Borderline Personality Disorder (BPD) and Post-Traumatic Stress Disorder (PTSD) are two mental health conditions that can have overlapping symptoms, but they are distinct disorders with different causes and treatments. Here, we will discuss the similarities and differences between BPD and PTSD. First it is important to know that the two conditions can be co-occurring or comorbid.  In a study of the comorbidity of borderline personality disorder and posttraumatic stress disorder in the U.S. population the researchers  reported that “Of individuals with BPD, 30.2% were also diagnosed with PTSD.” [1]  Other research teams have reported that the rates of co-occurring PTSD within samples of BPD patients range between 30% and 79%. [3]


Both BPD and PTSD can cause emotional instability, mood swings, and difficulties regulating emotions. People with BPD and PTSD may also have self-destructive behavior and intense fears of abandonment. However, PTSD is primarily associated with re-experiencing traumatic events, avoidance behaviors, and hyperarousal, while BPD is associated with a more generalized sense of emotional instability and relationship problems. Some researchers have found that the comorbid diagnosis of PTSD in BPD patients can aggravate some, but not all BPD symptoms. [3]


PTSD is caused by exposure to a traumatic event or series of events, such as a natural disaster, combat, or physical or sexual assault. BPD, on the other hand, is believed to have biological and psychosocial components, [2] with traumatic experiences during childhood, such as abuse or neglect, being a common contributing factor.


Both BPD and PTSD can be treated with a combination of therapy and medication. However, the specific types of therapy used may differ. For PTSD, trauma-focused therapies such as Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE) are effective. For BPD, therapies such as Dialectical Behavior Therapy (DBT) and Mentalization-Based Therapy (MBT) have shown to be beneficial.

At the Centre for Clinical Psychology, our clinicians are trained to identify BPD and PTSD.  Our focus of therapy is on PTSD. We use evidence-based approaches to help individuals manage their symptoms, improve their quality of life, and build fulfilling relationships. Our clinicians are dedicated to providing personalized care that is tailored to each individual’s needs.

If you or someone you love is struggling with BPD, PTSD, or both, don’t hesitate to seek help. Book an appointment with one of our clinicians at the Centre for Clinical Psychology in Melbourne by calling 03 9077 0122 or visiting https://ccp.net.au/booking/. We are here to support you on your journey to better mental health.


[1] Pagura, J., Stein, M. B., Bolton, J. M., Cox, B. J., Grant, B., & Sareen, J. (2010). Comorbidity of borderline personality disorder and posttraumatic stress disorder in the U.S. population. Journal of Psychiatric Research, 44(16), 1190–1198. https://doi.org/10.1016/j.jpsychires.2010.04.016

[2] Cattane, N., Rossi, R., Lanfredi, M. et al. Borderline personality disorder and childhood trauma: exploring the affected biological systems and mechanisms. BMC Psychiatry 17, 221 (2017). https://doi.org/10.1186/s12888-017-1383-2

[3] Cackowski, S., Neubauer, T. & Kleindienst, N. The impact of posttraumatic stress disorder on the symptomatology of borderline personality disorder. bord personal disord emot dysregul 3, 7 (2016). https://doi.org/10.1186/s40479-016-0042-4