Roughly 1 in 10 people has a personality disorder. A global meta-analysis published in The British Journal of Psychiatry estimated the worldwide prevalence at about 7.8% of the general population, while U.S. data from the National Institute of Mental Health puts the figure higher, at 9.1% of American adults. That translates to tens of millions of people in the United States alone.
Global Prevalence by Cluster
Personality disorders are grouped into three clusters based on shared traits. Cluster C disorders, characterized by anxious or fearful thinking patterns, are the most common worldwide at about 5.0%. Cluster A disorders, marked by unusual or eccentric behavior, affect roughly 3.8% of the population. Cluster B disorders, which involve dramatic or erratic behavior, come in at around 2.8%. These numbers add up to more than the overall prevalence because some people meet criteria for disorders in more than one cluster.
The most common individual personality disorder globally is obsessive-compulsive personality disorder, at 3.2%. (This is distinct from OCD, the anxiety condition.) Avoidant personality disorder follows at 2.7%, and paranoid personality disorder at 2.3%. On the other end, histrionic (0.6%), dependent (0.8%), and schizotypal (0.8%) personality disorders are relatively rare.
Prevalence in the United States
The most widely cited U.S. figure comes from the National Comorbidity Survey Replication, which found a 9.1% prevalence for any personality disorder among adults aged 18 and older. That survey collected data from 2001 to 2003, and no comparably large national survey has replaced it since. Borderline personality disorder, one of the most studied types, showed a prevalence of 1.4% in that same dataset.
A separate large U.S. study, the National Epidemiologic Survey on Alcohol and Related Conditions, produced noticeably different numbers for certain disorders. It estimated histrionic personality disorder at 1.8% and narcissistic personality disorder at 6.2%, figures far higher than what other surveys have found. These discrepancies highlight how sensitive prevalence estimates are to the specific interview methods and diagnostic criteria researchers use.
Gender Differences
Some personality disorders show stark differences between men and women. Antisocial personality disorder is diagnosed far more often in men. The Epidemiological Catchment Area survey found that 2% to 4% of men met criteria, compared with 0.5% to 1% of women. The National Comorbidity Study reported an even wider gap: 5.8% of men versus 1.2% of women. Borderline and histrionic personality disorders, by contrast, are diagnosed more frequently in women, though some researchers argue this partly reflects diagnostic bias rather than true differences in prevalence.
Why the Numbers Vary So Much
If you’ve seen different prevalence figures in different places, that’s normal. Personality disorder estimates are unusually sensitive to how the assessment is done. Structured clinical interviews tend to produce different rates than self-report questionnaires. The diagnostic manual matters too. Studies using DSM criteria and those using ICD criteria can arrive at different numbers for the same population.
The international diagnostic system recently underwent a major overhaul. The ICD-11, adopted by the World Health Organization, eliminated all the traditional personality disorder categories. Instead of diagnosing someone with, say, narcissistic or avoidant personality disorder, clinicians using ICD-11 assign a single diagnosis of “personality disorder” and rate it as mild, moderate, or severe. They then describe the person’s traits along five dimensions: negative emotionality, detachment, dissociality, disinhibition, and rigidity. The only legacy category that survived in any form is borderline personality disorder, preserved as an optional “borderline pattern qualifier.” This shift toward a spectrum model will likely change how prevalence is reported in future research, making direct comparisons with older studies more difficult.
Co-occurring Conditions
Personality disorders rarely exist in isolation. People who have one frequently meet criteria for at least one other mental health condition, most commonly depression, anxiety disorders, or substance use problems. This overlap is part of what makes diagnosis complicated. Someone might seek help for depression and never be assessed for an underlying personality disorder, or their personality disorder symptoms might be attributed entirely to another condition. The high rate of co-occurrence also means that effective treatment often needs to address more than one problem at a time.
The Gap Between Prevalence and Diagnosis
The 7 to 10% prevalence figures come from structured research interviews, not from clinical records. In everyday medical practice, personality disorders are diagnosed far less often. Many people with these patterns never seek mental health treatment, or they seek treatment for something else (like anxiety or relationship problems) without the underlying personality disorder being identified. Some clinicians are reluctant to give the diagnosis because of the stigma attached to it, particularly for borderline and antisocial personality disorders. Others lack training in the specific assessment tools needed to make the diagnosis reliably.
This means the actual number of people living with a personality disorder is almost certainly higher than the number who carry a formal diagnosis. The research data suggests that in any group of 100 adults, somewhere between 8 and 10 have a personality disorder, whether or not they know it.