title: The depressive illnesses: a research overview.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D003863:Depression / Q000175:diagnosis / Q000209:etiology; D004195:Disease Models, Animal; D000882:Haplorhini; D006801:Humans; D008875:Middle Aged; D009316:National Institutes of Health (U.S.); D012106:Research; D014481:United States