The diagnostic ambiguity of postpsychotic depression.

A clearly differentiated episode of depression in the aftermath of acute psychosis reportedly occurs in approximately 25 percent of all patients hospitalized with a diagnosis of acute schizophrenia. A comparison of premorbid functioning, symptomatology, and clinical course in patients with a postpsychotic depression following acute schizophrenic episodes and patients in the depressed phase of bipolar depressive illness suggests a high congruence between the two disorders. The results support the growing evidence that bipolar depressive illness is frequently misdiagnosed as acute schizophrenia.