A report on three patients with "rapid cycling" unipolar depression.

We report three cases of unipolar depression who meet criteria for "rapid cycling" by having four or more major depressive episodes within a 1-year period. This report describes the clinical characteristics of the three patients and discusses the concept of false unipolar depression, and compares these patients with the "pseudounipolar" group described by Akiskal et al. Our findings support the clinical notion that rapid cycling in unipolar depression is a rarity.