Should We Cure Bad Behavior?
Brain and genetic research is also beginning to illuminate some of the neurochemical sources of violence. For example, elevated levels of dopamine and norepinephrine are associated with impulsivity and violence. The gene for catechol-O-methyltransferase (COMT) comes in two varieties, one of which is four times slower in breaking down dopamine and norepinephrine. Studies indicate that people with the slow COMT variation are more prone to violence. Monoamine oxidase-A (MAOA) is another brain enzyme that inactivates dopamine, norepinephrine and serotonin. It too comes in two versions. A study in New Zealand found that men who carry the low activity version and who had been reared in abusive households are much more likely to commit crimes and be violent. The researchers explicitly noted that "these findings could inform the development of future pharmacological treatments."