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Autism spectrum disorder

Autism Spectrum Disorder (ASD) and Post-Traumatic Stress Disorder (PTSD) are two clinical entities whose relationship remains poorly understood, despite the growing body of knowledge on each of these disorders. While people with autism are more exposed to violence and traumatic events, their vulnerability to PTSD remains largely unknown. This lack of knowledge is partly due to the atypical manifestations of PTSD in autistic people, often confused with the characteristic features of ASD. The classic signs of PTSD, such as hypervigilance, reliving or avoidance, may present differently, or even go unnoticed, making them particularly difficult to identify.

This dossier addresses these issues, drawing on a review of recent research on the subject, interviews with specialists, and the testimony of a person concerned.

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Contents
A higher risk of PTSD in people with ASD
Atypical manifestations of PTSD
Diagnosis often delayed or misdiagnosed
Adapting care to the particularities of ASDs

A higher risk of PTSD in people with ASD?

The links between autism spectrum disorder (ASD) and post-traumatic stress disorder (PTSD) are still poorly understood. However, one thing is clear: people with autism seem to be affected by this disorder far more often than the general population. A systematic review of the literature published in 2024 by Prof. Alice M.G. Quinton, a researcher at King's College (London) and her colleagues, highlights the fact that autistic adults, like children, often present more severe symptoms of PTSD than those observed in neurotypical people, with a significantly higher prevalence.

A few years earlier, Rumball et al (2020) provided further clarification on the subject: almost 45% of autistic adults who have experienced a traumatic event meeting DSM-5 criteria have symptoms severe enough to make a probable diagnosis of PTSD. Even when the definition of trauma is broadened to include events which, although perceived as traumatic by those concerned, do not meet the classic DSM-5 criteria, this figure remains just as high, reaching around 43%.

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These figures beg the question: are autistic people more vulnerable to trauma because of specific characteristics? Or is the higher prevalence explained by more frequent exposure to hostile environments?

Read our article on childhood adversity

When vulnerability is combined with autistic features

The specific features of ASD can contribute to greater fragility in the face of traumatic experiences. Several factors aggravate this risk:

Cognitive rigidity and repetitive thinking

In people with autism, difficulties with mental flexibility are often accompanied by repetitive functioning, involving both behaviors and thoughts. This tendency to "loop" around negative memories or feelings is not a feature of PTSD in autistic people. However, when a trauma occurs, it can reinforce certain symptoms, by maintaining the distressing affects linked to the event.

Sensory hypersensitivity

A noisy or unpredictable environment can provoke intense panic reactions, amplifying the emotional charge of certain experiences. This phenomenon could explain why people with ASD develop PTSD more frequently after significant stress.

Specific social triggers

People with autism are more frequently socially rejected because of their interaction difficulties, and are more often the victims of harassment. In an interview with Cn2r, Professor Ofer Golan (Bar-Ilan University, Israel) explained that "certain situations, such as social exclusion, harassment or mockery, can be experienced as real aggression by people with ASD, even if they do not correspond to DSM-5 criterion A."

How can we adequately assess PTSD in people with ASD when current diagnostic criteria, designed for a neurotypical population, do not take these subjectively traumatic experiences into account?


Although the symptoms observed, notably hypervigilance and ruminations, may be reminiscent of those of classically observed PTSD, there seems to be a need for further research to better understand how these mechanisms are specifically articulated in people with autism, and to explore new diagnostic methods that might better reflect this reality.

Post-traumatic stress disorder (PTSD) in people with autism presents peculiarities that seriously complicate its clinical identification (Rumball et al., 2020). Conventional diagnostic criteria, designed for neurotypical populations, struggle to capture these atypical manifestations, often marked by cognitive rigidity, sensory hypervigilance and avoidance behaviors that can be misinterpreted.

Brooding rumination

In some people with autism, there is a marked tendency to ruminate repeatedly on events experienced as threatening, unfair or destabilizing, particularly when they involve social interactions. This form of rumination, known as broodingThis form of rumination, known as brooding, is characterized by passive, self-referential recollection, which takes hold over time without leading to distancing or emotional understanding.

This is not a phenomenon specific to ASD: rumination brooding is well documented in anxiety and depressive disorders, where it is a known risk factor. In a study of autistic adults without intellectual disability, Golan et al. (2021) showed that this form of rumination could play a mediating role between ASD and the intensity of PTSD symptoms, particularly in the dimensions of hyperactivation and negative alterations in mood and cognition.

Interviewed by Cn2r, psychology professor Ofer Golan from Bar-Ilan University (Israel) explains:"This type of rumination creates a mental loop in which the person constantly returns to what happened to them, to what they could have done, without being able to free themselves from it", before adding: "Rumination and attention to detail, combined with low mental flexibility, make it difficult to move on. The risk is to remain frozen in the event, without being able to integrate it."

