- 30th January 2025
Understanding CPTSD and BPD: Key Concepts
As a clinical psychologist in Melbourne, I’ve found that many of my clients often wonder whether their experiences are better described by Borderline Personality Disorder (BPD) or Complex Post-Traumatic Stress Disorder (CPTSD). It’s a common question in therapy, and for good reason. These two conceptualisations share overlapping features and have been extensively discussed and debated by psychologists and researchers. Gaining clarity about these distinctions can help in understanding yourself and identifying the kind of support that may feel most helpful.
In this blog, we’ll explore the similarities and differences between BPD and CPTSD, drawing on insights from recent research. We’ll also look at how understanding these conditions can guide effective treatment.
Table of Contents
An Overview of Borderline Personality Disorder (BPD)
Borderline Personality Disorder (BPD) is a mental health condition recognised in the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition), which is widely used by psychologists and psychiatrists to understand and classify mental health conditions. First introduced in the DSM-III in 1980, BPD has since undergone extensive research and redefinition. Historically, BPD has been heavily stigmatised, often misunderstood as a condition characterised solely by instability or manipulative behaviours. However, we now know that BPD stems from emotional dysregulation, often linked to early trauma or difficulties with attachment.
The DSM-5 identifies nine key traits of BPD, with a diagnosis requiring at least five of these to be present:
- Intense fear of abandonment, whether real or imagined.
- Unstable and intense interpersonal relationships, often swinging between idealisation and devaluation.
- A shifting or unstable sense of self and identity.
- Impulsive behaviours in at least two areas that are potentially self-damaging (e.g., reckless spending, substance misuse, unsafe driving).
- Recurrent suicidal behaviours, gestures, threats, or self-harming acts.
- Emotional instability, often experienced as rapid mood swings lasting hours to days.
- Chronic feelings of emptiness.
- Intense anger or difficulty managing anger.
- Stress-related paranoia or episodes of dissociation.
Understanding Complex Post-Traumatic Stress Disorder (CPTSD)
Complex Post-Traumatic Stress Disorder (CPTSD) is defined in the ICD-11 (International Classification of Diseases, 11th Revision), developed by the World Health Organisation. While it shares core features with PTSD – including intrusive re-experiencing, avoidance of trauma reminders, and hyperarousal – CPTSD expands on these symptoms by adding a cluster known as Disturbances in Self-Organization (DSO). These include:
- Emotional dysregulation, involving both heightened and numbed emotional responses.
- Negative self-perceptions, such as feeling worthless or like a failure.
- Difficulties in relationships, often marked by emotional detachment or a lack of trust.
CPTSD emerged as a way to better understand the experiences of individuals exposed to prolonged or repeated trauma, such as childhood abuse or neglect. Many researchers view CPTSD as a less stigmatising lens for understanding trauma-related difficulties. This is because CPTSD avoids the stereotypes often associated with personality disorders. Despite some overlapping features with BPD, CPTSD is increasingly recognised as a distinct cluster of experiences. Research has highlighted clear differences between the two, both clinically and conceptually, particularly in how trauma manifests in emotional regulation, self-perception, and relationships.
The evolving understanding of CPTSD has led to growing research into how it differs from both PTSD and BPD, paving the way for more targeted and effective approaches to care.
Similarities Between CPTSD and BPD
CPTSD and BPD share many overlapping symptoms, which can make it challenging to tell the two apart. Some research has even suggested that these conditions are so similar they may represent variations of the same underlying difficulties, with the main differences lying in how these symptoms are expressed.
One of the key connections between CPTSD and BPD is their strong link to trauma. While not everyone with BPD has experienced trauma, studies show that up to 97% of people diagnosed with BPD report significant traumatic experiences, such as childhood abuse or neglect. This shared foundation in trauma likely explains why both conditions often involve difficulties with emotional regulation, self-perception, and relationships.
It’s also common for people to meet the criteria for both conditions at different points in their lives. Research has found that a significant percentage of people diagnosed with BPD also meet the criteria for PTSD or CPTSD, and many individuals who recover from PTSD continue to face challenges associated with BPD.
