce cannabis withdrawal responses and examine how expanded knowledge about the regulatory mechanisms in the endocannabinoid system may lead to promising new therapeutic targets.

Integrated Cognitive Behavioral Therapy for Comorbid Cannabis Use and Anxiety Disorders

Cannabis use disorders (CUDs) co-occur with anxiety disorders at high rates, presumably because some individuals with anxiety disorders may rely on cannabis to manage anxiety. Motivation enhancement therapy (MET) combined with cognitive-behavioral therapy (CBT) is an efficacious intervention for CUD, yet outcomes are worse for patients with elevated anxiety. The integration of MET-CBT with False Safety Behavior Elimination Treatment (FSET) may be useful with anxious CUD patients, as the use of cannabis to manage anxiety can be targeted as a false safety behavior. Here, we describe the integrated treatment and the successful use of it among two patients-one with CUD and comorbid social anxiety disorder (SAD) and one with CUD and comorbid SAD and generalized anxiety disorder. Data support the feasibility of this integrated treatment as a viable approach to the treatment of CUD and comorbid anxiety disorders. Future controlled trials are now warranted to further evaluate the intervention.

Attempts to stop or reduce daily cannabis use: An intensive natural history study

We attempted to replicate and add to our prior study of attempts to stop or reduce cannabis use among daily cannabis users trying to change on their own, by observing a larger sample and adding further clinically relevant outcomes. Daily users (n = 193) who intended to stop or reduce sometime in the next 3 months called an Interactive Voice Response system each morning for 3 months to report on cannabis use, attempts to stop or reduce, withdrawal symptoms, and so forth, on the prior day. This study replicated our prior findings that (a) cannabis users trying to change make many, and often rapid, transitions among use as usual, reduction, and abstinence; (b) reduction attempts are more common than abstinence attempts; (c) quit and reduction attempts are short-lived and few participants achieve long-term abstinence; (d) alcohol and drug use are not greater on abstinence days; and (e) few users seek treatment. Novel findings included (f) a greater number of days of abstinence or intentional reduction predicted a greater decline in cannabis dependence, (g) most users do not prepare before their quit attempt, (h) coping outcomes during abstinence predict increased duration of abstinence, (i) tobacco use is less common on days of abstinence, and (j) withdrawal symptoms occur even with short quit attempts. Replication tests in more generalizable samples and of longer duration are indicated. Further natural history studies are likely to provide information to help improve the content of psychological treatments for cannabis use. (PsycINFO Database Record

Cannabis Withdrawal, Posttreatment Abstinence, and Days to First Cannabis Use Among Emerging Adults in Substance Use Treatment: A Prospective Study

Very little prospective research investigates how cannabis withdrawal is associated with treatment outcomes, and this work has not used the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) thresholds for cannabis withdrawal. The sample included 110 emerging adults entering outpatient substance use treatment who were heavy cannabis users with no other drug use and limited alcohol use. We used survival analyses to predict days to first use of cannabis and logistic regression to predict whether participants were abstinent and living in the community at 3 months. Those meeting criteria for cannabis withdrawal were more likely to return to use sooner than those not meeting criteria for cannabis withdrawal. However, the presence of cannabis withdrawal was not a significant predictor of 3-month abstinence. Emerging adults with DSM-5 cannabis withdrawal may have difficulty initiating abstinence in the days following their intake assessment, implying the need for strategies to mitigate their more rapid return to cannabis use.

Mobile App-Delivered Cognitive Behavioral Therapy for Insomnia: Feasibility and Initial Efficacy Among Veterans With Cannabis Use Disorders

Background

Cannabis is the most frequently used illicit substance in the United States resulting in high rates of cannabis use disorders. Current treatments for cannabis use are often met with high rates of lapse/relapse, tied to (1) behavioral health factors that impact cannabis use such as poor sleep, and (2) access, stigma, supply, and cost of receiving a substance use intervention.

Objective

This pilot study examined the feasibility, usability, and changes in cannabis use and sleep difficulties following mobile phone–delivered Cognitive Behavioral Therapy for Insomnia (CBT-I) in the context of a cannabis cessation attempt.

Methods

Four male veterans with DSM-5 cannabis use disorder and sleep problems were randomized to receive a 2-week intervention: CBT-I Coach mobile app (n=2) or a placebo control (mood-tracking app) (n=2). Cannabis and sleep measures were assessed pre- and post-treatment. Participants also reported use and helpfulness of each app. Changes in sleep and cannabis use were evaluated for each participant individually.

