MANY children who become criminals suffer from "conduct disorder", according to US studies. Such a child:

. violates moral rules and the rights of other people

. lies, steals and fights

. is hyperactive

. refuses to conform to rules and will not respond to normal kinds of parental authority

. is oppositional

. has no conscience and no awareness of the feelings of others

These are the kinds of kids who will hit their best friend over the head with a baseball bat and then have no understanding of why their friend will not be their friend anymore, says Dr Jim Sattersfield, associate clinical Professor of Psychiatry in the Division of Child Psychiatry in the Oregon Health Sciences University. "They simply do not appear to process information in the normal way. This can lead to sociopathic or psychopathic behaviour in later life, because children with conduct disorder are likely to become anti social adults," he says.

Dr Sattersfield and his spouse, Dr Breena Sattersfield, have been working with six to 12 year olds with diagnosed conduct disorder and have found that half of them are arrested for felony crimes in their teens and one in five goes on to get adult criminal records. By intervening with a range of various therapies before the age of 12, the Sattersfields have been able to rescue children who might otherwise have gone on to criminal behaviour. But these children have to be reached during a "window of opportunity" between ages six and 12.

"Age 12 is too late," says Dr Sattersfield.