Electronic Thesis and Dissertation Repository


Doctor of Philosophy




Dozois, David J. A.


This dissertation investigated the mechanisms by which problematic drinking contributes to depressive symptoms in two longitudinal, prospective, cohort-design studies. Distorted cognitive processes (dysfunctional attitudes, negatively-biased information processing, and rumination) were proposed as mediators in the relationship between problematic drinking and depressive symptoms over time. Study 1 (N = 1090) assessed participants’ levels of problematic drinking, dysfunctional attitudes, and depressive symptoms at three-month intervals for one year. Findings indicated that the social and occupational consequences of alcohol use (e.g., interpersonal conflict) significantly predicted depressive symptoms. The amount and frequency of alcohol consumption did not. Therefore, impairment, but not level of consumption, is predictive of psychopathology in the long-term. Longitudinal analyses found inconsistent evidence that dysfunctional attitudes mediated this relationship over time. Study 2 (N = 321) incorporated measures of ruminative thinking, biased information processing, and motivations behind drinking (e.g., drinking to cope), 8-12 weeks apart. There was no evidence of a significant predictive relationship between alcohol problems and depressive symptoms in this time frame. Rather, a third-variable relationship emerged, whereby cognitive variables predicted changes in both alcohol problems and depressive symptoms. Specifically, “drinking to cope” predicted drinking problems, negatively-biased information processing predicted both depressive symptoms and alcohol problems, and dysfunctional attitudes predicted depressive symptoms over time. Clinicians treating individuals with this comorbidity are encouraged to focus on and address the underlying distorted cognitive processes that contribute to the social and occupational consequences of their clients’ drinking patterns and help them actively manage their clinical impairment through cognitively-focused interventions.