Complex Trauma: A Spectre in Psychiatry

I graduated from my BSc in Psychology in 2020. At the time I was so focused on my research project which focused on trauma and psychosis-like experiences in healthy people, it made the pandemic feel thankfully distant.


I started an MSc in Neuroscience in 2020 too, and during this time I received a post-traumatic stress disorder (PTSD) formulation. Totally unrelated to the above events I should add — distant memories instead for me.


There are many though who will develop post-traumatic stress responses due to COVID-19, either directly through experiencing the illness, or as healthcare workers or loved ones, and indirectly through deficits in important social and support services or networks.


This is why I believe traumatic stress is such an important issue to discuss —  because it is an endemic issue at all levels of our society, in the past, present and unfortunately the future.


What is meant by complex trauma or complex post-traumatic stress disorder (CPTSD)?


You may be wondering what is the difference between PTSD and CPTSD (complex post-traumatic stress disorder), are they not the same thing? Most of us have heard of PTSD, but CPTSD is something we come across less. Would it truly make a difference for the provisions provided to individuals seeking help? This is a hotly debated topic for researchers and clinicians in this field.


CPTSD includes more symptoms than PTSD. Particularly, having trouble regulating emotions and disturbances in the sense of self, in addition to PTSD symptoms — PTSD symptoms typically include re-experiencing (flashbacks, nightmares, feeling numb, distant and avoidant, and hyperarousal symptoms (irritability, heightened vigilance, difficulty sleeping).


Many people who could be diagnosed with CPTSD receive diagnoses for other disorders including PTSD, ‘personality disorders’, anxiety, or depression, amongst others. This could be due to the fact that CPTSD is only included in one of the two main diagnostic manuals, the International Classification of Disease 11 (ICD-11). Diagnostic manuals, and the ICD in particular, is a manual used internationally to classify symptoms of disorders or disease, and sometimes the causes. However, when it comes to CPTSD, knowledge is not widely distributed among medical professionals and questions remain regarding the validity of the diagnosis (is it clinically useful? Is it a label that we can measure properly and separate from others?).


CPTSD was first formulated by Judith Herman (1992), citing the limitations of PTSD to describe the mental health consequences and behaviours associated with relatively brief experiences of trauma, compared to the far longer and repeated experiences of trauma that are unfortunately just as common. This includes experiences such as sexual abuse or physical abuse in childhood, sexual exploitation and human trafficking, prisoners of war or concentration camps. This is no means an exhaustive list; it is foreseeable how being in poverty, prolonged bullying or racial injustices might also produce a similar presentation.

Childhood trauma, as an example, is incredibly common, 1 in 5 children experience severe maltreatment in the U.K. and adverse experiences are associated with multiple physical and mental health consequences. In my perspective, trauma is a public health crisis like obesity, a significant and prevalent risk factor for mortality and morbidity.

Complex trauma in Psychiatry

Herman noted that CPTSD has a capacity to almost mirror any type of personality disorder due to the severe and enduring consequences it creates that PTSD is not sufficient to describe. The ICD-11 has quite a helpful way of thinking about personality disorders, which is to have a broad core personality disorder criteria involving dysfunction around how you see yourself and/or in relationships with others. Then it specifies prominent patterns of behaviour such as having borderline, dissocial (antisocial) or Anankastia (extreme perfectionism or rigidity) traits, amongst others. The CPTSD label can imbue a sense of causality to this, yet it may lose some specificity. This I believe is both the strength and weakness of the CPTSD label.

The prevalence and surprising severity of the trauma children experience would suggest complex trauma is everywhere, perhaps CPTSD is not just mirroring other mental health disorders, but for many, their diagnoses are part of the complex trauma they have experienced. For example, a review of studies conducted nearly a decade ago suggested childhood adversity was strongly associated with psychosis, accounting for 33% of cases. For many individuals with psychosis, do they not suffer from a form of complex trauma response?

Complex trauma in Psychosis:

The effects of trauma on the brains of those diagnosed with schizophrenia have been synthesised by a review which suggests that chronic stress hormone activity has been shown to damage cells in the brain in brain regions such as the prefrontal cortex, an area which important for appraising the processed information about our environment and valuating potential decisions and outcomes, and the hippocampus, a brain region implicated in our memory function.

