Factors Associated with Initiating Cannabis Use After Legalization in Canada: A Cross-Sectional Study.

Cannabis use has increased since the Government of Canada legalized nonmedical use in October 2018. We investigated demographic factors associated with initiating cannabis use after legalization. We used data from the 2018 and 2019 National Cannabis Survey and constructed multivariable regression models. Respondents' data were weighted and bootstrapped. We report relative measures of association as adjusted odds ratios (ORs) and absolute measures of association as adjusted risk increases (RIs). Among the 58,195 households surveyed, 28,566 provided complete data (49%) and our weighted analysis represented 27,904,258 Canadians aged ≥ 15 years. Approximately one in five Canadians endorsed use of cannabis (19.8%), predominantly for nonmedical (9.5%) or combined medical and nonmedical (5.8%) reasons. Those who initiated cannabis use in the past 3 months (1.9%) were more likely to be younger (25-34 years vs. ≥ 65 years; adjusted OR 1.7, 95% confidence interval [CI] 1.1-2.8; adjusted RI 1.1%, 95% CI 0.1-2.0%), endorse poor to fair versus good to excellent physical health (adjusted OR 2.0, 95% CI 1.3-3.1; adjusted RI 1.7%, 95% CI 0.3-3.1%), and reside outside of Quebec (adjusted OR 1.4, 95% CI 1.1-2.0; adjusted RI 0.1%, 95% CI 0.6-1.1%). The 1% of Canadians who endorsed initiating use of cannabis due to legalization were more likely to reside outside of Quebec (adjusted OR 1.9, 95% CI 1.1-3.2; adjusted RI 0.5%, 95% CI 0.2-0.9%). Canadians initiating cannabis use after nonmedical legalization were likely to be younger and endorse worse physical health, and half of those using cannabis reported therapeutic use. Stricter policies, lower social acceptance, and less availability of cannabis in Quebec appear to have curtailed initiation of use after legalization.