How Common Is Borderline Personality Disorder?

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Borderline personality disorder (BPD) is much more common than you might imagine. A recent study on the prevalence of mental health disorders in the U.S. found that about 1.6% of the population has BPD. While that number may sound small, that means that there are more than four million people with BPD in the U.S. alone. Although many people have never heard of BPD, it is actually more common than many well-known disorders, such as schizophrenia.

There is a large difference in the prevalence of BPD in women versus men; women are much more likely to be diagnosed with BPD. In fact, about 75% of those diagnosed with BPD in the U.S. are women. However, it is not known whether women are actually more prone to develop BPD or whether this is due to gender biases in the diagnosis of BPD. For example, it may be that men with the symptoms of BPD are just more likely to be misdiagnosed with other conditions like post-traumatic stress disorder or major depressive disorder.

Misdiagnosis as Bipolar Disorder

In addition, that 1.6% statistic may not be accurate because many people with BPD have not yet been diagnosed or they have been misdiagnosed. In one study from Brown University, more than 40% of those with BPD had originally been misdiagnosed as having bipolar disorder. One hypothesis for this issue is that bipolar disorder is more easily treated through medication, so it is more commonly diagnosed so that symptoms can be quickly managed with a prescription.

Misdiagnosis can be a serious problem, as no medications have been approved by the Food and Drug Administration (FDA) for BPD. Medications for bipolar disorder are often ineffective in treating BPD.

BPD patients who have been misdiagnosed may then be exposed to dangerous side effects from their prescriptions. Some patients have reported issues with endocrine and cardiac problems after taking these prescriptions.

While bipolar disorder and borderline personality disorder may share some symptoms, they are very different diseases. Bipolar disorder can cause severe depression or mood swings, but in between episodes, those with this condition are able to function normally. Those with BPD may have a more chronic condition that can cause self-harming behaviors or suicidal tendencies.

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

When a bipolar disorder patient is rapidly cycling, they can exhibit destructive or harmful behaviors very similar to BPD. Misdiagnosis is extremely common during these phases.

Another fact that makes defining the two more difficult is that some people can actually have both diseases. About 20% of those with borderline personality disorder have been found to have bipolar disorder as well.

Finally, other patients with BPD go undiagnosed because they refuse to seek treatment. Whether they feel they don't need help or that counseling will be useless, many people go without therapy and struggle with BPD on their own.

With these issues in mind, it is likely that the number of people with borderline personality disorder is much higher than 1.6%, but that is the only number researchers have been able to find evidence to support.

3 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Chapman J, Jamil RT, Fleisher C. Borderline Personality Disorder. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing.

  2. Ruggero CJ, Zimmerman M, Chelminski I, Young D. Borderline personality disorder and the misdiagnosis of bipolar disorder. J Psychiatr Res. 2010;44(6):405-8. doi:10.1016/j.jpsychires.2009.09.011

  3. Zimmerman M, Morgan TA. The relationship between borderline personality disorder and bipolar disorder. Dialogues Clin Neurosci. 2013;15(2):155-69.

Additional Reading

By Kristalyn Salters-Pedneault, PhD
 Kristalyn Salters-Pedneault, PhD, is a clinical psychologist and associate professor of psychology at Eastern Connecticut State University.