 

In this context, brooding appears not as a marker of PTSD in autistic people, but as a vulnerability factor likely to reinforce the onset and maintenance of post-traumatic symptoms, in certain exposed individuals.

How does brooding aggravate PTSD?

  • It feeds persistent psychic distress, keeping the focus on the most negative aspects of the event without allowing for distancing or emotional regulation.
  • The cognitive rigidity frequently observed in ASD limits the ability to interrupt this mental loop and consider alternative perspectives or interpretations.
  • Repetitive focus on self-referential thoughts - often centered on injustice, guilt or powerlessness - contributes to maintaining a state of physiological and cognitive hyperactivation.
  • By preventing the integration of the memory into a coherent narrative, this form of rumination complicates the processes of psychic elaboration needed to alleviate symptoms.

In their work, Horesh and Golan highlight the value of targeting these processes in therapeutic interventions. Although clinical research is still in progress, certain cognitive-behavioral approaches focusing on mental flexibility could help reduce the impact of these ruminations in autistic people confronted with trauma.

prims light falling face shirtless boy scaled - Cn2r

Higher exposure to violence and harassment

People with autism are particularly vulnerable to physical, emotional and sexual violence. Because of their communication difficulties and their sometimes literal interpretation of social interactions, they can find themselves helpless when faced with abusive or manipulative situations. "Social interactions are a major source of stress for people with ASD, especially when the implicit rules of communication are unclear," point out researchers Danny Horesh and Ofer Golan.

The figures are alarming: nearly 44% of people with autism have experienced some form of violence in their lifetime. Harassment affects 47% of them, cyberstalking 13%, childhood abuse around 16% and sexual assault 40%. Even more worrying, 84% of victims of one type of violence had also suffered other forms of abuse. Re-victimization appears to be common, and contributes to the intensification of PTSD symptoms.

Discover our dossier on sexual violence

Ordinary environments, not always protective

So-called "ordinary" living environments do not always provide autistic people with the necessary conditions of safety. In their meta-analysis, Trundle and colleagues (2023) indicate that, in the absence of appropriate support, these environments can foster isolation, and even expose people to various forms of violence or abuse, sometimes repeated. Conversely, when appropriate support is in place - whether within a school, a medical-social institution or an association - the risk of victimization seems to be better contained.

A neurobiological hypothesis
Researchers are beginning to understand why some people with ASD seem particularly vulnerable to PTSD. A recent study5 points to an atypical brain activity: that of parvalbumin interneurons. Their dysfunction could reinforce the memorization of traumatic events, exacerbating the emotional impact of these memories. A discovery that could pave the way for new treatment modalities adapted to people with ASD.

Diagnosis often delayed or misdiagnosed

Identifying post-traumatic stress disorder (PTSD) in people with autism remains a major challenge that goes far beyond the simple recognition of symptoms. This problem has its roots in a phenomenon known as "diagnostic overshadowing": clinicians often tend to systematically attribute clinical manifestations to autism spectrum disorder (ASD), even when underlying trauma is present.

When symptoms are confused with ASD

PTSD symptoms in people with autism can take on unexpected forms, seriously complicating their identification. Unlike clearly identifiable reliving or avoidance behaviors, the manifestations observed in this population are often assimilated to features of ASD, thus reinforcing diagnostic errors.

Among the manifestations of PTSD in people with autism, some can easily be confused with features of ASD, complicating their clinical recognition. These include:

  • An increase in repetitive behaviors, which may reflect an attempt to regulate anguish that is difficult to channel;
  • Strong, sometimes explosive emotional reactions to stimuli perceived as threatening, often interpreted as a simple difficulty in emotional regulation specific to autism;
  • Sensory or bodily hypersensitivity, often linked to a prolonged state of alertness, but mistakenly considered a sensory characteristic of ASD.
  • Difficulty identifying, formulating or sharing emotional experiences, linked to particularities such as alexithymia or communication disorders, which tend to mask suffering.

Symptomatic overlaps between autism spectrum disorder (ASD) and posttraumatic stress disorder (PTSD). Adapted from Stavropoulos, K. K.-M., Bolourian, Y., & Blacher, J. (2018). Differential Diagnosis of Autism Spectrum Disorder and Post Traumatic Stress Disorder: Two Clinical Cases. Journal of Clinical Medicine, 7(4), 71. https://doi.org/10.3390/jcm7040071

Untitled 4 - Cn2r

The challenge of differential diagnosis

In some people with autism, the symptoms of PTSD can manifest themselves in an atypical way, sometimes blending in with the characteristic features of ASD. This symptomatic proximity makes diagnosis particularly complex, especially when the traumatic history is not explicitly identified or formulated.

