Dysthymia

Dysthymia also known as persistent depressive disorder (PDD),is a mental and behavioral disorder, specifically a disorder primarily of mood, consisting of the same cognitive and physical problems as depression, but with longer-lasting symptoms.

In the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), dysthymia is a serious state of chronic depression, which persists for at least two years (one year for children and adolescents). Dysthymia is not a minor form of major depressive disorder, and for some may be more disabling.