Results

Both participants receiving CBT-I used the app daily over 2 weeks and found the app user-friendly, helpful, and would use it in the future. In addition, they reported decreased cannabis use and improved sleep efficiency; one also reported increased sleep quality. In contrast, one participant in the control group dropped out of the study, and the other used the app minimally and reported increased sleep quality but also increased cannabis use. The mood app was rated as not helpful, and there was low likelihood of future participation.

Conclusions

This pilot study examined the feasibility and initial patient acceptance of mobile phone delivery of CBT-I for cannabis dependence. Positive ratings of the app and preliminary reports of reductions in cannabis use and improvements in sleep are both encouraging and support additional evaluation of this intervention.

The impact of posttraumatic stress disorder on cannabis quit success

BACKGROUND

Though a growing number of US Veterans are being diagnosed with cannabis use disorders, with posttraumatic stress disorder (PTSD) observed as the most frequently co-occurring psychiatric disorder among this population, no research has investigated the impact of PTSD diagnosis on cannabis quit success.

OBJECTIVES

The present study sought to determine the impact of PTSD on cannabis use following a self-guided quit attempt.

METHODS

Participants included 104, primarily male, cannabis-dependent US Veterans (Mage = 50.90 years, SDage = 9.90). The study design was prospective and included an assessment immediately prior to the quit attempt, and assessments weekly for the first 4 weeks post-quit, and then monthly through 6 months post-quit.

RESULTS

Results indicated that PTSD diagnosis was not associated with time to first lapse or relapse. However, individuals with PTSD used more cannabis at baseline and evidenced a slower initial decline in cannabis use immediately following the quit attempt. All findings were significant after accounting for alcohol and tobacco use across the cessation period, as well as co-occurring mood and anxiety disorder diagnoses.

CONCLUSION

Findings highlight the potential utility of interventions for individuals with cannabis use disorder and co-occurring PTSD, particularly early in a cessation attempt.

Perceived risk of regular cannabis use in the United States from 2002 to 2012: differences by sex, age, and race/ethnicity

INTRODUCTION

Cannabis is one of the most widely used psychoactive substances in the United States (U.S.). Perceived risk of use is associated with substance use; the recent debate surrounding medicalization and legalization of cannabis in the U.S. has the potential to impact perceived risk of use. Recent estimates are needed to assess temporal changes in, and identify correlates of, perceived risk of cannabis use.

METHODS

Utilizing data from the 2002-2012 survey years of the National Survey on Drug Use and Health, chi-squared statistics and logistic regression were used to describe temporal changes in perceived risk of regular cannabis use (i.e., once or twice a week), to explore correlates of perceived risk, and to report frequency of cannabis use.

RESULTS

Between 2002 and 2012, perceived great risk of regular cannabis use varied significantly overall (p < 0.001). The prevalence of past year non-daily (p < 0.001) and daily use varied significantly during this time (p < 0.001). Controlling for survey year and other confounders, characteristics associated with increased odds of perceived great risk of regular cannabis use included: female sex; Non-White race/ethnicity; age 50+; and family income of $20,000-49,999. Characteristics associated with decreased odds of perceived great risk included: ages 12-17 and 18-25; high school education or greater; total family income of $75,000+; past year non-daily and daily cannabis use; and survey years 2008-2012.

CONCLUSIONS

Findings characterize trends of perceived risk of regular cannabis use, and past year non-daily and daily cannabis use. Longitudinal studies of the influence of legal status of cannabis at the state-level are needed.

Treatment of cannabis dependence using escitalopram in combination with cognitive-behavior therapy: a double-blind placebo-controlled study

BACKGROUND

Cannabis is the most frequently used illegal substance in the United States and Europe. There is a dramatic increase in the demand for treatment for cannabis dependence. Cannabis users frequently have co-morbid mood symptoms, especially depression and anxiety, and regular cannabis users may self-medicate for such symptoms.

OBJECTIVES

We report a double-blind, placebo-controlled treatment study, for the prevention of cannabis use in cannabis-dependent individuals.

METHOD

Regular cannabis-dependent users (n = 52) were treated for 9 weeks with weekly cognitive-behavior and motivation-enhancement therapy sessions together with escitalopram 10 mg/day. Urine samples were collected to monitor delta-9 tetrahydrocannabinol (THC) during treatment and questionnaires were administered to assess anxiety and depression.

RESULTS

We observed a high rate of dropout (50%) during the 9-week treatment program. Fifty-two patients were included in the intention-to-treat analysis. Of these, ten (19%) remained abstinent after 9 weeks of treatment as indicated by negative urine samples for THC. Escitalopram provided no advantage over placebo in either abstinence rates from cannabis or anxiety and depression scores during the withdrawal and abstinent periods.

