Dysthymic disorder refers to moderate Depression that persists for two (2) years or more.
Moreover, it is a Mood disorder involving chronic Depression of less intensity than major
depressive disorders; involving depressed mood, with low self-esteem, withdrawal, pessimism, or despair, present for at least 2 years, with no absence of symptoms for more than 2 months.
Dysthymic disorder is also called DD or Dysthymia
List of books: Dysthymic,disorder