Characteristics of Canadians likely to try or increase cannabis use following legalization for nonmedical purposes: a cross-sectional study

BACKGROUND: The Government of Canada legalized nonmedical use of cannabis in October 2018. Our objectives were to determine the percentage of Canadians intending to try or increase their cannabis use following legalization and to explore characteristics associated with this intent. METHODS: We used data from the 2018 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). RESULTS: Among the 39 000 households selected for recruitment for the survey, 17 089 respondents provided complete data (43.8%) and our weighted analysis represented 27 808 081 Canadians aged 15 years and older. An estimated 18.5% of respondents (95% confidence interval [CI] 17.6%-19.5%) indicated they intended to try or increase cannabis use following legalization. Being more likely to try or increase cannabis use was associated with younger age (15-24 yr v. ≥ 65 yr; adjusted OR 3.8, 95% CI 2.6-5.6; adjusted RI 20.1%, 95% CI 13.9%-26.2%), cannabis use in the past 3 months versus no use (adjusted OR 3.3, 95% CI 2.8-3.9; adjusted RI 20.4%, 95% CI 17.1%-23.6%), higher income (≥ $80 000 v. < $40 000; adjusted OR 1.5, 95% CI 1.3-1.9; adjusted RI 6.1%, 95% CI 3.2%-9.0%) and poor or fair mental health versus good to excellent mental health (adjusted OR 2.0, 95% CI 1.6-2.6; adjusted RI 11.5%, 95% CI 6.7%-16.2%). INTERPRETATION: Nearly 1 in 5 respondents reported that they intended to try or increase cannabis use after legalization; however, intention may not translate into behaviour. Continued monitoring should help to establish rates and patterns of cannabis use among Canadians following legalization.