Sex differences in birth patterns of schizophrenics

Birth patterns of non-aboriginal, first admission, Western Australian psychiatric patients born between 1920 and 1950 were compared statistically with those of the general population. Three I. C. D. categories were examined: schizophrenia, anxiety neurosis, and depressive neurosis. For both categories of neurosis no deviations from normal birth patterns were observed. For males, marked excesses in schizophrenic births were observed in June, and for females a similar excess occurred in September. Possible explanations for this sex difference are examined.