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Study breakdown

Occasional Cannabis Use Was Linked to Staying in Opioid Addiction Treatment Longer

Randomized Controlled TrialPreliminary evidence
The takeaway

Intermittent cannabis users stayed in naltrexone treatment for opioid dependence significantly longer (median 133 days) than abstainers (35 days) or consistent cannabis users (35 days), replicating a previous finding.

Read this if you are interested in harm reduction approaches to opioid addiction treatment.

Intermittent cannabis users stayed 133 days vs 35 days for abstainers (p=0.002)

What the researchers found

Sixty-three opioid-dependent patients were enrolled in a naltrexone trial and classified by their cannabis use during treatment: abstinent, intermittent, or consistent users.

Intermittent cannabis users showed dramatically superior treatment retention: median 133 days compared to just 35 days for both abstinent and consistent cannabis users. This difference was highly significant (p=0.002).

The effect remained after adjusting for baseline heroin use and cocaine use during treatment. Intermittent cannabis users also took their naltrexone medication more consistently.

Intensive behavioral therapy appeared to moderate the poor prognosis in the consistent cannabis use group.

Importantly, this replicated a previous finding from an independent sample.

Why it matters

Naltrexone is theoretically promising for opioid dependence but plagued by poor adherence. Finding that intermittent cannabis use predicts dramatically better retention challenges the assumption that all concurrent substance use is detrimental in addiction treatment.

The numbers in context

63 patients. Intermittent cannabis users: median 133 days retention (mean 112.8). Abstinent: median 35 days (mean 47.3). Consistent users: median 35 days (mean 68.3). Log rank test: p=0.002.

How the study worked

Secondary analysis of a randomized trial comparing two behavioral therapies with naltrexone for opioid dependence (N=63). Participants were classified into three cannabis use groups based on biweekly urine tests. Cox proportional hazards model adjusted for baseline heroin and in-treatment cocaine use.

What this study cannot tell us

Observational classification within a clinical trial (not randomized to cannabis use). Intermittent cannabis users may differ from abstainers and heavy users in ways not captured by the analysis. Small sample size. Association, not causation.

How to read the evidence

Replicated observational finding within a randomized trial. Cannabis use was not experimentally assigned, so selection effects are possible. Small sample (n=63).

When this study was published

Published in 2009. The relationship between cannabis use and opioid treatment outcomes has continued to be debated, with some subsequent studies supporting the harm reduction perspective.

The bigger picture

This finding raises provocative questions about harm reduction approaches in opioid addiction treatment. If moderate cannabis use helps people stay in treatment and take their medication, the net benefit could outweigh the concerns about concurrent cannabis use.

Questions still open

  • Is there a pharmacological mechanism through which cannabis improves naltrexone adherence? Would prescribing cannabis as part of opioid treatment improve outcomes? Or is intermittent cannabis use simply a marker for less severe addiction?

Common questions

Why would cannabis help people stay in opioid treatment?
The mechanism is unclear. Cannabis may help manage withdrawal discomfort, anxiety, or insomnia that drive people out of treatment. Alternatively, intermittent cannabis users may simply have different personality or motivational characteristics than abstainers or heavy users.
Does this mean people in addiction treatment should use cannabis?
The study found an association, not a treatment recommendation. While the replication strengthens the finding, randomized trials would be needed to determine whether cannabis use causally improves opioid treatment outcomes.

Read the original research

Intermittent marijuana use is associated with improved retention in naltrexone treatment for opiate-dependence.

The American journal on addictions, 18(4), 301-8

Citation

Raby, Wilfrid Noel; Carpenter, Kenneth M; Rothenberg, Jami; Brooks, Adam C; Jiang, Huiping; Sullivan, Maria; Bisaga, Adam; Comer, Sandra; Nunes, Edward V. (2009). Intermittent marijuana use is associated with improved retention in naltrexone treatment for opiate-dependence.. The American journal on addictions, 18(4), 301-8. https://doi.org/10.1080/10550490902927785

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