These results coincide with the results of other family studies in demonstrating a significant and specific familial aggregation of schizophrenia and nonpsychotic schizophrenia spectrum disorders among the biological relatives of schizophrenics.

In a prospective study of offspring of schizophrenic mothers, perinatal complications reported in midwife protocols were analysed for those offspring who, as adults, were diagnosed as schizophrenic, borderline schizophrenic or as not suffering from mental illness. The schizophrenics were found to have had the most complicated births, and the borderlines, the least complicated births. This difference is interpreted in terms of a 'diathesis-stress' model. It is proposed that birth complications can decompensate borderline individuals towards schizophrenic breakdown.

A taxometric analysis (R. R. Golden & P. E. Meehl, 1979) was conducted to test the hypotheses that liability for schizophrenia-spectrum disorders is dichotomously distributed and that this liability can be detected premorbidly with behavioral indicators analogous to many of the criteria for schizotypal personality disorder. Behaviors were assessed in 207 offspring of schizophrenic mothers and 104 matched offspring of normal parents in 1962, when participants' mean age was 15 years. Diagnoses on the basis of the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) were made in 1986-1989, when participants were nearly through the risk period for developing schizophrenia. The aggregation of indicators was consistent with a bimodal latent liability distribution. Membership in the schizotypal class was a sensitive and specific predictor of the emergence of schizophrenia-spectrum disorders in adulthood.

No abstract

A Group of 207 subjects with severely schizophrenic mothers and a matched group 104 subjects without known mental illness in the parents or grandparents have been followed since 1962 in a prospective study based on Mednick's learning theory of schizophrenia. The present paper describes an analysis of the clinical outcome based on a follow-up examination in 1972-1974. The examination consisted of a 3 1/2-hour clinical interview using three approaches (two with computer-derived diagnoses and one traditional clinical interview). 173 high-risk and 91 low-risk subjects were fully clinically reassessed. At the time of the assessment they were between 18 and 30 years old. The diagnostic distribution showed marked differences between the two groups with regard to type and degree of psychpathology. The results are discussed in relation to the methods used, and with regard to the case and non-case status of the subjects.