U. CHICAGO (US) — Psychopaths show less activity in areas of the brain linked to empathy when they view images of people in distress, a study shows.
Psychopathy affects approximately 1 percent of the United States general population and 20 percent to 30 percent of the male and female US prison population. Relative to non-psychopathic criminals, psychopaths are responsible for a disproportionate amount of repetitive crime and violence in society.
“A marked lack of empathy is a hallmark characteristic of individuals with psychopathy,” says Jean Decety, professor in psychology and psychiatry at the University of Chicago. “This is the first time that neural processes associated with empathic processing have been directly examined in individuals with psychopathy, especially in response to the perception of other people in pain or distress.”
Decety and colleagues believe the findings, published in JAMA Psychiatry, could help clinical psychologists design better treatment programs for psychopaths.
For the study, researchers tested 80 prisoners between ages 18 and 50 at a correctional facility. The men volunteered for the test and were tested for levels of psychopathy using standard measures. They were then studied with functional MRI technology, to determine their responses to a series of scenarios depicting people being intentionally hurt. They were also tested on their responses to seeing short videos of facial expressions showing pain.
Participants in the high psychopathy group exhibited significantly less activation in the ventromedial prefrontal cortex, lateral orbitofrontal cortex, amygdala, and periaqueductal gray parts of the brain, but more activity in the striatum and the insula when compared to control participants.
The high response in the insula in psychopaths was an unexpected finding, as this region is critically involved in emotion and somatic resonance. Conversely, the diminished response in the ventromedial prefrontal cortex and amygdala is consistent with the affective neuroscience literature on psychopathy.
This latter region is important for monitoring ongoing behavior, estimating consequences, and incorporating emotional learning into moral decision-making, and plays a fundamental role in empathic concern and valuing the well-being of others.
“The neural response to distress of others such as pain is thought to reflect an aversive response in the observer that may act as a trigger to inhibit aggression or prompt motivation to help,” the authors write in the paper.
“Hence, examining the neural response of individuals with psychopathy as they view others being harmed or expressing pain is an effective probe into the neural processes underlying affective and empathy deficits in psychopathy.”
Researchers from the University of New Mexico contributed to the study, which was supported by the National Institute of Mental Health.
Source: University of Chicago