While marijuana use decreased among younger Washington teens after legalization, use increased among working 12th graders relative to non-working peers, with stronger effects for those working more hours.
Parents of working teens, employers hiring minors, policymakers, and anyone interested in legalization effects on youth.
Working 12th graders: 34% higher marijuana use after legalization relative to non-working peers
What the researchers found
Between 2010 and 2016, marijuana use decreased among 8th and 10th graders regardless of work status. Among 12th graders, working youth showed significantly increased use relative to non-workers (AOR 1.34, 95% CI: 1.22-1.48). Youth in formal work settings (retail, service) were more likely to use than those in informal settings (babysitting).
Why it matters
Working 12th graders represent teens with the most independence, disposable income, and exposure to adult environments where cannabis may be more accessible. This group may need targeted prevention as legalization creates new access pathways.
The numbers in context
76,000+ students surveyed annually. Use decreased among working and non-working 8th/10th graders (2010-2016). Working 12th graders: AOR 1.34 (95% CI: 1.22-1.48) increase relative to non-working peers. Stronger associations with more work hours.
How the study worked
Difference-in-differences analysis using 2010 and 2016 data from Washington's Healthy Youth Survey (76,000+ youth annually), comparing marijuana use by work status and hours among 8th, 10th, and 12th graders in public schools before and after legalization.
What this study cannot tell us
Cross-sectional surveys at two time points cannot establish causation. Self-reported marijuana use. Cannot distinguish between legalization effects and secular trends. Work setting categories are broad.
How to read the evidence
Moderate: large representative sample with difference-in-differences analysis, but cross-sectional design at two timepoints.
When this study was published
Published in 2019, comparing 2010 and 2016 data.
The bigger picture
The overall decrease in younger teen use is reassuring, consistent with other post-legalization studies. But the increase among working 12th graders suggests the workplace may be an important and overlooked access point for cannabis among older teens.
Questions still open
- Are working 12th graders accessing cannabis through adult coworkers? Would workplace cannabis policies for employers of minors reduce this effect? Do other states with legalization show the same pattern?
Common questions
Did legalization increase teen marijuana use?
Why are working teens different?
Read the original research
Employment and Marijuana Use Among Washington State Adolescents Before and After Legalization of Retail Marijuana.
The Journal of adolescent health : official publication of the Society for Adolescent Medicine, 65(1), 39-45
Citation
Graves, Janessa M; Whitehill, Jennifer M; Miller, Mary E; Brooks-Russell, Ashley; Richardson, Susan M; Dilley, Julia A. (2019). Employment and Marijuana Use Among Washington State Adolescents Before and After Legalization of Retail Marijuana.. The Journal of adolescent health : official publication of the Society for Adolescent Medicine, 65(1), 39-45. https://doi.org/10.1016/j.jadohealth.2018.12.027
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