One of the most important questions of our previous common volumes about affective, schizoaffective, and schizophrenic disorders was the question of what connects and what separates psychotic disorders (Marneros and Tsuang, Schizo affective Psychoses, Springer-Verlag, 1986; Marneros and Tsuang Affective and Schizoaffective Disorders, Springer-Verlag, 1990; Marneros, Andreasen, and Tsuang, Negative and Positive Schizophrenia, Springer-Verlag 1993). The boundaries between various psychotic d...

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 ...