Bullies have increased hazard for violent offences, shows comprehensive study

Children who bullied others at the age of 8–9 have higher hazard for committing violent offences 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.

Boys and girls who were frequent bullies had an increased hazard for violent offences as opposed to children who never bullied others. Boys who bullied frequently also had higher odds for violent offences compared to those who bullied sometimes. The relative hazard for boys who were frequent bullies to commit a severe violent offence such as homicide or aggravated assault during the follow-up period was almost three times as large as for the boys who never bullied.
Being a victim of bullying was not associated with an increased risk of committing violent offences.  

The study considered the background factors of socioeconomic status and possible childhood psychopathology. The association between bullying and violent offences remained even when the data were controlled for parental education level, family structure and possible child psychopathology. The results were also not impacted by the bully’s possible other bullying experiences, such as being a victim of bullying.

"Our study showed an association between bullying and violent offences both in men and women. These findings further confirm the previous notions that preventing bullying could possibly decrease violent offences," says Researcher Elina Tiiri from the Research Centre for Child Psychiatry of the University of Turku.

Research-based knowledge helps prevent issues

The study is part of a larger research project that aims to discover the connections between childhood psychosocial problems and mental health disorders, substance abuse issues, mortality, self-harming, criminality, life management, and marginalisation in adulthood.

"The research project produces knowledge that helps us develop services, early interventions, and prevention," says Professor of Child Psychiatry Andre Sourander from the University of Turku.

The research was based on extensive, nationwide epidemiological data collected in 1989 in Finland. At the time of the data collection, the participants were 8–9 years old. When the participants were 30–31 years old, the researchers extracted information about their violent offence suspicions from the Finnish National Police Register. The study was participated by 5,400 subjects.

The study is part of the research flagship and centre INVEST, which aims at providing Finland and other societies with a new model of welfare state that is more equal and economically, demographically and socially more sustainable. INVEST is a research flagship of the Academy of Finland and joint research centre of the University of Turku and the Finnish Institute for Health and Welfare.