The offspring of schizophrenic parents in a North Swedish isolate.

This work concerns the children of schizophrenic parents born and resident in a North Swedish isolate during 1829-1960. The sample consists of 39 children whose parents were both schizophrenic and 514 children who had one schizophrenic parent. Controls were 624 children of unaffected parents of the same population and time period. Previous observations concerning lack of association between fecundity and schizophrenic psychoses were confirmed. The marriage rate for schizophrenics had decreased, probably because of earlier diagnosis and earlier hospitalization. These changes most likely depend on the integration of the isolate into the welfare state--a considerable change as compared to the conditions prevailing 30 or more years ago. The late fetal death ratio and the infant mortality rate were significantly increased for the offspring of schizophrenic parents. The occurrence of schizophrenic psychoses and mental deficiency was significantly higher among children of schizophrenics. No association was found between the sex of the schizophrenic parent and the sex of their offspring, the incidence of stillbirths, the infant mortality rate, and the incidence of schizophrenia or mental deficiency.