Classification of endogenous psychoses from a genetic viewpoint

The family-heredity findings serving as criteria for the classification of functional psychoses are discussed, presenting recent data. The global morbidity risk of the resp. psychosis showing secondary cases similar (homotypical) to the index case and no increased incidence of cases of the other type may be interpreted by the theory of two separated genetically transmitted diseases (schizophrenias and affective disorders). The classical schizophrenic subtypes differ in their global schizophrenia morbidity risk and show a tendency toward homotypical secondary cases. Monopolar and bipolar affective disorders were found to be very close together concerning family-genetic data-Schizo-affective psychotics were found to have among their relatives the highest incidence of all types of functional psychoses at all, a high rate of schizophrenics (esp. catatonic type) and affective psychotics and no homotypical secondary cases.