Brain abnormalities responsible for borderline personality disorder identified

December 24th, 2007 - 6:01 pm ICT by admin  

Washington , Dec 24 (ANI): A new study has led to the identification of abnormalities in the brain that are mainly responsible for borderline personality disorder in people.

Led by an interdisciplinary team of scientists at NewYork-Presbyterian Hospital/Weill Cornell Medical Center in New York City , the study discovered the activity in key brain areas associated with a core difficulty in patients with borderline personality disorder.

“It’s early days yet, but the work is pinpointing functional differences in the neurobiology of healthy people versus individuals with the disorder as they attempt to control their behavior in a negative emotional context, said Dr. David A. Silbersweig, one of the three lead researchers.

Such initial insights can help provide a foundation for better, more targeted therapies down the line, he added.

Borderline personality disorder is a devastating mental illness that causes infinite disturbance of patients’ lives and relationships. However, its fundamental biology is not very well understood.

The illness is characterized by impulsivity, emotional instability, interpersonal difficulties, and a preponderance of negative emotions such as angerall of which may lead to or be associated with substance abuse, self-destructive behaviours and even suicide.

“In this study, our collaborative team looked specifically at the nexus between negative emotions and impulsivitythe tendency of people with borderline personality disorder to ‘act out’ destructively in the presence of anger,” said Dr. Silbersweig.

“Other studies have looked at either negative emotional states or this type of behavioral disinhibition. The two are closely connected, and we wanted to find out why. We therefore focused our experiments on the interaction between negative emotional states and behavioral inhibition, he added.

It was possible to detect the brain areas of interest with greater sensitivity if not for the advanced brain-scanning technologies developed by the research team.

“Previous work by our group and others had suggested that an area at the base of the brain within the ventromedial prefrontal cortex was key to people’s ability to restrain behaviours in the presence of emotion,” explained Dr. Silbersweig.

However, tracking activity in this brain region was unfortunately very difficult using functional MRI (fMRI).

“Due to its particular location, you get a lot of signal loss,” said the researcher.

However, the Weill Cornell team used a special fMRI activation probe that was developed to eliminate that interference. This facilitated the study, including 16 patients with borderline personality disorder and 14 healthy controls.

A tailored fMRI neuropsychological approach was also followed to observe activity in the subjects’ ventromedial prefrontal cortex as they performed what behavioural neuroscience researchers call “go/no go” tests.

The rapid-fire tests required participants to press or withhold from pressing a button whenever they receive particular visual cues.

In order to reveal how negative emotions affect the participants’ ability to perform the task, the researchers gave a twist in the usual approach. Thus, performance of the task with negative words (related to borderline psychology) was contrasted with the performance of the task when using neutral words, to reveal.

The results were obvious as the negative emotional words caused participants with borderline personality disorder to have more difficulty with the task at hand, and act more impulsively, ignoring visual cues to stop as they repeatedly pressed the button.

However, what showed up on fMRI was really interesting.

“We confirmed that discrete parts of the ventromedial prefrontal cortexthe subgenual anterior cingulate cortex and the medial orbitofrontal cortex areaswere relatively less active in patients versus controls,” said Dr. Silbersweig.

“These areas are thought to be key to facilitating behavioral inhibition under emotional circumstances, so if they are underperforming that could contribute to the disinhibition one so often sees with borderline personality disorder, he added.

Simultaneously, the researchers observed heightened levels of activation during the tests in other areas of the patients’ brains, including the amygdala, a locus for emotions such as anger and fear, and some of the brain’s other limbic regions, which are linked to emotional processing.

“In the frontal region and the amygdala, the degree to which the brain aberrations occurred was closely correlated to the degree with which patients with borderline personality disorder had clinical difficulty controlling their behavior, or had difficulty with negative emotion, respectively,” indicated Dr. Silbersweig.

The study shed light not only on borderline personality disorder, but also on the mechanisms followed by healthy individuals to curb their tempers in the face of strong emotion.

The findings are featured in this month’s issue of the American Journal of Psychiatry. (ANI)

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