Urine Screening for Marijuana Among Methadone-Maintained Patients

Genetics of cannabis use in opioid use disorder: A genome-wide association and polygenic risk score study

BACKGROUND

Individuals with an Opioid Use Disorder (OUD) have increased rates of cannabis use in comparison to the general population. Research on the short- and long-term impacts of cannabis use in OUD patients has been inconclusive. A genetic component may contribute to cannabis cravings.

AIMS

Identify genetic variants associated with cannabis use through Genome-wide Association Study (GWAS) methods and investigate a Polygenic Risk Score (PRS). In addition, we aim to identify any sex differences in effect size for genetic variants reaching or nearing genome-wide significance in the GWAS.

METHODS

The study outcomes of interest were: regular cannabis use (yes/no) (n = 2616), heaviness of cannabis use (n = 1293) and cannabis cravings (n = 836). Logistic and linear regressions were preformed, respectively, to test the association between genetic variants and each outcome, regular cannabis use and heaviness of cannabis use. GWAS summary statistics from a recent large meta-GWAS investigating cannabis use disorder were used to conduct PRS's. Findings are limited to a European ancestry sample.

RESULTS

No genome-wide significant associations were found. Rs1813412 (chromosome 17) for regular cannabis use and rs62378502 (chromosome 5) for heaviness of cannabis use were approaching genome-wide significance. Both these SNPs were nominally significant (p<0.05) within males and females, however sex did not modify the association. The PRS identified statistically significant association with cannabis cravings. The variance explained by all PRSs were less than 1.02x10-2.

CONCLUSION

This study provides promising results in understanding the genetic contribution to cannabis use in individuals living with OUD.

Cannabis use during methadone maintenance treatment for opioid use disorder: a systematic review and meta-analysis

BACKGROUND

Rates of cannabis use among patients receiving methadone maintenance therapy are high, and cannabis use may be associated with outcomes of methadone maintenance therapy. We examined the effect of cannabis use on opioid use in patients receiving methadone maintenance therapy to test the hypothesis that cannabis use is associated with a reduction in opioid use.

METHODS

In this systematic review, we searched MEDLINE/PubMed, Embase, PsycINFO, CINAHL and ProQuest Dissertations and Theses Global from inception to July 12, 2018. We summarized the effects of cannabis use on opioid use during methadone maintenance therapy and treatment retention. We conducted meta-analyses using a random effects model.

RESULTS

We included 23 studies in our review. We performed a meta-analysis of 6 studies, with a total number of participants of 3676, examining use of cannabis and opioids during methadone maintenance therapy. Owing to high heterogeneity, we described the studies qualitatively but provide the forest plots as supplemental material. The overall quality of evidence was very low, with a high risk of bias, owing to the nature of observational studies.

INTERPRETATION

We found no consensus among studies that cannabis use is associated with reduced opioid use or longer treatment retention when used during methadone maintenance therapy in patients with opioid use disorder. PROSPERO Registration: CRD42015029372.

Association between cannabis use and methadone maintenance treatment outcomes: an investigation into sex differences

Background

Cannabis will soon become legalized in Canada, and it is currently unclear how this will impact public health. Methadone maintenance treatment (MMT) is the most common pharmacological treatment for opioid use disorder (OUD), and despite its documented effectiveness, a large number of patients respond poorly and experience relapse to illicit opioids. Some studies implicate cannabis use as a risk factor for poor MMT response. Although it is well established that substance-use behaviors differ by sex, few of these studies have considered sex as a potential moderator. The current study aims to investigate sex differences in the association between cannabis use and illicit opioid use in a cohort of MMT patients.

Methods

This multicentre study recruited participants on MMT for OUD from Canadian Addiction Treatment Centre sites in Ontario, Canada. Sex differences in the association between any cannabis use and illicit opioid use were investigated using multivariable logistic regression. A secondary analysis was conducted to investigate the association with heaviness of cannabis use.

Results

The study included 414 men and 363 women with OUD receiving MMT. Cannabis use was significantly associated with illicit opioid use in women only (OR = 1.82, 95% CI 1.18, 2.82, p = 0.007). Heaviness of cannabis use was not associated with illicit opioid use in men or women.

Conclusions

This is the largest study to date examining the association between cannabis use and illicit opioid use. Cannabis use may be a sex-specific predictor of poor response to MMT, such that women are more likely to use illicit opioids if they also use cannabis during treatment. Women may show improved treatment outcomes if cannabis use is addressed during MMT.

