OverviewDepression is defined as a mood disorder, and there are several subtypes. Bipolar disorder, also known as manic-depressive illness, is considered in a separate category.
Update Date 12/12/2014
Updated by: Paul Ballas, DO, Attending Psychiatrist, Friends Hospital, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.