CONCLUSIONS

Escitalopram treatment does not provide an additional benefit either for achieving abstinence, or for the treatment of the cannabis withdrawal syndrome. Due to limitations of our study, namely, a high dropout rate and effects of low abstinence rates on measures of anxiety, depression and withdrawal, it is premature to conclude that selective serotonin reuptake inhibitors are not effective for treatment of the cannabis withdrawal syndrome.

The Use of Motivational Interviewing in Conjunction With Adapted Dialectical Behavior Therapy to Treat Synthetic Cannabis Use Disorder

Little empirical information is established about synthetic marijuana, including the treatment of related disorders. Similar to organic marijuana, chronic synthetic use can lead to a variety of functional impairments, including diminished academic and workplace productivity and performance. Many traditional approaches emphasize treating co-occurring disorders separately, but the present case examines concurrent treatment for Diagnostic and Statistical Manual of Mental Disorders (4th ed., DSM-IV) Synthetic Marijuana Dependence and Generalized Anxiety Disorder by using Motivational Interviewing (MI) and Relapse Prevention (RP) in conjunction with an adapted form of Dialectical Behavior Therapy (DBT). A model for treatment and its potential effects are discussed.

CANDIS treatment program for cannabis use disorders: findings from a randomized multi-site translational trial

BACKGROUND

In a recent paper, we reported the efficacy of a modular cognitive-behavioral intervention for treating adolescents and adults with cannabis use disorders (CUD). In this study, we examine the outcome of this intervention after translating it into clinical practice.

METHODS

A multi-site, randomized controlled trial of 279 treatment seekers with ICD-10 cannabis use disorders aged 16- 63 years was conducted in 11 outpatient addiction treatment centers in Germany. Patients were randomly assigned to an Active Treatment (AT, n=149) or Delayed Treatment Control (DTC, n=130). Treatment consisted of 10 sessions of fully manualized individual psychotherapy that combined Cognitive-Behavioral Therapy, Motivational EnhancementTherapy and problem-solving training. Assessments were conducted at baseline, during each therapy session, at post-treatment and at three and six month follow-ups.

RESULTS

At post assessment 53.3% of AT patients reported abstinence (46.3% negative urine screenings) compared to 22% of DTC patients (17.7% negative drug screenings) (p<0.001, Intention-to-treat analysis). AT patients improved in the frequency of cannabis use, number of cannabis dependence criteria, severity of dependence, as well as number and severity of cannabis-related problems. Effect sizes were moderate to high. While abstinence rates in the AT group decreased over the 3-month (negative urine screenings: 32.4%) and 6-month (negative urine screenings: 35.7%) follow-up periods, the effects in secondary outcomes were maintained.

CONCLUSIONS

The intervention can successfully be translated to and applied in clinical practice. It has the potential to improve access to evidence-based care for chronic CUD patients.

The impact of perceived sleep quality and sleep efficiency/duration on cannabis use during a self-guided quit attempt

Poor sleep quality may play a significant role in observed high rates of sustained cannabis use among veterans attempting to quit. We investigated whether individuals with poorer perceived sleep quality (rather than sleep efficiency/duration), as measured via the Pittsburgh Sleep Quality Index (Buysse, Reynolds, Monk, & Berman, 1989), would have less of a reduction in cannabis use (measured via Timeline FollowBack; Sobell and Sobell, 1992) during the first 6 months following a self-guided quit attempt. We expected these effects to remain significant after adjusting for baseline age, posttraumatic stress symptoms, as well as alcohol, tobacco, and opioid use, and cannabis withdrawal severity over the course of 6 months following the cannabis cessation attempt. Generalized linear mixed modeling using a Poisson distribution was employed to test the hypotheses among 102 cannabis dependent, primarily male, military veterans. Results indicated that veterans with poor perceived sleep quality had less of a reduction in mean cannabis use following a self-guided cannabis cessation attempt compared to those with good perceived sleep quality, while efficiency/duration was unrelated to cannabis use outcomes. Conclusions from this study should be considered in light of limitations including the use of self-report measures and generalizability to non-veterans and women.

The effects of cannabis use expectancies on self-initiated cannabis cessation

AIMS

To prospectively investigate the relation between cannabis use expectancies and cannabis use prior to and during a self-initiated cannabis cessation attempt.

DESIGN

Cohort design that followed participants for 4 weeks following a self-initiated cessation attempt.

SETTING

United States Department of Veterans Affairs medical center.

PARTICIPANTS

One hundred cannabis dependent military veterans.