Marijuana use and achievement of abstinence from alcohol and other drugs among people with substance dependence: a prospective cohort study

BACKGROUND

Many with alcohol and other drug dependence have concurrent marijuana use, yet it is not clear how to address it during addiction treatment. This is partially due to the lack of clarity about whether marijuana use impacts one's ability to achieve abstinence from the target of addiction treatment. We examined the association between marijuana use and abstinence from other substances among individuals with substance dependence.

METHODS

A secondary analysis of the Addiction Health Evaluation And Disease management study, a randomized trial testing the effectiveness of chronic disease management. Individuals met criteria for drug or alcohol dependence and reported recent drug (i.e. opioid or stimulant) or heavy alcohol use. Recruitment occurred largely at an inpatient detoxification unit, and all participants were referred to primary medical care. The association between marijuana use and later abstinence from drug and heavy alcohol use was assessed using longitudinal multivariable models.

RESULTS

Of 563 study participants, 98% completed at least one follow-up assessment and 535 (95%) had at least one pair of consecutive assessments and were included. In adjusted analyses, marijuana use was associated with a 27% reduction in the odds of abstinence from drug and heavy alcohol use (adjusted odds ratio 0.73 [95% CI, 0.56-0.97], P=0.03).

CONCLUSIONS

Marijuana use among individuals with alcohol or other drug dependence is associated with a lower odds of achieving abstinence from drug and heavy alcohol use. These findings add evidence that suggests concomitant marijuana use among patients with addiction to other drugs merits attention from clinicians.

Impact of cannabis use during stabilization on methadone maintenance treatment

BACKGROUND AND OBJECTIVES

Illicit drug use, particularly of cannabis, is common among opiate-dependent individuals and has the potential to impact treatment in a negative manner.

METHODS

To examine this, patterns of cannabis use prior to and during methadone maintenance treatment (MMT) were examined to assess possible cannabis-related effects on MMT, particularly during methadone stabilization. Retrospective chart analysis was used to examine outpatient records of patients undergoing MMT (n = 91), focusing specifically on past and present cannabis use and its association with opiate abstinence, methadone dose stabilization, and treatment compliance.

RESULTS

Objective rates of cannabis use were high during methadone induction, dropping significantly following dose stabilization. History of cannabis use correlated with cannabis use during MMT but did not negatively impact the methadone induction process. Pilot data also suggested that objective ratings of opiate withdrawal decrease in MMT patients using cannabis during stabilization.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

The present findings may point to novel interventions to be employed during treatment for opiate dependence that specifically target cannabinoid-opioid system interactions.

Perceived stress and substance use in methadone-maintained smokers

BACKGROUND

In methadone maintenance treatment programs (MMTPs), 80-90% of participants smoke cigarettes. Patients in MMTPs are at particular risk for life stress, and nicotine, as well as other substances like alcohol, benzodiazepines, cocaine, marijuana, and opiates have been shown to reduce the effects of stress. Use of these addictive substances to cope with stress may precipitate illicit opiate relapse in MMTP patients. In the current study, we examined the relationship between perceived stress and substance abuse.

METHODS

Participants were 315 cigarette smokers recruited from nine MMTPs for a smoking cessation study. Logistic regression was used to evaluate the adjusted association of perceived stress with dichotomous indicators of hazardous alcohol use and recent substance use at baseline.

RESULTS

After controlling for demographic and smoking-related variables, perceived stress was associated positively and significantly with the likelihood of screening positive for hazardous drinking or alcohol-related problems (OR=1.13, 95%CI 1.02; 1.25), with the likelihood of recent cocaine use (OR=1.18, 95%CI 1.02; 1.37), and with the likelihood of recent benzodiazepine use (OR=1.24, 95%CI 1.07).

CONCLUSIONS

Perceived stress may be a marker of patients' risk for illicit substance use, a known risk factor for illicit opiate relapse. These findings indicate that cigarette use might not be sufficient in managing stress and methadone-maintained persons turn to other substances for relief.

Association of cannabis use with opioid outcomes among opioid-dependent youth

OBJECTIVE

Cannabis use is common among opioid-dependent patients, but studies of its association with treatment outcome are mixed. In this secondary analysis, the association of cannabis use with opioid treatment outcome is assessed.

METHODS

In the main study, participants (n=152) aged 15-21 years were randomized to receive psychosocial treatments and either a 12-week course of buprenorphine-naloxone with a dose taper to zero in weeks 9-12, or a 2-week detoxification with buprenorphine-naloxone. Drug use was assessed by self-report and urine drug screen at baseline and during study weeks 1-12. The association between cannabis and opioid use at weeks 4, 8, and 12 was examined using logistic regression models.

