Unruly behaviour 'may be illness'

Scientists at Cambridge University believe a reduced level of the stress hormone cortisol could be linked to adolescent males becoming unruly.

They said cortisol usually increases when people undergo the anxiety of experiences such as public speaking, sitting an exam or having surgery.

The hormone enhances memory formation and is thought to help people behave more cautiously and regulate their emotions, particularly their temper and violent impulses, the scientists said.

The research, funded by the Wellcome Trust, showed that disruptive male youths did not produce the same increase in cortisol when placed in a stressful situation.

This suggested some cases of anti-social behaviour may be a form of mental illness caused by a chemical imbalance of cortisol in the brain and body, the scientists said.

Led by Dr Graeme Fairchild and Professor Ian Goodyer, the researchers recruited participants from schools, pupil referral units and the Youth Offending Service.

Dr Fairchild said: "If we can figure out precisely what underlies the inability to show a normal stress response, we may be able to design new treatments for severe behaviour problems. We may also be able to create targeted interventions for those at higher risk.

"A possible treatment for this disorder offers the chance to improve the lives of both the adolescents who are afflicted and the communities in which they live."