MEASUREMENTS

The Marijuana Effects Expectancy Questionnaire at baseline; the timeline follow-back procedure at baseline and during the cessation attempt.

FINDINGS

Cannabis use at baseline was associated with positive (P = 0.01), but not negative (P = 0.25), expectancies. Cannabis lapse was associated with positive (P = 0.03) and negative expectancies (P = 0.01), and relapse was associated with positive (P = 0.04), but not negative (P = 0.21), expectancies. The trajectory of average cannabis use during the cessation period was associated with positive (P = 0.03), but not negative (P = 0.96), expectancies. Results were similar in effect and statistical significance when adjusting for demographic factors, motivation to quit cannabis, mental disorder diagnoses, and alcohol and tobacco use, and when analyzing complete data sets obtained through multiple imputation.

CONCLUSIONS

In the USA, cannabis use expectancies, especially those regarding the positive effects of cannabis use, appear to be strongly and consistently linked to cannabis use and quit failure.

Probability and predictors of cannabis use disorders relapse: results of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)

BACKGROUND

This study aims to estimate the odds and predictors of Cannabis Use Disorders (CUD) relapse among individuals in remission.

METHODS

Analyses were done on the subsample of individuals with lifetime history of a CUD (abuse or dependence) who were in full remission at baseline (Wave 1) of the National Epidemiological Survey of Alcohol and Related Conditions (NESARC) (n=2350). Univariate logistic regression models and hierarchical logistic regression model were implemented to estimate odds of relapse and identify predictors of relapse at 3 years follow up (Wave 2).

RESULTS

The relapse rate of CUD was 6.63% over an average of 3.6 year follow-up period. In the multivariable model, the odds of relapse were inversely related to time in remission, whereas having a history of conduct disorder or a major depressive disorder after Wave 1 increased the risk of relapse.

CONCLUSIONS

Our findings suggest that maintenance of remission is the most common outcome for individuals in remission from a CUD. Treatment approaches may improve rates of sustained remission of individuals with CUD and conduct disorder or major depressive disorder.

Dopamine response to psychosocial stress in chronic cannabis users: a PET study with [11C]-+-PHNO

A number of addictions have been linked with decreased striatal dopamine (DA) receptor availability and DA release. Stress has a key role in cannabis craving, as well as in modulation of dopaminergic signaling. The present study aimed to assess DA release in response to a laboratory stress task with [(11)C]-(+)-PHNO positron emission tomography in cannabis users (CU). Thirteen healthy CU and 12 healthy volunteers (HV) were scanned during a sensorimotor control task (SMCT) and under a stress condition using the validated Montreal imaging stress task (MIST). The simplified reference tissue model (SRTM) was used to obtain binding potential (BP(ND)) in striatal subdivisions: limbic striatum (LST), associative striatum (AST), and sensorimotor striatum (SMST). Stress-induced DA release (indexed as a percentage of reduction in [(11)C]-(+)-PHNO BP (ND)) between CU and HV was tested with analysis of variance. SMCT BP(ND) was significantly higher in CU compared with HV in the AST (F=10.38, p=0.003), LST (F=4.95, p=0.036), SMST (F=4.33, p=0.048), and whole striatum (F=9.02, p=0.006). Percentage of displacement (change in BP(ND) between SMCT and MIST PET scans) was not significantly different across groups in any brain region, except in the GP (-5.03±14.6 in CU, compared with 6.15±12.1 in HV; F=4.39, p=0.049). Duration of cannabis use was significantly associated with stress-induced [(11)C]-(+)-PHNO displacement by endogenous DA in the LST (r=0.566, p=0.044), with no effect in any other brain region. In conclusion, despite an increase in striatal BP(ND) observed during the control task, chronic cannabis use is not associated with alterations in stress-induced DA release.

Moderating effects of race in clinical trial participation and outcomes among marijuana-dependent young adults

BACKGROUND

Few studies have examined clinical trial participation rates and treatment outcomes among underserved young adults who are dependent on marijuana, the most commonly abused illicit drug.

METHOD

The present study was a secondary analysis of a trial of court-referred marijuana-dependent young adults (ages 18-25) randomized to one of four treatment conditions: Motivational Enhancement Therapy/Cognitive Behavioral Therapy (MET/CBT), MET/CBT+Contingency Management (CM), Drug Counseling (DC) or DC+CM. African American (N=81) participants were compared to White (N=31) participants with respect to rates of participation in phases of treatment and substance use outcomes. In addition, the interaction of race and treatment condition was examined to ascertain if the interventions yielded different effects based on race.

