Preadolescent individual, familial, and social risk factors associated with longitudinal patterns of adolescent alcohol, cannabis, and other illicit drug use in a population-representative cohort.

The aim of this exploratory study was to identify developmental patterns of adolescent concurrent alcohol, cannabis, and other illicit drug use and their preadolescent individual, familial, and social risk factors in a population-representative cohort from the province of Quebec, Canada (N = 1,593; 48.4% male). Age 12-17 years self-reports of alcohol, cannabis, and other illicit drug use were collected. Latent growth modeling was used to analyze developmental patterns of single- or polysubstance use (SU/PSU), and multinomial regression examined their association with risk factors assessed at age 10-12 years. Five developmental patterns were revealed, including nonusers (12.8% sample) and four classes reflecting different levels of SU/PSU (5.8%-37.5%), varying in severity based on onset, frequency, and type of substances used. Boys and girls were similarly represented throughout SU/PSU patterns. In comparisons with nonusers, several preadolescent risk factors were associated with increasing severity of SU/PSU. Possibly indexing fearlessness/disinhibition, low internalizing symptoms were common to all adolescent users. An earlier onset of substance use and increasing use of substances throughout adolescence were linked with having deviant peers for all user classes but later-onset users. Preadolescents manifesting externalizing problems and exposed to family adversity in addition to the above risk factors showed the earliest onset and most frequent adolescent SU/PSU, especially those also exposed to less appropriate parenting. Consistent with the developmental model of substance use, the nature, number, and severity of preadolescent risk factors distinguished between the type and severity of SU/PSU patterns in adolescence and call for a consistent strategy of universal, selective, and indicated preventive interventions. (PsycInfo Database Record (c) 2025 APA, all rights reserved).