Being bullied in the teen years is strongly linked to depression in young adulthood, according to a new study published in The BMJ.
There is a rapid increase in depression from childhood to adulthood and one contributing factor may be bullying by peers. But the link between bullying at school and adult depression has remained unclear due to research limitations.
This led a team of scientists to conduct one of the largest studies on the association between bullying by peers in teenage years and depression in early adulthood.
The researchers, headed by Lucy Bowes, Ph.D., at the University of Oxford, examined the relationship between bullying at 13 years and depression at 18 years. They did this by analyzing bullying and depression data on 3,898 participants in the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK community based birth cohort.
At 13 years old, the participants completed a self-report questionnaire about bullying. Then at 18 years, they completed an assessment that identified individuals who met internationally agreed criteria for depression.
Of the 683 teenagers who had been bullied frequently (more than once a week) at 13 years, 14.8 percent were experiencing depression at 18 years. And of the 1,446 teens who had experienced some bullying of one to three times over six months at 13 years, 7.1 percent were depressed at 18 years. Only 5.5 percent of teenagers who did not experience bullying were depressed at 18 years.
Around 10.1 percent of frequently bullied teenagers suffered from depression for more than two years, compared with 4.1 percent from the non-bullied group.
Overall, 2,668 participants had reported on bullying and depression as well as other factors that may have caused their depression, such as previous bullying in childhood, mental and behavioral problems, family situations, and stressful life events.
When these factors were taken into account, frequently bullied teenagers still had about double the chances of depression compared with those who did not experience bullying. This connection was the same for both males and females.
The most common type of bullying was name calling; 36 percent experienced this, while 23 percent had belongings taken from them.
If this were a causal relationship then up to 30 percent of depression in young adults could be attributed to bullying in their teen years, explain the authors, adding that bullying could make a significant contribution to the overall burden of depression.
While no definitive conclusions can be drawn about cause and effect, the researchers say that interventions to reduce bullying in schools could reduce depression in later life.