Altered DNA methylation in an MAOA region of interest spanning the first exonic and partial first intronic regions, among men and women, has been associated with mental disorders including anxiety disorders, depression, substance abuse disorders, post-traumatic stress disorder, antisocial personality disorder, borderline personality disorder, and schizophrenia (Melas and Forsell 2015; Checknita et al. 2015, 2018, 2020; Bendre et al. 2018; Ziegler and Domschke 2018). This evidence concerns the gene MAOA and major depressive disorder.