Youth Exposure to Recreational Cannabis Legalization: Moderation of Effects by Sex and Parental Cannabis Use during Adolescence

Abstract

Objective: Few studies of recreational cannabis legalization (RCL) have assessed adolescents both before and after RCL or considered moderators of RCL effects. The present study tested whether RCL was more strongly associated with cannabis use for girls and among youth whose parents had a history of cannabis use during adolescence.

Method: Data were pooled from 940 adolescents from three intergenerational studies that began in Washington (where RCL was enacted in 2012), Oregon (RCL year = 2015), and New York (RCL year = 2021). Youth were assessed repeatedly from ages 13 to 18 years (k = 3,650 person-years) from 1999 to 2020 (prior to RCL in New York). Parent cannabis use at or before age 18 years (yes/no) was assessed prospectively during the parent's adolescence. Multilevel models focused on the between-subjects effects of years of youth exposure to RCL on adolescents' mean cannabis use likelihood, and interactions with child sex and parent use history.

Results: Child exposure to RCL was associated with a higher likelihood of cannabis use if their parents had a history of adolescent use, (Estimate [SE] = 0.67 [0.25], p = 0.008), versus no such history (Estimate [SE] = -0.05 [0.28], p = 0.855). RCL effects were not moderated by child sex.

Conclusions: The effects of RCL on adolescents' cannabis use may depend on their parents' history of using the drug. Identifying other moderators of RCL effects, and understanding the mechanisms of these risks and the ways that parents and communities can offset them, are prevention priorities.

Keywords: Adolescence; cannabis legalization; longitudinal; parent cannabis use; sex differences.