Teens with severe antisocial behaviour have smaller brain structures

Scientists after scanning brains of aggressive and antisocial teenage boys with conduct disorder (CD) have discovered differences in the structures of the developing brain that could link to their behaviour problems.

The study revealed that the brain differences were present regardless of the age of onset of the disorder, challenging the view that adolescence-onset CD is merely a consequence of imitating badly behaved peers.

CD is a psychiatric condition characterised by increased aggressive and antisocial behaviour. It can develop in childhood or in adolescence.

Those affected are at greater risk of developing further mental and physical health problems in adulthood.

Neuroscientists at the University of Cambridge and the MRC Cognition and Brain Sciences Unit used magnetic resonance imaging to measure the size of particular regions in the brains of 65 teenage boys with CD compared with 27 teenage boys who did not display symptoms of behavioural disorder.

Their findings revealed that the amygdala and insula - regions of the brain that contribute to emotion perception, empathy and recognising when other people are in distress - were strikingly smaller in teenagers with antisocial behaviour.

The changes were present in childhood-onset CD and in adolescence-onset CD, and the greater the severity of the behaviour problems, the greater the reduction in the volume of the insula.

Smaller volume of structures in the brain involved in emotional behaviour has been linked to childhood-onset CD, in which behavioural problems manifest early in life.