Persistent depressive disorder, also known as dysthymia, is a mood or affective disorder. It is a chronic, mild depression that lasts for a long period of time (at least 2 years). The word dysthymia comes from Greek roots meaning "ill-humour." Persistent depressive disorder has less of the mental and physical symptoms that a person with major depressive disorder experiences.
The condition usually starts in early adulthood, and the disorder can last for years or even decades. Later onset is usually associated with bereavement or obvious stress, and often follows on the heels of a more extreme depressive episode. Women are twice as likely as men to suffer from persistent depressive disorder, in a similar ratio to that seen with major depression.
In the past, persistent depressive disorder had several other names: dysthymia, depressive neurosis, neurotic depression, depressive personality disorder, and persistent anxiety depression.