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


METHODS
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.


METHODS
Urban out-patient methadone clinic.


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


METHODS
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).


RESULTS
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.
Epstein
D H
DH
Clinical Pharmacology and Therapeutics Branch, Treatment Section, National Institute on Drug Abuse/Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA. depstein@intra.nida.nih.gov
Preston
K L
KL
D000328:Adult; D000701:Analgesics, Opioid / Q000627:therapeutic use*; D000704:Analysis of Variance; D002186:Cannabinoids / Q000652:urine; D016009:Chi-Square Distribution; D002986:Clinical Trials as Topic; D005260:Female; D006556:Heroin Dependence / Q000534:rehabilitation* / Q000652:urine; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000150:complications* / Q000652:urine; D008691:Methadone / Q000627:therapeutic use*; D008875:Middle Aged; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D016896:Treatment Outcome
D000701:Analgesics, Opioid; D002186:Cannabinoids; D008691:Methadone