Stress hormone cortisol, involved in our "fight or flight" response, may also limit aggressive antisocial behaviour, British researchers said on Wednesday, Reuters reported. In stressful situations cortisol levels failed to spike normally in boys with behavioural problems, the researchers found in a study which suggests that the roots of antisocial behaviour may be more biologically based than thought. "Most research has looked at social factors like peer groups, family life and socioeconomic factors," said Graeme Fairchild, a psychologist at the University of Cambridge, who led the study. "These findings basically indicate that antisocial behaviour is probably more biologically based than many people recognize and is similar to conditions like depression and anxiety." An estimated 3 percent to 5 percent of children in the developed world exhibit antisocial behaviour -- such as vandalism, mugging and starting fights -- that can get them expelled from school, in trouble with the police or even sent to jail, he said. The study involved 100 boys from mainstream schools aged between 14 and 18 and another 75 adolescents with known antisocial behaviour. Males are four times more likely than females to behave antisocially. The researchers first made sure the boys had similar cortisol levels, then they were brought to a lab to monitor changes in the hormone during a game rigged to provoke stressful responses. Cortisol levels in the students without aggression problems spiked during the experiments but remained steady in youths who had exhibited antisocial behaviour. The hormone is important in helping people form memories and people with high levels tend to be more cautious and better at controlling their impulses, Fairchild said. "They looked as if they weren't under stress even though they said they were because their bodies didn't show it," Fairchild said. Better understanding biological causes of antisocial behaviour raises the possibility that drug treatment could help some people curb their aggression, the findings published in the journal Biological Psychiatry said.
