• In two studies of depressed, manic, schizophrenic, and normal subjects, a scale for measuring the intensity of subjects' pleasureable responses to normally enjoyable situations (the Pleasure Scale) evidenced good internal reliability and moderate agreement with the Chapman Anhedonia Scale and indexes of depressive symptom severity. Only the depressed patients showed extremely anhedonic responses. Although more than half the depressed patients evidenced pleasure scores in the normal range, about 18% of them seemed more anhedonic than any normal subject. A mixture analysis resolved depressed patient scores into two distinct distributions: a normal-range distribution (88% of depressives) and an extremely anhedonic distribution (12%). The findings provide some support for the existence of a qualitatively distinct subtype of major depression that has been variously defined as "endogenomorphic" or "melancholic."
Fawcett J, Clark DC, Scheftner WA, Gibbons RD. Assessing Anhedonia in Psychiatric PatientsThe Pleasure Scale. Arch Gen Psychiatry. 1983;40(1):79-84. doi:10.1001/archpsyc.1983.01790010081010