To systematically describe when and how brief alcohol interventions delivered to adolescents in primary care settings reduce alcohol use and alcohol-related consequences among adolescents, using realist review methodology.

Eleven electronic databases, gray literature, and reference screening were searched up to June 2016; 11 brief interventions published in 13 studies met inclusion criteria. Intervention design components (delivery context and intervention mechanisms) underlying brief alcohol interventions for adolescents were extracted and linked to alcohol use and related consequences.

Brief interventions had either an indicated context of delivery (provided to adolescent patients with low-to-moderate risk for alcohol problems) or universal context of delivery (provided to general adolescent patient population). Interventions that used motivational interviewing in an indicated delivery context had 2 potential mechanisms—eliciting and strengthening motivation to change and providing direction through interpretation. These interventions resulted in clinically significant reductions in alcohol use and associated consequences. Peer risk also was identified among universal and indicated brief interventions as a potential mechanism for changing alcohol-related outcomes among adolescents who received the intervention. None of the studies tested the processes by which interventions were expected to work.

The current evidence base suggests that both indicated and universal delivery of brief alcohol interventions to adolescents in primary care settings can result in clinically important changes in alcohol-related outcomes. Studies that test brief intervention processes are now necessary to better understand how brief interventions work with adolescents in primary care settings.