One of the trickiest aspects of mental healthcare is the overlap of symptoms. Many mental health disorders, despite being very different, can display similar signs. For example, as we’re about to see, complex post-traumatic stress disorder (C-PTSD) and borderline personality disorder (BPD) are very distinct conditions that can be mistaken for one another. On top of that, C-PTSD and BPD are quite often co-morbid.

Such a scenario needs our full attention. Your clinician must identify which condition you have and, if both are present, which occurred first. With that in mind, let’s explore some of the similarities and differences between C-PTSD and BPD.

C-PTSD Basics

man covering faceMost of you are probably familiar with trauma and post-traumatic stress disorder (PTSD). Complex trauma, however, is different in some fundamental ways. In general, PTSD results from exposure to a singular traumatic experience. C-PTSD, on the other hand, arises from an ongoing series of traumatic events like, for example:

  • Physical, sexual, domestic, or emotional abuse
  • Neglect or abandonment
  • Children being compelled to take on the role of an adult
  • Being kidnapped
  • Living in a war zone
  • Human trafficking/Being prostituted
  • Torture

A complex trauma survivor may show signs similar to PTSD (intrusive thoughts, flashbacks, avoidance, and hyper-vigilance). In addition, common symptoms may include:

  • Dissociation
  • Inability to regulate emotions
  • Trauma bonding with those who hurt you
  • Dysfunctional relationships
  • Losing a sense of meaning in your life

BPD Basics

A hallmark of borderline personality disorder is having an unstable sense of self. Like C-PTSD, this can arise from past trauma but there are other factors related to genetics. Also, children of an unreliable, inconsistent caregiver can be at a higher risk of being diagnosed with BPD.

BPD symptoms include:

  • Impulsiveness
  • Intense angry outbursts
  • Fear of abandonment
  • A feeling of being “empty”
  • Dysfunctional relationships
  • Dissociation
  • Inability to regulate emotions
  • Self-harm
  • Suicidal thoughts

Some Differences and Similarities Between BPD and C-PTSD

Once again, these two disorders are distinct and discrete from each other. Their causes are different as are the treatment protocols. However, you surely noticed some overlap on the lists above. So, let’s have a look:


Yes, relationships can be dysfunctional for both — but for different reasons. A person with BPD, despite the difficulties, is far more likely to seek close friendships and partnerships. That said, such connections can be suddenly cut off out of fear. This is frequently called “splitting.”

An individual living with C-PTSD diagnosis will more typically choose avoidance and withdrawal. They have a tough time trusting anyone and will often choose isolation over community.


This is a counterproductive form of self-protection. For complex trauma survivors, dissociation serves to reduce the odds of re-living the ugly events. They’re already struggling with nightmares and flashbacks so they may sometimes opt for numbness over risk. Someone with BPD sees dissociation in a similar way. It tamps down the feelings of stress and distress that are common with borderline personality disorder.

Emotional Dysregulation

Once again, this is technically a symptom overlap, but the approach is much different. Put simply, people with BPD do less regulation of strong emotions while complex trauma survivors are all about over-regulation. Either choice is dysfunctional but in specific ways.

Self-Identity is a Key Difference

As mentioned above, people with BPD have an unstable sense of self. They can almost feel like different people from day to day. Conversely, someone with C-PTSD will almost always maintain a strong self-identity. This demarcation can be very useful for practitioners seeking to make a diagnosis.

Treatment Approaches

Each disorder has some particular protocols while other approaches may be tried for instances of co-morbidity. Reach out to learn more about how trauma therapy can help.