TUESDAY, Dec. 4, 2012 (HealthDay News) -- Bullied teenagers can develop post-traumatic stress disorder symptoms, according to a new study.
The findings suggest that victims of bullying may require long-term support, said the researchers from the University of Stavanger in Norway.
They looked at almost 1,000 teens, ages 14 and 15, and found that one-third of those who said they had been bullied had post-traumatic stress disorder (PTSD) symptoms, such as intrusive memories and avoidance behavior.
Those with the worst symptoms were bullying victims who also bullied others. The researchers also found that girls were more likely to have PTSD symptoms than boys.
The study was published recently in the Journal of Abnormal Child Psychology.
The findings are "noteworthy, but nevertheless unsurprising," study author and psychologist Thormod Idsoe said in a university news release.
"Bullying is defined as long-term physical or mental violence by an individual or a group," he explained. "It's directed at a person who's not able to defend themselves at the relevant time. We know that such experiences can leave a mark on the victim."
PTSD symptoms can create major problems for students.
"Pupils who are constantly plagued by thoughts or images of painful experiences -- and who use much energy to suppress them -- will clearly have less capacity to concentrate on schoolwork," Idsoe said. "Nor is this usually easy to observe -- they often suffer in silence."
Idsoe and his colleagues hope their study increases awareness that some bullied schoolchildren may require support even after the bullying is stopped.
"In such circumstances, adult responsibility isn't confined to stopping the bullying," he said. "It also extends to following up with the victims."
The U.S. Health Resources and Services Administration explains how to help children involved in bullying.