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

Addiction. 2003 Mar;98(3):269-79. doi: 10.1046/j.1360-0443.2003.00310.x.


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.

Publication types

  • Review

MeSH terms

  • Adult
  • Analgesics, Opioid / therapeutic use*
  • Analysis of Variance
  • Cannabinoids / urine
  • Chi-Square Distribution
  • Clinical Trials as Topic
  • Female
  • Heroin Dependence / rehabilitation*
  • Heroin Dependence / urine
  • Humans
  • Male
  • Marijuana Abuse / complications*
  • Marijuana Abuse / urine
  • Methadone / therapeutic use*
  • Middle Aged
  • Patient Compliance / statistics & numerical data*
  • Psychiatric Status Rating Scales
  • Regression Analysis
  • Retrospective Studies
  • Risk Factors
  • Survival Analysis
  • Treatment Outcome


  • Analgesics, Opioid
  • Cannabinoids
  • Methadone