Bullied students are more likely to carry weapons to school, according to a recent study.

Researchers found that adolescents who have been harassed or victimized in multiple ways are up to 31 times more likely to carry a gun or knife to school than those who have not been bullied.

According to research presented May 4, at the Pediatric Academic Societies (PAS) annual meeting in Vancouver, British Columbia, Canada, an estimated 200,000 high school students who are bullied bring weapons to school.

"Victims of bullying who have been threatened, engaged in a fight, injured, or had property stolen or damaged are much more likely to carry a gun or knife to school," Andrew Adesman, lead investigator and chief of developmental and behavioral pediatrics at Steven & Alexandra Cohen Children's Medical Center of New York, said in a statement.

For the study, researchers analyzed data from the 2011 Youth Risk Behavior Surveillance System. The system includes a nationally representative survey of more than 15,000 American high school students conducted by the Centers for Disease Control and Prevention. Students were asked if they had ever been bullied on school property in the past year and on how many days in the past month they carried a weapon on school grounds.

They looked at whether any of the following risk factors increased the likelihood that victims would carry a weapon to school: not going to school due to feeling unsafe in school or on the way to school; had property stolen or damaged; had been threatened or injured with a weapon; and had been in a physical fight. They also looked at what occurred when students experienced multiple risk factors.

They found that 20 percent of high school students reported being victims of bullying. Those who were bullied were more likely to be in lower grades, females and white. They also were more likely to carry a weapon to school than kids who were not bullied (8.6 percent vs. 4.6 percent).

"Large numbers of high school students report having been victimized by bullies and admit to carrying a weapon to school. Greater efforts need to be expended on reducing bullying in all of its many forms," Dr. Lana Schapiro, principal investigator of the study, said in a statement.

There was also a dramatic increase in the likelihood that victims of bullying went to school with a weapon if they experienced multiple risk factors. Up to 28 percent of students experiencing one risk factor brought a weapon to school, while up to 62 percent of those experiencing three risk factors carried a weapon on campus.

"With estimates of more than 200,000 victims of bullying carrying a weapon to high school, more effective prevention efforts and intervention strategies need to be identified," Dr. Schapiro said. "The greatest focus should not just be on bullies, but on the victims of bullies most likely to carry a weapon and potentially use deadly force if threatened."