In this context, the analysis of developmental history appears to be a central approach to better distinguish neurodevelopmental disorders from traumatic responses. As psychiatrist Hélène Vulser, also a senior lecturer at the Sorbonne and head of the Centre du Neurodéveloppement Adulte at Hôpital Pitié Salpêtrière, points out:

"Developmental history is an essential key to differentiating ASD from PTSD. If the disorders appeared after a trauma, then the hypothesis of psychotrauma must be seriously considered."

She also stresses the need to compare this history with the clinical examination, in order to assess whether the behaviors observed are ASD, PTSD or another disorder, such as ADHD.

Furthermore, a recent study published in the British Journal of Psychology by Sarr and colleagues highlights the value of specific clinical tools, such as the Coventry Grid, in refining this distinction. This observational scale, originally designed to differentiate between ASD and attachment disorders, can also be used to identify atypical post-traumatic manifestations, too often confused with autistic features.

How do you diagnose PTSD when communication is absent?

Most current tools rely on the patient's ability to verbalize symptoms. This excludes many people with limited communication skills. Quinton and colleagues (2024) stress the urgent need to develop more inclusive assessment methods, based on behavioral observation and adapted communication tools.

To better assess PTSD in these individuals, several strategies can be considered:

  • Observe sudden behavioral changes such as unexplained agitation, social withdrawal or severe avoidance of certain situations.
  • Use visual aids or alternative communication tools to express traumatic experiences without using spoken language.
  • Take into account the testimonies of loved ones and professionals who work with the person on a regular basis.
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Interview with Marie Rabatel: a look at the vulnerability of women with ASD to PTSD

A committed figure in the fight for recognition of violence against autistic women, Marie Rabatel shares her views with Cn2r. She looks at the mechanisms that make autistic women more vulnerable to PTSD, and the difficulties that still stand in the way of their recognition and treatment.

Read the interview with Marie Rabatel

Adapting care to the particularities of ASDs

When an autistic person is diagnosed with PTSD, it's hard to think of a treatment plan that's truly adapted to their particular needs. Existing treatments are designed primarily for neurotypical populations, and are therefore often inadequate. Appropriate intervention therefore requires careful adaptation, taking into account both the atypical manifestations of the trauma and the specific characteristics of autism.

Rethinking conventional therapies

Trauma-focused cognitive-behavioural therapies (TCB-CT) are now widely accepted as a treatment for PTSD. However, when it comes to autistic patients, their application requires meticulous adjustments: more structured communication, simplified but precise explanations, detailed visual aids. The involvement of loved ones is not incidental; it is essential, especially when trauma-related behaviors profoundly disrupt daily life.

The same imperative applies to the adaptation of drug treatments. Dr. Hélène Vulser explains: " With autistic patients, we start with lower doses and gradually increase, as people with neurodevelopmental disorders tolerate treatments less well." According to Dr. Vulser, educational approaches can also be a valuable recourse, particularly when the symptoms of trauma and profoundly alter daily life.

Creating an environment conducive to care

The care environment plays a decisive role. A place that seems innocuous can become a source of stress for an autistic person: sudden noises, overly intense lighting, aggressive sensory stimuli. The program developed by the UBC ASAP Lab (2023) at the University of British Columbia recommends simple but essential adjustments: regular breaks, soothing objects such as weighted blankets or anti-stress toys. Such adjustments can considerably improve the therapeutic environment.

Living differently with traumatic thoughts

Dealing with traumatic thoughts, particularly when they take the form of persistent rumination, is a major challenge. Acceptance and Commitment Therapy (ACT) proposes a different approach: accepting these thoughts without trying to chase them away at all costs. Using mindfulness and cognitive defusion techniques, this method helps to reduce their emotional grip, without necessarily imposing direct confrontation, which could amplify the distress.

 

What is cognitive defusion?
Cognitive defusion, inspired by Acceptance and Commitment Therapy (ACT), aims to change the relationship we have with our thoughts. It's not a question of fighting them or making them disappear, but of observing them with more distance. The idea is to recognize these thoughts as simple mental events, without giving them excessive power. (Source: Cognitive Defusion Self-help Resource, Sydney University (2024))

Cooperating to better meet needs

Given the difficulties involved in managing PTSD in autistic people, collaboration between psychotrauma specialists and ASD professionals is essential. " When an adult with autism suffers from PTSD, we work together to adapt care to their specific needs," explains Dr. Hélène Vulser. This collaboration takes the form of joint consultations, ongoing dialogue between teams and additional support provided by the Autism Resource Centers (Centres de Ressources Autisme - CRA).

Offering genuinely adapted care

Managing PTSD in people with autism requires more than just superficial adjustments. It's not simply a question of adapting existing treatments, but of building methods that truly respond to the specificities of ASD. To achieve this, more research, inter-professional collaboration and, above all, careful listening to the people concerned are essential.

The sources for this dossier are available in the pdf document at the top of the page.

PDF - TSA file
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