Interestingly, studies suggest that CPTSD often involves traits seen in BPD, but the reverse is less common. This reinforces the idea that while these conditions overlap, they may still represent distinct ways of experiencing and responding to trauma.
Recognising these similarities helps reduce stigma and fosters a more compassionate understanding of emotional and relational struggles. It also highlights the importance of looking beyond labels to focus on the individual’s unique experiences and needs.

Differences Between CPTSD and BPD
Though CPTSD and BPD overlap, they have distinct differences in how symptoms are experienced and understood. These distinctions can help provide clarity and guide more tailored approaches to support.
Origins and Timing
One key difference lies in how CPTSD and BPD are conceptualised. CPTSD is specifically linked to trauma, often developing after prolonged or repeated exposure to harm, such as childhood abuse or neglect. In contrast, BPD does not require trauma to meet diagnostic criteria, although research shows that many individuals with BPD have experienced significant trauma. This distinction highlights a difference in definitions rather than lived experiences, as trauma often plays an important role in both.
Emotional Dysregulation
Both CPTSD and BPD involve difficulties managing emotions, but these difficulties are expressed in different ways:
- CPTSD: Emotional dysregulation often involves chronic difficulties in calming anxiety and distress and may include emotional numbness.
- BPD: Emotional dysregulation is typically more intense and reactive, with rapid mood swings, heightened anger, and emotional instability. Suicidal and self-harming behaviours are more closely associated with BPD and are often a focus of treatment.
Self-Perception
How identity and self-perception are experienced varies between the two:
- CPTSD: Self-perception is often marked by a stable but deeply negative view of oneself, including persistent feelings of guilt, shame, and worthlessness.
- BPD: Self-perception tends to be unstable and fragmented, shifting between extremes of positive and negative views. This instability can contribute to a sense of identity confusion.
Relationships
Difficulties with relationships are central to both CPTSD and BPD, but the patterns differ:
- CPTSD: Relationship challenges often stem from a fear of closeness or harm, resulting in avoidance or emotional detachment. There is often a consistent distrust of others.
- BPD: Relationships are typically more intense and volatile, with patterns of idealisation and devaluation. Fears of abandonment often drive behaviours aimed at preventing rejection or disconnection.
Core Fears and Hypervigilance
The underlying fears in each conceptualisation also differ:
- CPTSD: Hypervigilance is often focused on potential harm or danger from others, shaped by past traumatic experiences.
- BPD: The focus of hypervigilance is typically on signs of abandonment, with a heightened sensitivity to rejection in relationships.
Impulsivity and Self-Harm
Although impulsivity and self-harming behaviours can appear in both CPTSD and BPD, they differ in frequency and underlying causes:
- CPTSD: These behaviours may occur but are less frequent and tend to be secondary to other symptoms, such as difficulties with emotional regulation or relational detachment.
- BPD: Impulsivity and self-harm are often central features, arising as coping strategies for managing intense emotional distress or fears of abandonment.
Dissociation
Dissociation, or feeling disconnected from oneself or the world, presents differently across CPTSD and BPD:
- CPTSD: Dissociation is often a chronic adaptation to trauma, particularly in cases involving prolonged victimisation. It may serve as a way to cope with persistent fear or distress.
- BPD: Dissociation tends to be more transient, often occurring during moments of intense interpersonal conflict or distress, such as perceived rejection or abandonment.
Although some overlap exists, particularly when symptoms of BPD and PTSD occur together, dissociation reflects different underlying processes in these conceptualisations.
Summary of Differences
CPTSD and BPD share some common features, but the ways symptoms manifest and are understood differ. BPD often involves intense emotional reactivity, impulsivity, and fears of abandonment, whereas CPTSD is more linked to chronic emotional numbing, a stable negative self-concept, and relational avoidance. Recognising these differences helps ensure that care focuses on the specific challenges and experiences unique to each individual.
