Washington, Mar 25 : Researchers at York University and Queens University have found that students who bully others tend to have difficulties with other relationships, such as those with friends and parents.

They also found that targeting those relationships, as well as the problems children who bully have with aggression and morality, may offer ideas for intervention and prevention.

For the study, the researchers looked at 871 students, out of which 466 were girls and 405 were boys, for seven years from ages 10 to 18.