Several contributions in our first book about schizo affective disorders (Marneros and Tsuang, Schizoaffective Psychoses, Springer-Verlag, 1986) supported the assumption that schizoaffective disorders differ in relevant ways from schizophrenic disorders. The classification of schizo affective disorders as a subgroup of schizophrenia has also been criticized, and empirical research in clinical, genetic, therapeutic, and prognostic areas supports the idea that there are some strong similari ...