An estimated 9% of Americans have a personality disorder, like narcissistic personality disorder, borderline personality disorder, or avoidant personality disorder.
According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, there are 10 personality disorders, which primarily affect a person's sense of self, identity, and relationships.
A person may develop a personality disorder as a coping mechanism for extreme or excessive abuse, abandonment, ridicule, neglect, or other childhood trauma, Anthony Smith, a licensed mental-health counselor with 17 years of experience diagnosing mental-health conditions in the Massachusetts court system, told Insider. Genes can also play a role.
For example, someone with borderline personality disorder may have experienced significant abandonment as a child, like if their parent went to prison for life or consistently failed to provide emotional support. As a result, they internalize the belief that everyone will leave them and, when triggered, act based on that overriding fear, Smith previously told Insider.
In the DSM-5, each of the 10 personality disorders fall under one of three "clusters" because people with them may have similar behaviors, ways of thinking, or predispositions of other mental-health problems, Smith said.
People in cluster A tend to exhibit semipsychotic and anxiety-driven behaviors, while those in cluster B may struggle more with anxiety and mood disorders (like bipolar disorder), impulse-control conditions, eating disorders, and substance abuse, according to Smith. Those in cluster C are also prone to anxiety, depression, and substance abuse.
Only licensed mental-health professionals can diagnose someone with a personality disorder. Experts may start to notice traits and behaviors that could signal a personality disorder when a person is in their teens, but most people aren't diagnosed until adulthood.
Since personality disorders tend to stem from early-in-life relational trauma, people who are diagnosed with one may also be diagnosed with another or exhibit overlapping traits, Smith said. Researchers are still studying the causes of personality disorders and don't have definitive answers.
Causes could include consistent neglect, abuse, or ridicule from a caretaker, being raised by someone who lacks boundaries and accountability or is overindulgent, or being raised by someone who doesn't prioritize relationships. With cluster A disorders, a family history of psychotic disorders could have an effect.
Smith added that personality disorder traits may manifest differently in men versus women.
Here are the potential behaviors, traits, and causes of the 10 personality disorders the DSM-5 recognizes.
