CLUSTER ANALYTIC VALIDATION OF THE DSM MELANCHOLIC DEPRESSION - THE THRESHOLD-MODEL - INTEGRATION OF QUANTITATIVE AND QUALITATIVE DISTINCTIONS BETWEEN UNIPOLAR DEPRESSIVE SUBTYPES

Cluster analysis was performed on the DSM-III symptoms of major depres sion and symptoms of melancholia identified in a study group consistin g of 220 unipolar depressed inpatients a melancholic and non-melanchol ic cluster. Patients allocated to the melancholic cluster were more se verely depressed and they were characterized by psychomotor disorders, a distinct quality of mood, diurnal variation, early morning awakenin g, and non-reactivity. Our results support the construct validity of t he DSM-IlI melancholic subtype of major depression. This study support s the integrated threshold model: (i) melancholic and non-melancholic depression may be regarded as continuous classes in terms of overall s everity of depression; and (ii) both groups form discrete categories w ith regard to the melancholic symptoms, which emerge as the severity o f depression increases. (C) 1997 Elsevier Science Ireland Ltd.