Which matters most? Demographic, neuropsychological, personality, and situational factors in long-term marijuana and alcohol trajectories for justice-involved male youth.

Justice-involved youth have high rates of alcohol and marijuana use. However, little is known about what may drive these rates over time. Using a large-scale (N = 1,056; 41.4% African American, 33.5% Hispanic) longitudinal study with strong retention (M retention = 90% over Years 1-7), we utilized random-effects regression to determine the comparative contribution of four sets of factors in justice-involved males' patterns of marijuana and heavy alcohol use (number of times drunk) over 7 years of follow-up: demographic, personality, situational, and neuropsychological factors. Across both marijuana and heavy alcohol use models, three factors were particularly strong contributors to lower rates of substance use: (a) Hispanic ethnicity, (b) less exposure (street) time, and (c) better impulse control. Similarly, two factors were strong contributors to increased rates of marijuana and heavy alcohol use: (a) delinquent peers and (b) family member arrest. Together, these findings indicate the relative superiority of these independent variables over other categories (i.e., neuropsychological factors) in predicting high-risk youths' long-term (7-year) rates of substance use. These findings also suggest the importance of evaluating the connection of these areas for high-risk, adjudicated youth.