Adolescent marijuana use in the United States and structural breaks : an age-period-cohort analysis, 1991 to 2018

Abstract

To investigate temporal patterns, socio-demographic gradients, and structural breaks in adolescent marijuana use in the United States from 1991 to 2018, we used hierarchical Age-Period-Cohort logistic models to separate temporal effects of marijuana use among 8th, 10th, and 12th graders from 28 waves of the Monitoring the Future survey. Structural breaks in period effects were further detected via a dynamic-programing-based method. Net of other effects, we found a clear age-related increase in the probability of marijuana use (10.46%, 23.17%, and 31.19% for 8th, 10th and 12th graders, respectively). Period effects showed a substantial increase over time (from 16.23% in 2006 to 26.38% in 2018), while cohort effects remained stable over the period of study. Risk of adolescent marijuana use varied by sex, racial group, family status, and parental education. Significant structural breaks during 1995-1996, 2006-2008, and 2011-2013 were identified in sub-populations. A steady increase in marijuana use among adolescents over the latter years of this time period was identified. Adolescents who were male, non-African American, lived in non-intact families, and who had less educated parents were especially at risk of marijuana usage. Trends of adolescent marijuana use changed significantly during times of macro events.