NO SEASON-OF-BIRTH EFFECT IN SCHIZOPHRENIC-PATIENTS FROM A TROPICAL ISLAND IN THE SOUTHERN-HEMISPHERE

The distribution of birth rates was examined in 668 schizophrenic pati ents born in Reunion, a tropical French island in the Southern Hemisph ere, and compared with that in the general local population, We failed to observe a significant season-of-birth effect, either in the total sample of schizophrenic patients or in subgroups categorized by gender , age, or family history of schizophrenia. Seasonal factors do not app ear to affect the yearly distribution of births among schizophrenic pa tients on Reunion Island. It is nevertheless possible that environment al factors which are seasonal in countries with more contrasting clima tes have a continuous effect, throughout the whole year, in subtropica l areas. Conversely, these findings provide some evidence against the hypothesis that there is an age-incidence artifact in seasonal studies from countries in the Northern Hemisphere.