[Circannual rhythm of schizophrenic births (author's transl)]

Seven studies (in Switzerland, USA, United Kingdom, Canada, Japan, Sweden, Denmark) have shown the probable existence of a circannual rhythm of schizophrenic birth with a peak in winter. Three hypothesis try to explain this fact: - a constitutional injure; - a different circannual rhythm in sexual activity of schizophrenic parents; - a chronobiological perturbation.