How Cannabis Laws and Advertising Shape Young Adults' Use Patterns Over Time
State cannabis laws and digital advertising exposure drive young adult cannabis and delta-8 THC use through shifts in risk perceptions and use motives.
Quick Facts
What This Study Found
Legal cannabis states saw lower DICP use motives but higher cannabis-only use frequency. More restrictive delta-8 laws increased cannabis-only (vs. both) use. Digital cannabis ads lowered risk perceptions and increased use, motives, intentions, and consequences. These associations were mediated by use motives and risk perceptions. Higher use frequency mediated associations with consequences.
Key Numbers
3,437 participants across two waves. Legal vs. illegal states: lower DICP motives, higher cannabis-only use. Digital ads associated with lower risk perceptions, higher use motives, higher use intentions, more consequences. Frequency mediated law/advertising effects on consequences.
How They Did This
Two-wave longitudinal survey (2023-2024) of 3,437 US young adults aged 18-34 (~50% past-month cannabis use by design). Multivariable regressions with parallel mediation assessed direct and indirect associations across state laws, advertising exposure, risk perceptions, motives, use, and consequences.
Why This Research Matters
This is among the first studies to trace the full causal chain from cannabis policy and marketing through psychological mechanisms to actual use behavior and consequences — showing exactly how and why these upstream factors affect downstream harm.
The Bigger Picture
The mediation through risk perceptions and motives suggests that how young adults think about cannabis — not just access — drives behavior. This means counter-advertising and education could be as important as legal restrictions.
What This Study Doesn't Tell Us
Self-reported survey data. ~50% past-month cannabis user sampling design may overrepresent users. State law assignment is cross-sectional even with longitudinal individual data. Digital ad measurement may not capture total exposure.
Questions This Raises
- ?Could counter-messaging campaigns effectively raise risk perceptions?
- ?Do delta-8 restrictions push users to unregulated markets?
- ?Would standardized cannabis marketing regulations reduce use consequences?
Trust & Context
- Key Stat:
- Evidence Grade:
- Longitudinal design with mediation analysis and large sample provides strong correlational evidence, though observational design limits causal conclusions.
- Study Age:
- Published 2026 with 2023-2024 longitudinal data, capturing the rapidly evolving DICP market.
- Original Title:
- A longitudinal mediated examination of legal, commercial, and individual determinants of cannabis and derived cannabis use behaviors and consequences among US young adults.
- Published In:
- Addictive behaviors, 172, 108526 (2026)
- Authors:
- LoParco, Cassidy R(26), Rossheim, Matthew E(14), Wang, Yan(20), Yang, Y Tony, Paichadze, Nino, Cavazos-Rehg, Patricia A, Berg, Carla J
- Database ID:
- RTHC-08443
Evidence Hierarchy
Frequently Asked Questions
Do cannabis laws actually affect how much people use?
Yes — young adults in legal cannabis states used more cannabis but less delta-8 THC. Importantly, the effects worked through psychological mechanisms: legal access changed people's risk perceptions and motives, which then changed behavior.
Does cannabis advertising influence use?
Digital cannabis advertising was associated with lower risk perceptions, stronger use motives, and more actual use and consequences among young adults — and these effects operated through the same psychological pathways affected by laws.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-08443APA
LoParco, Cassidy R; Rossheim, Matthew E; Wang, Yan; Yang, Y Tony; Paichadze, Nino; Cavazos-Rehg, Patricia A; Berg, Carla J. (2026). A longitudinal mediated examination of legal, commercial, and individual determinants of cannabis and derived cannabis use behaviors and consequences among US young adults.. Addictive behaviors, 172, 108526. https://doi.org/10.1016/j.addbeh.2025.108526
MLA
LoParco, Cassidy R, et al. "A longitudinal mediated examination of legal, commercial, and individual determinants of cannabis and derived cannabis use behaviors and consequences among US young adults.." Addictive behaviors, 2026. https://doi.org/10.1016/j.addbeh.2025.108526
RethinkTHC
RethinkTHC Research Database. "A longitudinal mediated examination of legal, commercial, an..." RTHC-08443. Retrieved from https://rethinkthc.com/research/loparco-2026-a-longitudinal-mediated-examination
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.