Teenage girls with behavioural disorders have abnormal brain structures, find UK researchers.
The study of 40 girls, published in the Journal of Child Psychology and Psychiatry, revealed differences in the structure of areas linked to empathy and emotions.
Previous work has found similar results in boys.
Conduct disorder is a psychiatric condition which leads people to behave in aggressive and anti-social ways, and which can increase the risk of mental and physical health problems in adulthood.
In this study, funded by the Wellcome Trust and Medical Research Council, UK and Italian researchers conducted brain scans of 22 teenage girls who had conduct disorder and compared them with scans of 20 who did not.
They also checked the scans against others previously taken of teenage boys with conduct disorder.
The team found part of the brain called the amygdala was smaller in the brains of male and female teenagers with conduct disorder than in their peers.
The amygdala is involved in picking up whether or not others feel afraid - and plays a role in people feeling fear themselves.
Girls with conduct disorder also had less grey matter in an area of the brain called the insula - linked to emotion and understanding your own emotions.
But the same area was larger in boys with conduct disorder than healthy peers, and researchers are not yet sure why that is the case.
The brains of those with the worst behaviour were most different from the norm.
"The origins of these changes could be due to being born with a particular brain dysfunction or it could be due to exposure to adverse environments such as a distressing experience early in life that could have an impact on the way the brain develops," the BBC quoted Dr Andy Calder, from the MRC cognition and brain sciences unit, who worked on the study, as sdaying.
Dr Graeme Fairchild, of the University of Cambridge who also worked on the study, said there were potential uses for the finding.
"It would also be possible to use scans where a person is at high risk of offending in the future," Dr Fairchild stated.
"More help could be given to the family and, in the same way that someone with language impairment receives extra help, help could be given to teach a person to understand emotions - and the emotions of others - better," he added.