California Marijuana Legalization Linked to Increased Adolescent Alcohol-Cannabis Co-Use
Analysis of 3.3 million California students found recreational marijuana legalization was associated with a 6% increase in alcohol-cannabis co-use overall, and a 58% increase among past-month drinkers.
Quick Facts
What This Study Found
Recreational legalization was associated with greater odds of co-use overall (OR=1.06) and much greater odds among past-month drinkers (OR=1.58) and heavy drinkers (OR=1.25). Paradoxically, among past-month marijuana users, co-use odds decreased (OR=0.76). Among co-users, marijuana use frequency increased.
Key Numbers
3,319,329 students. Overall co-use: OR=1.06 (95% CI 1.05-1.07). Among past-month drinkers: OR=1.58 (95% CI 1.52-1.62). Among heavy drinkers: OR=1.25 (95% CI 1.21-1.29). Among past-month marijuana users: OR=0.76 (95% CI 0.74-0.78). Among co-users, marijuana frequency increased (β=0.36).
How They Did This
Repeated cross-sectional data from 3,319,329 California 7th, 9th, and 11th graders participating in the California Healthy Kids Survey from 2010-2011 to 2018-2019. Multilevel regression analyzed changes before and after 2016 recreational legalization, controlling for demographics, survey year, and urbanicity.
Why This Research Matters
This is one of the largest studies examining whether marijuana legalization affects youth substance use patterns. The finding that alcohol-using youth are the most likely to add marijuana co-use has important implications for substance prevention programs.
The Bigger Picture
The differential effect is striking: legalization appears to pull alcohol-using teens toward adding marijuana, while marijuana-using teens actually became less likely to add alcohol. This asymmetry suggests legalization changes the social dynamics of substance use in complex ways.
What This Study Doesn't Tell Us
Cross-sectional design means individual students were not tracked over time. The study cannot definitively attribute changes to legalization versus other trends. Self-reported substance use may be affected by changing social desirability around marijuana. The overall 6% increase is small in absolute terms.
Questions This Raises
- ?Why does legalization increase co-use among drinkers but decrease it among marijuana users?
- ?Are the increased co-use patterns sustained years after legalization?
- ?Would higher marijuana taxes or fewer retail outlets reduce co-use among adolescents?
Trust & Context
- Key Stat:
- 58% increase in co-use among past-month drinkers post-legalization
- Evidence Grade:
- Strong: massive sample (3.3 million students) across 9 academic years with appropriate multilevel modeling.
- Study Age:
- Published in 2022, covering 2010-2019.
- Original Title:
- Recreational Marijuana Legalization and Co-use With Alcohol Among Adolescents.
- Published In:
- American journal of preventive medicine, 62(1), 57-64 (2022)
- Authors:
- Paschall, Mallie J(2), García-Ramírez, Grisel(2), Grube, Joel W(2)
- Database ID:
- RTHC-04129
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Did marijuana legalization increase youth drug use?
The overall co-use increase was modest (6%). The more important finding was that legalization had different effects depending on existing substance use: it pulled alcohol-using teens toward co-use with marijuana, while marijuana-using teens actually became less likely to also drink.
What can be done to reduce co-use among adolescents?
The authors suggest limiting retail outlet numbers and hours, restricting advertising, and raising taxes on both alcohol and marijuana. Prevention programs may also need to address co-use specifically rather than treating each substance separately.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-04129APA
Paschall, Mallie J; García-Ramírez, Grisel; Grube, Joel W. (2022). Recreational Marijuana Legalization and Co-use With Alcohol Among Adolescents.. American journal of preventive medicine, 62(1), 57-64. https://doi.org/10.1016/j.amepre.2021.06.003
MLA
Paschall, Mallie J, et al. "Recreational Marijuana Legalization and Co-use With Alcohol Among Adolescents.." American journal of preventive medicine, 2022. https://doi.org/10.1016/j.amepre.2021.06.003
RethinkTHC
RethinkTHC Research Database. "Recreational Marijuana Legalization and Co-use With Alcohol ..." RTHC-04129. Retrieved from https://rethinkthc.com/research/paschall-2022-recreational-marijuana-legalization-and
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.