Epigenetics of major depressive disorder

Abstract The etiology of major depressive disorder (MDD) is complex, with both genetic susceptibility and exposure to stressful life events being contributing factors. Stressors can change epigenetic marks, sometimes enduringly, and these changes may play an important role in the development of MDD. Because stress is so closely related to the development of MDD, we review here both the epigenetics of stress and the epigenetics of depression. Although candidate genes have been interrogated frequently in epigenetic studies, there has been little consistency in MDD association, with the one exception being BDNF, where increased methylation has been repeatedly found. There have now been 20 unbiased studies investigating DNA methylation changes across the genome in MDD, and while their top findings have differed, the possibility of convergence across these studies requires further attention. While much remains to be learned about the role of epigenetics in the pathogenesis of MDD, a summary methylation risk score in MDD patients might provide an opportunity for clinical applications of epigenetic data.