4 defining traits of borderline personality disorder, according to an expert

• Borderline personality disorder is an often stigmatized and misunderstood condition.
• The disorder can develop as a coping mechanism when a child is severely abandoned physically or emotionally.

An estimated 1.6% of Americans live with borderline personality disorder, a condition where a person acts out when they know, or wrongly believe, someone is going to emotionally or physically abandon them.

It's a largely misunderstood condition because it's less talked about than other personality disorders, like narcissistic personality disorder, Anthony Smith, a licensed mental health counselor with 17 years of experience diagnosing mental health conditions in the Massachusetts court system, told Insider.

Media portrayals of borderline personality disorder, like Glen Close's character Alex in "Fatal Attraction," also add to stigma and misunderstandings of the condition, he said.

Smith said all personality disorders stem from a child's upbringing and their early-in-life relationships, and genes can also play a factor. With borderline personality disorder, someone who experienced significant abandonment — like the child of a parent who went to prison for life, or one whose parent consistently failed to provide emotional support — learns to believe everyone will leave them.

"So they developed this sensitivity to abandonment and rejection and go through life trying to make sure that doesn't happen to them again," Smith said.

He added that people with borderline personality disorder often tell themselves, "I'm not good enough. If I was good enough, this thing wouldn't have happened to me, and Dad would still be here," to rationalize the pain as a child.

As an adult, these subconscious stories stick with them and affect their relationships, according to Smith.

Only a healthcare provider can diagnose someone with BPD, but behaviors like pushing away close relationships and uncontrollable outbursts could be signs.

They crave close relationships, yet seem to push them away

People with borderline personality disorder often find themselves in a push-pull dynamic in their relationships, whether platonic or romantic, Smith said.

If they think they're going to be abandoned, whether there's evidence of it or not, they'll switch to viewing someone they care for deeply as a "villain."

Smith gave the example of a person with borderline personality disorder who agreed she and her partner take turns calling each other on the phone each night at 8 PM. One night, her partner doesn't call, and she watches the clock anxiously. Moments later, she's likely thinking her partner is cheating on her and going to leave forever, even if he tells her he just forgot, said Smith.

As a result, they'll become irritated to the point they'll spread rumors about their partner or verbally abuse them. A few days later, they could apologize for their actions, but the damage is often already done and the relationship is over, said Smith.

They have uncontrollable angry outbursts when triggered

People with borderline personality disorder also have trouble controlling their anger, according to Smith.

He said people with the condition are so sensitive to rejection that they use anger to protect them from what they really feel, which is a fear of abandonment.

They have trouble seeing nuance, and look at people as "saviors" and "villains"

When it comes to relationships, people with condition either view those close to them as "saviors" or "villains," Smith said.

If someone with borderline personality disorder feels like a friend crossed them, and they have the means, they could go to extremes like filing lawsuits, telling lies about you at work, or getting you kicked off the school board, Smith said.

According to Smith, consistent and long-term therapy as well as relationships with people who set boundaries in a firm yet compassionate way can help people with borderline personality disorder reframe their mindsets and control their behaviors.

They have a tendency to self-medicate, self-harm, or emotionally eat

People with borderline personality disorder often first seek help for addiction problems they have as a result of the condition, which ultimately leads to their BPD diagnosis, Smith said.

Since people with borderline personality disorder often find themselves in cycles of negative self-talk, it can perpetuate behaviors like drinking too much alcohol, drug abuse, self-harm, emotional eating, and depression, according to Smith.

"That said, they usually don't enter treatment because they recognize, 'I have a fear of abandonment/rejection that engenders a vexing, tumultuous interpersonal style that creates problems for myself and others,'" Smith said.