Opening recreational cannabis stores was not linked to self-harm injuries, but alcohol outlet density was
Bayesian spatiotemporal analysis of California ZIP codes found no association between recreational cannabis outlet openings and self-harm, while alcohol outlet density showed a strong link to nonfatal self-harm.
Quick Facts
What This Study Found
Recreational cannabis outlets were not associated with fatal or nonfatal self-harm injuries; a hypothetical 20% reduction in alcohol outlets was associated with 1.59 fewer nonfatal self-harm injuries per 100,000; no interaction between cannabis and alcohol outlet densities.
Key Numbers
If cannabis outlets had never opened: -0.35 per 100,000 nonfatal self-harm (95% CI: -1.25, 0.51); 20% alcohol outlet reduction: -1.59 per 100,000 nonfatal (95% CI: -2.60, -0.59); strongest effects in ages 15-34.
How They Did This
Bayesian spatiotemporal analysis of quarterly ZIP code-level data from California (2017-2019) using statewide data on recreational cannabis outlets, alcohol outlets, and hospital discharges/deaths from self-harm; adjusted for confounders and spatial autocorrelation.
Why This Research Matters
Concerns that cannabis legalization might increase self-harm are not supported by this analysis, while alcohol outlet density remains a significant modifiable risk factor.
The Bigger Picture
This adds to growing evidence that cannabis retail access does not worsen population-level mental health outcomes, in contrast to alcohol availability.
What This Study Doesn't Tell Us
Three-year window may miss longer-term effects; ecological study cannot capture individual-level use patterns; California-specific results may not generalize; could not account for illicit market dynamics.
Questions This Raises
- ?Would longer follow-up reveal delayed effects of cannabis outlet openings?
- ?Do other states show similar null findings for cannabis outlets?
- ?Could cannabis outlet access reduce self-harm by displacing alcohol use?
Trust & Context
- Key Stat:
- Zero significant association between cannabis outlet openings and self-harm injuries
- Evidence Grade:
- Rigorous Bayesian spatiotemporal methodology with statewide data, though ecological design and short timeframe are limitations.
- Study Age:
- Published 2025, data from 2017-2019
- Original Title:
- Examining the Interactive Associations of Cannabis and Alcohol Outlets With Self-harm Injuries in California: A Spatiotemporal Analysis.
- Published In:
- Epidemiology (Cambridge, Mass.), 36(2), 196-206 (2025)
- Authors:
- Charris, Rafael, Ahern, Jennifer, Apollonio, Dorie E(6), Jent, Victoria, Jacobs, Laurie M, Jung, Shelley, Schmidt, Laura A, Gruenewald, Paul, Matthay, Ellicott C
- Database ID:
- RTHC-06187
Evidence Hierarchy
Follows a group of people over time to track how outcomes develop.
What do these levels mean? →Frequently Asked Questions
Did cannabis stores opening lead to more self-harm?
No. The analysis found no significant association between recreational cannabis outlet openings and either fatal or nonfatal self-harm injuries in California ZIP codes.
What about alcohol outlets?
Alcohol outlet density was strongly associated with nonfatal self-harm. A hypothetical 20% reduction in alcohol outlets was linked to 1.59 fewer nonfatal self-harm injuries per 100,000 people.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-06187APA
Charris, Rafael; Ahern, Jennifer; Apollonio, Dorie E; Jent, Victoria; Jacobs, Laurie M; Jung, Shelley; Schmidt, Laura A; Gruenewald, Paul; Matthay, Ellicott C. (2025). Examining the Interactive Associations of Cannabis and Alcohol Outlets With Self-harm Injuries in California: A Spatiotemporal Analysis.. Epidemiology (Cambridge, Mass.), 36(2), 196-206. https://doi.org/10.1097/EDE.0000000000001822
MLA
Charris, Rafael, et al. "Examining the Interactive Associations of Cannabis and Alcohol Outlets With Self-harm Injuries in California: A Spatiotemporal Analysis.." Epidemiology (Cambridge, 2025. https://doi.org/10.1097/EDE.0000000000001822
RethinkTHC
RethinkTHC Research Database. "Examining the Interactive Associations of Cannabis and Alcoh..." RTHC-06187. Retrieved from https://rethinkthc.com/research/charris-2025-examining-the-interactive-associations
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.