4 in 10 Opioid Treatment Patients Also Used Cannabis | Research

The takeaway

Among 128 patients in opioid maintenance therapy, 41% used cannabis, with most citing recreational motives and craving reduction as reasons, and cannabis dependence was more common in those on buprenorphine.

Addiction treatment providers, harm reduction advocates, researchers studying substance use co-occurrence

41% cannabis use prevalence in opioid maintenance patients

What the researchers found

Cannabis use was reported by 41% of opioid maintenance patients. Of cannabis users, 73% met criteria for dependence. Cannabis dependence was significantly more common in patients receiving buprenorphine than methadone. Higher methadone doses were also associated with increased cannabis use. Common reasons for use included mood enhancement and reduction of cravings for other substances.

Why it matters

Cannabis use among opioid treatment patients is common but understudied. Whether cannabis helps or hinders opioid recovery is debated, and the finding that medication type influences cannabis use patterns adds important clinical context.

The numbers in context

41% used cannabis. 73% of users met dependence criteria. 30% of the full sample had cannabis dependence. 85% of patients reported cannabis-related legal issues. Cannabis dependence was significantly more common with buprenorphine vs methadone.

How the study worked

Cross-sectional study of 128 patients (96 male, 32 female) receiving opioid maintenance therapy at a single center. Assessment used the Marijuana Smoking History Questionnaire, Cannabis Problems Questionnaire, and Severity of Dependence Scale.

What this study cannot tell us

Small sample (n=128) from a single center. Cross-sectional design cannot determine causation. Self-reported cannabis use may be underreported. Legal status of cannabis may influence reporting.

How to read the evidence

Preliminary: small single-center cross-sectional study with self-reported measures

When this study was published

Published in 2025

The bigger picture

The interaction between cannabis and opioid treatment is complex. Patients report using cannabis to manage cravings, which some view as harm reduction. But high rates of dependence complicate that narrative.

Questions still open

Does cannabis use actually reduce opioid cravings, or do patients just perceive it that way? Why is cannabis dependence more common with buprenorphine than methadone?

Common questions

Why did patients use cannabis during opioid treatment?

The most common reasons were recreational (mood change and enhancement) and reducing cravings for other substances. Patients reported cannabis helped them cope, though the study could not verify whether it actually reduced cravings.

Why was cannabis dependence more common with buprenorphine?

The study found this association but did not determine the mechanism. It may relate to differences in how buprenorphine and methadone affect the brain's reward system, or to differences in the patient populations prescribed each medication.

Read the original research

Cannabis Use in Opioid Maintenance Therapy: Prevalence, Clinical Correlates and Reasons for Use.

Brain sciences, 15(7)

View on PubMed ↗Publisher’s paper ↗

Citation

Backmund, Markus; Zámbó, Greta G; Schöfl, Susanne; Soyka, Michael. (2025). Cannabis Use in Opioid Maintenance Therapy: Prevalence, Clinical Correlates and Reasons for Use.. Brain sciences, 15(7). https://doi.org/10.3390/brainsci15070699