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.