Hypothalamus-Pituitary-Adrenal (HPA) axis, a brain region involved in managing the body’s stress response, is also dysregulated due to this chronic stress response, which means the brain is unable to manage its response to stress in later life, locked in a very distressing feedback loop. This has been linked with some of the differences in a neurotransmitter called dopamine, found in people with psychosis, which could be involved in producing some of the acute symptoms people experience, like hallucinations.

Trauma elsewhere:

Trauma also appears in more common mental health complaints. The research in this area is vast and complex with seemingly contradictory findings that need to be navigated. Some key takeaway findings from a review published in the scientific journal, Neuron, include the effects of early life stress increasing the risk of depression, bipolar disorder, PTSD and suicide, and numerous health risks in a dose-response way (i.e., multiple instances of early life stress increase risk cumulatively).

The experience of depression also increases the risk of developing PTSD from this early life stress. These experiences are associated with HPA-axis hyper or hypoactivity and this is associated with an increased or blunted stress hormone response and immune response. There are potentially two pathways here, one of increased function and one of decreased function, this is still an ongoing debate.

I should add, I’ve noticed they would often show trauma-related imagery in many human studies — so what would be the role of dissociation here? From what I understand of dissociation, including personally, it would detach and blunt my response to such images which might mean there would not be the expected hyperactivation.

Lastly, as seen in psychosis, it affects the brain as we develop, impairing brain growth and the capacity for neurons to communicate, this could point to a general effect of trauma on the developing brain. It is possible the clinical presentation, i.e., what diagnosis or formulation you might receive depends on genetic or contextual environmental factors that occurred during the early life trauma.

Where does this leave complex trauma?



If forms of complex trauma are everywhere in nearly all psychiatric diagnoses, it presents a significant, often key environmental risk factor to the severity of distress an individual might experience. Yet we also have a specified diagnosis of CPTSD which in the majority of incidences would relate to the very same early life trauma. So, would CPTSD reasonably explain the majority of psychiatric disorders for those with that life history, and if so, which way forward should we choose?


Psychiatric classification is a little bit taxonomic — like the animal kingdom. In the past, animal specimens would be classified based on superficial characteristics (i.e., the equivalent of symptoms), but the advent of genetic sequencing has inevitably led to discoveries that some specimens do not belong to certain species, as it is the case for psychiatry as the shared bio-psycho-social causes are uncovered that are common to different disorders, even in the case of genetic risk.


I found my formulation of PTSD to be validating. It is very possible to describe it as prolonged incidences as opposed to a single terrible incident, but the infrastructure to diagnose or formulate CPTSD is not widely available in the NHS. I wonder then, would such a diagnosis help that 1/3rd of psychosis cases attributable to trauma, when psychotic experiences are not included within its criteria? There is a risk of assigning an insensitive diagnosis that has none of the strengths of the previous one despite the strength of recognising the cause. Clearly, CPTSD is inadequate to be generalised beyond the scope of the initial criteria.


Yet a complex post-trauma stress response seems key to many more mental health complaints than those that would be included within the CPTSD diagnosis. Is that not another way of just saying CPTSD though? Perhaps it could look like the figure below.


Figure 1. This shows a simplified gradient between trauma presence/severity (blue) and genetic risk (red). Psychosis could be swapped with another mental health complaint and neither would it necessarily exclude multiple simultaneous complaints.

Back to the title — Complex trauma is indeed a spectre in psychiatry, it effectively haunts the classification system by threatening to undermine it, some may see this as a good thing, and others may not.


Complex trauma also haunts people and society but arguably the best window into alleviating this is through clinical recognition. It could come in the form of phenotypic stratification which is a way of classifying complaints more specifically on symptoms and inferences about causes than using often heterogenous diagnostic labels.


Alternatively, multi-dimensional continuums of human distress have been suggested, in which complex trauma could be included within, which I have attempted to show with Figure 1.


There is an irony perhaps that complex trauma is uncomfortably present, much in the same way it is with people who experience it.