RESULTS

Among those who started treatment, African American young adults were significantly less likely to complete the treatment and posttreatment phases of the clinical trial than their White counterparts. Irrespective of treatment type, substance use outcomes (i.e., percentage of marijuana-negative specimens and longest duration of continuous abstinence) did not vary by race. However, there was a significant interaction effect between treatment type and race; African American young adults did not benefit differentially from any specific type of treatment, but CM was effective in reducing proportion of marijuana positive samples among White young adults.

CONCLUSIONS

Findings suggest that clinical trial treatment and posttreatment completion rates vary by race in this population, as does response to specific treatment types. More treatment research focusing specifically on African American marijuana-dependent young adults is warranted.

Initiation of abstinence in adolescents treated for marijuana use disorders

This study assessed the time to initiation of marijuana abstinence in an adolescent treatment-seeking sample, and identified variables that were predictive of abstinence. Adolescents (N=69), ages 14 to 18 were randomly assigned to one of two 14-week behavioral treatments. Abstinence was measured with twice-weekly urine toxicology plus teen and parent reports. Discrete-time survival and hazard functions were conducted. The majority of adolescents achieved at least 1 week of abstinence, and 51% achieved 6 weeks of abstinence. Initiation of abstinence occurred by the sixth treatment week for 94% of teens with any abstinence suggesting that alternative, clinical approaches should be considered for those not responding by week 6. Teens with a drug negative urinalysis at intake, and teens that had two parents participating in treatment were more likely to achieve at least 6 weeks of abstinence. These findings, if replicated, can be used to inform clinical and research strategies that might lead to enhanced treatment efficacy and cost effectiveness for substance abuse treatment programming.

Effect of yohimbine stress on reacquisition of oxycodone seeking in rats

RATIONALE

Stress, a powerful precipitant of drug seeking during abstinence, may also accelerate the return to pathological patterns of intake after initial instances of drug reuse.

OBJECTIVE

To explore the effect of stress on a learning process underlying relapse, this study assessed the effect of yohimbine on reacquisition of oxycodone seeking.

METHODS

One hundred thirty-two male Sprague-Dawley rats underwent place conditioning with oxycodone (2 mg/kg, SC; ×6 days), extinction (vehicle × 6 days), and reconditioning with 0, 0.25, 2, or 5 mg/kg oxycodone (2 days). Yohimbine (0, 2.5, or 5 mg/kg, IP) was administered 30 min prior to reconditioning.

RESULTS

Pretreatment with 2.5 mg/kg yohimbine increased, while 5 mg/kg yohimbine decreased, reacquisition of oxycodone-induced place preference. A follow-up study (n = 30) further indicated that the effect of yohimbine was specific to reacquisition.

CONCLUSION

The observation that yohimbine can enhance reacquisition of oxycodone seeking supports the hypothesis that stress can facilitate learning processes involved in the unfolding of relapse.

Efficacy of a targeted cognitive-behavioral treatment program for cannabis use disorders (CANDIS)

AIMS

To examine the efficacy, 3- and 6-month follow-up effects of a psychological treatment for older adolescents and adults with DSM-IV cannabis use disorders. The program was tailored to the needs of this patient population.

EXPERIMENTAL PROCEDURES

A randomized controlled clinical trial of 122 patients aged 16 to 44 years with DSM-IV cannabis dependence as the main substance use diagnosis was conducted. Patients were randomly assigned to either Active Treatment (AT, n = 90) or a Delayed Treatment Control group (DTC, n = 32). Treatment consisted of 10 sessions of therapy, detailed in a strictly enforced manual. Assessments were conducted at baseline, during each therapy session, at post treatment and at follow-up assessments at 3 and 6 months.

RESULTS

The treatment retention rate was 88%. Abstinence was achieved in 49% of AT patients and in 13% of those in DTC (p < 0.001; intend-to-treat (ITT) analysis). Further, AT patients improved significantly (p < = 0.001) in the frequency of cannabis use per week, addiction severity, number of disability days, and overall level of psychopathology. Program effects were maintained over a 3-month- (abstinence rate: 51%) and 6-month follow-up (45%) period.

CONCLUSION

The treatment program is effective in obtaining abstinence as well as reducing cannabis use and improves the associated social and mental health burden.

Successful and unsuccessful cannabis quitters: comparing group characteristics and quitting strategies

BACKGROUND

In order to improve treatments for cannabis use disorder, a better understanding of factors associated with successful quitting is required.

