What exactly is a dysthymic disorder?

Dysthymia: Dysthymia, is a chronic type of depression that doesn't waver all that much in terms of intensity, as opposed to major depression which wavers widely in intensity. Metaphorically speaking, those with dysthymia experience it as having to wear a coat made of lead, 24-7, with little variation. Those with major depression experience the depressive lows almost like waves.

Dysthymic disorder: is the formal term for depressive neurosis. Individuals with dysthymic disorder suffer from a prolonged mild depression that may be either constant or episodic.