Schizophrenia, schizoaffective disorder, bipolar disorder
Schizophrenia, schizoaffective disorder, and bipolar disorder with psychotic features include varying degrees of psychosis and mood symptoms. As such, these disorders may represent three points on a spectrum rather than three categorically distinct disorders. This chapter outlines the key role of psychosis in characterizing these disorders and reviews the conceptual history of this characterization as embodied in the different editions of the Diagnostic and Statistical Manual of Mental Disorders. The inherent practical and conceptual problems associated with a categorical system for these diagnoses and for defining psychosis symptoms are emphasized. Finally, specific symptoms and their qualitative and quantitative features are compared and contrasted among schizophrenia, schizoaffective disorder, and psychotic bipolar disorder.