More than 71% of people with BPD have experienced a form of trauma. Genetics and biology can also factor into causing BPD.

Borderline personality disorder (BPD) is a mental health condition marked by patterns of mood changes, intense emotions, and feeling disconnected (aka dissociation).

BPD is one of the most common personality disorders. Around 1–3% of people are believed to live with BPD.

If you have BPD, it’s normal to feel uncertain about your role in the world and the way you see yourself. Fear of being abandoned and feelings of emptiness can also be common.

While the causes of BPD aren’t entirely known, it’s believed that a combo of environmental, genetic, and brain-related factors might increase someone’s chances of developing BPD.

Adverse life experiences — such as child abuse, neglect, or anything that causes long-term fear and distress — seem to play a key role in causing BPD.

In fact, some experts propose that BPD is a neurodevelopmental condition that stems from maladaptive responses (responses that make it harder to adapt) to trauma and stress.

According to an analysis of literature, people with BPD are 13 times more likely to report childhood trauma than those without BPD. Childhood trauma is also more likely to be linked to BPD than to other personality disorders, mood disorders, or psychosis.

Out of more than 5,000 people, 71.1% of people with BPD had at least one traumatic childhood experience.

People with BPD also reported similar childhood events and experiences, including:

  • physical neglect (48.9%)
  • emotional abuse (42.5%)
  • physical abuse (36.4%)
  • sexual abuse (32.1%)
  • emotional neglect (25.3%)

Stress in early life could also get in the way of brain development in certain areas. In turn, this can lead to more difficulties with:

  • cognition
  • emotional stability
  • coping skills
  • impulse control
  • interpersonal skills

Even if you didn’t experience childhood abuse, some parenting styles — especially harsh or invalidating ones — might also increase your chances of developing BPD.

When these parenting styles mix with genetic factors like temperament, it could mean an even higher likelihood a person may develop BPD.

BPD seems to have a strong genetic component and tends to run in families. This means people with BPD may be more likely to have certain temperamental traits.

Some traits that have been linked to BPD include:

  • a tendency to seek out new experiences
  • less self-direction
  • higher likeliness to want to avoid harm
  • lower cooperation

Having a close family member, like a parent or sibling, with BPD can also increase your chances of developing the condition.

In an older study on families of twins, researchers looked into the genetic roots of BPD. The study, which involved 711 pairs of twins and 561 parents, found that genetic material on “chromosome 9” was most connected with BPD.

Researchers say the study’s findings will help shed more light on the genetic causes of BPD. The findings could also help create better ways to help people manage BPD.

In another study, researchers investigated what parts of BPD could be genetic and whether gender impacts the likelihood of developing BPD.

The study found that across three countries, 42% of the signs and symptoms of BPD could be traced to genetic causes. Meanwhile, 58% were linked to environmental factors.

There wasn’t a big difference between males and females in terms of how BPD was passed on through genes. And overall, young adults seemed to show more signs of BPD than older adults.

Many studies have connected certain brain differences to BPD. These differences involve the structure of the brain and how it functions.

Parts of the brain involved with impulse control and emotion may be particularly tied to BPD.

For example, research suggests that people with BPD have less volume in certain parts of the brain, including the:

  • hippocampus
  • amygdala
  • medial temporal lobes

These parts of the brain are especially important for managing stress and emotions.

Research has also shown that people with BPD have higher levels of cortisol (aka the stress hormone). Major life stressors could be the reason — many people with BPD have a history of childhood trauma.

Critical parenting styles that cause anxiety and stress may also contribute to BPD in similar ways.

Child abuse can cause long-term changes in the brain. Some of these changes involve overstimulation of the hypothalamic-pituitary axis, or HPA (your hypothalamus, pituitary gland, and adrenal glands).

When your HPA is always “on,” too much cortisol is released. The extra cortisol causes stress responses that look a lot like many of the behavior patterns of BPD.

BPD could also be linked to chemical imbalances in the brain. Imbalances in the neurotransmitters serotonin and dopamine, for example, could impact emotional and physical well-being in a lot of ways.

If think you might have symptoms of BPD or another condition, you’ll likely want to start by talking with a mental health professional.

To make sure you get the right diagnosis, the clinician might:

  • ask you a series of questions about your symptoms
  • do a medical exam to rule out other causes
  • look at your family, medical, and mental health history

BPD can be tricky to diagnose. It can co-occur simultaneously with other conditions and share similar symptoms of other mental health conditions.

For example, someone with BPD may also have symptoms shared with:

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), some key signs and symptoms of BPD include:

  • fear of being abandoned by loved ones
  • in relationships, patterns of viewing the other person with alternating strong feelings like love or hate
  • difficulty forming a secure sense of self or identity
  • impulsive behaviors that may cause harm
  • self-harm or suicidal thoughts or behaviors
  • depressed, anxious, or irritable moods that last from hours to a few days
  • feelings of emptiness that don’t go away
  • intense anger or rage that feels hard to control
  • dissociation (feeling disconnected from yourself and your surroundings) or episodes of psychosis or paranoia

People with BPD are also more likely to have suicidal thoughts. Up to 69–80% of people in psychiatric treatment due to BPD reported suicidal thoughts.

And in another study in people with different diagnoses in inpatient care, those with BPD had higher levels of suicidal ideation than people with other mental health conditions.

If you have a BPD diagnosis, therapy is one of the most recommended treatments. Therapy for BPD can take place either one-on-one or in a group.

Group therapy can be especially helpful for those with BPD since it can help establish friendships and trust.

Since BPD is a personality disorder, it’s seen as a lifelong condition. But newer, evidence-based therapies are helping many people with BPD manage their symptoms and increase their well-being.

The first (and most important) step is reaching out for support. A therapist can help you or your loved one with BPD unravel deeply-ingrained patterns of thinking and behavior.

Finding a therapist who specializes in BPD can also help you get more support that fits your specific needs.

A couple common therapies for BPD include dialectical behavioral therapy (DBT) and cognitive behavioral therapy (CBT).

DBT is a popular approach for helping people manage BPD. In DBT, people learn more about how their emotions are tied to what’s going on around them. This helps some people manage strong emotions and prevent self-harming behaviors.

Meanwhile, CBT can help people learn about how their core beliefs impact the way they see themselves and interact with others, and change those beliefs to more productive ones.

Medications could also help with certain symptoms like depression or anxiety.

In addition to finding a good therapist, you might want to seek out a support group or online forum to connect with other people with BPD. It can be helpful to share experiences with others who understand what you’re feeling.

You can learn more about treatment options for BPD here.

BPD is a complex personality disorder with a range of symptoms and possible causes. Risk factors include childhood trauma or severe long-term stress, genetics, and certain brain differences.

Managing your BPD symptoms can have a learning curve, but there are many resources and treatment options that can help along the way.