Self-Determined Motivation for Alcohol Use and Drinking Frequency, Intensity, and Consequences.

Objective: Drinking motives predict drinking behaviors and outcomes among adults. Drinking motives are rarely studied using self-determination theory (SDT), which aligns with harm-reduction approaches to alcohol use, but SDT can offer a complementary theoretical framework to existing drinking motives frameworks that may help explain the observed heterogeneity in drinking motives and account for more variance in drinking outcomes. This study examined the associations between five SDT-based drinking motives with drinking frequency, intensity, and consequences. Method: A total number of 630 adults (M_age = 21.5, 55% female, 88% undergraduates) rated drinking motives using the Comprehensive Relative Autonomy Index for Drinking (CRAI-Drinking) and the Drinking Motives Questionnaire (DMQ), typical alcohol consumption, and negative and positive drinking consequences. Results: Poisson regressions indicated that intrinsic (IRR = 1.13) and identified (IRR = 1.11) regulations were significantly associated with drinking frequency, identified (IRR = 0.94) and positive introjected (IRR = 1.07) regulations were significantly associated with drinking intensity, and amotivation (IRR = 1.16) and intrinsic regulation (IRR = 1.09) were associated with negative and positive consequences, respectively, after controlling for other CRAI-Drinking and DMQ scores, sex, and drinking intensity. After accounting for DMQ scores and sex, CRAI-Drinking scores accounted for 1.7%-9.9% additional deviance in drinking behaviors and consequences. Conclusions: Adults high in autonomous reasons for drinking reported low-risk, high-enjoyment drinking experiences. In contrast, adults with higher scores for amotivation for drinking reported more negative consequences, even after accounting for drinking intensity, suggesting that high amotivation for drinking may be a novel signal for future alcohol-related risks. These findings support the idea that SDT provides a useful framework for understanding drinking motives, behaviors, and consequences.