Multimodal longitudinal prediction of alcohol-use trajectories in adolescents and young adults: Social context, real-life social affective benefit, and fronto-striatal involvement

Escalating alcohol use during adolescence and young adulthood confers substantial risk for later substance misuse and adverse mental health outcomes, yet the factors that determine early drinking trajectories remain poorly understood. Here, we examined alcohol use across social, affective, and neural domains in a cohort of 378 community-based young drinkers using a combination of longitudinal phenotyping, ecological momentary assessment (EMA) and functional neuroimaging. Across different levels of analysis, higher baseline alcohol consumption (standard drinks per week) was associated with immediate substance-use social context, greater social-affective benefit in daily life, and heightened engagement of the fronto-striatal reward circuitry. In a one-year longitudinal follow-up, individual social-affective benefit and substance-related social environmental factors showed the strongest predictive value for drinking trajectories in a follow-up of 219 individuals after one year. Our findings identify key social and neural reward-related determinants of youth drinking behavior, informing the development of evidence-based risk detection and prevention measures.