Developmental Trajectories of Gambling and Substance use Throughout Adolescence - A Population-Based Longitudinal Study of Preadolescent Risk Factors and Related Outcomes in Early Adulthood.

This population-based longitudinal study (N = 1,336; 43.9% boys) examined early adulthood gambling participation (GP), substance use (SU), and related problems as a function of adolescent GP-SU developmental patterns. A person-centered approach based on four assessments from ages 12 to 17 identified six joint GP-SU trajectory classes. Using non-users/non-gamblers as the reference class, multivariate models included 15 preadolescent individual, familial, and social risk factors previously linked to adolescent trajectories. The latter were then compared on nine early adulthood outcomes assessed at age 21. Results indicated clear developmental continuity between adolescent GP and SU trajectories and their corresponding early adulthood outcomes. Trajectory classes characterized by similar adolescent SU patterns (early or later onset) exhibited comparable SU outcomes in early adulthood, regardless of concurrent GP. These results suggest that adolescent co-occurrence does not confer a multiplicative increase in risk for later SU outcomes, but instead reflects an accumulation of addictive behaviors. In contrast, evidence of temporal cross-behavior continuity emerged from adolescent SU to early adulthood GP. Adolescent GP-SU trajectories contributed substantially to adult outcomes above and beyond preadolescent risk factors, with a stronger incremental contribution observed for SU than for GP. Findings support developmental and addiction-syndrome models and emphasize the long-term significance of adolescent involvement in addictive behaviors. Results also suggest that GP and SU may differ in the degree to which adolescent involvement consolidates into corresponding adult outcomes.