Indexed in terms of circulating levels, and genetic and epigenetic variations in the OXTR gene, OXT function is associated with risk for psychopathologies involving social-interpersonal functioning such as autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD) and other childhood psychiatric disorders [4, 5], as well as individual differences in complex traits and behaviors such as empathy, pair bonding, and mutual eye gaze [6, 7]. Here, OXTR is linked to attention deficit-hyperactivity disorder.