Unipolar depression/bipolar depression: Connections and controversies

Abstract

The modern dichotomous divide between unipolar and bipolar depressive disorders derives from several monographs that appeared in the mid-twentieth century. Studies of illness course and differing symptomatic profiles in unipolar and bipolar illness support this interpretation, but more recent descriptions of ‘bipolar spectrum disorders’ and genetic findings suggest otherwise. Whether these illnesses represent categories or points on a continuum remains an unresolved question.