A FAMILY HISTORY STUDY OF RAPID-CYCLING BIPOLAR DISORDER

Previous studies have yielded mixed evidence as to whether rapid-cycli ng bipolar disorder (four or more episodes per year) is associated wit h a distinctive pattern of patient characteristics and familial aggreg ation of affective disorder. In this study, Family History Research Di agnostic Criteria (FH-RDC) were used to interview 165 patients with ra pid-cycling bipolar disorder, non-rapid-cycling bipolar disorder, or r ecurrent unipolar depressive disorder about the psychiatric history of 812 adult first-degree relatives. In a validity study, FH-RDC diagnos es were demonstrated to agree reasonably well with best-estimate diagn oses by two psychiatrists/psychologists, based on direct interviews wi th the Structured Clinical Interview for DSM-III-R. Relatives of patie nts with recurrent unipolar depression were less likely to have bipola r disorder and more likely to have unipolar depression than were relat ives of rapid-cycling or non-rapid-cycling bipolar patients. Rapid-cyc ling patients were younger and more likely to be female than non-rapid -cycling patients. The relatives of rapid cyclers did not differ signi ficantly from those of non-rapid cyclers in the prevalence of bipolar disorder, unipolar disorder, rapid-cycling bipolar disorder, or substa nce abuse. However, there were nonsignificant trends for the relatives of rapid-cycling bipolar patients, compared with those of non-rapid-c ycling bipolar patients, to have more substance abuse and less bipolar disorder given the presence of affective disorder.