California high school students who frequently saw e-cigarette and cannabis posts on social media were significantly more likely to start using these substances, with posts from friends and micro-influencers showing the strongest associations.
Pediatricians, parents, social media platform policymakers, and adolescent health researchers.
What the researchers found
Frequent exposure to e-cigarette and/or cannabis social media posts at baseline was associated with higher odds of initiating e-cigarette, cannabis, and dual use at one-year follow-up among never-users. Posts from friends and micro-influencers showed the strongest associations with use.
Why it matters
Published in JAMA, this study provides strong evidence that social media exposure to cannabis and e-cigarette content predicts actual substance use initiation in teens — not just intentions but real behavior change over one year.
The numbers in context
Study 1: 4,232 adolescents (mean age 17.0, 52.1% female). 22.9% reported frequent baseline exposure. Study 2 examined exposure from five source types. Both conducted among California high school students.
How the study worked
Two studies: (1) a longitudinal study of 4,232 California high school students with one-year follow-up among baseline never-users, and (2) a cross-sectional survey examining exposure to posts from specific sources (friends, celebrities, micro-influencers, brands). Both used generalized estimating equations adjusted for sociodemographic and behavioral factors.
What this study cannot tell us
Observational design — social media exposure may reflect existing interest. California-specific. Self-reported substance use and social media exposure. Cannot determine which specific posts or platforms are most influential.
How to read the evidence
Longitudinal design with one-year follow-up among never-users provides stronger evidence than cross-sectional studies, published in a top-tier journal with appropriate adjustments.
When this study was published
Published 2025, baseline data from 2021–2023.
The bigger picture
This JAMA-published research strengthens the case for regulating substance-related content on social media platforms. The finding that micro-influencers and friends — not just brands — drive use initiation suggests regulations targeting only commercial advertising may be insufficient.
Questions still open
- Would restricting substance-related social media content reduce teen initiation rates? How do algorithms amplify cannabis and vaping content for teens? Should micro-influencer substance marketing face the same regulations as brand advertising?
Common questions
Does seeing cannabis on social media cause teens to try it?
Which social media sources had the biggest influence?
Read the original research
E-Cigarette and Cannabis Social Media Posts and Adolescent Substance Use.
JAMA network open, 8(6), e2517611
Citation
Vassey, Julia; Cho, Junhan; Vogel, Erin A; Iyer, Trisha; Chen-Sankey, Julia; Unger, Jennifer B. (2025). E-Cigarette and Cannabis Social Media Posts and Adolescent Substance Use.. JAMA network open, 8(6), e2517611. https://doi.org/10.1001/jamanetworkopen.2025.17611
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