THE HIGH PREVALENCE OF SOFT BIPOLAR (II) FEATURES IN ATYPICAL DEPRESSION

Seventy-two percent of 86 major depressive patients with atypical feat ures as defined by the DSM-IV and evaluated systematically were found to meet our criteria for bipolar II and related ''soft'' bipolar disor ders; nearly 60% had antecedent cyclothymic or hyperthymic temperament s. The family history for bipolar disorder validated these clinical fi ndings. Even if we limit the diagnosis of bipolar II to the official D SM-IV threshold of 4 days of hypomania, 32.6% of atypical depressives in our sample would meet this conservative threshold, a rate that is t hree times higher than the estimates of bipolarity among atypical depr essives in the literature. By definition, mood reactivity was present in all patients, while interpersonal sensitivity occurred in 94%. Life time comorbidity rates were as follows: social phobia 30%, body dysmor phic disorder 42%, obsessive-compulsive disorder 20%, and panic disord er (agoraphobia) 64%. Both cluster A (anxious personality) and cluster B (e.g., borderline and histrionic) personality disorders were highly prevalent. These data suggest that the ''atypicality'' of depression is favored by affective temperamental dysregulation and anxiety comorb idity, clinically manifesting in a mood disorder subtype that is prepo nderantly in the realm of bipolar II. In the present sample, only 28% were strictly unipolar and characterized by avoidant and social phobic features, without histrionic traits.