The impacts of cannabis legalization in the Americas: Insights from a systematic review

Background

The cannabis policy landscape in the Americas is dramatically changing, and other jurisdictions are implementing or considering their own policy changes—from the Australian Capital Territory to multiple countries in Europe. Even in the past 5 years, there have been further changes to recreational cannabis policies in Americas, including changes to supply models or product availability.  Understanding the consequences of these changes will be important to inform future policy developments in the Americas and beyond.  

Methods

We developed a search protocol, run in five academic databases and three grey literature sources to cover the period between July 2018 to October 2023. Empirical quantitative studies were included if they had credible counterfactuals, were peer-reviewed, conducted in English or Spanish, and conducted in Uruguay, Canada and U.S. states that had legalized recreational cannabis. Further inclusion criteria included using 1) a quasi-experimental design; 2) representative samples; 3) pre- and post-legalization periods. We also discuss articles that examine within-jurisdiction changes post-legalization.

Results and conclusions

We identified 178 studies, covering nine outcomes: 1) Perceptions and attitudes; 2) Use-related outcomes; 3) Other substance use; 4) Traffic collisions; 5) Healthcare-related outcomes; 6) Market-related outcomes; 7) Crime and criminal justice; 8) Labour markets and financial indicators; and 9) Other. The presentation will touch on all outcomes but largely focus on the health-related outcomes. From this review, there are lessons to be learned for other countries exploring changing their cannabis laws, particularly with changes to the European market.