RESULTS

Participants reported a median of 3.0 days (range=0-30) cannabis use in the past month; half (50.3%; n=77) reported occasional use, one-third reported no use (33.1%; n=50), and one-sixth reported daily cannabis use (16.6%; n=25). Median lifetime cannabis use was 4.0 years (range=0-11) and median age of initiation of use was 15.0 years (range 9-21). Neither past cannabis use (age of initiation and use in the month prior to baseline) nor concurrent use was associated with level of opioid use.

CONCLUSIONS

Overall, cannabis use had no association with opioid use over 12 weeks in this sample of opioid-dependent youth. While cannabis use remains potentially harmful, it was not a predictor of poor opioid treatment outcome.

Cannabinoid and opioid interactions: implications for opiate dependence and withdrawal

Withdrawal from opiates, such as heroin or oral narcotics, is characterized by a host of aversive physical and emotional symptoms. High rates of relapse and limited treatment success rates for opiate addiction have prompted a search for new approaches. For many opiate addicts, achieving abstinence may be further complicated by poly-drug use and co-morbid mental disorders. Research over the past decade has shed light on the influence of endocannabinoids (ECs) on the opioid system. Evidence from both animal and clinical studies point toward an interaction between these two systems, and suggest that targeting the EC system may provide novel interventions for managing opiate dependence and withdrawal. This review will summarize the literature surrounding the molecular effects of cannabinoids and opioids on the locus coeruleus-norepinephrine system, a key circuit implicated in the negative sequelae of opiate addiction. A consideration of the trends and effects of marijuana use in those seeking treatment to abstain from opiates in the clinical setting will also be presented. In summary, the present review details how cannabinoid-opioid interactions may inform novel interventions in the management of opiate dependence and withdrawal.

CNR1 gene polymorphisms in addictive disorders: a systematic review and a meta-analysis

The aim of the present work was to systematically review all association studies of cannabis receptor 1 (CNR1) polymorphisms with dependence syndrome and to perform a meta-analysis. Odds ratios (ORs) were estimated by contrasting the ratio of counts of the 'high risk' versus 'low risk' alleles in cases with dependence versus controls. Studies were analyzed by random-effects meta-analysis using pooled OR. Eleven full text articles met our eligibility criteria and nine meta-analyses were performed on three polymorphisms of CNR1: rs1049353, rs806379 and the AAT repeat. Of these, only the AAT polymorphism showed a significant association with illicit substance dependence but only in the Caucasian population samples and using a risk allele definition of ≥ 16 repeats. Our analysis showed a small effect size (OR = 1.55, P = 0.045), with strong heterogeneity (Q = 19.87, P < 0.01 with I² = 85%). In line with the polygenic model, our meta-analysis supports a minor implication for CNR1 AAT polymorphism in illicit substance dependence vulnerability. Further studies in well-phenotyped samples and using more polymorphisms are needed to conclude on the actual influence of cannabinoid receptor polymorphisms.

Pharmacotherapy in the treatment of addiction: methadone

Methadone maintenance treatment (MMT) is the most widely available pharmacotherapy for opioid addiction and has been shown to be an effective and safe treatment over a period of 40 years. Although women comprise approximately 40% of clients currently being treated in MMT programs, comparatively little research geared specifically toward this group has been published. This article begins with an overview of neurobiological studies on opioid addiction, including a discussion of gender differences, followed by a review of the pharmacology of methadone. The authors then examine the particular needs and differences of women being treated in MMTs, including co-dependence with other substances, women's health issues, and psychosocial needs unique to this population. Research shows that women have different substance abuse treatment needs in comparison to their male counterparts. One New York City MMT program that has attempted to address these differences is highlighted.

Retention and illicit drug use among methadone patients in Israel: a gender comparison

OBJECTIVES

To examine gender differences or similarities regarding the retention rate in the course of a 13-month treatment and in long-term retention up to 14 years among 2,683 patients treated in eight (of 10) methadone maintenance clinics located in communities in Israel.

METHODS

The study is based on a computerized set of data on 2,683 (331 female and 2,352 male) patients older than 18 years of age (mean age=43.30 SD=8.53) who underwent treatment in one of eight methadone maintenance programs in Israel sometimes (or all the time) between January 1, 1991 and October 30, 2005.

RESULTS

79.6% of the patients had a 100% retention rate in the 13-month time slot examined. The survival curves for the long-term retention show that retention in treatment was similar for both female and male patients. However, long-term retention is higher among female patients aged 31-40.

CONCLUSION

It is premature to conclude that there are no gender differences in retention since there seem to be different profiles of female patients, characterized by different retention rates, as implied by the great variability in the females' retention behavior found in the regression analysis.

