Victims of bullying -- and the bullies themselves - are at increased risk of suicidal thinking and are also more likely to attempt suicide than their peers who aren't involved in bullying, according to a systematic review of 37 studies conducted in 16 different countries.

And those who were both bullies and victims were at greatest risk, Dr. Young Shin Kim of Yale University School of Medicine in New Haven, Connecticut, and Dr. Bennett Leventhal of the University of Illinois College of Medicine in Chicago found.

"It is imperative that there now be a common goal to intervene actively to reduce bullying in all communities and to seek out both victims and perpetrators to protect them from suicidality and other potential lethal adverse consequences of this serious public health problem," the researchers conclude in the International Journal of Adolescent Mental Health.

Kim and Bennett reviewed the quality of existing research examining the relationship between suicide and bullying.

About three quarters of the studies included youth in the general population, while the rest looked at special populations such as homosexual or bisexual young people, people with developmental disorders, and young people with legal problems.

Most studies of bully victims found increased risk of suicidal behavior, with victims being up to 5.6 times more likely to have suicidal thoughts and up to 5.4 times more likely to have made suicide attempts.

But bullies themselves were up to 9 times more likely than their peers in the general population to have considered suicide, while they were up to 9.9 times more likely to try suicide.

Those who were both victims and perpetrators were up to 10-fold more likely to have suicidal thoughts. Some, but not all, of the studies found an increased risk for females.

Bullying also increased the likelihood of suicidal thoughts and attempts among people with learning disabilities, drug abuse, delinquent behavior, or who were homosexual or bisexual.

"Although many adolescents may experience bullying, either as participants or observers, the observation that it is common does not imply that it is 'normal' and, hence, an acceptable part of 'normal development,'" the researchers write.

"Indeed, the evidence from this review suggests that exposure to bullying, especially for participants, is harmful."

Reuters