Researchers have found that people with narcissistic personality disorder have less gray matter in the left anterior insula, a region of the brain linked to empathy.

Narcissistic personality disorder is a mental disorder in which the sufferers have an inflated sense of their own importance and a lack of empathy. They generally suffer from low self-esteem and feelings of inferiority, but have displays of arrogance and vanity.

For the study, researchers used magnetic resonance imaging (MRI) to scan the brains of 34 participants, including 17 individuals who suffer from narcissistic personality disorder, and found that pathological narcissists have less gray matter in a part of the cerebral cortex called the left anterior insula.

Gray matter mainly consists of neuron cell bodies and non-neuron brain cells that provide nutrients and energy to neurons, rather than sending and receiving information.

One of the hallmark traits of pathological narcissists is their clear lack of empathy, said Stefan Röpke, M.D., a professor in the department of psychiatry at the Charité – Universitätsmedizin Berlin in Germany. Patients with this disorder are able to recognize what others feel and think, but outwardly show little compassion.

The left anterior insula region of the brain, generally thought to be involved with cognitive functioning and the regulation of emotion, has also been tied to compassion and empathy.

“This was already a region of interest for empathy, but for the first time, we were able to show that it is structurally correlated in the brain,” sid Röpke.

The researchers discovered that the degree to which a person was able to exhibit empathy was tied to the amount of gray matter in the brain, both in the healthy individuals as well as in those with narcissistic personality disorder.

The findings suggest that regardless of personality disorders, the left anterior insula plays an important role in feeling and expressing compassion, Röpke said.

“These results are important because they stick very well with our theories of narcissistic personality disorder,” Röpke said.

In future studies, the researchers are going to investigate how the volume of gray matter in the cerebral cortex affects the exchange between various regions of the brain. This time they will use functional magnetic resonance imaging to study the functions of the left anterior insula and how the brain’s various networks differ in patients with the disorder.

“It’s not just one region or brain location that is responsible for empathy,” Röpke said. “We want to understand how this region works, and what happens when it doesn’t function well.”

Source: Journal of Psychiatric Research

Person getting an MRI photo by shutterstock.