Children who are bullied are three times more likely than others to self-harm by the time they are 12 years old, according to a new study.

A team of researchers from the United States and the United Kingdom said its findings, published in the British Medical Journal, could help identify those at greatest risk for this type of behavior.

Examples of self-harming behaviors included cutting and biting arms, pulling out clumps of hair, head-banging and attempted suicide by strangulation, the study said.

The researchers examined sets of twins born between 1994 and 1995 in England and Wales. Six months before their 12th birthday, the twins' risk for self-harm was assessed. This information was available for 2,141 participants.

The investigators found that 237 of the children were the victims of bullies. Of these kids, 8 percent engaged in self-harm. In contrast, of the 1,904 children who had not been bullied, only 2 percent had self-harmed.

Among the bullied children, the study authors pointed out several factors that further increased their risk for self-harm, including:

• A family history of self-harming behavior
• Maltreatment
• Behavioral and emotional problems.

The researchers also noted in a journal news release that girls were more likely to self-harm than boys.

Source: U.S. News & World Report
http://health.usnews.com/health-news/news/articles/2012/04/27/bullied-children-at-greater-risk-for-self-harm-study-finds