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

Autores: Ariadne Rivera-Aguirre | Alvaro Castillo-Carniglia | Hannah S. Laqueur | Kara E. Rudolph | Silva S. Martins | Jessica Ramírez | Rosario Queirolo | Magdalena Cerdá

Background and Aims: In 2013, Uruguay became the first country to legalize and regulate the production and distribution of cannabis for recreational use. We measured whether Uruguay’s non-commercial model of recreational cannabis legalization was associated with changes in the prevalence of risky and frequent cannabis use among secondary school students.

Design: We used data from repeated cross-sectional surveys of secondary students in Uruguay and Chile (2007–2018). Using a difference-in-difference approach, we evaluated changes in the prevalence of past-year, past-month, any risky and frequent cannabis use following enactment (2014) and implementation (2016) of cannabis legalization among the full sample of secondary students and among students who reported pastyear/month use. We examined changes separately for students ages 12 to 17, and students for whom cannabis became legally accessible, ages 18 to 21.

Setting: Uruguay and Chile (2007–2018).

Participants: Secondary school students in 8th, 10th and 12th grade (n = 204 730).

Measurements: Past-year and past-month cannabis use; any risky cannabis use measured with the Cannabis Abuse Screening Test (CAST); and frequent cannabis use (10-days in the past-month).

Findings: We found a decrease in past-year and past-month use following enactment or implementation. Among students ages 18 to 21, post-enactment, we observed a transitory increase in 2014 that decreased thereafter for: any risky use among those who reported past-year use (prevalence difference [PD] = 13.5%; 95% CI: 2.0, 24.9), frequent use in the full sample (PD = 4.5%; 95% CI: 1.0, 8.1), and frequent use among those who reported past-month use (PD = 16.8%; 95% CI: 1.9, 31.8).

Conclusion: The legalization of recreational cannabis in Uruguay was not associated with
overall increases in either past-year/past-month cannabis use or with multi-year changes
in any risky and frequent cannabis use among young people