44% of medical cannabis patients reported drinking less alcohol after starting cannabis | Research

The takeaway

Among 973 Canadian medical cannabis patients who regularly drank alcohol, 44% reported decreasing their drinking frequency and 8% stopped drinking entirely after starting medical cannabis.

Addiction specialists, public health researchers, and policy makers evaluating cannabis-alcohol substitution.

44% reduced alcohol frequency; 8% stopped drinking entirely

What the researchers found

In a survey of 2,102 Canadian medical cannabis patients, 973 who regularly drank alcohol reported that after starting medical cannabis, 44% decreased drinking frequency, 34% reduced drinks per week, and 8% stopped drinking entirely. Being under 55 and having higher baseline alcohol use predicted greater reductions. Intending to use cannabis to reduce alcohol was associated with both reducing and stopping drinking.

Why it matters

Alcohol causes more health harm than cannabis by most measures. If medical cannabis genuinely reduces alcohol consumption, the net public health effect could be substantially positive.

The numbers in context

2,102 total respondents; 973 regular alcohol users; 44% decreased frequency; 34% reduced drinks/week; 8% stopped entirely; age <55 and higher baseline use predicted greater reductions.

How the study worked

Cross-sectional survey of 2,102 Canadian medical cannabis program enrollees, analyzing retrospective self-reported changes in alcohol use among the 973 (44%) who reported regular alcohol use before cannabis initiation.

What this study cannot tell us

Retrospective self-report; no control group; participants already enrolled in medical cannabis program (self-selection bias); cannot distinguish substitution from coincidental changes; cross-sectional design.

How to read the evidence

Moderate: large sample with detailed outcome measures, but retrospective self-report with no control group.

When this study was published

Published 2020.

The bigger picture

The substitution hypothesis (cannabis replacing more harmful substances) has significant policy implications. If confirmed by longitudinal studies, cannabis access programs could be framed partly as alcohol reduction interventions.

Questions still open

Would a prospective study with a control group confirm the substitution effect? Does the type of medical cannabis condition matter for alcohol substitution?

Common questions

Does medical cannabis reduce alcohol use?

In this survey, 44% of regular drinkers reported decreased alcohol frequency after starting medical cannabis, and 8% stopped entirely. However, this was self-reported and retrospective.

Who was most likely to reduce alcohol?

People under 55, those with higher baseline drinking, and those who specifically intended to use cannabis to reduce alcohol had the greatest odds of reducing or stopping.

Read the original research

Reductions in alcohol use following medical cannabis initiation: results from a large cross-sectional survey of medical cannabis patients in Canada.

The International journal on drug policy, 86, 102963

View on PubMed ↗Publisher’s paper ↗

Citation

Lucas, Philippe; Boyd, Susan; Milloy, M-J; Walsh, Zach. (2020). Reductions in alcohol use following medical cannabis initiation: results from a large cross-sectional survey of medical cannabis patients in Canada.. The International journal on drug policy, 86, 102963. https://doi.org/10.1016/j.drugpo.2020.102963