Since its inception in 1980 PTSD was the primary diagnosis that related to the experience of trauma. Over time many other things have been identified as potentially associated with trauma such as depression, anxiety and substance use difficulties. In 2019 the diagnosis of Complex Posttraumatic Stress Disorder (CPTSD) was included as a diagnostic category in the International Classification of Diseases, 11th Edition, adding more options for a clinician to think about when diagnosing a client.
Since 2019 There has been much discussion in the research literature regarding this diagnosis. This article will highlight some of the discussion. Given that diagnosis has the purpose of indicating treatment, this will also be discussed.
What is complex PTSD, how is it defined
Complex posttraumatic stress disorder (CPTSD) consists of six symptom clusters: three PTSD criteria of reexperiencing, avoidance, and hypervigilance, in addition to three disturbances of self-organization (DSO) symptoms defined as emotional dysregulation, interpersonal difficulties, and negative self-concept.
The Challenge of Diagnosis and Complex PTSD.
The challenge of most diagnoses is understanding the overlap between disorders so that we may differentiate between difficulties or symptoms and work towards providing therapy that is effective.
One of the challenges with complex PTSD is the overlap with other disorders, and the dimensional nature of some symptoms. This difference has meant that there is no inclusion of complex PTSD in the DSM 5.
Several authors have examined the construct of complex PTSD compared to other diagnoses. Jowett et al. (2020) published an article aimed at differentiating complex PTSD from borderline personality disorder.
Borderline personality disorder (BPD) shares similar features to the DSO cluster of symptoms in CPTSD. BPD is commonly associated with PTSD. Pagura et al. (2010) reported of individuals (living in USA) with BPD, 30.2% also have a diagnosis with PTSD.
Jowett et al. (2020) examined the question how is CPTSD distinct from BPD? They used Latent Class Analysisconducted on a sample of 195 treatment-seeking adults at a specialist trauma service.
The latent class analysis determined three distinct classes:
1) CPTSD/High BPD class characterized by high symptom endorsement across both conditions.
2) CPTSD/Moderate BPD class characterized by high PTSD and DSO symptom endorsement and moderate BPD.
3) PTSD/Low BPD class characterized by PTSD symptoms and low DSO and BPD symptom endorsement.
They reported that the two CPTSD classes were associated with greater exposure to multiple, interpersonal traumas earlier in life and exhibited higher functional impairment. Jowett et al. (2020) stated that their findings support the construct of a CPTSD diagnosis as a separate entity although BPD features seem to overlap greatly with CPTSD symptoms in their highly traumatized clinical sample. Clearly overlap makes diagnosis a challenge.
In another study Bertin et al. (2025), assessed the distinction between PTSD and C-PTSD through a Latent Profile Analysis (LPA) and identified four distinct latent classes that differed primarily in terms of the intensity of symptoms rather than the presence of specific symptoms. The classes were:
(1) Severe C-PTSD,
(2) Moderate C-PTSD,
(3) Imbalanced C-PTSD, and
(4) Low PTSD symptoms.
Bertin et al. (2025) concluded that within their sample, every patient seemed to suffer from C-PTSD except those with low PTSD symptoms. They stated that this supports a more dimensional understanding of patients suffering from PTSD. Once again diagnostic challenges due to unclear differences.
What to do?
Based on these two findings PTSD and CPTSD seem to be distinct from BPD, but not so distinct from each other. What do we do treatment wise? In regard to BPD the most heavily researched therapy is Dialectal Behaviour therapy (Linehan,1993). In regard to PTSD and CPTSD, there are two papers that indicate a pathway for therapy.
Slotema et al. (2020) systematic review and meta-analysis of psychotherapy for PTSD in patients with borderline personality disorder concluded that psychotherapy for PTSD is efficacious and safe for patients with borderline personality disorder and should not be withheld from these vulnerable individuals.
Karatzias et al. (2019) reviewed interventions for CPTSD they found that for trial participants with CPTSD, trauma-focused CBT (TF-CBT)-which includes CPT, exposure alone, and EMDR were effective (compared to usual care) in treating symptoms of PTSD. They also reported that these interventions influenced the CPTSD disturbances of self-organization (DSO) symptoms. They reported:
- Moderate-large or large effect sizes of negative self-concept.
- Moderate or moderate-large effect sizes on interpersonal relationships.
- Few RCTs reported affect dysregulation data.
Summary
Despite the challenges, trauma focussed therapies do seem to have some impact on CPTSD. With diagnostic confusion and without alternatives, trauma focussed PTSD therapies seem to be the choice.
References
Bertin, F., Clarys, D., Tapia, G., Chami, L., El-Hage, W., & Vancappel, A. (2025). Are all PTSD cases complex PTSD? Results from a latent profile analysis. European Journal of Trauma & Dissociation, 9(1), Article 100494. https://doi.org/10.1016/j.ejtd.2024.100494
Jowett, S., Karatzias, T., Shevlin, M., & Albert, I. (2020). Differentiating symptom profiles of ICD-11 PTSD, complex PTSD, and borderline personality disorder: A latent class analysis in a multiply traumatized sample. Personality Disorders: Theory, Research, and Treatment, 11(1), 36–45. https://doi.org/10.1037/per0000346
Karatzias, T., Murphy, P., Cloitre, M., Bisson, J., Roberts, N., Shevlin, M., … & Hutton, P. (2019). Psychological interventions for ICD-11 complex PTSD symptoms: Systematic review and meta-analysis. Psychological medicine, 49(11), 1761-1775.
Linehan, M. (1993). Cognitive-behavioral treatment of borderline personality disorder. Guilford press.
Pagura J, Stein MB, Bolton JM, Cox BJ, Grant B, Sareen J. Comorbidity of borderline personality disorder and posttraumatic stress disorder in the U.S. population. J Psychiatr Res. 2010 Dec;44(16):1190-8. doi: 10.1016/j.jpsychires.2010.04.016. Epub 2010 May 26. Erratum in: J Psychiatr Res. 2013 Mar;47(3):423. PMID: 20537660; PMCID: PMC4209725.
Slotema, C. W., Wilhelmus, B., Arends, L. R., & Franken, I. H. A. (2020). Psychotherapy for posttraumatic stress disorder in patients with borderline personality disorder: A systematic review and meta-analysis of its efficacy and safety. European Journal of Psychotraumatology, 11(1), 1796188. https://doi.org/10.1080/20008198.2020.1796188
