Link between brain structure and personality disorders revealed

“Understanding how personality is based in the brain is important both for insights into personality disorders and for conditions in which personality may confer vulnerability, such as anxiety disorders,” commented Dr Scott Rauch, director of the psychiatric neuroscience research division at Massachusetts General Hospital (MGH) and co-lead author of the paper.

In a follow-up to earlier findings that an area of the brain called the medial orbitofrontal cortex (mOFC) appears thicker in those who can better control their emotional response to unpleasant memories, the investigators found that study participants who exhibited better fear inhibition also score higher in measures of extraversion – an energetic, outgoing personality.

Combining the results of the personality tests with the previously reported data revealed that both improved extinction retention and a thicker mOFC were associated with higher levels of extraversion and lower neuroticism.

Most individuals initially respond with physical and emotional distress to situations that bring back memories of traumatic events, but such responses usually diminish over time, as the situations are repeated without unpleasant occurrences. The ability to suppress those negative responses is called “extinction memory,” and its deficiency may lead to anxiety disorders such as post-traumatic stress disorder.