A test of the tripartite model's prediction of anhedonia's specificity to depression: patients with major depression versus patients with schizophrenia.

The tripartite model of depression and anxiety suggests that anhedonia represents a relatively specific marker of depression. A strong version of this view is that anhedonic symptoms would particularly characterize depressed patients, even when compared to another diagnostic group-schizophrenic patients-for whom anhedonic symptoms represent a well-studied feature. This prediction was tested among 102 VA psychiatric inpatients (95 men), ages 21-72 (M=43.56; S.D.=8.47), all of whom received diagnoses of either major depression (n=50) or schizophrenia (n=52) based on structured diagnostic interviews. As predicted, patients with major depression scored significantly higher on the anhedonic symptoms scale of the Beck Depression Inventory (BDI) than did patients with schizophrenia. However, there was no difference between the two groups on the BDI total score or the BDI non-anhedonic symptoms score. Consistent with the tripartite model, anhedonic symptoms were more related to depressive vs. schizophrenic diagnostic status, whereas non-anhedonic depressive symptoms were not. Within the study's limitations, results were interpreted as relatively strong support for the validity and extension of the tripartite model.