For a long time the link between trauma and psychosis was not seen

For example:

The well-known Yale psychologist Woo-kyoung Ahn studied mental health care and concluded that clinicians think in terms of a ‘biological versus psychosocial’ divide.

This dichotomy holds that traumatising events in childhood are a good explanation for later mental health problems such as depression, anxiety and bulimia, but not for ‘serious’ conditions such as ‘schizophrenia’. The assumption is that serious conditions such as ‘schizophrenia’ are caused by internal biological factors.

For a long time this was how things worked in mental health care, especially in its dominant version from North America:

If you had depression and were traumatised, psychotherapy was considered indicated to process the traumas.

If you had a diagnosis of ‘schizophrenia’ (psychosis susceptibility) or bipolarity (bipolar mood susceptibility) and you were (severely) traumatised? Then no psychotherapist wanted to treat you, because of the myth (never investigated or demonstrated) that trauma treatment would further destabilise your ‘brain disease’. You would destabilise, with a risk of relapse, chronicity and even suicide.

In summary

Trauma in childhood was not allowed to be a cause of psychotic states. And if these people had gone through trauma anyway, psychotherapy was contraindicated because it would destabilise their ‘brain disease’. From North America these ideas found their way into academic psychiatry in Europe, especially in the United Kingdom, and also in the Netherlands.

Resistance to a possible role for trauma in psychosis

The psychiatrist and researcher Fuller Torrey

The American psychiatrist and researcher Fuller Torrey has always worked hard for people who are more susceptible to psychosis than average. He drew attention to the appalling situation of people in American prisons, and to the inhumane way in which people in the big cities were (and are) left to their fate, condemned to a life on the streets full of violence.

Yet scientific consideration of the possibility that these people’s symptoms might have something to do with childhood trauma met with his most sarcastic opposition. He painted a picture of psychotherapists falsely talking people with a diagnosis of schizophrenia or another psychosis into having a trauma, in order to further their own financial interests.

Searching with conviction for the ‘schizo-virus’

Fuller Torrey himself has spent his whole life searching for a ‘schizo-virus’ or ‘schizo-parasite’. It was a road with plenty of funding from influential and wealthy American families, but without concrete results.

For him and for others, the belief that an early viral infection was the cause of people’s distress was a self-evident truth. They wanted nothing to do with the idea that early trauma might play a role. More than that: to them it was proof of charlatanism.

I mention him here to illustrate how much good intentions and a distorted view can be at odds with each other.

Is the resistance over?

John Read and Richard Bentall wrote a fascinating article in the British Journal of Psychiatry about the history of the denial of the role of adverse childhood events in psychosis (Read & Bentall, 2012). As a consequence of this denial, mental health care still pays too little attention to it.

With psychosis susceptibility and bipolar mood susceptibility in particular, questions about adverse events in childhood are often asked too little, or with too little sensitivity.

A trauma-informed mental health service

There is also too little attention for the fact that it almost always concerns a cluster of circumstances that reinforce each other.

Such as:

• Poverty
• Neglect
• Maltreatment
• Abuse
• Bullying
• Health problems
• Learning delays
• Addiction problems, and so on

In practice, little is done with the fact that clusters of adversity and adverse events show transgenerational patterns that are sometimes hard to break.

In addition, there is too little recognition of mental and physical phenomena that have to do with the ‘defensive wall’ and the physical and mental survival mechanisms of early adversity and adverse events.

If these are not recognised, the crucial step towards psychoeducation and treatment cannot be taken. Mental health care will therefore have to be trauma-informed.

Subjectivity bias and the link between trauma and psychosis

A shift is now visible. That people with a diagnosis of ‘schizophrenia‘ speak strikingly often about severe trauma in childhood had been noticed for some time and was well documented in research with groups of participants.

But it had never been studied very seriously in academic psychiatry, in the form of methodologically more mature case-control and cohort studies.

The relationship between early trauma and later schizophrenia

Research into the relationship between early trauma and later schizophrenia is quite a challenge, given the various methodological problems it runs into.

People with severe mental health problems will naturally look for reasons why they have been so unlucky. All kinds of things in the past can then be magnified and pointed to as the reason for the distress.

For example:

Perhaps someone witnessed all kinds of arguments between their parents as a child, and remembers how bad they felt about it at the time. Perhaps there was once an uncle who touched someone in a way that made him feel uncomfortable as a child. Perhaps someone remembers that the piano teacher tended to touch her during lessons more often than seemed proper.

Every person has memories of things that happened in the past and that were experienced as more or less traumatic. When we develop mental health problems as adults, we automatically go looking for the ‘why’: every person looks for the reason for their distress. There is nothing wrong with that, but in scientific research it can lead to problems.

