Depressive Disorders: Toward a Unified Hypothesis

Abstract
Our scientific understanding of psychiatric syndromes, including the phenomena of depression, has been hampered because of: (i) the use of metapsychological concepts that are difficult to test; (ii) methodological and linguistic barriers that prevent communication among psychoanalysts, behaviorists, experimental psychologists, and psychiatrists; and (iii) the reluctance of psychiatrists to accept animal models as possible approximations of certain aspects of human psychopathology.