By shifting the production, sale, and consumption of marijuana from the illicit market to a regulated system, legalization has the potential to make marijuana less accessible to youth. A growing body of research indicates that the adoption of medical and adult-use marijuana laws decreases youth marijuana usage rates. According to a February 2019 study published in The American Journal of Drug and Alcohol Abuse, researchers found that the passage of a medical marijuana law “was associated with small significant reductions…of 1.1 percentage points in current marijuana use” among adolescents.

Source: Rebekah Levine Coley, Summer Sherburne Hawkins, Marco Ghiani, Claudia Kruzik & Christopher F. Baum (2019) A quasi-experimental evaluation of marijuana policies and youth marijuana use, The American Journal of Drug and Alcohol Abuse, DOI: 10.1080/00952990.2018.1559847