“cannabis legalization was associated with a 26% increase in the overall prevalence of cannabis use”
Findings In this cross-sectional study of 106 032 adolescents, cannabis legalization was associated with a 26% increase in the overall prevalence of cannabis use, a 43% increase in edible cannabis use, a 34% increase in cannabis smoking, and a 28% increase in co-use of alcohol and cannabis. The legalization was also associated with lower perception of cannabis harms.
Meaning The increase in adolescents’ cannabis use associated with the legalization highlights 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.
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.
In October 2018, Canada legalized sale of dried or fresh cannabis and cannabis oil to individuals above the minimum legal age (set at 18 or 19 years across provinces).1 Subsequently, in October 2019, the sale of cannabis edibles and extracts was legalized across Canada, with the exception of Quebec. These products included items particularly appealing to adolescents, such as cannabis-infused chocolates, candies, and desserts and cannabis vaping products (referred to hereafter as youth-friendly cannabis edibles and extracts).2 Quebec banned the sale of youth-friendly cannabis edibles and vaping products to protect children and youths from accidental cannabis poisoning and to reduce the normalization of cannabis use among them. However, home production of these products was still allowed.3 The sale of certain non–youth-friendly edibles and extracts (such as dried cauliflower and dehydrated beets) was allowed in Quebec, but this only began in July 2022.4 Quebec’s government stated that the bans on youth-friendly cannabis edibles and extracts would protect children and youths from accidental cannabis poisoning and reduce normalization of cannabis use among youths.5,6 Three of the Atlantic provinces also restricted sales of cannabis vaping products, and bans on cannabis and hemp edibles have been made by health authorities in other jurisdictions in both Canada and the US.7–9
One of the intended goals of the cannabis legalization was to prevent adolescent cannabis use.10 However, leading up to this historic policy change, health professionals had strongly argued that the legalization would pose serious health risks for adolescents,11 highlighting the increased risk of psychiatric disorders and poor cognitive and adverse educational outcomes associated with cannabis use in adolescence.12,13 The legalization of youth-friendly cannabis edibles and extracts further heightened these concerns. Cannabis edibles are appealing to adolescents not only due to their taste (eg, chocolates, candy, desserts, and sodas) but also because they can be secretly consumed. A qualitative study of adolescents aged 15 to 17 years noted that those who are concerned about smoking or want to consume cannabis discreetly prefer edibles over smoking.14 Moreover, cannabis edibles carry a high risk of overdose due to the delayed appearance of psychoactive effects, difficulty in dosing, and differences in tetrahydrocannabinol (THC) metabolism.15 Meanwhile, the legalization of cannabis extracts can increase adolescent cannabis vaping. In the absence of well-enforced caps, cannabis vaping products often have higher THC potencies than other forms of cannabis, which can lead to both stronger psychoactive effects16 and increased respiratory risks.17,18 Cannabis vaping among adolescents is becoming increasingly popular19 and more than 75% of e-cigarette or vaping-associated lung injuries cases in the US have been associated with vaping THC products.17 Additionally, legalizing cannabis edibles and extracts may normalize cannabis use. Previous studies have shown that adolescents who use edible cannabis have a lower perception of cannabis risks than those who do not.20,21
There is also a question about whether legalization of youth-friendly cannabis edibles and extracts affects adolescent use of other substances such as alcohol. Literature suggests a positive association of cannabis use intensity with alcohol craving.22 If the legalization increases adolescent cannabis use, it could also encourage co-use of alcohol and cannabis.
Currently, there exists little evidence on the impact of legalizing youth-friendly cannabis edibles and extracts to inform these discussions. One study23,24 examined the association of dried and edible cannabis legalization with unintentional cannabis hospitalizations among children aged 0 to 9 years; it found that after dried cannabis was legalized across Canada, cannabis hospitalization rates increased similarly (nearly 3-fold) in all provinces. However, after cannabis edibles were legalized, hospitalization rates doubled in provinces that legalized edibles but did not change in Quebec.23,24
Our study has 3 objectives. Using data from a large survey of Canadian adolescents in grades 7 to 11 and difference-in-differences (DD) design, we first examined the association of legalization of youth-friendly cannabis edibles and extracts (referred to as legalization hereafter) with overall prevalence of adolescent cannabis use. Next, we studied the association of the legalization with modes of cannabis consumption (ie, cannabis edibles, cannabis smoking, and cannabis vaping) and the co-use of alcohol and cannabis. Finally, we assessed the association of the legalization with adolescents’ perception of harm from cannabis use. We hypothesized that the legalization was associated with increased cannabis use (via each mode), higher co-use of cannabis and alcohol, and lower perception of cannabis harms among adolescents.
