Substance Use Problem Trajectories in Canadian Adolescents: A Longitudinal Study.

Background Adolescents experience rapid changes and are more vulnerable for developing substance use problems than other age groups. Many studies have focused on the trajectories of adolescent substance use frequencies, rather than symptoms. Objective The present study examined the trajectory of substance use disorder symptoms, particularly beginning in early adolescence and within a Canadian context. Methods Data were drawn from a Canadian longitudinal project, in which a province-wide survey was administered to students across three biennial waves starting in grades 7-8. The final sample was comprised of 765 adolescents (baseline M age = 12.73, SD = 0.67, 49.7% female, 57.6% White). Latent class analysis was conducted to identify substance use disorder symptom classes based on participants' responses on a substance use disorder screener across the three waves. Group differences tests were also computed to examine if the substance use classes differed in participants' demographics. Results Four classes were identified, labelled as low stable (n = 538, 70.3%), deteriorating (n = 169, 22.1%), recovered (n = 12, 1.6%), and high-risk relapse (n = 46, 6.0%) substance use. Among the demographic variables, non-White ethnicity, both parents being born outside of Canada, and parents' completion of post-secondary education were significantly associated with a less severe substance use class. Conclusions Results fill a gap in the evidence on the trajectory of symptoms of substance use disorder among adolescents, using a Canadian sample, an area of limited study. Results highlight an at-risk group (i.e., high-risk relapse class) that warrants further tailored prevention and intervention efforts.