METHOD

This study examined differences between successful (n=87) and unsuccessful (n=78) cannabis quitters. Participants completed a questionnaire addressing demographic, mental health, and cannabis-related variables, as well as quitting strategies during their most recent quit attempt.

RESULTS

Eighteen strategies derived from cognitive behavioral therapy were entered into a principal components analysis. The analysis yielded four components, representing (1) Stimulus Removal, (2) Motivation Enhancement, (3) (lack of) Distraction, and (4) (lack of) Coping. Between groups comparisons showed that unsuccessful quitters scored significantly higher on Motivation Enhancement and (lack of) Coping. This may indicate that unsuccessful quitters focus on the desire to quit, but do not sufficiently plan strategies for coping. Unsuccessful quitters also had significantly more symptoms of depression and stress; less education; lower exposure to formal treatment; higher day-to-day exposure to other cannabis users; and higher cannabis dependence scores.

CONCLUSIONS

The findings suggest that coping, environmental modification, and co-morbid mental health problems may be important factors to emphasize in treatments for cannabis use disorder.

[Cannabis cessation interventions offered to young French users: predictors of follow-up]

INTRODUCTION

Cannabis use is very problematic among young French people, because of the young age of first consumption and its health consequences. Indeed, the average age of cannabis experimentation is about 15 in France and 49.5% of 17 year-olds report having used cannabis in their lives. To prevent this problem, tobacco and cannabis cessation services are dedicated to handle patients who want to stop tobacco and/or cannabis. Moreover, in 2004, specific medical outpatient services have been implemented to address the problem of young cannabis users. Since their establishment, some studies have reported demographic and clinical characteristics of the patients attending these services, but we still lack data on their follow-up and their medical and psychological care.

OBJECTIVE

The aim of this study is to describe the clinical and psychiatric characteristics of young patients referred to tobacco/cannabis cessation consultations or specific young cannabis users' consultations and to evaluate their medical care and monitoring.

PATIENTS AND METHODS

We designed a retrospective study in seven cessation clinics in the Paris area between 2005 and 2007. Eligible patients were regular cannabis users aged under 40. An electronic medical database was completed using patients' medical records. Medical files reported demographic and clinical data. Psychiatric disorders were assessed using the HAD and the Beck scores. Nicotine dependence was evaluated by Fagerström's score. The history of addictions, and data about consumption of cannabis, tobacco, alcohol and other drugs were recorded in the medical file. The follow-up of patients was defined by having at least two visits at the medical outpatient services. Tobacco and cannabis cessations were assessed at one-month follow-up. Univariate and multivariate logistic models were used to assess factors associated with patients' follow up and monitoring.

RESULTS

Four cessation clinics accepted to participate in our study. One hundred and eight eligible patients were listed during the study period. One hundred and eleven patients (75%) were males and seventy-nine (53%) were employed. The average age of patients was 26 years old (±6.8). Fifty patients (34%) came to the clinic on their own decision, thirty-three (22%) were referred by a hospital and twenty-eight (19%) came because of their family's advice. The mean age of first cannabis consumption was 16 years old (±7.3) and cannabis consumption was most often associated with tobacco use. Fifty-nine percent of patients had anxiety disorders and 28% had depression according to D-HAD score. The dropout rate after first visit was about 40%. The most frequent therapy proposed to young cannabis users was nicotine replacement therapy. Follow-up data were collected for 135 patients and only 85 (37%) patients made at least two visits at the outpatient services. The average number of consultations was five (±3.8). Multivariate analysis found an association between follow-up and previous cannabis cessation (P=0.04), pharmacological treatment of tobacco withdrawal (P=0.04), and antidepressant treatment (P=0.04). Only one quarter of patients had quit cannabis and/or tobacco at one-month follow-up.

DISCUSSION

This study describes clinical characteristics of patients attending cannabis consultations in France. As reported in other studies, anxiety disorders and depression are important problems in this population and should be considered during their medical care. The efficacy of specific French medical outpatient services is difficult to evaluate because of the high rate of dropout. Some patients' characteristics seem linked to their monitoring but other studies should be assessed to confirm these results. As pharmacological treatments seem associated with patients' follow-up, new research should be implemented to develop therapeutic solutions for cannabis addiction.

Separate and combined effects of the cannabinoid agonists nabilone and Δ⁹-THC in humans discriminating Δ⁹-THC

BACKGROUND

Agonist replacement treatment is a promising strategy to manage cannabis-use disorders. The aim of this study was to assess the combined effects of the synthetic cannabinoid agonist nabilone and Δ⁹-tetrahydrocannabinol (Δ⁹-THC) using drug-discrimination procedures, which are sensitive to drug interactions. Testing the concurrent administration of nabilone and Δ⁹-THC was also conducted to provide initial safety and tolerability data, which is important because cannabis users will likely lapse during treatment.