Heroin transition risk among daily and non-daily cannabis users who are non-injectors of heroin

AIMS

Non-injecting heroin use (NIU) has been identified as a potential precursor for the transition to injecting drug use (IDU). This paper examines and compares heroin transition risks between two groups of Mexican American cannabis users (daily (DU) vs. non-daily (NDU)) who are NIUs.

METHODS

Data for this analysis are from structured interviews with 300 street-based recruited male and female NIUs in San Antonio, Texas using an adaptive sampling methodology. Three variables (being a former injector, daily heroin use, and being dependent on heroin) were used to create a summative scale measuring heroin transition risk and dichotomized into "no attributes" and "1-3 attributes".

RESULTS

Initial univariate logistic regression analysis indicated an association between heroin transition risk and the cannabis user groups with three fourths of the NDU having transition risk attributes. In the multivariate model, three factors were found to be independently associated with heroin transition risk. Heroin transition risk was positively associated with having used heroin for a longer period of time. An inverse relationship was found with DU of cannabis and those reporting alcohol use in the past month being less likely to be associated with heroin transition risks.

CONCLUSIONS

Findings tentatively indicate that DU of cannabis may be interpreted as a form of self-regulation and potentially deterring problematic heroin use among Mexican American NIUs and possibly other polydrug users in similar social environments. However, the authors discuss alternative interpretations of these findings. Nevertheless, findings may be used to inform specific policies and intervention strategies to prevent transitions to injecting and other harmful health consequences among NIUs.

Chronic cannabis use does not affect the normalization of hypothalamic-pituitary-adrenal (HPA) axis induced by methadone in heroin addicts

The hypothalamic-pituitary-adrenal (HPA) axis activity is usually altered by heroin use. In the present study we evaluated in one hundred twenty-one heroin addicts the effects of marijuana smoking on the normalization of HPA axis upon methadone treatment. The study showed that in heroin addicts who are chronic cannabis smokers a treatment with methadone lasting 12 months was able to normalize both plasma corticotropin (ACTH) and cortisol levels, as well as to control both heroin withdrawal symptoms and opioid craving. As expected in the same group of patients marijuana smoking and its craving were not reduced by methadone treatment. Our data confirm that methadone treatment outcomes are not modified by cannabis use and they add in the literature the evidence that chronic cannabis use is not able to affect the normalization of HPA axis upon methadone treatment in heroin addicts.

A stepped care approach for reducing cannabis use in opioid-dependent outpatients

This study evaluated rates of cannabis use and the effectiveness of an adaptive stepped care intervention for reducing cannabis use in methadone maintenance patients. Patients testing cannabis positive during a 6-month baseline were advanced to more weekly counseling (up to 9 hours per week) until producing four consecutive weeks of cannabis- and other drug-negative urine samples. Patients were followed up for 1 year. Continued access to uninterrupted methadone delivery was ultimately contingent upon attending scheduled counseling and achieving abstinence from all drug use. The results showed that 18% of the clinic census (n = 57) tested positive for cannabis. The effectiveness of the intervention was assessed for 15 patients testing positive for cannabis exclusively. Ten of these patients (67%) discontinued cannabis use prior to the intervention and remained at reduced care. Four of the five patients who were advanced to higher steps of care ultimately discontinued cannabis use; one left treatment against medical advice. The results suggest that motivated stepped care is an effective intervention for reducing cannabis use.

Cannabis abuse is not a risk factor for treatment outcome in methadone maintenance treatment: a 1-year prospective study in an Israeli clinic

OBJECTIVE

We addressed the following questions. What are the current and lifetime prevalence of cannabis abuse in an Israeli methadone maintenance treatment (MMT) clinic? Does cannabis abuse change over time during MMT? Is cannabis abuse related to treatment outcome measures such as retention rate and the abuse of drugs? Is the abuse of cannabis related to psychopathology, HIV/HCV risk-taking and infectious diseases? Do cannabis abusers (CAs) have a different psychosocial and demographic profile than nonabusers (NCAs)? Is cannabis abuse part of a polydrug abuse tendency or a distinct substance of abuse?

METHOD

Overlapping samples of either the entire clinic population (n = 283) or all the patients who had completed 1 year of MMT treatment (n = 196 of which 20 were re-entering) underwent random and twice-weekly observed urine analysis for various drugs of abuse, responded to self-report questionnaires (SCL-90-R; HIV/HCV risk-taking behaviours; n = 164), interviews (ASI, n = 176; SCID, n = 151) and hepatitis C and HIV testing (n = 149).

