Canadian medical cannabis registrations declined after recreational legalization

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.

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.

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 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.

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.