An increasing number of jurisdictions including Mexico, New Zealand, Russia, Luxembourg and several US states are looking to legalize non-medical cannabis. The decision to legalize cannabis however comes with a contentious question for policymakers: What should be the minimum legal age (MLA) for cannabis consumption? While a low MLA can discourage the underground cannabis market, cannabis consumption before age 25 is said to negatively impact brain development. Policymakers, thus, face a difficult tradeoff between curtailing illegal economic activity and safeguarding adolescents’ well-being.
Our study published in BMC Public Health shows that there is merit in choosing 19 as the MLA for non-medical cannabis use. We reached this conclusion by looking at how Canadians, who started using cannabis at different young ages, differ in several important outcomes (educational attainment, cigarette smoking, self-reported general and mental health) later in life.
Why did we do this study?
Canada was the second country in the world to legalize non-medical cannabis in October 2018. Ahead of the legalization, the federal government recommended a MLA of 18 years. However, after public consultations and for harmonization with the existing minimum legal ages for alcohol and tobacco use, most Canadian provinces set 19 as the minimum legal age; the two exceptions were Quebec and Alberta which opted for 18. Two years into legalization, the policy on MLA for cannabis use in Canada is still evolving. In particular, Quebec revised its MLA to 21 in October 2019 and there have also been calls to raise minimum legal age to 21 in Ontario. Notably, evidence that could shed light on the merits of different proposed MLAs was lacking.
What do our findings imply?
Individuals starting cannabis at age 19 have later life outcomes that are better than those starting it ate age 18
We found that most later life outcomes are better for individuals starting cannabis at age 19 than those starting it at age 18 but not worse than those starting cannabis between age 20 and 25. These results imply that age 19 is the optimal MLA for cannabis use.
This finding of MLA of 19 is different from the Canadian federal government’s recommendation of 18 and stands in contrast with medical community’s support for age 21 or 25. Yet, it appears to be plausible: age 19 is high enough to address concerns over potential adverse outcomes associated with using cannabis at young age while low enough to discourage the illegal market for the underage.
Our findings will be useful for policymakers in jurisdictions planning to legalize non-medical cannabis. Meanwhile, in Canada, as the post-cannabis legalization era evolves, it will be important to watch trends in youth’s and young adults’ use and monitor harms over time while ensuring that the legal market is tightly regulated and that cannabis companies do not stray from restrictions on marketing, sales, and packaging that might make products more appealing and accessible to children.