A statistical analysis of the classification of depression in a mixed community and clinical sample.

Depressive symptoms in three samples are assessed using grade-of-membership analysis to clarify the distribution of depressive symptoms across traditional affective diagnoses. The technique is used to examine whether depressive symptoms and symptoms frequently associated with depressive disorders cluster into recognizable syndromes or pure types that parallel current operational diagnoses. Three hundred and ninety subjects were studied to address the question: among a mixed population with a range of depressive symptoms, will syndromes resembling endogenous depression and demoralization emerge from the range of presentation of depressive symptoms? A single pure type is nearly identical to the DSM-III classification of major depression with melancholia. No such pure type emerged that resembled demoralization.