Ontology highlight
ABSTRACT: Introduction
In the past decade, marijuana use prevalence among adolescents has remained relatively steady while cigarette and alcohol prevalence has declined. We examined historical trends in: average grade of onset of marijuana, alcohol, and cigarette use by 12th grade; proportion who try alcohol/cigarettes before first marijuana use, among those who use by 12th grade; and conditional probability of marijuana use by 12th grade after trying alcohol/cigarettes.Methods
Data were drawn from 40 yearly, cross-sectional surveys of 12th grade US adolescents. A subset of students (N = 246,050) were asked when they first used each substance. We reconstructed cohorts of substance use from grade-of-onset to determine sequence of drug use, a
SUBMITTER: Keyes KM
PROVIDER: S-EPMC6390293 | biostudies-literature | 2019 Jan
REPOSITORIES: biostudies-literature