MAOA and psychiatric disorder: Robust evidence shows that MAOA genotype moderates the association between maltreatment and mental disorders (Wermter et al. 2010; Mandelli and Serretti 2013; Byrd and Manuck 2014), and recent evidence shows associations between MAOA methylation and mental disorders (Melas et al. 2013; Melas and Forsell 2015; Checknita et al. 2015; Ziegler et al. 2016).