Question: Is it true that children who were born in the winter have an increased risk of developing bipolar disorder?
Answer: There have been some reports that adults with bipolar disorder are more likely to have been born in the winter than in the summer, spring, or fall months.
However one has to be careful when interpreting that kind of data because it doesn't mean that if you were born in the winter you're more likely to develop bipolar disorder.
It means that probably people who have a genetic predisposition towards bipolar disorder might be more prone to develop it with a certain viral interaction.
So, a small percentage of people who are going to develop bipolar disorder might have viral ideologies. This has led some people to examine whether or not there's some sort of infectious cause for bipolar disorder.
But overall the risk that you have by being in the winter does not increase it great enough to be clinically significant. Having said that with schizophrenia there is more data pointing out that winter months births are more likely to lead to schizophrenia.