One in 10 teenage girls self-harm each year, claims the largest-ever study of self-harm among 15 to 16-year-olds by Bath and Oxford universities.
The survey found 11% of girls self-harmed compared to 3% of boys
In a survey of 6,000 teenagers, researchers found girls are four times more likely to have self-harmed compared with boys.
The survey found 64.5% of self-harm was inflicted by cutting.
The research took place in 41 schools across Oxfordshire, Northamptonshire and Birmingham in 2000 and 2001.
The survey also found 11% of girls had self-harmed in the last year compared with 3% of boys. Only 13% of self-harming incidents the pupils reported resulted in a hospital visit.
Coping with stress
Pupils were asked to complete a questionnaire which explored issues surrounding self-harm and suicidal thoughts, together with other personal factors such as depression, anxiety, impulsivity and self-esteem.
"The reasons why boys and girls decide to self-harm are varied but the most frequent motive expressed was as a means of coping with distress," said Dr Karen Rodham, from the Department of Psychology at the University of Bath.
For both sexes, deliberate self-harm increased with consumption of cigarettes or alcohol and all categories of drug use.
Self-harm was more common in pupils who had been bullied and was strongly associated with physical and sexual abuse in both sexes.
Also, pupils of either sex who had recently been worried about their sexual orientation had relatively higher rates of self-harm.
The majority of those who said they self-harmed said that it was an impulsive act rather than something they had thought about for a long time.
Almost half of those who cut themselves and more than a third who took overdoses said they thought about harming themselves for less than an hour beforehand.