Attempts to disentangle the relative contributions of the array of genetic and environmental factors that influence antisocial behavior have consistently supported a role for both nature and nurture. [3–6] Questions persist, however, about which aspects of the environment most critically influence antisocial development in the population. Following Widom’s classic “Cycle of Violence” study [7], squarely implicating the salient role of child maltreatment, subsequent research has shown that inherited factors render some children particularly vulnerable to the effects of child abuse and neglect.[8] A landmark study by Caspi and colleagues [9] provided the first evidence of the interaction between a specific candidate gene (Monoamine Oxidase A) and the occurrence of child maltreatment predicting enduring patterns of antisocial behavior. A meta-analysis of subsequent studies examining that interaction [10] supported the original finding, but recent studies have also suggested that the magnitude-of-effect of inherited vulnerability (whether incurred by MAOA or other parameters of genetic risk) varies as a function of the presence or absence of numerous modifying factors such as gender, ethnicity, and the severity of adversity of life events. [11] [12] [13]
