Aspects of the epidemiology of schizophrenia.

Reasons are given why the hospital diagnosis of schizophrenia may be accurate enough for the proper study of certain aspects of its epidemiology. Studies in the seasonality of admissions and of births in schizophrenic patients have produced consistent results in different countries and at different times. The results are summarized, and causal hypotheses based on them are discussed. The idea that schizophrenia is a relatively recent disease is compatible with these hypotheses.