And when kids go on a murderous rampage, as they did this week in Littleton, Colo., we cite lack of supervision by parents and educational authorities, and the slow official reaction to behavioral warning signals. Typically, there are calls to pay greater attention to these contributing factors in the hope of preventing further tragedies. And while it's important to try, these efforts won't completely fend off outbreaks of violence. What's often missing from analyses of mass murders is a deeper understanding of violence and why some adults and children will snap, no matter what kind of anti-violence programs we put in place. To understand violence, we must not deny the vulnerability of the brain and how it can break down unpredictably and unleash savagery.
Some research links physical and chemical changes in the brain to violence.
Head injuries or other brain damage, for example, can cut off a person's ability to process emotions. Viral infections, potent drugs, alcohol, toxic substances, including metals absorbed from air pollution, paint and foods, and the presence of tumors or cysts can all destabilize brain chemistry. Scientific data also show that environmental stimuli can change the levels of brain chemicals. Most engaging is research suggesting that threatening environments, including impoverished ones and those in which there is early childhood abuse or neglect, may change brain chemistry into a mode that makes violent behavior more likely. It therefore shouldn't be surprising to learn that mass murderers often have either wounded brains, deeply troubled histories or both.