AFTER nearly 40 years in the wilderness, the diagnosis of complex post-traumatic stress disorder (cPTSD) was incorporated into the 11th edition of the International Classification of Diseases (ICD-11), in June 2018. This arguably allows for a better understanding of the symptoms presented by individuals affected by prolonged, severe or repeated trauma exposure.

For those of us who work with survivors of trauma, the recognition of post-traumatic stress disorder (PTSD) in 1980 remains a historical watershed. PTSD appeared to have brought together 150 years of psychiatric description captured in labels such as “railway spine”, “shell shock”, “traumatic neurosis”, “combat fatigue” and “gross stress reaction”. The formal recognition of PTSD occurred after concerted advocacy by trauma researchers, clinicians and survivor groups, particularly Vietnam veterans who felt abandoned by veteran services with no adequate diagnosis to account for their debilitating symptoms following their return from the theatre of war. The reader should be under no misconception, PTSD was a highly controversial and divisive diagnosis at the time, actively opposed by government, employer and insurance groups worried that such a diagnosis would lead to an outbreak of litigation and compensation claims. 

Once introduced, the diagnosis gave official recognition to the experiences of individuals exposed to trauma considered “outside the realm of normal human experience”. We now know that such forms of trauma exposure are much more common than then realised and that only a minority of individuals will develop PTSD after exposure to the majority of trauma types (here and here). Risk of PTSD has been shown to be primarily determined by the severity and the cumulative dose of trauma exposure (here and here). For affected people, the recognition of PTSD as a psychiatric condition validated their experiences that traumatic stress responses can endure long after exposure to the traumatic event and that such responses can be profoundly disabling. From a scientific perspective, the diagnosis established a clear set of criteria to reliably identify the condition and led to an explosion of clinical and neuroscientific research, with over 31 000 peer-reviewed articles indexed against PTSD since 1980 within PubMed.

However, from the outset there was concern that the 1980 diagnosis of PTSD failed to capture the complexity of clinical reactions seen following exposure to trauma that is severe, prolonged or repeated. The characterological effects of exposure to such forms of prolonged trauma had long been acknowledged. In Auschwitz survivors, Lesniak (1961) (cited here) reported permanent personality changes in the majority of patients, characterised by “lack of interpersonal trust, suspiciousness and social isolation, irritability, explosiveness, nervousness and emotional over-reactivity”.

To capture this more complex trauma response, Judith Herman proposed the term “cPTSD”, building on her clinical work with adult survivors of sexual and physical abuse and the writings of the earlier generation of clinicians caring for concentration camp survivors, prisoners of war, and those exposed to state-sponsored organised violence and torture (here, here, here and here). The primary contention behind cPTSD is that exposure to prolonged and repeated forms of trauma, particularly when escape is limited, results not only in risk of PTSD but also alters the fundamental structure of personality, leading to pathogenic personality change. 

That disturbances in the structure of personality can occur following exposure to severe trauma is hardly controversial. An overwhelming body of research shows that exposure to severe, prolonged or repeated trauma, particularly of an interpersonal nature, during childhood has severe developmental consequences and is a precursor to adult personality pathology (here and here) as well as other mental disorders (here and here). Similarly, the association between adult exposure to catastrophic trauma and personality pathology has been repeatedly documented. This finding appears to extend to service-related trauma, with Southwick and colleagues concluding that chronic war-related PTSD is “often accompanied by diffuse, debilitating, and enduring impairments in character,” a finding supported by subsequent research with veteran populations (here and here).

What has eluded the field since 1980 is how this association can be captured diagnostically. Is it preferable to make use of the existing range of mental disorder and personality disorder diagnostic categories to account for post-traumatic personality change, or should this association be recognised by a specific diagnosis that gives description to this clinical outcome that has been long noted?

Previous attempts to capture the impact of repeated or prolonged exposure to severe trauma in a diagnostic entity have been unsuccessful. The American Psychiatric Association proposed a diagnosis of extreme stress not otherwise specified (DESNOS) in draft documents leading up to the publication of the Diagnostic and Statistical Manual of Mental Disorders (DSM) IV. After field trials, the ill-fated category was found to lack pathogenic specificity and reproducibility (here and here). In 1990, ICD-10 incorporated the diagnosis of enduring personality change after catastrophic experience (EPCACE). This diagnosis failed to gain traction and was rarely used, with virtually no research to validate it as a diagnostic entity.

A final death knell for the construct of cPTSD appeared to have occurred in the lead-up to DSM-5, when Resick and colleagues published a scathing critical review of research undertaken until that time into cPTSD. The authors noted a lack of consistency in symptom descriptions across studies, a lack of clarity regarding how to differentiate simple and complex trauma, and a major overlap between cPTSD, PTSD, borderline personality disorder and major depressive disorder.

