Uruguay's Cannabis Legalization Did Not Increase Youth Use or Risky Consumption | Research

The takeaway

Using data from over 204,000 students in Uruguay and Chile, researchers found that Uruguay's 2013 cannabis legalization was not associated with increases in past-year or past-month use, or sustained increases in risky or frequent cannabis use among secondary students.

Cannabis policy researchers; legislators considering legalization models; international drug policy organizations.

No sustained increases in youth cannabis use after Uruguay legalization

What the researchers found

Past-year and past-month cannabis use decreased after legalization. Among students 18-21 (legally eligible), there was a transitory increase in risky use in 2014 that decreased afterward. No sustained increases in risky or frequent cannabis use were found for any age group.

Why it matters

Uruguay was the first country to fully legalize recreational cannabis. This large-scale evaluation provides crucial evidence that a non-commercial legalization model did not increase youth cannabis use, countering a primary concern about legalization.

The numbers in context

204,730 students. Past-year and past-month use decreased after enactment/implementation. Ages 18-21 showed transitory increases in 2014: risky use PD=13.5% (95% CI 2.0-24.9), frequent use PD=4.5% (95% CI 1.0-8.1), but these decreased after 2014.

How the study worked

Difference-in-differences analysis comparing repeated cross-sectional surveys of secondary students in Uruguay and Chile (control) from 2007-2018. 204,730 students in 8th, 10th, and 12th grade. Examined changes after enactment (2014) and implementation (2016) of legalization.

What this study cannot tell us

Chile as a control country may not be perfectly comparable. School surveys miss adolescents who have dropped out. Self-reported cannabis use may be affected by changing social norms post-legalization. The implementation period was gradual, making effect attribution difficult.

How to read the evidence

Strong: large sample, appropriate difference-in-differences design with a control country, covering 11 years of data.

When this study was published

Published in 2022, covering data from 2007-2018.

The bigger picture

Uruguay's non-commercial model (state-regulated pharmacies, home growing, cannabis clubs) is fundamentally different from the commercial models adopted in US states and Canada. The finding that this model did not increase youth use adds support for regulated non-commercial approaches.

Questions still open

Would a commercial legalization model produce different youth outcomes? Did the transitory 2014 increase reflect curiosity that naturally faded? How do youth in Uruguay perceive cannabis risk after legalization?

Common questions

Did legalizing cannabis increase teenage use in Uruguay?

No. This study found that past-year and past-month cannabis use actually decreased after legalization. There was a brief uptick in risky use among 18-21 year olds in the first year, but it subsided quickly.

Is Uruguay's legalization model different from the US?

Yes. Uruguay uses a non-commercial model with state-regulated pharmacies, registered cannabis clubs, and home growing. There is no commercial advertising or branded retail as seen in many US states, which may contribute to different youth outcomes.

Read the original research

Does recreational cannabis legalization change cannabis use patterns? Evidence from secondary school students in Uruguay.

Addiction (Abingdon, England), 117(11), 2866-2877

View on PubMed ↗Publisher’s paper ↗

Citation

Rivera-Aguirre, Ariadne; Castillo-Carniglia, Alvaro; Laqueur, Hannah S; Rudolph, Kara E; Martins, Silva S; Ramírez, Jessica; Queirolo, Rosario; Cerdá, Magdalena. (2022). Does recreational cannabis legalization change cannabis use patterns? Evidence from secondary school students in Uruguay.. Addiction (Abingdon, England), 117(11), 2866-2877. https://doi.org/10.1111/add.15913