Gene Variant in Abused Boys Linked to Antisocial Behavior

For four years, the case has been building that a short variant of the monoamine oxidase a (MAOA) gene, when combined with harsh discipline, physical abuse, or other forms of maltreatment, puts youngsters at risk for antisocial behavior.

In 2002, Avshalom Caspi, Ph.D., of the Institute of Psychiatry in London and his coworkers were the first to report such a connection in a sample of more than 400 young men who had been followed since childhood. In 2004, Debra Foley, Ph.D., an assistant professor of human genetics at Virginia Commonwealth University, and colleagues reported that they had made the same association in youth aged 8 to 17 (Psychiatric News, September 3, 2004). And now Julia Kim-Cohen, Ph.D., an assistant professor of psychology at Yale University, and her team have reported the association once again, but in 7-year-old children. They published their findings in the October Molecular Psychiatry.

This latest inquiry included 975 boys. At ages 5 and 7, the boys had DNA samples taken and were assessed for physical mal-treatment, such as fractures, dislocations, or being burned with matches. The scientists then looked to see whether boys who had been physically abused and possessed the short variant of the MAOA gene (16 subjects) had significantly greater mental health problems than did boys who had been physically abused and possessed the long variant of the gene (46 subjects). This turned out to be the case.

The researchers then classified the mental health problems into emotional difficulties, antisocial behavior, or attention and hyperactivity difficulties. Again they found that children who possessed the short MAOA gene version and who had been exposed to physical abuse had more emotional problems, more antisocial behavior, and more attention and hyperactivity difficulties than did those children with the long gene version who had been abused. However, only the attention-hyperactivity results yielded a clear statistical significance.