Nearly one in five violent offenders exhibits the traits of a psychopath, a personality disorder characterized by a lack of empathy, no remorse, manipulative behavior, and extreme selfishness. A new MRI study explains a possible reason why a psychopath might fail to benefit from a rehabilitation program. Psychopathic violent offenders have abnormalities in the parts of the brain related to learning from punishment, say a research duo hailing from Montreal and London.

“Psychopathic offenders are different from regular criminals in many ways,” Dr. Nigel Blackwood, who is affiliated with King's College London, said in a release. “Regular criminals are hyper-responsive to threat, quick-tempered, and aggressive, while psychopaths have a very low response to threats, are cold, and their aggression is premeditated.”

Combined with past research, evidence from Blackwood’s current study shows that both types of offenders have abnormal brain development beginning at a young age. However, each is distinctive.

Alike, Yet Radically Different 

Most of us learn from punishment. We learn from the imagined punishment, say, of having to recover in a hospital bed, to never step in front of moving cars and we learn from the real punishments in our past (delivered by our parents or a teacher) to never hit people for no reason. Yet some people have a long history of being punished — by parents, teachers, and the legal system — yet they persist in their anti-social, sometimes violent behavior. Could it be they simply cannot learn from punishment the way others do?

To investigate this possibility, Blackwood and Dr. Sheilagh Hodgins of the University of Montreal used MRI scans to study brain structure and function in three separate groups: 12 violent offenders with antisocial personality disorder and psychopathy, 20 violent offenders with antisocial personality disorder but not psychopathy, and 18 healthy non-offender volunteers. The researchers recruited all the offenders, who had been convicted of murder, rape, attempted murder, and grievous bodily harm, from Britain's probation service.

Once inside a brain scanner, participants completed a task that assessed their ability to adjust their behavior. They played an image matching game, where points were awarded for correctly pairing images. After a certain time period, though, the game shifts and points are no longer awarded for correct pairs. And here, the violent offenders separated themselves from the healthy volunteers.

The violent offenders "failed to learn from punishment cues, to change their behavior in the face of changing contingencies, and made poorer quality decisions despite longer periods of deliberation," Blackwood said. The brain scans told a similar if more precise story.

The researchers saw structural abnormalities "in both gray matter and specific white matter fiber tracts among the violent offenders with psychopathy," Hodgins explained. Gray matter is mostly involved with processing information and cognition, while white matter coordinates the flow of information between regions of the brain.

While the violent offenders without psychopathy showed similar brain function as the non-offenders, the violent offenders with psychopathy, by contrast, displayed abnormal activity.

Gray 

"We observed reductions in gray matter volumes bilaterally in the anterior rostral prefrontal cortex and temporal poles relative to the other offenders and to the non-offenders," Hodgins said. These brain regions are involved in empathy, the processing of pro-social emotions such as guilt and embarrassment, and moral reasoning. "Abnormalities were also found in white matter fiber tracts in the dorsal cingulum, linking the posterior cingulate cortex to the medial prefrontal cortex," Blackwood added. Such abnormalities have been linked to a lack of empathy yet these same regions are known to be involved in learning from rewards and punishment.

"These results suggest the violent offenders with psychopathy are characterized by a distinctive organization of the brain network that is used to learn from punishment and from rewards,” Blackwood explained.

The study offers valuable insight that may help other researchers design programs for children showing recognizable patterns of aggression. "Since most violent crimes are committed by men who display conduct problems from a young age, learning-based interventions that target the specific brain mechanisms underlying this behavior pattern... would significantly reduce violent crime," Hodgins noted.

Source: Gregory S, Blair RJ, ffytche D, et al. Punishment and the psychopath: an fMRI investigation of reinforcement learning in violent antisocial personality disordered men. Lancet Psychiatry. 2015.