Lifetime rates of alcoholism in adults with anxiety, depression, or co-morbid depression/anxiety: a community survey of Ontario

Background: Separate lines of research have demonstrated strong associations linking alcohol misuse with major depression on the one hand, and anxiety disorders on the other. In the current study we examined the possible confounding and/or additive effects of co-morbid depression/anxiety in understanding these relationships. Methods: A total of 7195 individuals in Ontario, aged 15–64, were interviewed using the CIDI. Based on lifetime diagnoses, we compared rates of alcohol abuse/dependence in four groups consisting of normal controls, individuals with unipolar major depression but no anxiety disorders, individuals with one or more anxiety disorders without depression, and individuals with co-morbid major depression and anxiety. Age of onset of alcoholism in the four study groups was also compared. Results: In both genders, there were significantly higher rates of alcoholism in all three psychiatric groups relative to controls. In females only, there was also a significantly higher rate of alcoholism in the depressed/anxious group than in the pure anxious group. The age of onset of alcoholism was the same across all four study groups. Limitations: Due to limitations related to sample size, we combined subjects with various anxiety disorders into a single anxiety group and concurrent and sequential co-morbidity were not distinguished. Conclusions: Both gender effects and depression/anxiety co-morbidity may be important considerations in the design and interpretation of studies on alcohol misuse. This may be particularly relevant when considering the strength of the association between alcoholism and anxiety disorders in women. Depression and anxiety do not appear to influence the age of onset of alcoholism. Furthermore, no single temporal pattern of onset was identified in individuals with all three disorders, suggesting no obvious cause-effect relationship among them.