This study examined the G×E interaction of MAOA genotype and maltreatment in predicting risk for aggression, rule breaking, and inattention in children of different racial backgrounds. The children in our study represent the extreme on a continuum of adversity and were assessed at a time of extreme stress—shortly after removal from their parents’ care due to abuse or neglect. The interaction between MAOA-L and adversity held up to moderate levels of trauma exposure, with the maltreated children with moderate level of trauma in our study roughly comparable in terms of maltreatment experiences to the subjects living with birth families with definite maltreatment in the Caspi study. However, MAOA-L did not contribute to explaining variability in children’s aggression scores at extreme levels of trauma. The children with the most severe traumatic experiences had high aggression scores, regardless of MAOA genotype.
