Introduction

This study investigated whether legalization of recreational marijuana sales and retail availability of marijuana in Oregon counties were associated with higher levels of marijuana use and related beliefs among adolescents.

Methods

Biennial data for 6th, 8th, and 11th graders from the 2010–2018 Student Wellness Survey in 35 Oregon counties ( n=247,403) were analyzed in 2019 to assess changes in past 30–day marijuana use and beliefs (e.g., perceived availability of marijuana) in counties that allowed recreational marijuana sales in unincorporated areas beginning in October 2015 versus counties that did not. Analyses were also conducted with 2016 and 2018 Student Wellness Survey data ( n=101,419) to determine whether the association between allowing recreational marijuana sales and marijuana use could be accounted for by retail marijuana outlet density and beliefs.

Results

Higher rates of past 30–day marijuana use and more favorable beliefs were observed in counties that allow recreational marijuana sales in unincorporated areas, both before and after legalization of recreational sales in 2015. The prevalence of past 30–day marijuana use increased, relative to the downward secular trend, after legalization both in counties that did and did not allow recreational marijuana sales. There were parallel changes in beliefs favorable to marijuana use. Analyses with 2016 and 2018 Student Wellness Survey data suggested that the association between allowing recreational marijuana sales and past 30–day marijuana use could be accounted for by retail marijuana outlet density and beliefs.

Conclusions

Legalization and greater retail availability of recreational marijuana are positively associated with marijuana use among adolescents.