A longitudinal study in Finland shows that male school bullies and male victims of bullying are more likely to commit violent offences as adults. This association was much less clear in females. The study was published in the European Child & Adolescent Psychiatry. .
Children who bullied others at the age of 8-9 have higher hazard for committing violent offenses by the age of 31. This was shown in a Finnish Nationwide Birth Cohort Study conducted at the Research Centre for Child Psychiatry at the University of Turku, Finland.