Relationship between impairment of prenatal brain growth and family history of psychosis in schizophrenia.

Recently McNeil et al. (1993b), showed that schizophrenics had smaller head circumference (HC) at birth than controls. This small head size at birth was observed more commonly among schizophrenics without a family history of psychosis than among familial schizophrenics, suggesting that some prenatal environmental factors, rather than genetic factors, are related to the impaired brain growth in utero. We attempted to replicate this finding in 100 Japanese schizophrenics (DSM-III-R), using contemporaneous data on body measures at birth. Conversely, in the current study, HC at birth was found to be significantly smaller in schizophrenics with a family history of psychosis (N = 19) than those without (N = 81). A multiple regression analysis, controlling for gender, gestational age, maternal age, birth order and year of birth, yielded an overall reduction of about 1 cm in HC at birth among familial schizophrenics compared with non-familial schizophrenics. When HC at birth in family history positive and negative groups was compared separately with the local population norms with adjustment for gender and gestational age, familial and non-familial schizophrenics were both found to have significantly smaller HC at birth, although the difference was less marked for the latter. These results suggest that schizophrenics have delayed cerebral development in utero, and that genes which operate on prenatal neurodevelopment may play an important role in the aetiology of schizophrenia, although it is possible that some environmental factors may also be involved in the impaired brain growth.