Cyclothymia is a chronic, but less extreme, form of bipolar disorder that consists of short periods of mild depression alternating with short periods of hypomania. The onset of each phase is separated by short periods of normal mood. This diagnosis is excluded if the patient has had either a manic episode or a major depressive episode.
This disorder is a milder form of bipolar II disorder consisting of recurrent mood disturbances between hypomania and dysthymic mood.