Depression is a mental state of depressed mood characterized by feelings of sadness, despair, and discouragement.
Depression ranges from normal feelings of 'the blues' to major depression.
Symptoms of depression may be recurring, prolonged, and severe. Depression can occur in some persons after the loss of a loved one, or the loss of certain capacities or roles. Canadian Mental Health Association. Dorland's Illustrated Medical Dictionary . W.B. Saunders Co., 1988.