Cannabis Research Considerations

While research on the effects of cannabis and tobacco co-use is accumulating^1-8, many questions remain about the health impact of cannabis use and the social consequences of legalization of recreational cannabis use through California’s Proposition 64. Though in May 2024 the federal Drug Enforcement Agency (DEA) issued a notice of proposed rulemaking transferring cannabis from a Schedule I to a Schedule III substance, for now, cannabis remains a Schedule 1 drug, classified as a drug with “no currently accepted medical use” in the United States, and the Justice Department is permitted to intervene with legal authority in matters that involve cannabis.

While Californians have relatively easy access to cannabis products, more scientific evidence is needed to support health benefit claims from the industry and to understand the health consequences of using this drug. TRDRP encourages investigators to engage in rigorous scientific research at the intersection of cannabis and tobacco into the health effects and social and policy consequences associated with cannabis and to clarify any potential health benefits.

Given the continuing contradiction in state and federal law (as of the summer of 2024), we encourage investigators interested in cannabis research to remain familiar with University policies that inform types of research that require a DEA license/FDA approval and research that does not need federal oversight; for example, observational studies that do not involve providing product. Please refer to materials included in the links below for general guidance and considerations:

Information for Researchers on Conducting Cannabis Research at the University of California. This link goes to guidance prepared by the Research Policy Analysis & Coordination unit of UCOP Research & Graduate Studies in consultation with UC Legal. The document affirms that UC research remains subject to the same federal rules and regulations as before the passage of Proposition 64. The bulk of the document reminds researchers and administrators of applicable law, regulations and UC policies, as well as whom to contact on campus before deciding to undertake research involving cannabis.

References

Manthey J, Jacobsen B, Hayer T, Kalke J, López-Pelayo H, Pons-Cabrera MT, Verthein U, Rosenkranz M. The impact of legal cannabis availability on cannabis use and health outcomes: a systematic review.International Journal of Drug Policy. 2023 Jun 1;116:104039.
Gravely S, Driezen P, Smith DM, Borland R, Lindblom EN, Hammond D, McNeill A, Hyland A, Cummings KM, Chan G, Thompson ME. International differences in patterns of cannabis use among adult cigarette smokers: findings from the 2018 ITC Four Country Smoking and Vaping Survey.International Journal of Drug Policy. 2020 May 1;79:102754.
Weinberger AH, Zhu J, Lee J, Xu S, Goodwin RD. Cannabis use and the onset of cigarette and e-cigarette use: a prospective, longitudinal study among youth in the United States.Nicotine and Tobacco Research. 2021 Mar;23(3):609-13.
Wang Y, Duan Z, Self-Brown SR, et al. Longitudinal associations between e-cigarette use and onset of multiple modes of cannabis use among US adolescents.Addict Behav 2022;131:107316.
Driezen P, Gravely S, Wadsworth E, Smith DM, Loewen R, Hammond D, Li L, Abramovici H, McNeill A, Borland R, Cummings KM. Increasing cannabis use is associated with poorer cigarette smoking cessation outcomes: findings from the ITC four country smoking and vaping surveys, 2016–2018.Nicotine and Tobacco Research. 2022 Jan;24(1):53-9.
Weinberger AH, Delnevo CD, Wyka K, Gbedemah M, Lee J, Copeland J, Goodwin RD. Cannabis use is associated with increased risk of cigarette smoking initiation, persistence, and relapse among adults in the United States.Nicotine and Tobacco Research. 2020 Aug;22(8):1404-8.
Akbar SA, Tomko RL, Salazar CA, Squeglia LM, McClure EA. Tobacco and cannabis co-use and interrelatedness among adults.Addictive behaviors. 2019 Mar 1;90:354-61.
Strong DR, Myers MG, Pulvers K, Noble M, Brikmanis K, & Doran N (2018). Marijuana use among US tobacco users: Findings from wave 1 of the population assessment of tobacco health (PATH) study.Drug and Alcohol Dependence, 186, 16–22.