Evidence supporting the independent inheritance of primary affective disorders and primary alcoholism in the families of bipolar patients

Background: This study explored the nature of the association between bipol ar disorder and alcoholism. Methods: The authors studied 814 first-degree r elatives of 121 bipolar patients, divided on the basis of response to lithi um prophylaxis. Logistic regression analysis was used to analyze the contri bution of demographic, familial and clinical variables to the risk of prima ry alcoholism in the relatives. Results: The risk of primary alcoholism in relatives was not related to the degree of affective loading in the family or to the proband's lithium response. Conclusion: This study does not suppo rt a shared genetic liability between bipolar disorder and alcoholism. Limi tations: This study lacked a control group, but the analysis accounted for this, Clinical Relevance: These disorders are not alternative forms of the same illness. (C) 1998 Elsevier Science B.V. All rights reserved.