major depression

One of the mood disorders characterized by such symptoms as loss of interest in one's usual activities, irritability, poor appetite, sleeplessness or excessive sleeping, decreased sexual drive, fatigue, psychomotor agitation, feelings of hopelessness, inability to concentrate, and suicidal ideation. Major depression can be subdivided into two groups: the "single episode" (at least four symptoms present almost daily for more than two weeks) and the "recurrent episode" (the episodes come and go for intervals of at least two consecutive months). Someone with major depression may be distinguished from someone with a bipolar disorder by the fact that he or she has not had a manic episode. Major depression may be distinguished from dysthymic disorder in that its symptoms are more severe but occur in discrete episodes that can be distinguished from the person's usual functioning; in dysthymic disorders, the symptoms are almost continuous.