Interplay between personality and antisocial peer affiliation as prospective predictors of marijuana use and academic achievement in the transition into and out of college.

Marijuana use has increased in recent cohorts and is associated with several negative outcomes, including poorer academic achievement. Less is known about how personality and peer factors in the first two years of college work together to predict problematic marijuana use and potentially co-occurring academic problems three years later. The longitudinal College Experiences Study (N = 209) was used to address this (N = 209, ~90% white, ~40% male); this study collected data from students in their first year of college, as well as ~1 year later (retention = 85%), and again ~4 years after the initial data collection (retention = 80%). Longitudinal data were analyzed via the traditional cross-lagged panel (CLPM) and the random-intercept CLPM approach. Results were consistent in that there was strong stability in problematic marijuana use, constraint, and antisocial peer affiliation across time, which were predominately influenced by stable, trait-like influences. These factors were also highly correlated but there was less evidence that one predicted the other over time. Nonetheless, greater constraint at Wave 1 was associated with significantly greater cumulative GPA in the transition out of college (βs = 0.43-0.44). Results support the importance of early prevention and intervention of problematic marijuana use, as well as the possibility of using personality-targeted approaches in the first year of college to promote growth in behaviors related to constraint (e.g., staying organized, risk avoidant) in an effort to improve academic success and correlated substance use outcomes by the transition out of college.