A Multi-Method Investigation of the Effects of Alcohol on Depression in Undergraduate Students Who Drink to Cope with Depression
The self-medication hypothesis has been proposed as one potential explanation for the comorbidity between alcohol use and depressive disorders. More recent work investigating drinking motives (theorized to be the most proximal factors to alcohol use) has found that some individuals report using alcohol to cope with depression. Despite epidemiological and experimental evidence supporting the tenets of the self-medication hypothesis for alcohol use and depression, the reinforcement mechanisms underlying this relationship remain unclear. This is due, in part, to the varied effects of alcohol on mood (some of which are experienced as pleasant and some as aversive). To increase our understanding of the effects of alcohol on various components and correlates of depression, my dissertation research aimed to: (1) identify, via qualitative methods, specific effects of alcohol on depressive affect, cognition, and behaviour that might be reinforcing for individuals who report using alcohol to cope with depression (Study 1), and (2) to experimentally examine the effects of alcohol (compared to placebo and to a no-alcohol condition) on positive mood, depressed mood, and recall of self-relevant depressed information of coping-with-depression motivated drinkers compared to an enhancement motivated (EM) drinker comparison (Study 2). In Study 1, undergraduate students reporting high coping-with-depression drinking motives (CWDM) reported several effects of alcohol on affective, cognitive, and behavioural depressive symptoms. They described most of these as providing relief from depressive symptoms but also reported some effects as involving a worsening of depressive symptoms. Study 2, revealed that, relative to the EM comparison group, CWDM participants in the no alcohol condition displayed greater biased processing recall of self-relevant depressed-content adjectives; this bias was eliminated in CWDM who received alcohol and attenuated in CWDM who received placebo. This pattern suggests that both expectancy and pharmacological effects of alcohol affect processing of self-relevant information in CWDM drinkers. With respect to mood, Study 2 results showed that all participants experienced increases in positive mood after alcohol consumption relative to baseline but no change in depressed mood. Taken together, findings from my dissertation highlight the numerous potential effects of alcohol on various symptoms related to depression, particularly affective and cognitive symptoms, many of which might be reinforcing for individuals who drink to cope with depression. Findings also highlight the complex, and at times contradictory, effects of alcohol on mood. In light of the present findings, it is important that future research investigate multiple potential pathways underlying the relationship between depression and alcohol use, including reciprocal relations between the two phenomena. In addition, the present findings have important clinical implications for the treatment of comorbid depression and alcohol misuse.