A study that scanned the brains of 142 prison inmates showed different neural patterns for two constellations of traits associated with psychopathy. The results were published in the Journal of Neuroscience today.
Scientists have long established that two clusters of traits make up the psychopathic personality. The first involves traits such as shallow emotions, manipulation of others, and superficial charm. The second involves impulsive and antisocial traits such as irresponsibility, recklessness, and criminal behavior.
“Our study shows that these two different clusters of traits have different representations in the brain,” Dr. Michael Koenigs, associate professor of psychiatry at the UW School of Medicine and Public Health. “If these different brain characteristics reflect different underlying causes, then from a treatment standpoint it may be helpful to target these traits separately with different types of therapy.”
The first cluster — callous lack of empathy and shallow charm – is associated with reduced communication between the parts of the brain that control thoughts and behavior. The researchers found this reduced connectivity in three neural networks governing thoughts and behavior, but not in comparison networks that process hearing and seeing.
The second cluster, related to impulsive and violent behavior, showed up in the brain as increased connectivity in those same three networks.
“Psychopathy appears to be linked to deficient communication between the main information-processing hubs of the brain that ultimately control thoughts and behavior,” Koenigs explains “This is a more complex neuropsychological deficit than simply an inability to experience fear or anxiety, as others have proposed.”
The fMRI scans took place at a medium-security prison in Wisconsin and involved 46 psychopathic and 49 non-psychopathic inmates. Prisoners who volunteered for the study were graded for the two clusters of psychopathy symptoms on a standard psychiatric test. Consistently, those scoring higher on emotional and interpersonal traits such as callousness and egocentricity also had lower connectivity between the frontal and parietal regions of the brain. Those who scored higher for antisocial lifestyle traits such as impulsivity had higher connectivity between those regions.
While it seems counter-intuitive, Koenigs explains that the reason for these different (in some cases opposite) patterns of brain-behavior relationship is that researchers used a statistical technique that identifies brain connectivity that is uniquely related to either type of trait.
Dr. Carissa Philippi is lead author on the study and collaborators include psychiatry department colleagues Maia Pujara and Julian Motzkin; Professor Joseph Newman of the UW psychology department, and Dr. Kent Kiehl, professor of neuroscience, law and psychology at the University of New Mexico.
The study was supported by National Institutes of Health grants MH070539, DA026505, MH078980, MH087525, and MH090169.
University of Wisconsin School of Medicine and Public Health