Studies across different countries have given credence to the connection between schizophrenia and winter births. In 2012, scientists performed the largest study around this connection ever conducted in England, which involved 57,971 patients and also explored bipolar affective disorder and recurrent depressive disorder. (BPD seemed linked to winter birth, whereas RDD correlated with late spring births.) Though no definitive causal link has been described that can explain this association, researchers have speculated that it may have to do with vitamin D deficiency.
Originally published on Daily Curiosity