Bipolar disorder, schizoaffective disorder and schizophrenia: epidemiologic, clinical and prognostic differences.

The validity and nosologic status of schizoaffective disorder is still a controversial issue. This study was conducted to analyze the demographic, clinical and prognostic variables that determine the validity of the diagnosis of schizoaffective disorder bipolar type. We analyzed and compared 138 outpatients: 67 with type I bipolar disorder, 34 with schizoaffective disorder bipolar type and 37 with schizophrenia. They were all diagnosed following research diagnostic criteria and assessed according to the Schedule for Affective Disorders and Schizophrenia. Schizoaffective unipolar patients were excluded. The results reaffirmed that, from the standpoints of demographics, clinical features and prognosis, schizoaffective disorders bipolar type can be classified as a phenotypic form at an intermediate point between bipolar I disorder and schizophrenia. These results emphasize the importance of longitudinal follow-up in the diagnosis and assessment of psychotic syndromes. Although cross-sectional symptoms were closer to the schizophrenia spectrum, the course of the illness resembled more that of bipolar patients, resulting in an intermediate outcome.