Clinical evaluation and natural course of depression.
Lehmann H E·The Journal of clinical psychiatry
Without antidepressant therapy, episodes of clinical depression last from 2 months to several years, with an average of around 5 to 6 months. One-third of the patients recover within a year; probably one out of four untreated episodes may last more than 2 years. Depressive episodes occur, on the average, every 2 to 3 y…