Psychopaths may have faulty brains
A biological defect in the way blood flows in the brain rather than a psychological defect could be one reason why some people become criminal psychopaths, a new study shows.
Researchers from the Institute of Psychiatry at King's College London monitored the emotional responses of six men who had committed repeat offences such as attempted murder, rape with strangulation and grievous bodily harm.
All six subjects scored highly on the Hare Psychopathy Checklist, a test that looks for the presence of cunning, manipulative or exploitative behaviours as well as lack of guilt or remorse.
It is thought that people with psychopathic disorders lack empathy because they cannot process when someone is distressed, for instance a face that looks scared.
To test this, the people in the study were shown images of fearful, happy and neutral faces.
Their brains were then imaged with functional MRI, a type of brain scan that shows which parts of the brain 'light up' in response to these images.
Their brain scans were then compared to those of healthy control subjects.
"We've never been able to look directly in the brain before and what we found is that when psychopaths were exposed to frightened faces the distress cue didn't increase the psychopath's blood flow. It decreased it," says author Professor Declan Murphy.
He adds psychopaths might not stop their attacks because they may have learned to dampen their brain's response to other peoples' distress signals.
Tom Fahy, professor of forensic mental health and co-author of the study, which is published in the latest issue of the British Journal of Psychiatry, says criminal psychopathy may be inherited or acquired through very deprived and abusive childhoods.
He adds the findings of the study open possibilities for new treatments other than counselling therapies and could be used to identify people who had a higher risk of re-offending.
"Psychopaths currently respond pretty poorly to treatment but this biological problem could be used as a marker for people who say they have recovered but actually haven't," Murphy says.