The epidemiology of depressive disorders.

The Zürich cohort study of a community sample identified, up to age 35, a lifetime prevalence rate for DSM mania/hypomania of 5.5%, half of these cases also met the criteria for major depressive episodes. The lifetime prevalence rates obtained for major depressive disorder were 17.85% and the rate for all depressive subgroups including dysthymia, minor depression, recurrent brief depression and major depression was 35.4%. Data on the validity of the diagnostic subgroups suggest that these high prevalence rates are based on clinically relevant case definitions.