Analysis of over 377,000 California 11th graders found frequent cannabis use increased after retail legalization in 2018, with jurisdictions newly permitting storefronts seeing sustained elevated rates while ban jurisdictions saw declines.
Local policymakers, school administrators, public health officials, and parents interested in how cannabis retail access affects youth use.
377,205 students; frequent use increased post-legalization (OR 1.30)
What the researchers found
Frequent cannabis use among 11th graders increased post-retail legalization. Any past-30-day use initially rose then slowly declined, except in jurisdictions newly allowing storefront and delivery retail, where elevated rates persisted. Cannabis use was consistently lower in jurisdictions that banned retail and lacked pre-existing medical sales.
Why it matters
This is one of the largest studies examining how local cannabis retail policies affect youth use. The finding that local bans were associated with lower use, while new retail access sustained higher rates, has direct implications for communities making zoning decisions.
The numbers in context
377,205 11th graders surveyed. Any past-30-day use increased post-legalization (OR 1.06, p=.013) then slowly declined (OR 0.97 per period, p=.001). Frequent use increased substantially (OR 1.30, p<.001 for level change; OR 1.13, p<.001 for slope change). Results varied significantly by local retail policy.
How the study worked
Adjusted interrupted time-series multilevel models analyzed cross-sectional data from the 2015/2016 to 2019/2020 California Healthy Kids Surveys (n=377,205 11th graders). Changes in past-30-day and frequent cannabis use were assessed pre- and post-retail legalization, stratified by local city and county cannabis retail policies.
What this study cannot tell us
Cross-sectional survey design cannot track individual students over time. Self-reported data subject to social desirability bias. Data ends spring 2020, so pandemic effects are a potential confounder. Pre-existing community norms likely influenced both local policies and baseline use rates.
How to read the evidence
Strong: very large sample, rigorous interrupted time-series design with multilevel modeling, and meaningful policy-stratified analysis.
When this study was published
Published 2026. Data from 2015/2016 to 2019/2020 school years.
The bigger picture
This study bridges the gap between state-level legalization research and local policy effects. It suggests that while statewide legalization sets the legal framework, local retail decisions meaningfully shape youth exposure and use patterns.
Questions still open
- Do the observed patterns persist post-pandemic? How do delivery-only jurisdictions differ from storefront jurisdictions in long-term youth use trends? Are lower rates in ban jurisdictions driven by policy or by pre-existing community norms?
Common questions
Did cannabis legalization increase teen use in California?
Do local cannabis bans reduce youth use?
Read the original research
Local Cannabis Policy and Cannabis Use by California High School Students Before and After Statewide Retail Legalization.
The Journal of adolescent health : official publication of the Society for Adolescent Medicine, 78(1), 69-77
Citation
Simard, Bethany J; Padon, Alisa A; Silver, Lynn D; Timberlake, David S; Young-Wolff, Kelly C. (2026). Local Cannabis Policy and Cannabis Use by California High School Students Before and After Statewide Retail Legalization.. The Journal of adolescent health : official publication of the Society for Adolescent Medicine, 78(1), 69-77. https://doi.org/10.1016/j.jadohealth.2025.09.003