Changes in cannabis attitudes and perceptions in the five years following recreational legalization in Canada: Findings from an observational cohort study of community adults

BACKGROUND: Social acceptability and perceived risks/benefits are key attitudinal factors that influence substance use, and a major concern about cannabis legalization is an increase in more favourable attitudes ultimately leading to greater cannabis misuse. This study investigated perceptions of cannabis acceptability and risks/benefits over the 5 years following legalization in Canada, the first G7 nation to have legalized cannabis nationally, in a longitudinal observational cohort of community adults. METHODS: Participants (60 % female, median age = 29, 48% reporting cannabis use pre-legalization) were non-clinical adults from the general community who were assessed up to 11 times from September 2018 to October 2023 (mean waves = 9.9). Overall temporal attitudinal changes and whether changes were moderated by pre-legalization cannabis use status were examined. RESULTS: Significant increases over time were present for social acceptability of any recreational cannabis use (OR [95% CI]: 1.06 [1.05, 1.07]) and trying cannabis (1.02 [1.01, 1.03]), while acceptability of medical cannabis use decreased (0.95 [0.94, 0.96]). Meanwhile, regular cannabis use was perceived as riskier (0.97 [0.96, 0.98]) and addiction potential was perceived as greater (0.94 [0.93, 0.95]) over time. Perceived health-related benefits of cannabis were significantly less likely to be endorsed over time, while there were significant increases in perceived risks, including exacerbating stress, anxiety, and depression; exacerbating existing medical conditions; and disrupting sleep. Moderator analyses found participants not using cannabis pre-legalization showed significantly steeper increases towards greater social acceptability of occasional and regular use, and less steep increases in endorsement of cannabis-related risks. CONCLUSIONS: Shifting social acceptability of cannabis post-legalization in Canada is paralleled by increases in perceived health-related risks and decreases in perceived benefits. Continued surveillance of attitudinal changes following legalization in Canada is warranted to inform the impacts in the largest national legal cannabis jurisdiction as well as other jurisdictions considering regulatory reform.