| Few longitudinal studies exist that assess adolescents' reports of substance use from late childhood through adolescence. Additionally, Canadian adolescents have rarely been included in such longitudinal studies. The present study comprised longitudinal data from 746 Ontario adolescents, gathered in eight waves over seven years, beginning when the youth were 10, 11, or 12 years old. Most adolescents reported engaging in some form of substance use before the age of 17 years. Five distinct trajectories of substance use were found including: chronic-high, childhood onset-rapid high, childhood onset-moderate, adolescent onset-moderate, and non-use groups. During late childhood, risk factors associated with high levels of substance use included delinquency, academic disengagement, poor parental monitoring, and associating with peers who also used substances. In adolescence, externalizing problems emerged as an additional risk factor for the most severe substance using group. Implications for substance use prevention and intervention strategies are discussed. |
