Complex post-traumatic stress disorder (cPTSD) and borderline personality disorder (BPD) share some common symptoms. Moreover, the two mental health disorders often occur co-morbidly – where an individual is diagnosed with both conditions.

Despite this, scientists maintain that the two conditions are different from one another, with overlapping yet distinct symptom profiles.

So, what exactly are cPTSD and BPD, and what are their key similarities and differences?

Complex PTSD

Complex posttraumatic stress disorder is a subset of posttraumatic stress disorder, a fear-based disorder caused by exposure to trauma or abuse. While PTSD may develop after a single experience of trauma, complex PTSD is typically a response to chronic or long-term exposure to traumatic events, often involving childhood abuse or neglect.

Complex PTSD symptoms may include:

  • emotional numbing
  • being withdrawn and avoiding close relationships with others
  • flashbacks or nightmares of traumatic events
  • stable and chronic feelings of guilt, shame, and worthlessness
  • perception of the world as dangerous and of people as untrustworthy
  • difficulty self-calming when experiencing emotional distress
  • dissociation

Borderline Personality Disorder

Borderline personality disorder is a personality disorder characterised by an unstable sense of self and perception of the world. The causes of BPD are not fully understood. While many people living with BPD have experienced physical, sexual, or emotional abuse in childhood, other factors such as genetics may also play a role in the development of the disorder.

BPD is strongly associated with disorganised attachment to a primary caregiver during childhood. Disorganised attachment happens when a parent or other caregiver switches between showing love and care to a child and hurting or abusing them. The child forms an unstable attachment to the caregiver, simultaneously seeking closeness and protection while withdrawing from fear of being hurt.

BPD symptoms overlap with c PTSD symptoms, but there are key differences. BPD symptoms include:

  • intense anger
  • unstable interpersonal relationships
  • chronic feelings of emptiness
  • dissociation as a transient reaction to extreme stress
  • impulsiveness
  • fear of abandonment
  • difficulty regulating emotions
  • alternating idealisation and devaluation of others
  • self-harm and suicidal thoughts

Characterising Personality Disorders

Personality disorders are a way to describe patterns of behaviour and thoughts that can make daily life difficult to manage. However, some people disagree with the conceptualisation of personality disorders like BPD. They may see their emotions and behaviours as a normal response to difficult events and believe treatment should focus on the problems in their life that may have contributed to their responses, not on themselves as an individual.

If you are unhappy with the concept of personality disorders or want to explore the issue, Mind offers some helpful information here.

cptsd vs bpd

What Are the Key Differences and Similarities Between BPD and Complex PTSD?

Interpersonal Relationships

People living with a complex PTSD diagnosis may avoid close interpersonal relationships altogether, seeing others as untrustworthy as a result of their experiences.

On the other hand, people with BPD may seek close relationships but find them difficult to sustain. Individuals with BPD may suddenly end a relationship due to perceived fear of abandonment or as a result of “splitting” (seeing another person as all good or all bad).


Both BPD and cPTSD can involve dissociation. Dissociation can act as a protective mechanism to avoid re-experiencing a complex trauma among people with cPTSD. Individuals may disassociate to avoid intense emotions or when they encounter a trigger of a traumatic event. Disassociation may also manifest as memory gaps surrounding traumatic events.

With BPD, disassociation is a recognised symptom as a transient reaction to extreme stress or real or imagined abandonment. Disassociation is most common among BPD individuals who have experienced childhood abuse – and is more common in BPD than any other personality or mood disorder except PTSD.


One key difference between cPTSD and BPD lies in the individual’s sense of Self. Individuals with cPTSD tend to have a more stable sense of Self but struggle with consistent feelings of low self-worth, guilt, and shame. Individuals with BPD, on the other hand, have a more unstable sense of Self – they may not know who they are at their core and frequently change their interests and hobbies.

Sometimes, individuals with cPTSD may have their sense of Self disrupted by episodes of disassociation when they are not able to remember traumatic events and the surrounding periods. When someone experiences repeated traumatic events in childhood, this may affect a child’s ability to integrate their experience and prevent the development of a coherent personality structure.

Emotion Dysregulation

While both mental disorders involve emotional dysregulation, there are some differences between the two.

Individuals with complex PTSD often over-regulate emotions, using emotional numbing, withdrawing, or dissociation to cope with reminders of traumatic experiences. On the other hand, BPD is characterised by under-regulation of intense emotions, resulting in expressions of intense anger or self-harm.


PTSD and BPD often occur co-morbidly. In a group of individuals receiving inpatient psychiatric treatment, 79% of people with cPTSD also had BPD; and 40.5% of people with BPD also had cPTSD.

Treating PTSD and BPD

Both PTSD and BPD can make daily life hard to manage. However, evidence-based treatments are available to help individuals cope with mental illnesses and form stable and supportive relationships with those around them.

Borderline Personality Disorder

Treatment for BPD usually involves individual or group psychotherapy. One of the most common treatment approaches is dialectical-behavioural therapy (DBT), a type of cognitive-behavioural therapy developed specifically for people with BPD. DBT focuses on the dual goals of self-acceptance and positive change, supporting BPD clients to love and accept themselves while developing skills to manage symptoms.

Other treatments for BPD may include:

  • mentalisation-based therapy
  • art therapy
  • therapeutic communities

Complex PTSD

Treatment for complex PTSD often involves psychotherapy methods used to treat non-complex PTSD. This may include:

  • eye movement desensitisation and reprocessing therapy (EMDR)
  • trauma-focused cognitive-behavioural therapy

People who live with both BPD and cPTSD may benefit from tailored therapies such as DBT-PTSD that consider both sets of symptoms in the treatment process. DBT-PTSD supplements DBT with trauma memory processing, compassion-focused therapy, and acceptance and commitment therapy. Research suggests that DBT-PTSD can effectively reduce dissociation, depression, and BPD symptoms.

Mental Wellness Treatment at the Wave

The Wave offers a transformative treatment experience for young people looking for mental wellness support. We are specialists in trauma treatment, eating disorders, mental health, and addiction treatment for young adults, drawing on decades of experience and unequalled expertise.

The Wave offers a holistic approach to treatment that focuses on full recovery and positive growth. We understand that every young person is different, and we provide individualised and flexible programmes that suit their unique needs. Our treatment plans combine psychotherapy with experiential activities and body-mind approaches to promote deep and meaningful healing.

At The Wave, recovery means more than just managing symptoms. We want young people to leave our centre ready to follow their dreams. We help adolescents rediscover their purpose in life and equip them with the skills they need to reach their goals.

We understand that being apart from your child can be hard, so we ensure that families are included from the beginning to the end of the treatment process. We offer regular updates, information, and comprehensive explanations for your peace of mind.

If you’re looking for a transformative recovery experience that combines mental wellness treatment with a GAP year journey, contact us today. We’re here to help.

Fiona - The Wave Clinic

Fiona Yassin is the founder and clinical director at The Wave Clinic. She is a U.K. and International registered Psychotherapist and Accredited Clinical Supervisor (U.K. and UNCG).

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