The psychopaths They are self-centered individuals, who lack empathy (they are not capable of putting themselves in another’s place, nor of feeling sorry for the pain of others), and they have no feeling of guilt or remorse for their bad actions. We have seen them develop with ease as the protagonist of a thriller psychological or as a serial killer, but most are well integrated into society and do not usually commit crimes, except if they satisfy certain instincts or achieve their goals (money, power, living off their victims…). But many wonder what differentiates a psychopath from someone ‘normal’.
Psychopathy is not exactly a mental illness, but rather a widespread personality disorder, and although its causes are not exactly known at this time, a team of neuroscientists from the Nanyang Technological University of Singapore (NTU Singapore), the University of Pennsylvania and California State University, has found a biological difference between psychopaths and non-psychopaths.
Using magnetic resonance imaging (MRI) they discovered that a region of the forebrain known as the striatum it was on average 10% larger in psychopathic individuals compared to another group of control individuals who had little or no psychopathic traits.
The striatum is located in the forebrain and is responsible for coordinating many aspects of cognition, including motor and action planning, decision making, motivation, reinforcement, and reward perception. The new study, which has been published in Journal of Psychiatric Researchshows that there is a significant biological difference between people with psychopathic traits and those who do not.
The brains of psychopaths do not develop normally.
Not all psychopaths break the law, and not all criminals meet the criteria to be diagnosed with psychopathy, but there is a two-way relationship and there is evidence that psychopathy is associated with more violent behaviour. Understanding the role biology plays in antisocial and criminal behavior can help find treatment options.
“In addition to social environmental influences, there may be differences in biology, such as the size of brain structures, between antisocial and non-antisocial individuals”
The researchers scanned the brains of 120 people in the United States, whom they also interviewed using the Revised Psychopathy Checklist, a psychological assessment tool that determines the presence of psychopathic traits in people. The results linked having a larger striatum with a greater need for stimulation through emotions and a greater likelihood of impulsive behaviors.
Assistant Professor Olivia Choy, from NTU’s School of Social Sciences, a neurocriminologist and co-author of the study, explained: “The results of our study help advance our understanding of what underlies antisocial behavior such as psychopathy. We found that in addition to social environmental influences, it is important to consider that there may be differences in biology, in this case the size of brain structures, between antisocial and non-antisocial individuals.”
“Because biological traits, such as the size of the striatum, can be inherit from parents to childrenthese findings give additional support to the neurodevelopmental perspectives of psychopathy: that the brains of these criminals do not develop normally during childhood and adolescence,” says Professor Adrian Raine, from the Departments of Criminology, Psychiatry and Psychology at the University of Pennsylvania, co-author of the study.
In the study, the researchers examined 12 women and observed, for the first time, that psychopathy is also related to an enlarged striatum in women. Since the striatum typically gets smaller as the child matures, this finding suggests that psychopathy may be related to differences in the way the brain develops.
Adds Choy: “A better understanding of the development of the striatum is still needed. Many factors are likely involved in why one individual is more likely to have psychopathic traits than another individual. Psychopathy may be related to a structural abnormality in the brain that may be developmental in nature. At the same time, it is important to recognize that the environment can also have effects on the structure of the striatum.”
Professor Raine concludes: “We have always known that psychopaths go to great lengths to seek rewards, including criminal activities involving property, sex and drugs. We are now discovering a neurobiological basis for this impulsive and stimulant behavior in the form of enlargement of the striatum, a key brain area involved in rewards”.