From Genes to Brain to Antisocial Behavior

This review summarizes recent brain-imaging and molecular-genetic findings on antisocial, violent, and psychopathic behavior. A genes to brain to antisocial behavior model hypothesizes that specific genes result in structural and functional brain alterations that, in turn, predispose to antisocial behavior. For instance, a common polymorphism in the monoamine oxidase A (MAOA) gene has been associated with both antisocial behavior and also reductions in the volume of the amygdala and orbitofrontal (ventral prefrontal) cortex-brain structures that are found to be compromised in antisocial individuals. Here I highlight key brain regions implicated in antisocial behavior, with an emphasis on the prefrontal cortex, along with ways these areas give expression to risk factors for antisocial behavior. Environmental influences may alter gene expression to trigger the cascade of events that translate genes into antisocial behavior. Neuroethical considerations include how responsibility and punishment should be determined given the hypothesis that neural circuits underlying morality are compromised in antisocial individuals.