Is Borderline Personality Disorder Genetic?

Borderline personality disorder (BPD) is a complex mental illness that is often misunderstood and misdiagnosed. While there's still much that doctors and researchers don't know about BPD, many studies have been done on what contributes to the disorder, including whether there's a genetic component involved.

BPD is a mental health condition that has to do with regulating emotions, according to the National Alliance on Mental Illness (NAMI). Those who have BPD often experience deep, intense feelings for long periods of time, and may struggle to get back to a baseline after the triggering event. This difficulty with self-regulation can lead to poor self-image, impulsivity, an intense fear of abandonment, unstable relationships, intense responses to stressors, and self-harm. Only an estimated 1.4% of the U.S. population experiences BPD, though nearly 75% of those diagnosed are women.

Since BPD can often co-occur with other mental health disorders, like post-traumatic stress disorder, it can be difficult to diagnose (via National Institute of Mental Health). While it used to be thought that BPD was untreatable, there are very effective forms of therapies that those with BPD respond positively to, such as dialectical behavior therapy and mentalization-based therapy (via Verywell Health).

How do genetics contribute to borderline personality disorder?

If you have a close family member with BPD, you are more likely to develop it yourself (via Verywell Health). For example, if you have a full sibling with BPD, you're 4.7 times more likely to develop it. If you have a fraternal twin with BPD, that risk goes up to 7.4. However, researchers are still exploring whether this is due to genetic components or environmental factors. Current research shows that there are two genes — DPYD and PKP4 — that increase the risk of developing BPD. However, these two genes are also linked to an increased risk of bipolar disorder and schizophrenia.

A 2019 Swedish twin study published in Molecular Psychiatry looked at the risk of BPD in identical twins. Researchers found that the risk of BPD in identical twins was much higher than in fraternal twins, pointing to the likelihood of a genetic cause (via Verywell Health). However, the study also found that there was a 54% contribution of environmental factors, meaning that there were unique factors that may not be shared by the twins that could also affect a person's risk of developing BPD. Other research has found that risk factors for BPD can include traumatic life events, childhood physical abuse, childhood sexual abuse, and childhood neglect.

The outlook for those with borderline personality disorder

Early diagnosis and intervention for BPD are critical. If left untreated, BPD can be dangerous (via Cleveland Clinic). In fact, those with BPD are 40 times more likely to die by suicide than the general population, with 8-10% of those living with BPD dying by suicide. People with BPD are also at an increased risk of substance use disorder, depression, and self-harm. However, with proper treatment, symptoms often gradually decrease with age, and some people even see their symptoms disappear in their 40s. It's very possible for the quality of life to greatly improve for those living with BPD.

If you know someone who's experiencing BPD, you can support them by educating yourself about the disorder so you can understand what they're going through. Encourage them to seek treatment and always offer patience and understanding. Take care of your own mental health by supporting yourself and seeking therapy if necessary. 

If you or someone you know is in immediate distress or thinking about hurting themselves, call the National Suicide Prevention Lifeline at 1-800-273-TALK (8255) or reach the Crisis Text Line by texting HELLO to 741741.