Genetic risk for violent behavior?
By Jacob Russel
United Press International

WASHINGTON, Nov. 27 -- British Prime Minister Tony Blair might be on to something in his recent call to clamp down early on antisocial behavior, a recent study shows.

"If we are not prepared to predict and intervene far more early, then there are children that are going to grow up in families that we know perfectly well are completely dysfunctional," Blair said. "And the kids a few years down the line are going to be a menace to society and actually a threat to themselves.

Dr. Essi Viding, professor in the Department of Psychology at the University of London, and Uta Frith, professor at the Institute of Cognitive Neuroscience and the Department of Psychology at University College London, collaborated on recent research on genes for susceptibility to violence.

The study shows that low activity in the MAOA gene, which produces the enzyme monoamine oxidase-A, is linked to aggressive behavior in men. MAOA-L, the term used to describe low-activity carriers, may contain a vulnerable neural signature that could turn violent in a bad environment, particularly in the amygdala. The amygdala is located between the right and left cerebral hemispheres and controls the emotions. Patients with MAOA-L appear to have a shorter amygdala stem than others.

The research indicates that if carriers of the MAOA-L gene grow up in high-risk families, they will be more susceptible to violent behavior.

Though no one appears to know exactly what Blair is up to, the assumption is that he recognizes that personality disorders do not come as a surprise when an individual turns 18. He is aware of the importance of early environmental problems, particularly for those who come from families that have concentrated psychiatric vulnerability.

Viding supports this.

"The discovery that psychopathic tendencies are strongly heritable suggests that we need to get help for these youngsters early on," she said.

She suggests it would be important to provide support structures and programs that take place during the important phase of early brain development.

"Animal studies suggest that if (social circumstances) are changed early enough, this is effective," she told United Press International. "Early enough being the key. Given what we know about different brain profiles of different subtypes of antisocial behavior, we may also need to think about tailoring the treatment. For example, we should take different approaches depending on a risk genotype. ... I believe that MAOA-L is only part of the bigger picture."

While the MAOA-L gene can be a predictor, it is important to recognize that the genes influencing behavior have a very small effect. Even combined with stressful environments, there is no perfect indication that one will become antisocial.

This issue is not fundamentally genetic, said Dr. Sujatha Byravan, president of the Council for Responsible Genetics. She said Blair's claims targeted children raised by single mothers who become a menace to society. Blair was suggesting identifying the kinds of situations that put children at risk and addressing the problem before birth.

"We don't have a genetic reason for criminal behavior," she said. "But it's interesting that genetics as the reason for criminal behavior continues to appear."

"Gene therapy has not worked," she said. "Maybe you can repair (the problem) by changing the social circumstances in a person's life or doing other things, but you can't change it just by changing someone's genes."

Viding agrees. "Fixing the genes is totally unrealistic and I doubt Mr. Blair would propose that. The effect of any one gene on behavior is so minute, and it does not spell destiny. We are not talking about dominant genes for eye color here. You need accumulative genetic risk."