METHODS

Six cannabis users learned to discriminate 30 mg oral Δ⁹-THC from placebo and then received nabilone (0, 1 and 3mg) and Δ⁹-THC (0, 5, 15 and 30 mg), alone and in combination. Subjects completed the multiple-choice procedure to assess drug reinforcement, and self-report, task performance and physiological measures were collected.

RESULTS

Δ⁹-THC and nabilone alone shared discriminative-stimulus effects with the training dose of Δ⁹-THC, increased crossover point on the multiple-choice procedure, produced overlapping subject ratings and decreased skin temperature. Nabilone alone also elevated heart rate. In combination, nabilone shifted the discriminative-stimulus effects of Δ⁹-THC leftward/upward and enhanced Δ⁹-THC effects on the other outcome measures.

CONCLUSIONS

These results replicate a previous study demonstrating that nabilone shares agonist effects with the active constituent of cannabis in cannabis users, and contribute further by indicating that nabilone would likely be safe and well tolerated when combined with cannabis. These data support the conduct of future studies to determine if nabilone treatment would produce cross-tolerance to the abuse-related effects of cannabis and reduce cannabis use.

Polysomnogram changes in marijuana users who report sleep disturbances during prior abstinence

BACKGROUND

Abrupt discontinuation of heavy marijuana (MJ) use is associated with self-reports of sleep difficulty. Disturbed sleep is clinically important because MJ users experiencing sleep problems may relapse to MJ use to improve their sleep quality. Few studies have used polysomnography (PSG) to characterize changes in sleep architecture during abrupt abstinence from heavy MJ use.

METHODS

We recorded PSG measures on nights 1, 2, 7, 8, and 13 after abrupt MJ discontinuation in 18 heavy MJ users residing in an inpatient unit.

RESULTS

Across abstinence, Total Sleep Time (TST), Sleep Efficiency (SEff), and amount of REM sleep declined, while Wake after Sleep Onset (WASO) and Periodic Limb Movements (PLM) increased. Furthermore, quantity (joints/week) and duration (years) of MJ use were positively associated with more PLMs.

CONCLUSION

The treatment of sleep disturbance is a potential target for the management of cannabis use disorders since poor sleep could contribute to treatment failure in heavy MJ users.

Effects of baclofen and mirtazapine on a laboratory model of marijuana withdrawal and relapse

RATIONALE

Only a small percentage of individuals seeking treatment for their marijuana use achieves sustained abstinence, suggesting more treatment options are needed.

OBJECTIVES

We investigated the effects of baclofen (study 1) and mirtazapine (study 2) in a human laboratory model of marijuana intoxication, withdrawal, and relapse.

METHODS

In study 1, daily marijuana smokers (n = 10), averaging 9.4 (+/-3.9) marijuana cigarettes/day, were maintained on placebo and each baclofen dose (60, 90 mg/day) for 16 days. In study 2, daily marijuana smokers (n = 11), averaging 11.9 (+/-5.3) marijuana cigarettes/day, were maintained on placebo and mirtazapine (30 mg/day) for 14 days each. Medication administration began outpatient prior to each 8-day inpatient phase. On the first inpatient day of each medication condition, participants smoked active marijuana (study 1: 3.3% THC; study 2: 6.2% THC). For the next 3 days, they could self-administer placebo marijuana (abstinence phase), followed by 4 days in which they could self-administer active marijuana (relapse phase); participants paid for self-administered marijuana using study earnings.

RESULTS

In study 1, during active marijuana smoking, baclofen dose-dependently decreased craving for tobacco and marijuana, but had little effect on mood during abstinence and did not decrease relapse. Baclofen also worsened cognitive performance regardless of marijuana condition. In study 2, mirtazapine improved sleep during abstinence, and robustly increased food intake, but had no effect on withdrawal symptoms and did not decrease marijuana relapse.

CONCLUSIONS

Overall, this human laboratory study did not find evidence to suggest that either baclofen or mirtazapine showed promise for the potential treatment of marijuana dependence.

