Teen cannabis use increased after legalization in Canada, study finds

CNN

22-04-2025

Legalization of cannabis products may be linked to growing use among teens, a new study found.
Teen use of cannabis rose 26% in Canadian provinces that legalized the sale of edibles and extracts in October 2019, according to the study, which published Friday in the journal JAMA Network Open.
Edible use increased 43%, raising concerns about youth-friendly forms of the drug, such as cannabis chocolates, candies, sodas and desserts — the same products responsible for a growing number of child hospitalizations in the US.
Based on surveys of more than 106,000 students aged 12 to 17 years old, the study found use remained stable in Quebec, where the sale of these products was still banned.
Canada legalized dried cannabis use in October 2018, and all Canadian provinces except Quebec followed a year later by legalizing the sale of cannabis edibles and extracts.
While Canada's 2018 law prohibits the sale of cannabis to individuals under 18, the study suggests legalization could have made these products more accessible to teens and influenced their attitudes surrounding use.
Canadian laws require child-resistant, plain and clearly labeled packaging for cannabis edibles, but illicit products sold online and by unauthorized distributors often look like other snacks, according to the study.
'This finding is important in light of previous literature regarding potential long-term adverse health effects of cannabis use for adolescents,' said senior author Dr. Hai Nguyen, a professor in the School of Pharmacy at Memorial University of Newfoundland, in an email.
Teens using cannabis products regularly are at a greater risk for developing dependency disorders later in life, according to neuroscientist Joshua Gowin, who was not involved in the study.
'Some (studies) suggest that cannabis use during adolescence, especially heavy use, could alter brain development,' said Gowin, an assistant professor of radiology at the University of Colorado School of Medicine. 'If you start using earlier, it may be harder to change that trajectory later on.'
Cannabis use can affect parts of the brain that deal with attention, coordination, learning, decision-making and emotional regulation, according to the US Centers for Disease Control and Prevention.
Use at an early age has been linked to mental health issues such as depression, anxiety, and a heightened risk of developing longer-lasting mental health disorders, such as schizophrenia, in adulthood.
Despite these risks, the study found the students perceived less harm from occasional cannabis use because of its legalization.
Using both cannabis and alcohol at the same time, which studies show can lead to higher and more frequent consumption of both, was 28% more prevalent after legalization as well.
When it comes to social attitudes around drug use, causality is often complicated to prove, because laws can change in response to cultural changes as well, Gowin said. For this reason, other research methods beyond surveys can play an important role in understanding the effects of legalization for future policymaking decisions.
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In the US, the relationship between adolescent use and legalization may be even more complex to study because of variations in state and local regulations, Gowin said.
Federally, cannabis is illegal, but 47 states have legalized it for medical uses and 24 states for adult recreational purposes. Each state has its own laws about marketing, packaging and distribution of these products.
Nguyen also noted his research only addresses short-term effects based on one point in time after legalization, so it's important to continuously study how use patterns evolve and reflect changes in the laws.
In the meantime, Nguyen recommended policymakers focus on striking the right balance between adult access and teen protection. Further enforcement may be needed to crack down on marketing and packaging that appeals to younger people, he noted, and local regulators can ensure cannabis distributors are located an appropriate distance away from schools.
'It is also essential to invest in public education campaigns that raise awareness about the risks of cannabis use among adolescents,' Nguyen said, adding that multimedia public health campaigns, school-based awareness efforts and parent-child communication are all important prevention strategies.
Parent-youth communication guides can help families have more informed conversations at home and navigate common misconceptions about edible use, Nguyen said.
'It's not about scaring people,' Gowin said. 'Honesty and truth can be at the forefront of the conversations and hopefully people can make up their own minds about what's the best thing for them, their families and their communities.'