Project Summary/Abstract Alcohol problems are prevalent in young adulthood, with one in ten young adults meeting criteria for alcohol use disorder (AUD). It is therefore essential to identify and respond to risk factors for alcohol misuse during this developmental period. One underappreciated risk factor for the development of problematic drinking is the social context in which young adults consume alcohol. Recent reviews have demonstrated that young people who engage in solitary alcohol use (compared to their social-only drinking peers) are at increased risk for alcohol problems and a host of negative psychosocial outcomes (e.g., increased negative affect, aggression). Importantly, several prospective studies have demonstrated that solitary alcohol use is an independent and robust early risk marker for AUD. Despite the known risks, critical information about young adult solitary alcohol use remains unknown. Large national samples are needed to provide estimates of prevalence and historical change in young adult solitary alcohol use, as well as information on developmental changes in solitary alcohol use across young adulthood and risk/protective factors associated with solitary alcohol use. The proposed study will be the first to provide such information using self-report data on solitary alcohol use collected from the national Monitoring the Future study from 1976 to 2023 in those aged 18-30. We aim to (1) estimate the prevalence of young adult solitary alcohol use by age and sex, and model overall and sex-specific historical trends from 1976-2023, (2) model developmental trajectories of solitary alcohol use across young adulthood, examine sex associations with such patterns, and determine whether certain trajectories differentially predict age 35 AUD symptoms after controlling for covariates, and (3) identify risk and protective factors associated with young adult solitary alcohol use, and determine whether associations between risk/protective factors and solitary alcohol use change across young adulthood, including the extent to which trajectories of coping motives and solitary alcohol use co-vary by age. Findings from this study will inform knowledge about young adult solitary alcohol use and associated risk/protective factors and speak to the optimal timing for delivering interventions aimed at reducing solitary alcohol use and, ultimately, AUD.

Project Narrative Young adult alcohol consumption is a major public health problem in the United States, and it is therefore essential to identify and respond to risk factors for alcohol misuse during this developmental period. Young adult solitary alcohol use is a robust and unique predictor of future alcohol problems above and beyond other established risk factors (e.g., binge drinking), but key information about young adult solitary alcohol use remains unknown. Using national samples of US young adults, this research aims to provide prevalence rates, historical changes, developmental trajectories, and risk factors associated with young adult solitary alcohol use.