Psychopaths are more likely to have larger forebrain region, study finds

A brain region known as the striatum was on average 10 per cent larger in psychopaths compared to those with no psychopathic traits, according to a new study.

The study, published on Tuesday in the Journal of Psychiatric Research, used magnetic resonance imaging (MRI) scans to assess the brains of psychopathic individuals with an egocentric antisocial personality, marked by a lack of remorse for their actions, and a lack of empathy for others.

Scientists, including those from Nanyang Technological University (NTU), Singapore, compared the results of the scans with those from individuals who had low or no psychopathic traits.

They scanned the brains of 120 participants in the US and interviewed them using the “Psychopathy Checklist – Revised”, an assessment tool to determine the presence of psychopathic traits in individuals.

While previous studies have hinted at overly active striatum – a part of the forebrain – in psychopaths, the new research found that the striatal volumes in psychopathic individuals were increased by about 10 per cent compared with controls.

This region of the brain, scientists say, coordinates multiple aspects of cognition, including both motor and action planning, decision-making, motivation, reinforcement, and reward perception.

“We find that in addition to social environmental influences, it is important to consider that there can be differences in biology, in this case, the size of brain structures, between antisocial and non-antisocial individuals,” study co-author Olivia Choy from NTU said in a statement.

The findings add support to perspectives of psychopathy that the brains of some of these violent offenders may not be developing normally throughout childhood and adolescence, researchers say.

“By replicating and extending prior work, this study increases our confidence that psychopathy is associated with structural differences in the striatum, a brain region that is important in a variety of processes important for cognitive and social functioning,” study co-author Andrea Glenn from The University of Alabama said.

Scientists believe future studies can shed more light on the factors contributing to these brain structural differences,