Comparison of psychotic bipolar disorder, schizoaffective disorder, and schizophrenia: an international, multisite study

SA was consistently intermediate between BDp and SZ. The three diagnostic groups ranked: BDp > SA > SZ related to lesser morbidity or disability. The findings are not consistent with a dyadic Kraepelinian categorization, although the considerable overlap among the three DSM-IV diagnostic groups indicates uncertain boundaries if they represent distinct disorders.