The Role of Diagnosis in Understanding Your Experience
For some people, receiving a diagnosis can bring clarity and validation. For others, symptoms may not fit neatly into one category, and a more flexible approach to understanding mental health can be helpful. Whether your experiences align more with CPTSD, BPD, or elements of both, what matters most is finding the right support for you. Psychological frameworks can provide insight into emotional struggles, but they do not define who you are or limit your potential for growth. Healing is about building self-awareness, developing effective coping strategies, and improving relationships in ways that feel manageable and meaningful.
A Broader Approach to Treatment
Recent research highlights the complexity of trauma-related difficulties and suggests that a transdiagnostic approach—one that looks beyond strict diagnostic categories—can be particularly beneficial. Rather than focusing solely on labels, treatment that targets key difficulties, such as emotional regulation, identity stability, and relational patterns, may be more effective for many people. Interventions that help reduce emotional avoidance, support healthier relationships, and strengthen self-identity can provide meaningful relief, regardless of diagnosis.
Trauma-Informed Therapy and Support
A trauma-informed approach can be helpful if you’re struggling with BPD or CPTSD, as both can bring deep emotional distress and challenges with self-identity and relationships. While these conditions are distinct, they often share a history of trauma, so it’s important to focus on what you’re experiencing rather than just the diagnosis. Therapy is most effective when it’s tailored to you—helping with emotional regulation, relationship patterns, and self-perception in a way that acknowledges your past without defining you by it.
Finding the Right Support with a Psychologist in Melbourne
If you relate to aspects of both BPD and CPTSD, you might be wondering what that means for you and what kind of support would be most helpful. While understanding these experiences can bring clarity, the most important thing is finding an approach to therapy that addresses what you’re struggling with in a way that feels meaningful and effective.
At Cova Psychology, we take a personalised, trauma-informed approach to therapy. Our psychologists in Melbourne draw on a range of evidence-based treatments, including DBT, EMDR, Mentalisation Based Therapy (MBT), and trauma-focused interventions, to help people manage intense emotions, build a more stable sense of self, and improve relationships.
If you’re looking for support, we’re here to help. Therapy offers a supportive space to explore your experiences, build coping strategies that work for you, and find ways to improve your well-being and relationships.
References
Ford, J. D., & Courtois, C. A. (2021). Complex PTSD and borderline personality disorder. Borderline Personality Disorder and Emotion Dysregulation, 8(1), 16. https://doi.org/10.1186/s40479-021-00157-7
Karatzias, T., Bohus, M., Shevlin, M., Hyland, P., Bisson, J. I., Roberts, N. P., & Cloitre, M. (2023). Is it possible to differentiate ICD-11 complex PTSD from symptoms of borderline personality disorder? World Psychiatry, 22(3), 486–498. https://doi.org/10.1002/wps.21098
Lawless, J., & Tarren-Sweeney, M. (2023). Alignment of borderline personality disorder and complex post-traumatic stress disorder with complex developmental symptomatology. Journal of Child & Adolescent Trauma, 16, 433–446. https://doi.org/10.1007/s40653-022-00445-6
Stopyra, M. A., Simon, J. J., Rheude, C., & Nikendei, C. (2023). Pathophysiological aspects of complex PTSD – A neurobiological account in comparison to classic posttraumatic stress disorder and borderline personality disorder. Reviews in the Neurosciences, 34(1), 103–128. https://doi.org/10.1515/revneuro-2022-0047
Su, W.-M., & Stone, L. (2020). Adult survivors of childhood trauma: Complex trauma, complex needs. Australian Journal of General Practice, 49(7), 423–427. The Royal Australian College of General Practitioners. https://doi.org/10.31128/ajgp-08-19-5039


Dr. Chris Coleiro
Chris is Clinical Psychologist and a co-director of Cova Psychology, located in the Melbourne CBD, where he provides supervision to psychologists whilst cultivating a supportive culture within the Cova team. Chris has worked extensively in the assessment and treatment of trauma, PTSD, and Borderline Personality Disorder. He combines a range of therapies in his approach including CBT, Schema Therapy, EMDR and IFS. Chris is a member of the Australian Psychological Society (APS), the APS college of Clinical Psychology, and of the Eye Movement Desensitisation Reprocessing Australian Association (EMDRAA).