Children diagnosed with mental health disorders were three times more likely to be identified as bullies, according to new research presented at the American Academy of Pediatrics (AAP) National Conference and Exhibition in New Orleans.

Bullying is a form of youth violence defined as repetitive, intentional aggression that involves a disparity of power between the victim and perpetrator. A 2011 nationwide survey found 20 percent of U.S. high school students were bullied during the preceding 12 months. And while it is well-established that victims of bullying are at increased risk for mental health illness and suicide, few studies have investigated the mental health status of those who do the bullying.

In the study, "Association Between Mental Health Disorders and Bullying in the United States Among Children Aged 6 to 17 Years," researchers reviewed data provided by parents and guardians on mental health and bullying in the 2007 National Survey of Children's Health, which included nearly 64,000 children.

In 2007, 15.2 percent of U.S. children were identified as bullies by a parent or guardian. Overall, children with mental health disorders were three times more likely to bully other children. A sub-analysis by type of mental health disorder found that children with a diagnosis of depression were three times more likely to bully, while a diagnosis of Oppositional Defiant Disorder (ODD) was associated with a six fold increase in the odds of being identified as a bully.

"These findings highlight the importance of providing psychological support not only to victims of bullying, but to bullies as well," said study author Frances G. Turcotte-Benedict, MD, a Brown University master's of public health student and a fellow at Hasbro Children's Hospital in Providence, RI."

"In order to create successful anti-bullying prevention and intervention programs, there certainly is a need for more research to understand the relationship more thoroughly, and especially, the risk profile of childhood bullies."