The majority of people will, at some point, experience a traumatic event, but only 3.9-5.6% will develop a post-traumatic stress disorder, or PTSD (WHO, 2024).

In autistic people, PTSD may be especially pronounced through maladaptive coping and traumatic memories. Autistic individuals tend to exhibit high avoidance coping, attentional bias towards threatening stimuli, and other autism-associated characteristics or tendencies that, despite being precursors of PTSD, are often dismissed as a ‘normal’ part of ASD (Ehlers & Clark, 2000; Lage et al., 2024).

This can lead to a ‘diagnostic overshadowing’ bias, which means that the PTSD-related challenges and unique features of PTSD in autistic people go unrecognised. Quinton and colleagues (2024) from King’s College London bring this bias into the spotlight in their review of the methods of PTSD assessment and the core symptoms of PTSD in autism.

Methods

The authors followed PRISMA guidelines and the inclusion criteria as in Rumball (2019). The review included studies published in English and samples with formal diagnoses of PTSD and ASD. The authors reviewed a wide range of studies: cross-sectional, case studies, case-control, experimental, longitudinal, and randomised controlled trials.

A total of 18 studies were included in the review. These were the new studies identified after Rumball’s review (2019). For quality assessment, the researchers used the modified Newcastle-Ottawa Scale and Joanna Briggs Institute checklist.

Results

All studies in this systematic review had an assessment of PTSD in autistic people. Three of the 18 studies were case studies; the other 15 will be referred to as “group studies” (like in Quinton et al., 2024). Most studies had mixed genders, with the proportion of women/girls ranging from 15.4% to 61.92%. Three studies out of seven that considered the role of gender reported sex differences, reported that autistic women had significantly more PTSD symptoms, whilst other studies found no sex differences.

Assessment and Prevalence of PTSD

Group studies balanced the use of questionnaires and open-ended questions/interviews to assess trauma exposure in autistic people. Example events/experiences included difficulties socialising, being bullied, being abandoned, experiencing abuse, and following an autism intervention. Overall, autistic populations had higher trauma exposure and negative social events than their non-autistic peers. Also, autistic people had more PTSD symptoms than their non-autistic counterparts. These symptoms were intrusion, negative cognition, thought suppression, rumination, and poorer working and everyday memory.

The review identified these measurement tools used across the studies to assess PTSD symptoms in autistic people:

• PLC-5 (PTSD checklist for DSM-5);
• Impact of Event Scale-Revised;
• Adapted Anxiety Disorders Interview Schedule;
• Self-report of professional psychiatric diagnosis;
• PTSD-specific item from Child and Adolescent Symptom Inventory;
• UCLA post-traumatic stress disorder reaction index for DSM-5.

The authors estimated that around 5.14% of autistic children and adolescents reported current PTSD diagnosis and 5.22% reported lifetime PTSD diagnosis. Among autistic adults, up to 20% reported a PTSD diagnosis in their lifetime.

Treatment of PTSD

The review identified four studies that looked at the treatment of PTSD in autistic people.

Eye Movement Desensitisation and Reprocessing (EMDR) is a therapy where patients briefly focus on trauma memories while undergoing stimulation of the left and right sides of the body through guided eye movements. EMDR aims to reduce the intensity and emotional impact of traumatic memories. One study in this review (Lobregt-van Buuren et al., 2019) showed that EMDR reduced PTSD symptoms and psychological distress, and, therefore, may be an effective treatment option for autistic people with PTSD.

Meanwhile, three case studies considered other treatment options, including Narrative Exposure Therapy, adapted CBT, trauma-informed care, and exposure-based intervention. The latter was found to be distressing as it worsened the participant’s avoidance symptoms (Kildahl & Jørstad, 2022). Other interventions showed some benefits for reducing symptoms including self-harm, but some results were not reported (e.g., for adapted CBT).

Adaptations that were undertaken to tailor interventions for autistic people included dedicating more time to therapy and informed consent completion. Staff members were informed about non-verbal communication in autism, and one study conducted sessions during outdoor walks for participants’ comfort.

Quality assessment of included studies

The review reports that most studies were of high quality, but several areas require more attention:

• Potential selection bias towards the population who has an official diagnosis.
• Online studies had a predominantly female sample, while in-person studies involved predominantly male participants.
• Most studies did not differentiate between sex and gender, limiting gender inclusivity.
• Studies tend to recruit autistic people with good verbal abilities and higher-than-average IQ.
• None of the studies were participatory.

Conclusions

The authors concluded that since Rumball’s review in 2019, academic interest in PTSD in autistic people has increased, but the field is still in its infancy. The rates of PTSD in the autistic population were comparable to those in neurotypical populations, but symptom prevalence was higher in autistic cohorts. More research is necessary to understand the aetiology differences between autistic people with PTSD and their non-autistic counterparts. The authors emphasised that it is crucial to:

understand specific cognitive strengths and vulnerabilities that autistic people have in relation to the development and maintenance of PTSD
– Quinton et al., 2024, p. 29

Additionally, researchers should account for how these differences may impact the assessment and treatment of PTSD in autistic people, as:

this will ultimately lead to effective ways to diagnose and address PTSD in autistic children and adults
– Quinton et al., 2024, p.32

This underscores the importance of considering the unique cognitive profiles of autistic individuals, to improve outcomes for those with PTSD.

