[Seasons of birth of schizophrenic patients. Retrospective study of a hospitalized population in Tunisia].

Epidemiological research concerning the seasons of births of schizophrenics show for the greatest part that there's an excess of births in winter and in the beginning of spring. Research about the environmental theories of schizophrenia suggest that there would exist one or many seasonal environmental factors affecting the foetus and the neonate, and which would be likely to increase the risk of a subsequent development of schizophrenia. As no research concerning this subject have been published so far in Africa, the writers propose to study the distribution of births of a population of schizophrenics born in Tunisia in comparison to the general population and to compare it to a group of patients hospitalized because of major affective disorders. The results achieved show a significant decrease in the number of schizophrenics births during the third trimester and an excess of births during the month of october, the risk being greater in the case of disorganized schizophrenia. The greater risk for people born in october to develop subsequently schizophrenia is not found in the case of major affective disorders but it is found rather in the case of schizo-affective disorders. More over, we notice a decrease in the number of births during the month of July for the patients presenting major affective disorders and for those presenting schizo-affective disorders. Results seem to demonstrate that there would exist seasonal environmental factors specific to North Africa which are likely to affect the subsequent appearance of schizophrenic disorders. A particular interest should be given to viral infectious to enteroviruses which are responsible for summer diarrhea in Tunisia.(ABSTRACT TRUNCATED AT 250 WORDS)