Brain scans reveal shocking difference between psychopaths and people without condition

Scientists have discovered a key difference in the brain between people with psychopathic traits and those.

The 'psychopath' label is usually associated with someone who commits unthinkable crimes, either in real life or in a superhero movie.

Yet, the definition of the mental health problem is much broader than that. Not every person with psychopathic traits breaks the law, though a long line of research has found a link between psychopathy and a higher risk of violent or anti-social behaviour.

For instance, the NHS describes a psychopath as someone with: "an antisocial personality disorder, which means they: lack empathy, are manipulative and often have a total disregard for the consequences of their actions."

A scientist from Nanyang Technological University shows her findings. (Nanyang Technological University)

It has often been assumed that psychopathy was largely shaped by social and environmental experiences, but a new study has found evidence that biology may play a significant role.

Researchers from the Nanyang Technological University, Singapore (NTU Singapore), the University of Pennsylvania, and California State University MRI scanned 120 people in the USA, then gave the participants the Psychopathy Checklist before comparing the brain scan images between those who displayed psychopathic traits and those who did not.

The results, published in the Journal of Psychiatric Research, found that the striatum region of the brain was about 10 per cent larger on average in psychopathic individuals.

An MRI scan shows what our brain looks like. (ALAIN JOCARD/AFP via Getty Images)

The striatum is located deep in the brain as part of the basal ganglia and and is linked to thinking, social behaviour, rewards and motivation.

Assistant Professor Olivia Choy, from NTU's School of Social Sciences, a neurocriminologist who co-authored the study, told sciencedaily: "Our study's results help advance our knowledge about what underlies antisocial behaviour such as psychopathy.

"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."

While scientists have come to understand the striatum was more active than usual in psychopaths, it was not clear if its size was an active factor, until now.

These findings could have a positive result, as it may now help researchers further understand how biology impacts psychopathic tendencies and help further develop methods to treat and prevent the condition.