Evidence supporting the independent inheritance of primary affective disorders and primary alcoholism in the families of bipolar patients
Duffy A., Grof P., Grof E., Zvolsky P., Alda M.
Background: This study explored the nature of the association between bipolar disorder and alcoholism. Methods: The authors studied 814 first- degree relatives of 121 bipolar patients, divided on the basis of response to lithium prophylaxis. Logistic regression analysis was used to analyze the contribution of demographic, familial and clinical variables to the risk of primary 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 support a shared genetic liability between bipolar disorder and alcoholism. Limitations: This study lacked a control group, but the analysis accounted for this. Clinical Relevance: These disorders are not alternative forms of the same illness.