PSYCHIATRIC-DISORDERS IN THE RELATIVES OF DEPRESSED PROBANDS .2. FAMILIAL LOADING FOR COMORBID NON-DEPRESSIVE DISORDERS BASED UPON PROBAND AGE-OF-ONSET

This study examined familial loading for non-depressive disorders in f irst-degree relatives (FDRs) of early- (< 20 years of age) and adult-o nset (greater than or equal to 20 years of age) depressed probands. Ou r previous work, which demonstrated that FDRs of early-onset probands have higher rates of major depression as compared to FDRs of adult-ons et probands, has not yet examined risk for non-depressive disorders in FDRs. In this paper, we focus on best-estimate diagnoses of anxiety d isorders, alcoholism, and antisocial personality conducted on 639 firs t-degree relatives. The FDRs of early-onset probands had significantly higher rates of comorbid transmission of alcoholism and depression, a nd antisocial personality and depression, respectively. Significant co -transmission of anxiety disorders and depression was found in the FDR s of both early- and adult-onset probands. Future genetic studies of d epression, especially early-onset depression, should hence broaden the ir definitions of phenotypes to include comorbid disorders when search ing for the etiology of this complex disorder. (C) 1997 Elsevier Scien ce B.V.