Highly recurrent unipolar may be related to bipolar II

Unipolar and bipolar disorders may be subgroups of a single mood disorder, of which the key feature is not polarity, but the episodic, recurrent course. The aim of this study was to determine whether highly recurrent unipolar was related to bipolar II, by comparing clinical and family history features. Eighty-nine consecutive unipolar and 151 consecutive bipolar II outpatients, presenting for major depressive episode (MDE) treatment, were interviewed using the Structured Clinical Interview for DSM-IV (SCID) and the Family History Screen. Unipolar patients were divided into highly recurrent (>4 MDEs) (HRUP) and low recurrent (