Testing the efficacy and mechanisms of an SMS intervention focused on motivating peer network support to reduce alcohol consumption in non-collegiate young adults: Protocol for a randomized trial.

BACKGROUND

Non-collegiate young adults engage in high rates of heavy drinking but are less likely to access alcohol-related counseling or treatment. Peers play a significant role in shaping drinking behavior, yet few interventions target close peer influence in this population.

METHODS

This two-arm randomized controlled trial will enroll 300 young adults aged 18-25 who report 2+ heavy drinking days (HDD; defined as 4+ drinks for a woman and 5+ drinks for a man) in the past 30 days and are not enrolled in college. Participants are randomized (1:1) to receive either (1) an SMS intervention focused on self-monitoring and goal-related strategies (i.e. Commitment-based Binge drinking prevention Intervention: CBI) or (2) ASPIRE, which adds feedback on peer influences and encouragement for positive support. Outcomes are assessed via REDCap-administered surveys at baseline, 3, 6, and 12 months. Additional data include twice-weekly SMS assessments during the 3-month intervention period and GPS-based mobility tracking with simultaneous ecological momentary assessment (EMA) during 7-day windows following each assessment time point. The primary outcome is number of heavy drinking days (HDD) in the past 30 days. Mediation analyses will assess cognitive, social, and environmental mechanisms of change using multilevel structural equation modeling.

DISCUSSION: This trial advances the science of digital interventions for alcohol harm reduction in a high-risk and underserved population. ASPIRE is among the first interventions to integrate encouragement for positive peer network support into a scalable mobile platform. The use of high-frequency behavioral and geolocation data allows for novel insights into mechanisms of change.