Residents of US states that legalize recreational cannabis are more likely to start using the drug

Peer reviewed: Yes
Method of research: Observational study
Subject of study: People  

A new study of more than 20,000 Americans published in the scientific journal Addiction has found that once a state legalizes recreational cannabis, state residents are more likely to start using the drug.  The study compared four US states with legalized recreational cannabis (California, Massachusetts, Nevada, and Maine) with states that had not.  

This study is groundbreaking in four ways:

  • It is the first study to estimate the association between recreational cannabis laws and individual-level changes in cannabis use among a nationally representative longitudinal cohort in the US.
  • It examines cannabis use initiation in both youths and adults.
  • It has a much larger sample size than  similar longitudinal studies: 6,925 youths and 14,938 adults, 21,863 in total.
  • The study provides evidence against the claim that legalization would not increase cannabis use among youth. 

Professor Yuyan Shi of Herbert Wertheim School of Public Health and Human Longevity Science at University of California San Diego, the Principal Investigator of this study, says “Our findings provide useful information to policymakers and public health practitioners interested in understanding the consequences of legalizing recreational cannabis.  It’s especially concerning that increased cannabis use occurs among young people because of the detrimental health effects associated with cannabis use at a young age, including impaired respiratory function, cardiovascular disease, and adverse effects on mental health.”  

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For editors:

This paper is free to read for one month after the embargo lifts from the Wiley Online Library: or by contacting Jean O’Reilly, Editorial Manager, Addiction,

To speak with author Professor Yuyan Shi, please contact her through Yadira Galindo, Director of Communications, Herbert Wertheim School of Public Health and Human Longevity Science at University of California San Diego by email ( or telephone (619-379-3977).

Full citation for article: Gunadi C, Zhu B, and Shi Y (2022) Recreational Cannabis Legalization and Transitions in Cannabis Use: Findings from a Nationally Representative Longitudinal Cohort in the United States.  Addiction: doi: 10.1111/add.15895

Funding: This research was supported by grant R01DA042290 and grant R01DA049730 from the US National Institute on Drug Abuse.

Declaration of interests:  The authors report no financial relationships with commercial interests.

Addiction is a monthly international scientific journal publishing peer-reviewed research reports on alcohol, substances, tobacco, and gambling as well as editorials and other debate pieces. Owned by the Society for the Study of Addiction, it has been in continuous publication since 1884.