Neural paths for borderline personality disorder

People prone to stormy social lives display brain activity that may prompt oversensitivity to emotion and an inability to resolve conflicting information

People diagnosed with the mental ailment known as borderline personality disorder hemorrhage emotion. Real or perceived rejections, losses or even minor slights trigger depression and other volatile reactions that can lead to suicide.

New brain-imaging research suggests that in people with borderline personality disorder, specific neural circuits foster extreme emotional oversensitivity and an inability to conceive of other people as having both positive and negative qualities.

Psychiatrist Harold Koenigsberg of Mount Sinai School of Medicine in New York City described his team’s results January 17 in New York City at the winter meeting of the American Psychoanalytic Association.

“I suspect that in social situations, people with this disorder activate the brain in unique ways,” Koenigsberg says.

Koenigsberg’s findings unveil brain networks that may underlie the “faulty brakes” that borderline personality patients attempt to apply to their emotional reactions, remarks psychiatrist John Oldham of Baylor College of Medicine in Houston. It’s not yet clear whether the types of brain activity observed in the new study also occur in any of a handful of other personality disorders, Oldham adds.

Borderline personality disorder affects one in five psychiatric patients. It most frequently affects women, especially those who are also depressed, and men who also display violent and criminal tendencies classed as antisocial personality disorder. About one in 10 people with borderline personality disorder commit suicide. This condition is extremely difficult to treat, Koenigsberg notes.

His group first tested 19 adults diagnosed with borderline personality disorder and 17 others who had no serious psychiatric conditions. Participants reclined in a functional MRI scanner as they viewed five pleasant images — such as a laughing man playing with two children — and five disturbing images, including a scowling man assaulting a young woman. Each image appeared for six seconds.

Compared with emotionally healthy volunteers, borderline personality disorder patients displayed markedly heightened blood flow — a marker of neural activity — in the brain’s chief visual area as well as in the amygdala, a key structure in emotion regulation. Visual and emotional areas are closely connected in the brain.

This finding fits with earlier evidence that borderline personality disorder patients detect brief emotional expressions on others’ faces that, typically, emotionally healthy people do not notice. “Borderline patients may have a visual system that lets them see others’ facial emotions through a high-powered lens,” Koenigsberg says.

In a second functional MRI experiment, the researchers asked 18 borderline personality disorder patients and 16 emotionally healthy volunteers to view a series of emotionally neutral images and disturbing images. On some trials, participants were asked to simply look at the images; on others, participants tried to assume the role of a detached observer.

As detached observers of disturbing scenes, emotionally healthy participants displayed pronounced activity in brain areas that have been implicated in regulating attention and in resolving internal conflicts between competing impulses or choices. Borderline personality disorder patients showed almost no activity in those brain regions when trying to take a detached perspective.

Most people have an important capacity for resolving conflict: the ability to perceive both favorable and negative aspects of the same person. Lacking this skill, borderline patients find it easier to veer back and forth between regarding those they know as either wonderful or awful, Koenigsberg suggests.

His findings follow another team’s 2008 report that borderline patients, compared with healthy volunteers, fail to recognize when unfair transactions take place in an economic cooperation game and lack neural reactions in an area linked to trusting others.

“We can’t say to what extent brain changes in borderline personality disorder are inherited or acquired,” Koenigsberg says. Some genetic variants promote depression only in those who experience childhood abuse or trauma, a pattern that may also apply to borderline personality disorder, he hypothesizes. Borderline patients often report having endured childhood physical or sexual abuse.

Koenigsberg’s team is now repeating its functional MRI experiments with avoidant personality disorder patients, people who feel highly anxious around others and avoid personal contact.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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