The Conundrum of Schizoaffective Disorder: A Review of the Literature

Our understanding of schizoaffective disorder can be organized in fi ve different models (see Sidebar, page 170). One approach holds that schizoaffective disorder is its own illness, separate from others, as appears to be the case superfi cially by its separate diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).1 A second model holds that schizoaffective disorder represents a middle clinical picture on a psychotic continuum that extends from bipolar disorder to schizophrenia; in other words, this model rejects the Kraepelinian dichotomy of bipolar disorder and schizophrenia.2,3 A third model argues that schizoaffective disorder represents the comorbidity of affective disorders and schizophrenia, thereby maintaining the Kraepelinian dichotomy and explaining overlap symptoms as chance co-occurrence.4 A fourth theory views schizoaffective disorder as basically a variant of bipolar disorder,5 and a fi fth sees schizoaffective disorder as a variant of schizophrenia.6