Cause: Lack of Sunlight/Vitamin D
Studies have indicated that children who born during certain times of the year (winter and early spring) have a higher than normal incidence of schizophrenia.
According to an article in the New Scientist magazine, research suggests people who develop schizophrenia in Europe and North America are more likely to be born in the winter and early spring (February and March in the Northern Hemisphere) In other words, the subjects who were born during these months had a slightly higher than average rate of schizophrenia, while subjects born in August and September had a slightly lower than average rate. There seems to be about a 10% difference in risk of schizophrenia between the high (Winter and Spring) and low risk months of birth.
One possible reason for the association between winter/spring births and schizophrenia may be related to sunlight exposure. A lack of sunlight (for example, during the shorter days of winter) can lead to vitamin D deficiency, which scientists believe could alter the development of a child's brain in the mother's womb and after birth.
Read the full article here: Low Sunlight Exposure/Vitamin D deficiency is associated with higher risk of schizophrenia