Cannabis substitution for opioids was common but not affected by legalization status | Research

The takeaway

Among 44,119 cannabis consumers in the US and Canada, 79-84% of those using cannabis for pain reported substituting it for opioids or prescription pain medication, regardless of whether cannabis was legally available.

Policymakers evaluating cannabis legalization arguments, pain management clinicians, and public health researchers.

79-84% substitution rate regardless of legal status

What the researchers found

Between 14-33% of cannabis consumers used it for pain. Of those, 78-84% reported substituting cannabis for opioids or prescription pain medication. There was no significant association between recreational cannabis legalization and the rate of substitution.

Why it matters

The finding that opioid substitution rates are similarly high regardless of legal status challenges the argument that legalization will drive a public health benefit through opioid replacement.

The numbers in context

44,119 total respondents. 14-33% used cannabis for pain. Substitution rates: Canada 78-79%, US illegal states 80-83%, US legal states 83-84%. No significant legal status effect (Canada AOR 0.98, US AOR 1.11).

How the study worked

Repeat cross-sectional survey from the International Cannabis Policy Study (2018-2019) in Canada and the US. 44,119 respondents aged 16-65 who had ever tried cannabis. 15,092 analyzed for substitution outcomes. Weighted binary logistic regression compared legal versus illegal jurisdictions.

What this study cannot tell us

Cross-sectional design cannot establish causation. Self-reported substitution may not reflect actual opioid reduction. Two-year window may be too short to capture legalization effects. Online panel recruitment may introduce bias.

How to read the evidence

Strong: very large cross-national sample with repeat waves and weighted regression analysis.

When this study was published

Published in 2022.

The bigger picture

While cannabis-opioid substitution is widespread among pain patients who use cannabis, this behavior appears to be driven by individual decision-making rather than legal access, suggesting policy alone may not shift opioid use patterns.

Questions still open

Does self-reported substitution translate to actual reductions in opioid prescriptions or overdoses? Would longer post-legalization timeframes show different patterns? Are certain pain conditions more amenable to cannabis substitution?

Common questions

Does cannabis legalization reduce opioid use?

This study found no significant association between recreational cannabis legalization and the rate at which people substitute cannabis for opioids. Substitution was equally common in legal and illegal jurisdictions.

How many cannabis users substitute it for opioids?

Among those who use cannabis for pain (14-33% of all consumers), approximately 79-84% reported substituting it for opioids or prescription pain medication.

Why does legalization not affect substitution rates?

People appear to make substitution decisions based on personal experience with cannabis for pain, regardless of its legal status. Those who find it helpful substitute regardless of legality.

Read the original research

Legal status of recreational cannabis and self-reported substitution of cannabis for opioids or prescription pain medication in Canada and the United States.

Substance abuse, 43(1), 943-948

View on PubMed ↗Publisher’s paper ↗

Citation

Wadsworth, Elle; Hines, Lindsey A; Hammond, David. (2022). Legal status of recreational cannabis and self-reported substitution of cannabis for opioids or prescription pain medication in Canada and the United States.. Substance abuse, 43(1), 943-948. https://doi.org/10.1080/08897077.2022.2060431