Psychopaths share similarities in brain structure that differ to the rest of the population, a new study reveals, a discovery which could be crucial in developing our understanding of this personality disorder and how it might be treated.
Led by researchers from the Research Center Jülich and RWTH Aachen University in Germany, the study compared brain scans of men diagnosed as psychopaths against brain scans from male volunteers without the condition.
“Psychopathy is one of the greatest risk factors for serious and persistent violence,” write the researchers in their published paper.
“In order to detect its neurobiological substrates, we examined 39 male psychopathic subjects and matched controls using structural magnetic resonance imaging and the Psychopathy Check-List (PCL-R).”
Related: How Psychopaths Process Pain Could Explain Their Lack of Empathy
The PCL-R combines interview results with professional assessments and official records to produce three scores: an overall score, a factor 1 score that measures interpersonal and emotional traits, and a factor 2 score that measures impulsive and antisocial behavior.
While there were only slight differences in brain structure corresponding to factor 1 scores, when it came to factor 2, the researchers found significant reductions in certain brain regions among people who scored highly – including in the pons part of the brainstem, the thalamus, the basal ganglia, and the insular cortex.
Research has shown these regions mediate control over involuntary actions, and are linked to emotional processing, interpreting sensory information, motivation, and decision making. In other words, these functions play a critical role in determining how we react to our environment.
What’s more, the brains of psychopathic subjects were found to be around 1.45 percent smaller than those of control subjects, on average. This is tricky to interpret, but might point to developmental problems in people classed as psychopaths.
“The present results suggest that the behavioral disturbances that are captured by the PCL-R factor 2 are associated with volume deficits in regions which belong to frontal-subcortical circuits that could be involved in behavioral control,” write the researchers.
This is a relatively small-scale study with limited diversity of subjects, so further research will be needed to gather more data. The results imply antisocial and impulsive behaviors in those with psychopathic personalities could be heavily influenced by shared neurological characteristics.
Future studies may also consider other possible reasons for these differences in brain structure – which could include drug abuse, for example, or traumatic experiences – to help identify cause and effect more clearly.
The debate continues about exactly how to classify psychopathy, which typically manifests itself as a chronic lack of empathy, manipulative behavior, and a tendency to be impulsive and take risks.
Although the level of psychopathy can vary from person to person, it can also lead to aggressive and violent actions, as the researchers behind this latest study point out – and with a better understanding of the condition, that might be something we can change.
“In conclusion, these findings are compatible with the dimensionality of the PCL-R construct, and suggest a particularly strong association of antisocial behavior to smaller volumes in widespread subcortical-cortical brain regions,” write the researchers.
The research has been published in the European Archives of Psychiatry and Clinical Neuroscience.
