What Causes Persistent Depressive Disorder?

Persistent depressive disorder, otherwise known as dysthymia, is a chronic state of depressed mood. It is not as severe to be classified as recurrent depressive disorder. While some patients may experience days of a normal mood, they would describe themselves as chronically tired and depressed, with symptoms usually lasting years. It is unclear why some patients experience persistent depressive disorder, but factors related to the underlying personality, psychosocial stressors, and genetic factors have been implicated.