After Canada legalized recreational cannabis, medical patient registrations declined substantially, but remaining patients increased their purchase sizes and stabilized purchasing frequency.
Medical cannabis patients, cannabis policy researchers, countries considering recreational legalization
Medical registrations declined post-legalization
What the researchers found
Medical cannabis patient registrations initially increased but slowed after the law passed and decreased after edibles became available. Purchasing frequency decreased but stabilized after edibles arrived. Purchase sizes began increasing after edibles became available.
Why it matters
As more countries consider recreational legalization, understanding how it reshapes existing medical programs helps policymakers plan for transitions that protect patients who rely on medical cannabis access.
The numbers in context
Data from 10 Canadian provinces, April 2017-December 2022. Three policy events: law passage (June 2018), recreational sales start (October 2018), edibles/vapes arrival (December 2019).
How the study worked
Linear regressions of interrupted time series models analyzed medical cannabis patient registrations, purchase frequency, and purchase sizes across Canada's 10 provinces from April 2017 to December 2022, testing relationships with three policy milestones.
What this study cannot tell us
Administrative data cannot capture reasons for registration changes. Cannot distinguish medical patients who switched to recreational from those who stopped using cannabis entirely. Provincial variation in recreational market rollout not fully captured.
How to read the evidence
Interrupted time series analysis of national data provides strong quasi-experimental evidence, though cannot capture individual-level behavior changes.
When this study was published
2024 analysis of Canadian data from 2017-2022
The bigger picture
The pattern suggests many medical patients were using the medical system as a legal access point and shifted to recreational once available. But the remaining medical patients appear to be genuine therapeutic users who maintained and even increased their consumption.
Questions still open
- Are patients who left the medical system getting appropriate dosing guidance from recreational sources? Do countries with different medical cannabis frameworks see similar patterns after recreational legalization?
Common questions
Did all medical cannabis patients leave after legalization?
When did the biggest changes happen?
Read the original research
Canada's Recreational Cannabis Legalization and Medical Cannabis Patient Activity, 2017-2022.
American journal of public health, 114(S8), S673-S680
Citation
Armstrong, Michael J. (2024). Canada's Recreational Cannabis Legalization and Medical Cannabis Patient Activity, 2017-2022.. American journal of public health, 114(S8), S673-S680. https://doi.org/10.2105/AJPH.2024.307721