If you’ve ever asked what causes borderline personality disorder (BPD), you’re not alone. Many people are curious about where it comes from and how it develops.
There isn’t one single cause of BPD. Instead, it usually happens due to a mix of factors. These may include your biology, your early life experiences, and the environment around you.
This article explains what we know so far about the causes of BPD in simple, straightforward language. If you haven’t already, it might help to familiarise yourself with what BPD is.
Table of Contents:
Is there a single cause of BPD?
No. BPD doesn’t have one clear cause. Most experts agree that it develops due to a combination of:
- Biological factors
- Childhood experiences
- Social and environmental influences
We’ll look at each of these in more detail below.
Biological factors
Family history and genetics
Some studies suggest that BPD can be more common in families. If a close relative has BPD or another mental health condition, your chances of developing it may be slightly higher.
This doesn’t mean it’s guaranteed, and many people with BPD do not have any family history. Mental health conditions are complex and usually influenced by many genes rather than one single one.
Genes that affect mood, stress response, and emotional control may be involved.
Brain differences
Research has shown that certain areas of the brain may work differently in people with BPD. These areas include:
- The amygdala, which is involved in emotions like fear and anger
- The hippocampus, which plays a role in memory and emotional responses
- The prefrontal cortex, which helps with planning and controlling behaviour
These differences may make it harder for someone to manage emotions or react calmly in stressful situations. However, not everyone with BPD shows these brain patterns, and they do not explain the full picture.
Childhood experiences
Many people with BPD have experienced difficulties in their early years. These experiences can affect emotional development and how someone relates to others later in life.
Trauma and neglect
BPD has been linked to childhood trauma, including:
- Physical, emotional or sexual abuse
- Emotional neglect
- Long-term separation from caregivers
- Growing up in an unstable or unpredictable home
These types of experiences can make it harder to feel safe, develop trust, or understand emotions. They may also affect self-esteem and coping skills.
It’s important to note that not everyone with BPD has had trauma. And many people who go through trauma do not develop BPD. But trauma can increase the risk.
Relationships in early life
Our first relationships with caregivers help us learn how to manage feelings and interact with others. If a caregiver is supportive and responsive, we usually develop a strong sense of safety and self.
If a caregiver is often absent, critical or inconsistent, we may learn that our feelings don’t matter or that others can’t be trusted. This can make it harder to form stable relationships and understand emotions later in life.
This isn’t about blaming parents or caregivers. Many factors contribute to these patterns, including stress, illness or lack of support.
Environmental and social factors
Outside of biology and childhood, other life experiences can also affect mental health.
Stressful events later in life
Some people develop BPD traits after difficult events during their teenage years or adulthood. These might include:
- Bullying
- Sexual assault
- Domestic abuse
- Loss of a loved one
- Difficult breakups or friendships
These experiences can lead to changes in how a person sees themselves, others and the world. If someone already finds it hard to manage emotions, these events can have a stronger impact.
Emotional invalidation
Emotional invalidation means being told that your feelings are wrong, dramatic or unimportant. This can happen in childhood, at school or in adult relationships.
Examples of invalidation include:
- Being told to “stop overreacting”
- Having feelings ignored or laughed at
- Being punished for expressing sadness or anger
Over time, invalidation can make it hard to trust your own emotions. It can also lead to confusion about how to express feelings in a healthy way.
Social and cultural pressures
The wider environment can also affect how someone develops emotionally. For example:
- Some cultures or communities discourage emotional expression
- There may be pressure to hide distress or “tough it out”
- Access to mental health care may be limited
These factors don’t directly cause BPD, but they can make it harder to cope and to ask for help.
Personality traits and temperament
Some people are more emotionally sensitive from a young age. They may:
- Feel emotions strongly
- React quickly to stress
- Take longer to calm down
These traits are part of normal personality differences. But when combined with difficult experiences, they can make someone more vulnerable to developing BPD.
For example, a person who is highly sensitive and grows up in an invalidating or unstable environment may be more at risk.
Again, this is not anyone’s fault. It simply shows that each person’s experiences and traits can interact in different ways.
Can BPD be prevented?
There’s no guaranteed way to prevent BPD, but there are steps that may reduce the risk or help with early symptoms.
Some helpful approaches include:
- Supporting children with strong emotions in positive, patient ways
- Teaching emotional skills at home and in schools
- Creating safe and respectful relationships
- Providing early support for teenagers who struggle with mood, identity or behaviour
Therapies like DBT (dialectical behaviour therapy) have been shown to help people manage strong emotions and build healthy relationships. Starting therapy early can be especially helpful.
Why does it help to understand the causes?
Understanding the possible causes of BPD can help in several ways:
- It reduces stigma by showing that BPD is not a choice
- It increases self-awareness and understanding
- It helps others respond with empathy rather than judgment
- It can guide better treatment and support
Knowing the causes also shows that change is possible. While BPD may come from difficult experiences, people can learn new ways to manage emotions and build meaningful relationships.
Final thoughts: The causes of BPD
BPD develops from a mix of factors. These can include your genetic makeup, your early relationships, your environment and your emotional sensitivity.
No single cause explains BPD for everyone. Each person’s story is unique, and it often involves more than one factor.
The most important thing to know is that BPD is treatable. With the right help and support, people with BPD can make changes, feel more stable, and improve their quality of life.
