The causes of severe anti-social behaviour may differ between teenage boys and girls, a new study suggests.
This could pave the way for new sex-specific treatments or prevention programmes as the findings indicate there are differences between the sexes in the causes of anti-social behaviour.
Academics in the UK, Europe and Canada used MRI scanners to map the brains of 200 teenagers aged 14 to 18 years to analyse the differences between children with conduct disorder and those without.
Roughly half of those teenagers in the study had conduct disorder and the findings show the brain's prefrontal cortex - the region responsible for long-term planning, decision-making, and impulse control - is thinner in boys and girls with the condition compared to those without it.
The study found that boys and girls with severe forms of conduct disorder have a more abnormal brain structure.
It also revealed specific areas of the brain differ in structure between boys and girls with conduct disorder. For example, some brain areas showed lower cortical thickness in boys with conduct disorder but higher thickness in girls with the condition.
For the first time, this highlights that there may be sex differences in the brain-based causes of conduct disorder.
The academics said conduct disorder was poorly understood and thought to be under-diagnosed and often untreated.
Symptoms range from lying and truancy, through to physical violence and using weapons at its more extreme end.
They said it was thought at least 5% of school age children are affected by the disorder and it is three times more common in boys than girls.
Previous studies have shown that around half of those who develop conduct disorder in childhood go on to show serious anti-social behaviour or criminality in adulthood.
Current treatments largely depend on parenting programmes, as the condition is often attributed to poor parenting or growing up in a dysfunctional family.
The researchers behind the new study were keen to point out that although sometimes useful, these programmes are not widely available and may not get to the root of the problem.
No specific drug treatment exists yet for conduct disorder although ADHD medication, such as Ritalin, is sometimes given.
Senior author Dr Graeme Fairchild, from the University of Bath, said: "Our results indicate that the development of the brain is disrupted in boys and girls with severe anti-social behaviour.
"These findings suggest that the causes of severe anti-social behaviour, and particularly the biological basis of these behaviours, may differ between boys and girls.
"This could lead to the development of sex-specific treatments or prevention programmes for at-risk young people."
Lead author Dr Areti Smaragdi, from the Centre for Addiction and Mental Health in Toronto, added: "We hope that our findings will prompt other researchers to consider possible sex differences in future studies of anti-social behaviour and other disorders that are more common in boys, such as ADHD.
"Our findings may also have practical implications for treatment or prevention programmes."
:: The study, Sex Differences In The Relationship Between Conduct Disorder And Cortical Structure In Adolescents, is published in the Journal of the American Academy of Child and Adolescent Psychiatry.