Young adulthood is marked by increased peer influence susceptibility and high alcohol consumption levels, often resulting in unplanned drinking—consuming alcohol despite prior intentions not to drink. According to the Model for Unplanned Drinking, this behavior is particularly risky as it occurs without harm-reduction strategies in place, potentially leading to more severe alcohol-related consequences. However, several areas remain underexplored: the frequency of unplanned drinking among diverse young adults, the influence of impulsivity traits, the role of peer influence, and the relationship between unplanned drinking and negative consequences. Therefore, this study aims to identify person- and event-level predictors of unplanned drinking days in a diverse sample of young adults and examine the relationship between unplanned drinking frequency and alcohol-related negative consequences.
The study analyzed secondary data from 938 young adults (aged 18-25) who completed ecological momentary assessment surveys twice weekly over 14 weeks. Variables included person-level factors (demographics, alcohol use severity, impulsivity, consequences, intervention exposure) and event-level factors (drinking intentions, consumption, social contact, day of week). Mixed-effects logistic regression examined predictors of unplanned drinking days, with random intercepts for individual differences and fixed effects for significant predictors (p<0.05). Missing drinking data (11.6%) were imputed using temporal patterns. Zero-inflated negative binomial regression analyzed the relationship between predictors and alcohol consequences at follow-up.
The study findings revealed that among 938 participants (mean age 22.1 years, 70% female, 36.6% Black), 77% experienced unplanned drinking episodes, with unplanned drinking occurring on 21.3% of days participants initially planned not to drink. At the person level, older age, African American race, higher AUDIT-C scores, and greater negative urgency were associated with increased odds of unplanned drinking, while intervention conditions (USE and COMBO) showed protective effects. At the day level, unplanned drinking was 63% more likely on weekends and significantly associated with the presence of drinking friends. Participants averaged 2.7 negative alcohol consequences at follow-up, with higher AUDIT-C scores, baseline drinking quantity, and frequent unplanned drinking (highest category showing 26% higher rates) predicting more consequences, while GOAL and COMBO interventions reduced consequences by 19% and 14%, respectively.
Takeaway: Unplanned drinking among diverse young adults is influenced by both individual characteristics (impulsivity, alcohol severity) and situational factors (weekends, drinking friends), with frequent unplanned drinking significantly increasing negative alcohol-related consequences.