Legalizing Youth-Friendly Cannabis Edibles and Extracts and Adolescent Cannabis Use.

Importance: A year after dried cannabis was legalized across Canada in October 2018, Canadian provinces except Quebec legalized sales of cannabis edibles and extracts, including youth-friendly edibles such as cannabis chocolates, candies, and desserts and cannabis vaping products. Little is known about the association of this legalization with adolescent cannabis use. Objective: To investigate changes in adolescent cannabis use and cannabis harm perceptions associated with the legalization of youth-friendly cannabis edibles and extracts in Canada. Design, Setting, and Participants: This serial cross-sectional study analyzed data from students in grades 7 to 11 who participated in the nationally representative Canadian Student Tobacco Alcohol and Drugs Surveys in 2018 to 2019 and 2021 to 2022. A differences-in-differences design compared changes in outcomes in provinces that legalized cannabis edibles and extracts with changes in Quebec where youth-friendly cannabis edibles and cannabis vaping products were banned. Data were analyzed from June 2024 to January 2025. Exposure: Legalization of youth-friendly cannabis edibles and extracts across provinces in Canada (except Quebec) in October 2019. Main Outcomes and Measures: The primary outcomes were cannabis use in the past 12 months, past 12-month use of edible cannabis use, cannabis smoking, cannabis vaping, and co-use of alcohol and cannabis. Secondary outcomes were perception of harm from occasional and regular cannabis use. Results: In the study sample of 106 032 students in grades 7 to 11 (54 441 male [weighted percentage, 51.3%]), between 2018 to 2019 and 2021 to 2022, past 12-month cannabis use increased from 14.6% (6081 of 41 477 students) to 15.9% (6163 of 38 675 students) and use of edible cannabis increased from 7.9% (3268 of 41 373 students) to 9.5% (3678 of 38 556 students) in provinces that legalized youth-friendly cannabis edibles and extracts. Meanwhile, past 12-month cannabis use declined from 17.4% (2264 of 13 030 students) to 15.6% (1960 of 12 550 students) and use of edible cannabis declined from 7.3% (955 of 13 002 students) to 5.9% (739 of 12 533 students) in Quebec. Regression analyses indicated that the legalization was associated with a 3.8 percentage point (95% CI, 1.1 to 6.6 percentage points; P = .01) or 26% increase in past 12-month cannabis use and a 3.4 percentage point (95% CI, 1.9 to 4.9 percentage points; P = .001) or 43% increase in use of cannabis edibles among adolescents. While there was no statistically significant change in cannabis vaping associated with the legalization, cannabis smoking increased by 4.4 percentage points (95% CI, 1.8 to 7.0 percentage points; P = .004) or 34% and co-use of alcohol and cannabis increased by 2.4 percentage points (95% CI, 0.5 to 4.3 percentage points; P = .02) or 28%. The legalization was also associated with a lower perception of harm from occasional cannabis use. Conclusions and Relevance: In this serial cross-sectional study of adolescents in grades 7 to 11, legalization of cannabis edibles and extracts was associated with an increase not only in edible cannabis use and cannabis smoking, but also in the overall prevalence of cannabis use and co-use of alcohol and cannabis, highlighting the need for stricter policy measures to curb adolescents' access to cannabis edibles and extracts and greater awareness among adolescents about harms of cannabis use.