A longitudinal study in Finland shows that male school bullies and male victims of bullying are more likely to commit violent offenses as adults. This association was much less clear in females. The study was published in the European Child & Adolescent Psychiatry.
Bullying is “an unwanted repetitive aggressive behavior that takes place within an unequal power relationship that inflicts harm or distress on the victim”. Often associated with school environments, bullying has been linked to students carrying out school shootings and adolescents carrying weapons. It has enormous impact on well-being of individuals and societies. However, due to the complexity of conducting studies over longer periods of time, there is much less knowledge on the long-lasting effects of bullying and how bullying related experiences in school years might affect a person later in life.
To study the association between bullying at 8 years of age and violent offenses at 31, Elina Tiiri and her colleagues analyzed a part of the data from the Finnish Nationwide 1981 Birth Cohort Study that was collected in 1989 and cross-referenced it with the 2012 data on violent offenses from the Finnish National Police Register.
The study included 5,405 persons, who represented a bit less than 10% of the population of Finland of that age. In 1989, the children were asked questions aimed to assess bullying or whether the child was a victim of bullying. Similar information about each child has been requested from their parents and teachers. Demographic data were collected from parents and psychopathology was assessed by teachers, who were asked to complete the Rutter Teacher Questionnaire.
Data on violent offenses were collected from the Finnish National Police register electronic database in 2012. It included data on participant’s involvement in violent offenses registered in Finland between the time they turned 15 till the date of collection. Authors report that a total of 515 participants or 9,5% were registered for violent offenses.
In the group of males, violent offenses were much more frequent both in persons who used to be bullies and in persons who used to be victims of bullying. Around 10% of males who were not bullies in school were involved in violent offenses of different severity, but 35% of those who were assessed as being frequent bullies. These same percentages are 14% and 24% for male victims of bullying.
In the group of females, this connection is less clear as there were almost no females involved in severe violent offenses or homicides (a total of 3). When minor offenses are considered, only 2.4% of females who were not assessed as perpetrators of bullying in school were involved in violent offenses later, but 18,2% of females who were assessed as frequent bullies.
In the group of female victims there does not seem to be an association between violent offenses and being a victim of bullying – only 1 (1.1%) person who was frequently bullied was involved in a violent offense, while it was 2.8% of participants who were not assessed as victims of bullying.
The association between childhood bullying and violent offenses in adulthood remained even when the victimization by bullying, parental education, family structure and child psychopathology were taken into account. However, the association between severe violent offenses and frequent bullying among men became considerably weaker when child psychopathology was accounted for.
The study highlighted the link between childhood bullying and violent offenses in adulthood, both of which may be manifestations of an underlying propensity for violence. Authors also note that although the registry of violent offenses likely does not contain data on all violent offenses participants were involved in and for a small percentage of participants data could not be retrieved, this source of information on violent offenses is clearly superior to the reliance on self-report measures found in previous studies on the topic.
The study, “Bullying at 8 years and violent offenses by 31 years: the Finnish nationwide 1981 birth cohort study”, was authored by Elina Tiiri, Jaakko Uotila, Henrik Elonheimo, Lauri Sillanmäki, Anat Brunstein Klomek, and Andre Sourander.