Symptoms and traits of borderline personality disorder may run in families: U of T research

According to a series of studies by researchers at the University of Toronto, family members of people with borderline personality disorder (BPD) show similarities in their brains and personalities – and even interpret some facial expressions in the same way.

“One of the most pressing questions I hear when speaking with family groups is whether the disorder can be passed from parents to their children,” says Anthony C.Ruocco, Professor, Acting Graduate Chair and Director of Clinical Education in the Department of Psychological Clinical Sciences at the University of Toronto at Scarborough.

“We are among the first researchers to investigate how factors in addition to symptoms and personality traits might operate in families with BPD.”

Borderline personality disorder is a personality disorder categorized in part by impulsivity and difficulty in emotional regulation. BPD studies tend to focus on people with the disorder, but Ruocco wanted to identify what social and biological factors beyond a BPD diagnosis were present in families. He says these features could offer clues to what causes the disorder to develop and what can prevent it.

Diagnoses other than borderline personality disorder observed in relatives

Ruocco discovered that symptoms of borderline personality disorder persist in families beyond those actually diagnosed with the disorder. For example, relatives show the same bias toward sad facial expressions, a pattern of weakness and strength in self-regulation skills, and distinct patterns of brain activation during impulse control.

Ruocco conducted his research at the Clinical Neuroscience Laboratory, where he serves as Director. It compared 103 people with BPD, 73 first-degree biological relatives (parents, siblings and children) and 99 people with no history of psychiatric illness. Participants completed a series of tests, including interviews, questionnaires, emotion perception tests, problem-solving tasks and brain scans. These results informed four articles published between 2019 and 2021.

It found that people with borderline personality disorder and those close to them had higher levels of depression and substance use disorders. Relatives also received similar psychiatric diagnoses and showed more personality traits associated with emotional dysregulation and impulsivity.

“Even if you don’t see the full diagnosis of borderline personality disorder commonly in first-degree relatives, even having a few of the symptoms can be quite disabling,” he says. “This research really shines a light on some of the mental health issues that many loved ones of people with BPD face.”

Families see fear in sad faces

Families of someone with BPD are prone to interpersonal conflict – and Ruocco wondered if facial expressions played a role. Several parents told her that they tried to show no emotion when their child with BPD was upset, but often received the response, “Why are you mad at me?”

It is well documented that people with BPD interpret facial expressions differently than those without, but Ruocco found that their loved ones too. When shown a sad expression, people with BPD and those close to them took longer to decode the emotion, and both were more likely to interpret it as fear.

“This model could suggest an increased sensitivity to threat cues in families with BPD, which could lead to arguments between family members, for example,” he says. “It’s important to understand what we can do to better align social-emotional communication to improve family functioning.”

Strengths and Weaknesses Found in Impulse Control

Another part of the study examined impulse control via brain imaging. Researchers measured oxygen levels in the frontal part of the brain when participants viewed images and were told to withhold responses for certain images.

People with borderline personality disorder activated their prefrontal cortex less than the control group without a psychiatric diagnosis, but relatives had more brain activity than both. This pattern could mean that relatives use more brain resources to control impulses, or that they use similar resources differently to regulate themselves.

Ruocco calls impulsivity “potentially the most dangerous symptom of borderline personality disorder.” Reckless driving, binge eating, overspending, and substance abuse are all examples of impulsivity. It is also associated with self-harm and suicide.

Ruocco’s latest article examined which cognitive abilities are associated with impulsivity and borderline personality disorder. These abilities are known as executive functions, which are the complex thinking skills used to identify goals and plan the steps to achieve them.

People with borderline personality disorder tend to struggle more with executive functions, and the researchers expected loved ones to show similar difficulties. But relatives who did not have a psychiatric illness showed both strengths and weaknesses. These parents had better impulse control and abstract thinking skills, although they also had less effective problem-solving skills. This matches the stories Ruocco heard from parents.

“People who have a child with BPD sometimes say to me, ‘We need to be able to regulate ourselves better to help regulate our child,'” he says. “These findings may also highlight forces of self-regulation that may protect relatives of people with BPD from developing psychiatric illness themselves.”

Funded by the Canadian Institutes of Health Research, Ruocco hopes his work can help validate the experiences of people with BPD and their families and inspire new directions for treatment.

“As we better understand these family factors, we can begin to incorporate these findings into treatments for families with BPD.”

About Roberto Frank

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