Social class, marriage, and fertility in schizophrenia.

The hypothesis is presented that the etiology of schizophrenia is neurodevelopmental: schizophrenia is a disorder occurring in extremely late maturers, whereas manic-depressive psychosis affects early maturers. This hypothesis is related to recent neurobiological findings and also to the following epidemiological and demographic topics covered by the author in her review of social class, marriage, and fertility in schizophrenia: Kretschmer's observations of body type differences between patients with schizophrenia and manic-depressive psychosis; trends in the incidence of schizophrenia and manic-depressive psychosis in industrialized versus developing economies; changing epidemiology of the subtypes of schizophrenia and of manic-depressive psychosis; sex differences in manic-depressive psychosis and schizophrenia; fertility and childlessness in schizophrenia; selection for marriage in schizophrenia; marriage patterns, inbreeding, and schizophrenia; social class, social mobility, and occupation in schizophrenia; social mobility and social selection; excess of schizophrenia in the lowest strata of society; social class, course, and outcome; and social stress and schizophrenia.