Alcohol consequences, not quantity, predict major depression onset among first-year female college students

Alcohol use and its consequences have often been associated with depression, particularly among female college students. Interpretation of this association has been challenging due to potential reverse causation. The current study sought to clarify the temporality of these relationships. We examined: (1) the association between alcohol consumption and onset depression among female college students, and (2) the association between drinking consequences and onset depression among drinkers only. We used a prospective longitudinal design. Participants were first-year female college students who completed a baseline survey at study entry, and monthly assessments of alcohol consumption, drinking consequences, and depression symptoms. Cox proportional hazards regression with time-varying covariates were constructed among the full sample (N = 412) and the drinkers only sample (N = 335). Adjusted hazard ratios accounted for known risk factors for depression such as race/ethnicity, academic challenge, not getting along with one's roommate, sexual victimization prior to college, marijuana use, and socioeconomic status. For each additional average drink per week, adjusting for all covariates, there was no (95% CI: -4%, +4%) increased risk of onset depression. For each additional alcohol consequence, adjusting for all covariates, there was a 19% (95% CI: 5%, 34%) increased risk of onset depression. This significant relationship remained after adjusting for quantity of alcohol consumption. Quantity of alcohol consumed did not predict incident depression. However, experiencing alcohol consequences, regardless of consumption, did increase the risk of incident depression. College substance use and mental health interventions should aim to reduce not only alcohol consumption, but also alcohol-related consequences.