Narcissistic traits are linked to a brain area governing emotional control

A recent study reveals that the physical structure of a specific brain region acts as a bridge between narcissistic personality traits and the habit of hiding one’s emotions. By looking at brain scans of healthy adults, researchers found that the volume and surface folding of the anterior insula correspond to both narcissistic tendencies and emotional suppression. The research was published in the Journal of Affective Disorders.

Narcissism is often thought of as a single personality flaw, but psychologists divide it into two main dimensions. Grandiose narcissism is characterized by an inflated sense of self-importance, a constant need for admiration, and a lack of empathy for others. Vulnerable narcissism is marked by fragile self-esteem, hypersensitivity to criticism, and social withdrawal. Both types share an underlying core of self-focus and difficulties with interpersonal relationships.

A common thread linking both grandiose and vulnerable traits is a struggle with emotion regulation. Emotion regulation refers to the mental strategies people use to manage how they feel and how they express those feelings to people around them. One strategy is cognitive reappraisal, which involves changing the way one thinks about a stressful situation to alter its emotional impact. This approach is generally seen as a protective factor against anxiety and mood disorders because it neutralizes a negative emotion before it fully takes hold.

Another strategy is expressive suppression. This involves actively hiding outward signs of an emotion, like keeping a straight face when feeling sad or angry. Expressive suppression requires constant mental effort because the emotion is already fully active in the body, which can drain cognitive resources over time. Previous research has linked both types of narcissism to a heavy reliance on expressive suppression.

Because people with high levels of narcissistic traits often struggle to process their emotions in healthy ways, researchers want to know how these behavioral patterns manifest in the physical structure of the brain. Lead author Lisa Schmidt and her colleagues at the Philipps-Universität Marburg in Germany designed a study to examine these interacting factors. They focused on a brain region called the anterior insula. Positioned deep within the cerebral cortex, the anterior insula acts as a sensory integration center for the brain.

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The anterior insula is intimately involved in processing physical sensations, emotional awareness, and empathy. It helps translate bodily signals into conscious feelings, allowing people to recognize when they are anxious, excited, or upset. Because self-awareness and empathy are frequent challenges for individuals with pronounced narcissistic traits, the anterior insula is a logical target for anatomical investigation.

Schmidt and her team recruited 172 healthy adults between the ages of 18 and 45. None of the participants had a history of psychiatric or neurological disorders. The choice to use a healthy cohort allowed the researchers to study normal variations in personality without the complicating factors of medication or severe mental illness.

Participants completed descriptive questionnaires to assess their personality and emotional habits. To measure narcissism, they took an assessment that evaluates both grandiose and vulnerable traits across multiple sub-categories, such as exploitative behavior, grandiose fantasies, and contingent self-esteem. To measure emotion regulation, they answered questions about how frequently they use cognitive reappraisal and expressive suppression in their daily lives.

The researchers then analyzed the participants’ brains using a high-resolution magnetic resonance imaging scanner. They utilized specialized software to measure different structural aspects of the anterior insula. These measurements included the overall volume of gray matter in the region as well as the degree of gyrification. Volume generally reflects the number of neurons and supportive cells in a specific location. Gyrification refers to the extent of folding on the brain’s surface, which allows a larger cortical surface area to fit inside the skull.

Brain folding happens early in human development. Because of this timeline, the degree of gyrification is often considered an indicator of how the brain formed during early life stages, rather than a trait that changes drastically day to day. To understand the connections between brain anatomy, emotion regulation, and narcissism, the team ran statistical mediation models.

A mediation model is a mathematical tool used to test whether a third variable helps explain the relationship between a starting point and an endpoint. Imagine three points forming a triangle. If point A is linked to point C, a mediation model tests if the path accurately passes from A, through B, to reach C. In this case, the researchers wanted to see if emotion regulation habits could explain the link between brain structure and narcissism, or vice versa.

The brain scans revealed a negative association between narcissistic traits and the size of the anterior insula. Individuals who scored higher on measures of both grandiose and vulnerable narcissism tended to have slightly smaller volumes in the right anterior insula. For vulnerable narcissism, this negative relationship also extended to the left anterior insula.

The mediation analysis added a layer of nuance to these negative anatomical correlations. The researchers found that the habit of expressive suppression statistically mediated the relationship between right anterior insula volume and narcissistic vulnerability. It also mediated the connection between the right insula’s surface folding and both grandiose and vulnerable traits.

The statistical models also worked in reverse. Narcissistic traits mediated the relationship between the volume of both the left and right anterior insula and the use of expressive suppression. This indicates a three-way dynamic where the tendency to hide emotions shapes the link between brain anatomy and personality, while personality simultaneously shapes the link between emotional habits and brain anatomy.

The study included exploratory analyses of the whole brain to see if other regions were involved. The researchers noted positive associations between specific sub-traits of narcissism and the folding of the anterior insula. They also observed changes in the cortical thickness of the precuneus, a brain area located in the parietal lobe toward the back of the head. The precuneus becomes highly active when people think about themselves, reflect on their past, or evaluate their own traits compared to others.

The researchers did not find expected associations in the prefrontal cortex. Other behavioral studies have sometimes linked narcissistic traits to this frontal area, which governs higher-level decision making and social behavior. The authors suggest this discrepancy might be due to the specific questionnaires used or the fact that previous studies often looked at simple sum scores rather than breaking narcissism down into diverse behavioral sub-traits.

There are a few limitations to keep in mind regarding these results. The study relied solely on self-reported questionnaires to gauge emotional habits and personality traits. While standard in psychological research, self-reports can sometimes be subject to personal biases or a lack of self-awareness, especially when answering questions about relationship habits.

The participants were relatively young and free from any psychiatric diagnoses. The authors note that the findings might not translate in the exact same ways to clinical populations, such as individuals formally diagnosed with a personality disorder. Expanding this research to include patients receiving psychiatric treatment could help scientists see if these anatomical patterns hold up in more extreme cases.

The concept of narcissism is complicated and heavily overlaps with other personality dimensions, such as negative emotionality and social dominance. Separating these overlapping factors is a consistent challenge in behavioral neuroscience. Future studies might benefit from gathering an even wider array of behavioral data to isolate the unique brain signatures of narcissistic traits.

These findings highlight the anterior insula as a convergence zone in the brain, where self-image, physical structure, and emotional habits meet. Understanding how this brain region manages emotional suppression could eventually help clinicians tailor therapeutic approaches. Addressing the underlying habit of hiding emotions might prove beneficial for individuals struggling with the personal and social costs of narcissistic behavior.

The study, “The interrelation of emotion regulation, anterior insula structure, and narcissistic traits,” was authored by Lisa Schmidt, Alejandra Dominguez-Ruiz, Tina Meller, and Igor Nenadić.