A study published in this month's Archives of General Psychiatry examined the social and psychological risk factors associated with cyberbullying. Researchers in Finland surveyed more than 2,200 teens in the seventh and ninth grades. The study found the majority of victims who were repeatedly attacked in cyberspace perceived a definite or severe amount of difficulty in their lives. They reported having headaches, ongoing physical pains and trouble sleeping. One in four felt unsafe.

"The feeling of being unsafe is probably worse in cyberbullying compared with traditional bullying," says study author Andre Sourander, a professor at Turku University, in the report. "Traditional bullying typically occurs on schoolgrounds, so victims are safe at least within their homes. With cyberbullying, victims are accessible 24 hours a day, seven days a week. There is no time when messages cannot be left on mobile telephones or sent via e-mail."

The study found that cyberbullies also perceived their lives to be rife with difficulty. They reported emotional problems and trouble concentrating. The said they felt hyperactive and struggled to get along with other people. The bullies also reported being drunk frequently.

"Cyberbullying and cybervictimization are associated with psychiatric and psychosomatic problems," Sourander says in his study. "The most troubled are those who are both cyberbullies and cybervictims."

The rate of cyberbullying in the United States and the United Kingdom is as high as 20 percent, according to some surveys. In his study, Sourander warns parents that cyberbullying is potentially traumatizing and calls for more research into ways to effectively reduce it.

The Cyberbullying Research Center and U.S Department of Health Resources and Services Administration have advice for parents about cyberbullying.