The risk for self-harm was much higher among children with behavioural or emotional difficulties and those from troubled families.
According to the study’s findings, about half of 12-year-olds who subjected themselves to deliberate injury had been frequently picked on.
The study authors have called for more effective programs to prevent bullying in schools, suggesting efforts should focus on improving the ways in which children cope with emotional distress.
“Bullying by peers is a major problem during the early school years,” they said.
“This study found that before 12 years of age a small proportion of children frequently exposed to this form of victimisation already deliberately harmed themselves and in some cases attempted to take their own lives.
“Frequent victimisation by peers increased the risk of self-harm.”
The researchers also raised fears over the long-term implications of bullying, which they said could result in psychological issues, serious injury or death.
“This study adds to the growing literature showing that bullying during the early years of school can have extremely detrimental consequences for some children by the time they reach adolescence,” they wrote.
“This finding is even more concerning given that studies have suggested that early patterns of self-harm can persist through adolescence into adulthood and increase the risk of later psychological problems.
“Therefore, such maladaptive coping strategies need to be tackled in childhood and early adolescence before they become a persistent problem or lead to serious injury or death.”
The authors, from King’s College London, looked at more than 1000 pairs of twins – born between 1994 and 1995 in England and Wales – at five, seven, 10 and 12 years of age.
Some 237 children were victims of frequent bullying.
Of that number, 18 (about 8%) self-harmed by cutting or biting arms, pulling out clumps of hair, head-banging against walls or attempting suicide.
Of 1904 children who were not bullied, 44 (2%) self-harmed.
As first appeared in Medical Observer, 27 April 2012
BMJ 2012; online 26 April