Imagine:

Imagine two people who went through something unpleasant in childhood to exactly the same degree. One developed a mental health condition as an adult and the other did not.

If a researcher comes along to question the two, one as ‘patient’ and the other as ‘control’ in a case-control comparison, the person with the mental health problems may be much more inclined than the control person to explain to the researcher that he had a traumatised childhood.

Although the two went through exactly the same amount of trauma, in the memory of the person with the mental health condition it may have been magnified, in the search for reasons behind the present ordeal.

Bias

In methodological terms there may be a ‘bias’ in the research, a form of distortion that can lead to wrong conclusions. In this case one could conclude that childhood trauma is a risk factor for the mental health condition in question.

While in reality the difference between the ‘control’ and the ‘patient’ rests on a subjective reinterpretation of the past under the influence of mental distress. Because of the subjectivity factor, a link between trauma and the mental health condition could be wrongly inferred.

For a long time this problem remained the great point of doubt. It meant that the trauma stories of countless people with psychosis were not heard, let alone that treatment was offered for them.

Research into trauma and psychosis provided the evidence

Despite the formidable problem of the subjectivity bias described above, innovation in research eventually made it possible to prove the link between trauma and psychosis. This research appeared from the early 2000s onwards.

Longitudinal research in children with objectively established trauma

The most important progress came from longitudinal research in Australia and Denmark, in children with objectively established trauma during childhood, whom child protection services had removed from the traumatising environment.

At follow-up, these children turned out to have psychosis more often. Even the most hardened methodologist can say little against this: subjectivity bias, at any rate, cannot explain the findings.

Longitudinal research from the Netherlands also contributed

In the early 2000s the group of the Dutch researcher Jim van Os published with Tony Morrison and John Read (Read et al, 2005) on the possible link between trauma in childhood and psychosis in adulthood. That may be common knowledge now, but at the time it was simply not taken seriously.

There was also a collaboration between the Trimbos Institute in the Netherlands and the same Dutch researchers in 2004. This study of more than 7,000 Dutch people, randomly selected from the general population (the NEMESIS-1 study), showed that exposure to trauma in childhood, established at the first measurement in healthy people, predicted psychotic experiences at later measurements (Janssen et al, 2004).

At the same time, researchers in England devised a fine study too

They examined to what extent the traumas that people reported could be verified by other people around them. The subjectivity bias turned out to be very limited: people with psychosis did not report less objectively about their past than healthy controls.

Overview of all research on the relationship between trauma and psychosis

In 2012 the Dutch group, together with the group of Richard Bentall in Liverpool (Varese et al., 2012), published the first complete overview of all research on the relationship between trauma and psychosis. It showed that trauma is an important risk factor for psychotic syndromes, including syndromes that go by the name of schizophrenia.

The myth that people cannot talk objectively about their traumas was ready to be buried, at least in Europe. In the United States this is far from accepted.

The evidence that treating your trauma in psychosis is safe and effective

Around the same time that research showed a link between trauma and psychosis, researchers also started trials on the treatment of trauma in psychosis. That seems quite ordinary now, but at the time it was seen as a daring experiment.

People with post-traumatic stress disorder (PTSD) and psychosis

The first historic study came from the group of Kim Mueser, in people with post-traumatic stress disorder (PTSD) and psychosis.

Psychotherapy focused on trauma gave a large improvement in PTSD symptoms, other symptoms, perceived health, negative trauma-related beliefs, knowledge about PTSD and the therapeutic relationship with the clinician (Mueser et al, 2008).

The second study in 2009

The second study was published the following year (Frueh et al, 2009). Here too, treatment showed a significant and lasting improvement in PTSD symptoms and other clinical measures, which held at three months of follow-up. The participants also no longer met the criteria for PTSD.

Treatment of trauma is safe and effective

These studies showed for the first time that treatment of trauma can be carried out safely and effectively in people with psychosis susceptibility. This has since been confirmed by many replication studies, including in the Netherlands.

Do you need help now?

PsychosisNet offers information. We do not offer a chat, a helpline or crisis support. If you or someone else is in immediate danger, call the emergency number in your country. If you are thinking about suicide, or you need to talk to someone now, see Need help now? for helplines by country.

Prof. dr. Jim van Os, Chair Division Neuroscience, Utrecht University Medical Centre. Jim works at the interface of ‘hard’ brain science, health services research, art and subjective experiences of people with ‘lived experience’ in mental healthcare. 

Jim has been appearing on the Thomson-Reuter Web of Science list of ‘most influential scientific minds of our time’ since 2014. In 2014 he published his book ‘Beyond DSM-5‘, and in 2016 the book ‘Good Mental Health Care’. In 2026 he published 'Wat psychisch lijden is'.

Want to read more?

Blogs by Jim van Os can be read here

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