Teen anger ’caused by brain shape’

UK Telegraph 26 February 2008

Adolescent anger and aggression can be traced to differences in brain structure, scientists say. Variations in the sizes of parts of youths’ brains were found to be linked to different levels of aggression, belligerence and anxiety during discussions with their parents. Researchers filmed 137 adolescents aged 11 to 14 having discussions with their mothers and fathers, involving provocative topics such as “lying” and “talking back to parents”.

They were rated using standard scales used by psychologists for traits including anger, contempt, belligerence, anxiety, or being happy or caring. Each adolescent participant then had his or her brain structure mapped using a magnetic resonance imaging (MRI) scanner. Scientists then measured the sizes of different brain regions. They found that a larger than average amygdale – an almond-shaped brain structure known to be involved in emotions and memory – was associated with longer duration of aggression in both boys and girls. Boys with a smaller left anterior cingulate cortex (ACC) than right ACC, exhibited more anxious behaviour and “whined” more. The findings were reported yesterday in the journal Proceedings of the National Academy of Sciences.