Strengths and limitations

This review has several strengths, such as transparency, a clear research question, and use of validated tools to assess study quality.

The authors raised a limitation of excluding people who self-identify as autistic, suggesting a bias towards a limited number of individuals who can afford to get diagnosed. In the UK, only 4.9% of people with referrals for autism assessment get the appointment within the recommended timeframe (NHS, 2024). The alternative is a private assessment that costs, on average, around £2,000, according to Gesher Assessment Centre (2024). However, I would argue that there is an additional issue with trust in self-diagnosis; e.g., autistic individuals report clinicians’ mistrust as one of the key barriers to receiving a timely diagnosis (Lewis, 2017). It is important to bridge this gap by increasing the affordability and accessibility of formal autism assessment and through recognising self-diagnosis in participant recruitment.

Current literature also appears to have limited sample diversity. For instance, the studies only included individuals with high IQ and good verbal abilities, which creates a biased view of PTSD in the autistic community. There was also an interesting pattern of more females taking part in online studies, while more males participated in in-person studies. I would be keen to understand the reasons behind such distribution; e.g., is female “camouflaging” involved in online participation? Or, potentially, do autistic men/boys receive more support than autistic women/girls? Finally, I appreciated that Quinton and colleagues noted that most studies were gender-binary, calling for more gender-inclusive research practice.

Implications for practice

This review opens up avenues for future investigation of the unique symptoms of PTSD and its aetiology in the autistic population, as well as the individual differences within the autistic populations (e.g., IQ, gender, race, etc.). Additionally, the subjective experience of trauma is, perhaps, even more important than what ‘objectively’ qualifies as ‘traumatic’. One way to address this gap is through qualitative studies, which were not included in the review but have a strong potential to unveil the unique experiences of the autistic population.

As for clinical implications, there is emerging evidence that EMDR might be a promising treatment. However, clinicians should be aware of the potential harms of exposure-focused treatments due to their propensity to enhance avoidance symptoms that maintain PTSD. Additionally, clinicians working with individuals with ASD should be mindful of the ‘diagnostic overshadowing’ bias. For instance, reflecting on the root causes of certain difficulties being due to potential trauma or associated with the autistic profile. This can be supplemented with the existing measures, such as PLC-5, but further development of autism-specific scales is warranted. Finally, when enquiring about potential traumatic experiences, clinical practitioners should account for differences in what is experienced as traumatic by individuals with ASD and build a formulation accounting for these differences.

Statement of interests

No conflict of interest to declare.

Links

Primary paper

Quinton, A. M. G., Ali, D., Danese, A., Happé, F., & Rumball, F. (2024). The assessment and treatment of post-traumatic stress disorder in autistic people: a systematic review. Review Journal of Autism and Developmental Disorders. https://doi.org/10.1007/s40489-024-00430-9

Previous systematic review

Rumball, F. (2019). A systematic review of the assessment and treatment of posttraumatic stress disorder in individuals with autism spectrum disorders. Review Journal of Autism and Developmental Disorders, 6(3), 294-324. https://doi.org/10.1007/s40489-018-0133-9

Other references

Ehlers, A. and Clark, D. M. (2000). A cognitive model of posttraumatic stress disorder. Behaviour Research and Therapy, 38(4), 319-345. https://doi.org/10.1016/s0005-7967(99)00123-0

Gesher Assessment Centre. (2024, Jul 29). How much does a private autism assessment cost?

Kildahl, A. N. and Jørstad, I. (2022). Post-traumatic stress disorder symptom manifestations in an autistic man with severe intellectual disability following coercion and scalding. Journal of Intellectual & Developmental Disability, 47(2), 190-194. https://doi.org/10.3109/13668250.2021.1995930

Lage, C., Smith, E. S., & Lawson, R. P. (2024). A meta-analysis of cognitive flexibility in autism spectrum disorder. Neuroscience & Biobehavioral Reviews, 157, 105511. https://doi.org/10.1016/j.neubiorev.2023.105511

Lewis, L. F. (2017). A mixed methods study of barriers to formal diagnosis of autism spectrum disorder in adults. Journal of Autism and Developmental Disorders, 47(8), 2410-2424. https://doi.org/10.1007/s10803-017-3168-3

Lobregt-van Buuren, E., Sizoo, B., Mevissen, L., & Jongh, A. d. (2018). Eye movement desensitization and reprocessing (EMDR) therapy as a feasible and potential effective treatment for adults with autism spectrum disorder (ASD) and a history of adverse events. Journal of Autism and Developmental Disorders, 49(1), 151-164. https://doi.org/10.1007/s10803-018-3687-6

National Health Service. (2024, Nov 14). Autism Statistics, October 2023 to September 2024.

World Health Organization. (2024, May 27). Post-traumatic stress disorder.

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