Yet, at the time of the Resick and colleagues’ publication, a key development in the conceptualisation of cPTSD had occurred. The ICD-11 working party for disorders associated with stress developed a diagnostic approach to assessing cPTSD that addressed the weakness of earlier approaches while maintaining a core understanding of the purpose of the diagnosis. The key to this was the recognition that patients with cPTSD must meet full diagnostic criteria for PTSD, and they must also experience a set of symptoms associated with disturbances in self-organisation, which include affect dysregulation, negative self-concept and disturbances in relationships (here and here).

These dimensions of disturbances in self-organisation have been operationalised in ICD-11 as:

• severe and pervasive problems in affect regulation;
• persistent beliefs about oneself as diminished, defeated or worthless, accompanied by deep and pervasive feelings of shame, guilt or failure related to the traumatic event; and
• persistent difficulties in sustaining relationships and in feeling close to others.

The delineation of disturbances in self-organisation as the differentiating factor between PTSD and cPTSD has been accompanied by validated assessment instruments, the most widely used being the International Trauma Questionnaire. In a relatively short period, an impressive number of studies have provided support for the reliability and utility of cPTSD and for the construct and discriminate validity of the new diagnostic entity (here, here, here and here). This includes confirmatory factor analysis across diverse samples showing that symptoms of disturbances in self-organisation can be consistently differentiated from the intrusive, avoidance and arousal clusters of PTSD (here and here). Studies applying person-centred statistical approaches have delineated the presentation of PTSD from cPTSD, the latter characterised by high PTSD and high disturbances in self-organisation symptoms (here and here). These presentations can also be differentiated from borderline personality disorder, depression and anxiety (here, here and here).

General population epidemiological research has returned population estimates of ICD-11 PTSD and cPTSD that are within the expected range, with most trauma-affected individuals presenting with PTSD and a smaller number of individuals presenting with cPTSD (eg, population prevalence of 9.0% and 2.6%, respectively). The risk for developing cPTSD has also been linked with the severity and dose of the trauma exposure and is consistent again with the fundamental tenants of the cPTSD diagnosis.

The approach of ICD-11 in identifying two types of traumatic stress responses distinguished by qualitative differences in symptom profile and severity appears preferable to the approach adopted by DSM-5, which incorporated many of the disturbances of self-organisation symptoms into the diagnostic criteria of PTSD, substantially shifting the focus of PTSD from its original conceptualisation in 1980 (here and here). While the battle between diagnostic approaches is yet to be fully resolved, the emerging body of evidence supporting the diagnostic integrity of the ICD-11 conceptualisation of cPTSD is likely to provide the foundation for significant research advancements over the years ahead.

Now that the core features of the cPTSD response can be reliably and validly identified, the next step will be to determine the course and prognosis of cPTSD and establish what, if any, are the implications of cPTSD for management and treatment.

It is likely that patients with cPTSD may benefit not only from trauma-focused interventions but also interventions that target the disturbances of self-organisation components of their clinical presentation. If evidence of improved outcomes through the combination of treatments is provided for this group, then the question of how to optimally deliver this will be important. Traditionally, a triphasic approach has been recommended that involves establishing safety and skills development, followed by trauma-focused intervention and reintegration. Whether such a treatment sequence is preferable is an empirical question that requires further clinical research.

For those of us who work with survivors of trauma, and indeed for survivors themselves, the delineation of cPTSD in ICD-11 may represent an equally important watershed in advancing the understanding of traumatic stress responses as was the initial recognition of PTSD in 1980. The coming years will be a critical time for the research and clinical community to better understand the implications of this new diagnosis.

Professor Zachary Steel, psychologist, holds the Professorial Chair of Trauma and Mental Health at St John of God Richmond Hospital, and is based at the Black Dog Institute and the School of Psychiatry UNSW.

Dr David Berle is a Senior Lecturer in the Discipline of Clinical Psychology for the Graduate School of Health at the University of Technology, Sydney. Dr Berle has worked as a clinical psychologist in a variety of community-based and inpatient mental health settings since 2001, and has particular experience in the treatment of anxiety disorders. He has conducted numerous research projects in clinical settings and was a Senior Research Fellow in trauma and mental health in the School of Psychiatry UNSW and St John of God Health Care.

Dominic Hilbrink is a senior clinician at St John of God Richmond Hospital. A social worker by training, Dominic has worked as a specialist in the area of service-related trauma since 2001, treating veterans from a range of conflicts, emergency services personnel and civilians with complex trauma histories.

Associate Professor Samuel Harvey, is Chief Psychiatrist at the Black Dog Institute where he runs the depression clinic and leads the Workplace Mental Health Research Program.