Underdeveloped brain structure explains lack of empathy in teenage yobs--study

British researchers observed a “stunted brain growth” in regions associated with empathy in teenage boys displaying anti-social and aggressive behaviour.

Scientists at the University of Cambridge suspect structural variations in the brain as a plausible explanation to behavioral problems such as 'conduct disorder'. The emotional centres of the brain are poorly developed in boys indicted of antisocial activities ranging from theft to violence.

Notwithstanding the discovery of a biological basis, they do acknowledge well-established links between poor upbringing in initial years and uncouth adolescents.

Brain scanning for 'conduct disorder'
A latest study used brain scanning technology for the first time in a quest for cues to explain the behaviour of boys diagnosed with intense forms of 'conduct disorder'-- a doctoral term to describe aggressive and antisocial traits.

'Conduct disorder' affects almost five percent of school-going kids and contributes to classic 'yob' behaviour such as pathological lying, thieving, breaking into homes, weapon use, fighting, and acts of violence.

A traditional take at this adolescent behaviour has been that kids simply copy badly behaved peers. But the new research found similar areas of the brain were affected in boys who engaged in antisocial acts irrespective of age.

MRI conducted on 92 teenagers
The scientists carried out magnetic resonance imaging (MRI) of 65 teenagers with an average age of 18 with 'conduct disorder' and 27 'healthy' teenagers to study their brain structures.

Some of the troubled teens developed psychological problems at an early age and some began displaying aggressiveness in adolescence.

MRI measures blood flow to different parts of the brain as a way to pinpoint brain activity.

A meticulous examination led them to the two areas, the amygdala and insula, which contribute to emotional perception, empathy, and the cognition to recognise agonised people, and found them to be markedly smaller in yobs.

High-tech computer processing was used to identify the differences, and brought out that insula volume shrank as behavioural problems got more severe.

The findings are published in the 'American Journal of Psychiatry' online.

The expert comments
Professor Ian Goodyer, one of the researchers at Cambridge University, said, "Further studies are now needed to investigate whether these changes in brain structure are a cause or consequence of the disorder".

Earlier research has proven that home and parental influences are critical in explaining problems in 'yobs and delinquents', he added.

"I don't think there's any doubt in anyone's mind that there are significant environment antecedents in virtually all cases of conduct disorder", he said. Factors such as impaired parenting, sexual and physical abuse affect later stages of life albeit there were always some individuals who exhibited 'resilience in the face of adversity', he further noted.

The study suggests changes in brain patterns underlie behavioral transitions as teenagers grow up.

Dr Andy Calder, from the Medical Research Council's cognition and brain science unit, provided a major contribution. "Studies like these are tremendously important in understanding the causes of conduct disorder," he said.

According to the scientists, the study did not prove a 'foolproof test' that could be helpful in this field, primarily because of overlap between the children studied. Not all with different brain patterns were badly behaved, and some crooks had 'normal' brains.

Co-researcher Dr Graeme Fairchild, now at the University of Southampton, informed, "Changes in grey matter volume in these areas of the brain could explain why teenagers with conduct disorder have difficulties in recognising emotions in others".

The investigation was jointly funded by the Wellcome Trust and the Medical Research Council(MRC).