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Written by:Jill E. Daino, LCSW-R

Published On: June 22, 2022

Medically reviewed by: Meaghan Rice, PsyD., LPC

Reviewed On: June 22, 2022

Updated On: July 5, 2023


Borderline personality disorder (BPD) is a severe mental health condition that falls into the category of a personality disorder. BPD is characterized by significant self-esteem issues and difficulty managing emotions.

The causes of borderline personality disorder are not fully understood. That said, it’s widely accepted that a number of factors, including genetics or traumatic life events, play a huge part in whether or not someone might end up with a BPD diagnosis.

While we have learned a lot about BPD, there’s still much more for us to discover about what causes borderline personality disorder.

Read on to learn what we know and understand so far, so you can have a better understanding of this common condition that affects an estimated 1.4% of the adult population in the United States.

What Research Says About BPD Causes

Studies on genetics

When researching what causes borderline personality disorder, scientists have found a strong link between BPD and genetics. A study with monozygotic twins (commonly known as identical twins) supports a genetic link to BPD. In this study of 92 pairs of identical twins, 35% were diagnosed with BPD.

There are numerous other explorations of genetic borderline personality disorder causes, although no specific genes have yet been identified as causing BPD.

Studies on the brain

In addition to genetics, many borderline personality disorder symptoms have been linked to abnormalities in the frontolimbic networks of the brain. These networks are the parts of the brain that are vital in promoting goal-directed behavior. In part, they support resistance to emotional distraction. Neuroimaging research lends to a theory that a dysfunctional frontolimbic network is possibly part of what causes BPD.

Another study found that those with BPD have a smaller hippocampus. Smaller volumes are associated with higher trauma-related clinical symptoms. So, it’s definitely possible that a smaller hippocampus is one of the causes of borderline personality disorder.

Studies on childhood trauma

Childhood trauma and abuse are known risk factors for developing borderline personality disorder in teens and young adults because cranial trauma received during childhood may result in lasting brain function abnormalities that could result in borderline personality disorder symptoms. Unfortunately, it does seem that neglect and/or child abuse is likely one of the potential BPD causes.

Some research has been done using a non-invasive testing approach called ERPs (Event-Related Potentials), offering hope that they might help us make diagnoses. ERPs work by measuring electrical brain activity related to cognitive and sensory events.

Through this research, scientists found that P3 (considered an index of attention) is slightly delayed in some people with BPD. They also found that there was a P3 profile similar to younger patients, showing a failure of maturation that may be a factor in the lack of development of a sense of self common in some people who have BPD.

“While there’s no one cause for BPD, it’s important to understand that BPD has many factors and can be managed with the support of a licensed mental health professional. Being able to understand how personal factors (genetic, brain chemistry/structure, upbringing) contribute to BPD symptoms can help you navigate the best course for treatment and well-being.”

Licensed Clinical Social Worker (LCSW-R), BC-TMH Jill Daino

Common Causes of Borderline Personality Disorder

Though we don’t yet have a firm understanding of the exact causes of BPD, much research and work have been put into furthering our grasp of this condition. Below is a more in-depth discussion of these 3 factors that are accepted as likely contributions or risks to someone developing borderline personality disorder.  

“BPD has complex factors that contribute to its development and it’s unique to each person who has a BPD diagnosis. Genetics, brain chemistry/structure, and upbringing may all play a role, and knowing this can help the person better understand and manage their experience.”

Licensed Clinical Social Worker (LCSW-R), BC-TMH Jill Daino


There’s a lot to still learn about BPD and genetics, but the research completed thus far shows a definite link. Studies have found an association between BPD and a mutation in a gene that regulates how the brain uses serotonin (a natural neurotransmitter in the brain).

Findings indicate that people with this particular genetic variant might be even more likely to develop BPD if they also had a difficult childhood (for example, separation, neglect, or abuse from supportive caregivers).

Personal environmental factors

Certain personal environmental factors may also increase the likelihood of developing BPD. Things such as childhood trauma and sexual abuse, neglect, and bullying are common in people diagnosed with BPD. It’s thought that the interplay of biological variables, coupled with a non-nurturing early environment, might play a role in predisposing someone to develop BPD.

Brain differences

Research shows that some people who have borderline personality disorder have higher levels of activation in the limbic system than those who don’t. The limbic system controls fear, anger, aggression, and impulsivity — this disparity might be linked to BPD’s emotional instability symptoms like fear of abandonment and intense anger.

Understanding More About BPD

To fully understand borderline personality disorder, there’s a lot to know. There are several main issues that can help you get a fundamental grasp on how it works, how it’s diagnosed, and what an eventual diagnosis might mean for you or a loved one. Below are some of the more common things to note and be aware of.


Only a certified mental health practitioner with experience in diagnosing and treating mental conditions — such as a trained psychiatrist, psychologist, or clinical social worker — can diagnose borderline personality disorder.

They’ll make a diagnosis based on a thorough interview and discussion of symptoms. They may also do blood work and a physical exam to rule out any other physical health conditions that may be causing similar BPD symptoms. Borderline personality disorder is frequently diagnosed in late adolescence or early adulthood.


Once a diagnosis is made, it’s important that treatment is pursued. A healthcare provider can refer you to a certified mental health expert with experience treating borderline personality disorder. Commonly, people will seek help from a psychiatrist, social worker, psychologist, or therapist.

Many patients with BPD report fewer and less severe symptoms — including improved functioning and a higher quality of life — after receiving psychotherapy and/or medicine. These, along with other healthy lifestyle changes, are the first lines of treatment for BPD.

  • Therapy for BPD: BPD therapy, like dialectical behavior therapy or cognitive behavioral therapy, can help you learn to manage uncomfortable emotions, identify unhealthy thought and behavior patterns, reduce impulsive behavior, and work on improving interpersonal relationships.
  • Medication for BPD: Psychotherapy, is the primary method to treat borderline personality disorder. However, BPD medication is sometimes used as well. While there’s no recommended medication specifically to treat BPD, a doctor may prescribe something to treat symptoms like anxiety or depression. Occasionally, mood stabilizers or antipsychotics are suggested.

Ultimately, BPD treatment can help you develop skills to manage and cope with your condition. Whether you struggle with intense mood swings or have unstable relationships, a proper BPD treatment plan will help you lead a better life. Effective treatment, however, takes time, patience, and dedication.

Find out how online therapy at Talkspace can help you or a loved one learn to manage and cope with borderline personality disorder today. You can get control over BPD, and you don’t have to do it alone.

See References

Jill E. Daino, LCSW-R

Jill E. Daino, LCSW-R, BC-TMH, is a clinical social worker with over 25 years of experience as a therapist, clinical supervisor, and program director. She works to support quality clinical care at Talkspace. Her work as a clinician and trainer focuses on the mental health impact of body image concerns and eating disorders across the lifespan.

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