RESULTS

Lifetime abuse prevalence was found in 75% and current abuse at MMT intake in 25%. Abuse did not increase significantly over a 1-year period. Cannabis abusers were found to be more often polydrug abusers than NCAs. Cannabis abusers did not suffer from more psychological distress, infectious diseases, and did not engage in more HCV/HIV risk-taking behaviour, nor did they leave treatment earlier than NCAs.

CONCLUSIONS

Cannabis abuse MMT patients should be treated as polydrug abusers, although no specific influences of cannabis abuse on psychological and medical conditions of MMT patients have been observed. Treatment policy should take these results into consideration.

Does cannabis use predict poor outcome for heroin-dependent patients on maintenance treatment? Past findings and more evidence against

AIMS

To determine whether cannabinoid-positive urine specimens in heroin-dependent out-patients 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.

DESIGN

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 post-treatment. For the present analyses, data were pooled across trials where appropriate.

SETTING

Urban out-patient methadone clinic.

PARTICIPANTS

Four hundred and eight polydrug abusers meeting methadone-maintenance criteria.

MEASUREMENTS

Participants were categorized as non-users, 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).

FINDINGS

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 0.95 to detect an r2 of 0.11 between cannabis use and heroin or cocaine use; the r2 we detected was less than 0.03 and non-significant. 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 associated weakly with psychosocial problems at post-treatment follow-up.

CONCLUSIONS

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.

Concurrent substance use and outcome in combined behavioral and naltrexone therapy for opiate dependence

The effect of concurrent nonopiate drug use on outcome of treatment for opiate dependence.

METHOD

Forty-seven opiate-dependent patients received a 6-month course of outpatient treatment with naltrexone and cognitive-behavioral therapy (behavioral naltrexone therapy, BNT) at a university-based research clinic. Opiate-negative urines and naltrexone ingestion were rewarded with monetary vouchers. Abstinence from other drugs was encouraged verbally, but no contingencies were placed on nonopiate drug use. The proportions of all urines (collected twice weekly) positive for cocaine, cannabis, and benzodiazepines over the course of treatment were evaluated as predictors of outcome of opiate dependence treatment, as measured by proportion of opiate-positive urines, days retained in treatment, and proportion of naltrexone doses taken, using Pearson product moment correlations and one-way analysis of variance (ANOVA).

RESULTS

The majority of patients (78%) used a nonopiate drug at least once during the trial. There were no significant correlations between concurrent drug use measures and opiate dependence treatment outcomes, indicating no simple linear relationship between these measures. However, when concurrent drug use was trichotomized into abstinent, intermittent, and heavy use groups, groups with intermittent use had superior outcome compared to both abstinent and heavy use groups in several contrasts.

CONCLUSIONS

Intermittent use of nonopiate drugs is common during outpatient treatment for opiate dependence and may be a favorable prognostic indicator. This may support a "harm reduction" approach as opposed to a strict abstinence-oriented approach. Further research is needed to identify the optimal therapeutic stance toward other drug use during treatment for opiate dependence.

Factors associated with lapses to heroin use during methadone maintenance

This prospective, observational study investigated factors predicting a lapse to heroin use in 74 heroin-abstinent methadone maintenance patients. After baseline data collection, participants were assessed twice per week for 7 weeks and again at 6 months after baseline. Proportional hazards regression and logistic regression were used to investigate the effects of study predictors on heroin use. A goal of absolute heroin abstinence consistently predicted a lower risk of a lapse, whereas marijuana use was associated with a greater risk. Stress variables were not predictive. The abstinence goal and stress results were consistent with the authors' previous studies of other drug treatment samples. This line of research suggests that factors influencing lapses are similar across drug treatment populations and the role of stress in precipitating relapse remains unresolved.

College on problems of drug dependence meeting, Puerto Rico (June 1996) marijuana use and dependence

Discoveries concerning an endogenous cannabinoid system and observations of dramatic increases in marijuana use among youth in the United States have fueled a recent increase in basic and clinical research to better understand and treat marijuana dependence. At the annual meeting of the College on Problems of Drug Dependence (Puerto Rico, 1996) a symposium 'Marijuana Use: Basic Mechanisms, Epidemiology, and Clinical Issues' reviewed a number of important areas of ongoing research that address marijuana dependence. Overviews and original research were presented regarding the development of dependence (preclinical and clinical research), motivational effects (laboratory models), the epidemiology of dependence and its development, clinical management of marijuana use among patients seeking treatment for other drugs of abuse, and treatment for adult marijuana dependence. This paper summarizes the symposium presentations and provides discussion of recent scientific developments concerning marijuana use and dependence.