Cannabis use disorder: epidemiology and management

This paper provides an overview of the epidemiology of cannabis use, cannabis use disorders and its treatment. Cannabis is the most commonly used illicit drug internationally. While use is decreasing in the developed world, it appears to be stable or increasing in developing countries and some indigenous communities. Early initiation and regular adolescent use have been identified as particular risk factors for later problematic cannabis (and other drug) use, impaired mental health, delinquency, lower educational achievement, risky sexual behaviour and criminal offending in a range of studies. It is estimated that approximately one in ten people who had ever used cannabis will become dependent with risk increasing markedly with frequency of use. There has been an increase in the proportion of treatment provided for cannabis use. There are as yet no evidence-based pharmacotherapies available for the management of cannabis withdrawal and craving. Relatively brief cognitive behavioural therapy and contingency management have the strongest evidence of success, and structured, family-based interventions, provide potent treatment options for adolescents. With criminally involved young people and those with severe, persistent mental illness, longer and more intensive therapies provided by interdisciplinary teams may be required.

Pharmacotherapy for cannabis dependence: how close are we?

Cannabis is the most widely used illicit drug in the world. Treatment admissions for cannabis use disorders have risen considerably in recent years, and the identification of medications that can be used to improve treatment outcomes among this population is a priority for researchers and clinicians. To date, several medications have been investigated for indications of clinically desirable effects among cannabis users (e.g. reduced withdrawal, attenuation of subjective or reinforcing effects, reduced relapse). Medications studied have included those: (i) known to be effective in the treatment of other drug use disorders; (ii) known to alleviate symptoms of cannabis withdrawal (e.g. dysphoric mood, irritability); or (iii) that directly affect endogenous cannabinoid receptor function. Results from controlled laboratory studies and small open-label clinical studies indicate that buspirone, dronabinol, fluoxetine, lithium and lofexidine may have therapeutic benefit for those seeking treatment for cannabis-related problems. However, controlled clinical trials have not been conducted and are needed to both confirm the potential clinical efficacy of these medications and to validate the laboratory models being used to study candidate medications. Although the recent increase in research towards the development of pharmacotherapy for cannabis use disorders has yielded promising leads, well controlled clinical trials are needed to support broad clinical use of these medications to treat cannabis use disorders.

Neurobiological mechanisms of cannabinoid addiction

The endocannabinoid system is implicated in the regulation of a variety of physiological processes, among which conditioning, motivation, habit forming, memory, learning, and cognition play pivotal roles in drug reinforcement and reward. In this article we will give a synopsis of last developments in research on cannabinoid actions on brain reward circuits coming from behavioral, neurochemical and electrophysiological studies. Central cannabinoid-induced effects as measured by animal models of addiction, in vivo cerebral microdialysis, in vitro and in vivo electrophysiological recording techniques, will be reviewed. Brain sites that have been implicated in the mediation of addictive cannabinoid properties include primarily the ventral tegmental area, the nucleus accumbens, and the medial prefrontal cortex, although the amygdala, the substantia nigra, the globus pallidus, and the hippocampus have also been shown to be critical structures mediating motivational and reinforcing effects of cannabinoids. Putative neurobiological mechanisms underlying these effects will be delineated.

Effects of THC and lofexidine in a human laboratory model of marijuana withdrawal and relapse

INTRODUCTION

Individuals seeking treatment for their marijuana use rarely achieve sustained abstinence.

OBJECTIVES

The objectives of the study are to determine if THC, a cannabinoid agonist, and lofexidine, an alpha(2)-adrenergic receptor agonist, given alone and in combination, decreased symptoms of marijuana withdrawal and relapse, defined as a return to marijuana use after a period of abstinence.

MATERIALS AND METHODS

Nontreatment-seeking, male volunteers (n = 8), averaging 12 marijuana cigarettes/day, were maintained on each of four medication conditions for 7 days: placebo, tetrahydrocannabinol (THC) (60 mg/day), lofexidine (2.4 mg/day), and THC (60 mg/day) combined with lofexidine (2.4 mg/day); each inpatient phase was separated by an outpatient washout phase. During the first three inpatient days, placebo marijuana was available for self-administration (withdrawal). For the next 4 days, active marijuana was available for self-administration (relapse). Participants paid for self-administered marijuana using study earnings. Self-administration, mood, task performance, food intake, and sleep were measured.

RESULTS

THC reversed the anorexia and weight loss associated with marijuana withdrawal, and decreased a subset of withdrawal symptoms, but increased sleep onset latency, and did not decrease marijuana relapse. Lofexidine was sedating, worsened abstinence-related anorexia, and did not robustly attenuate withdrawal, but improved sleep and decreased marijuana relapse. The combination of lofexidine and THC produced the most robust improvements in sleep and decreased marijuana withdrawal, craving, and relapse in daily marijuana smokers relative to either medication alone.

CONCLUSIONS

These data suggest the combination of lofexidine and THC warrant further testing as a potential treatment for marijuana dependence.