A 2025 study using data from the Québec Longitudinal Study of Child Development found that 60% of adolescents did not use cannabis between ages 12 and 17, 20% started cannabis before age 15 and by age 17 were using at least once a month, and the remaining 20% began in their late teens and were using less than once a month by age 17.
October 29, 2025
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Population-level distribution of adolescent cannabis use trajectories measured between ages 12 and 17.