We all probably indulge in selfies at some point – but then there are the people whose Facebook feeds are full of them. To call these people narcissistic would be accurate. To call them narcissists may or may not be correct, depending on how much their behavior affects their relationships.

Narcissistic personality disorder is one of 11 classifiable personality disorders, with conditions characterized by problematic chronic behaviors, emotions and thoughts. The personality disorders include antisocial, avoidant, borderline, dependent, histrionic, narcissistic, obsessive-compulsive, paranoid, schizoid, schizotypal and dissociative identity. One telltale sign of a personality disorder is that “the person really has a difficult time getting along in the world and with other people,” says John Grohol, a Boston psychologist and the founder and CEO of Psych Central, a website providing mental health resources.

“Everyone has a unique personality, and we all have moments where we might not be at our most adaptive,” adds Mark Lenzenweger, a professor at both Weill Cornell Medical College and the State University of New York at Binghamton. But those with personality disorders have “just enough deviation to impair their ability to function” in social or occupational settings. An estimated 10 percent of the American population has a personality disorder.

At the same time, this spectrum of disorders wasn't formally recognized in the clinical world until relatively recently, which meant people with them often fell through the cracks and didn't receive proper treatment. It wasn’t until the 1980s, when the American Psychiatric Society revised its manual, that a number of the disorders were formally recognized with explicit diagnostic criteria to guide physicians, Lenzenweger says.

Before that, in the 1940s and 50s, people with these disorders fell somewhere between a diagnosis of psychosis, which is characterized by distortions of reality, and neurosis, which is now better known as mild depression and anxiety, Lenzenweger continues.

“For decades, what we knew was that standard treatments were not effective. Traditional psychoanalytic methods did not work with personality disorders, and clinical behavioral therapy did not work,” he adds. “In the ensuing 30 years, new treatments were developed, tested and scientifically investigated.”

Nature vs. Nurture

Just as you inherit part of your personality from your parents, personality disorders are also partly inheritable. “The level of genetic input isn’t going to be as high as for schizophrenia or bipolar,” Lenzenweger says, adding that the environment also plays a role. That can include traumatic experiences or abuse, “but there are plenty of people who do not have that in their history,” he adds.

Culture is another factor to consider when diagnosing someone with a personality disorder, he continues. While in some cultures, stealing an apple from a neighbor’s apple tree might merely merit a slap on the wrist, in others it’s a major transgression of criminal proportions that could label a person with antisocial disorder.

Schizotypal personality disorder is characterized by superstitions, bodily illusions, lack of friends or blunted emotions. Again, in some cultures, these symptoms might be part of cultural beliefs, say in spirits, rather than symptomatic of a disorder, Lenzenweger says. “If that’s culturally sanctioned, that’s not necessarily going to be viewed as pathological. Make sure you are evaluating where this person’s belief falls vis-à-vis the culture.”

As with many psychiatric conditions, family or friends are often behind a patient’s decision to seek help. Lenzenweger recalls patients who have told him things like: “‘My boss said if I don’t get some help, I will lose my job,’” he says. Other patients come of their own accord: after their third marriage just broke up, or relationship problems were clearly recurring.

Although personality disorders typically emerge by late adolescence or adulthood, they're often not diagnosed until people are well into adulthood. “This is behavior that goes on for years and years and years,” Grohol says, adding that kids are usually not diagnosed because their brains are still developing.

Common Disorders

Two of the most prevalent disorders are borderline personality disorder and antisocial disorder. People with borderline personality disorder are usually very impulsive and have intense mood swings. They also engage in self-harming behavior, with 10 percent committing suicide. The good news is that in the past 15 years, a number of treatments have emerged for this disorder, Lenzenweger says. They include dialectical behavioral therapy, which focuses on mindfulness and building behavioral skills, and transference-focused psychotherapy, which involves biweekly psychotherapy sessions that focus on getting patients to overcome the misunderstandings arising from their tendency to sense that their own negative feelings are coming from others.​ “Our view is much more optimistic today. People can be treated and get better,” Lenzenweger says, adding that similar things can be said about narcissistic personality disorder.

Men and women suffer equally from borderline personality disorder, but antisocial disorder, which is commonly known as sociopathy and characterized by deceit and disrespect of others' feelings and rights, is more common in men. ​

Tom Widiger, ​a psychology professor at the University of Kentucky, recalls a patient with narcissistic disorder who recently came in because of relationship problems. The person was arrogant and lacked empathy. At first, Widiger had to help the person realize that “the problem was more within them … that took a year for them to realize,” he says.

A patient’s recognition of the disorder is the first step and sometimes the bulk of a treatment plan, Grohol says. And studies have shown that people can get better, Lezenweger adds. “Thirty or 40 years ago, there was a perception that these were set in stone, but we now know that’s not true. These conditions show a certain amount of plasticity,” he says. And while “there’s no pill for a person with a personality disorder, the psychological treatments are working.”

This is a good thing, not least because of a certain stigma attached to personality disorders. Unlike anxiety or depression, which might be momentary occurrences that just happen to people during “a discrete period of life,” Widiger says, personality disorders “describe their entire sense of self,” he adds. “[A personality disorder] is really saying that the way you are is itself a disorder.”