[M]ore than 100 investigators and research groups… combed through the genomes of 33,403 people with schizophrenia, 19,924 with bipolar disorder, and 32,408 with major depressive disorder, as well as 109,946 controls (people without any of these diagnoses).
Their goal was to understand why these major psychiatric disorders differed between the sexes. For example, women have a significantly higher risk for major depressive disorder, whereas the risk for schizophrenia is significantly higher among men. The risk of bipolar disorder is about the same for both women and men, but disease onset, course, and prognosis differ markedly between the two.
By taking advantage of large psychiatric databases, the investigators were able to demonstrate that the risks for schizophrenia, bipolar disorder and major depressive disorder are affected by interactions of specific genes with sex, apart from the effects of sex hormones such as estradiol or testosterone.
For example, the investigators found interactions with schizophrenia and depression and sex in genes controlling for the production of vascular endothelial growth factor, a protein that promotes the growth of new blood vessels.
The investigators emphasize that although the specific causes of the diseases they studied are still unknown, “our study underscores the importance of designing large-scale genetic studies that have the statistical power to test for interactions with sex,” [researcher Jill Goldstein says.]