Alcohol, Marijuana and Other Illicit Drugs Use Throughout Adolescence: Co-occurring Courses and Preadolescent Risk-Factors.

This study examined developmental patterns of co-occurrent alcohol, marijuana, and other illicit drugs use during adolescence and the associated preadolescent risk factors in a longitudinal sample of 926 boys from low-socioeconomic, urban neighborhoods. Latent growth mixture modeling revealed six developmental patterns: non-/low-alcohol and non-illicit drug users (61% sample) and five polysubstance user-groups varying in severity based on onset, frequency and type of substances used. In comparisons with non-/low-users, several preadolescent risk factors were associated with increasing severity of polysubstance use. Higher sensation-seeking and lower anxiety were associated with all user-groups. Low self-esteem and family-related risk factors differentiated all user-groups from later-onset users. Higher impulsivity and school problems characterized early-onset and frequent polysubstance users. Impulsive sensation-seekers with lower anxiety and self-esteem cumulated a larger number and higher severity of risk factors and were at risk of early-onset frequent polysubstance use, emphasising the importance of indicated prevention for these high-risk boys.