DNMT1 and major depressive disorder: In animal models, an imbalance between the generation and suppression of ROS, neuroinflammation, and apoptosis is associated with the onset of depression (Kubera et al., 2011; Uchida et al., 2018) and DNA methyltransferase (DNMT) activity plays a role in depression in animals (LaPlant et al., 2010; Uchida et al., 2011).