Co-occurrence and contransmission of affective disorders and alcoholism in families.

The analysis of patterns of co-occurrence and cotransmission of affective disorders and alcoholism in families may provide clues for understanding the excess comorbidity between these conditions in clinical settings and in the general population. This paper reports the results of a family study of the relatives of patients with bipolar disorder, unipolar depression and alcoholism, and combinations thereof. Excess comorbidity between affective disorders and alcoholism was observed in all groups of relatives. However, the sharing of familial aetiological components was not a major contributor to the excess comorbidity between affective disorders and alcoholism. Unipolar depression and alcoholism segregated independently in families, whereas a modest correlation between familial components of alcoholism and bipolar disorder was observed.