Is there a genetic relationship between alcoholism and depression? - Research Update

Alcohol Research & Health, Fall, 2002 by John I. Nurnberger, Jr., Tatiana Foroud, Leah Flury, Eric Meyer, T., Ryan Wiegand

The findings summarized in this article suggest a genetic relationship between depression and alcohol dependence in some families where both disorders are transmitted. This conclusion is consistent with the idea that depression can be caused by many different genes (i.e., is a genetically heterogeneous condition). The results obtained so far have no direct implications for the treatment of patients with depression and/or alcohol dependence. However, they do reinforce the idea that some heavy drinkers may have genetic vulnerability to depression, as well as the observation that treatment of depressed alcoholic patients with antidepressants has generally had beneficial effects on the depression, and sometimes on the drinking as well (McGrath et al. 2000). In the future, genetic studies are likely to contribute to clinical treatment by identifying specific genes and their biochemical pathways, which could result in new therapeutic options for patient subgroups.

The major advantage of the COGA study is its multisite design with similar methods employed at each site, which allowed the investigators to generate very large data sets. One limitation of the study is that by design it focused on families densely affected with alcohol dependence for linkage analysis (although all families of alcoholic probands are included in the prevalence studies). Although such families are ideal for genetic studies, they may not be fully representative of the spectrum of people who suffer from alcoholism, depression, or both. Despite this limitation, the study's results, in combination with prior studies, suggest that the pattern of disorders in the family is a reasonable clinical characteristic to use for the differentiation of subgroups within alcoholism.