By Emma Hinze, Professor Tony Attwood and Dr. Michelle Garnett.
When experiences are extremely emotionally painful, cause psychological distress and significantly overwhelm an individual’s capacity to cope, we refer to them as trauma. These experiences vary widely, from interpersonal conflicts to life-threatening events, and can have profoundly different impacts depending on an individual’s sensory sensitivities and communication differences. It’s important to note that while traumatic experiences are common, not all lead to posttraumatic stress disorder (PTSD). PTSD is a specific psychiatric condition characterised by persistent symptoms such as intrusive recollections of the trauma (e.g. nightmares), active avoidance of reminders associated with the trauma, significant mood alterations, and daily heightened autonomic arousal. The likelihood of developing PTSD increases with each additional exposure to trauma, particularly interpersonal traumas such as physical assault or bullying, which can be more psychologically damaging due to their personal and invasive nature (Suliman et al., 2009; Briere et al., 2016).
Trauma Memory Processing in PTSD
Understanding PTSD is best approached by understanding how the brain processes traumatic memories. The dual-system model, as proposed by Brewin et al. (1996), suggests that trauma memories are encoded and stored via two distinct systems: verbally accessible memory (VAM) and situationally accessible memory (SAM). VAM is thought to integrate trauma memories into an individual’s ongoing narrative, facilitating a coherent story of the event and recovery from trauma without developing PTSD. SAM processes the sensory and emotional aspects of the trauma, often leading to vivid, involuntary recollections known as flashbacks. When traumatic memories are stuck in SAM, the development of PTSD symptoms is more likely to lead to increased negative appraisals, hyperarousal, and intrusive recollections.
For autistic individuals, heightened sensory sensitivity may intensify the sensory and emotional encoding of memories, leading to more vivid and persistent flashbacks. Moreover, challenges in working memory and social reasoning can further disrupt the integration of trauma memories into a cohesive narrative, making it harder to process and store these memories in a way that aids recovery. When we understand these neurocognitive differences our definition of trauma can broaden to include sensory and social experiences that many nonautistic people do not experience as being traumatic.
Increased Vulnerability of Autistic Individuals to Trauma
Autistic challenges in social communication and sensory processing can increase their vulnerability to traumatic experiences in other ways. For example, difficulties in interpreting social cues and navigating social interactions can lead to frequent misunderstandings, bullying, and social exclusion, all of which can be seen as traumatic experiences that are reported at higher rates in the autistic population compared to their neurotypical peers (Haruvi-Lamdan et al., 2018; Hoover, 2015; Kerns et al., 2015). These experiences significantly contribute to the elevated risk of trauma in autistic individuals.
Increased Vulnerability of Autistic Individuals to PTSD
Memory Challenges
Autistic individuals often experience difficulties with working memory and everyday memory, which play a mediating role in the relationship between traumatic experiences and PTSD symptom severity. These challenges affect how trauma memories are processed and recalled, complicating the encoding of contextually rich, verbally accessible memories of trauma. Many autistic individuals have a detailed-focused and sensory-laden processing style, which intensifies the emotional and sensory components of trauma memories. This can lead to the formation of trauma memories that are highly charged and more easily triggered by environmental cues, thereby increasing the likelihood of experiencing PTSD symptoms such as flashbacks and intrusive thoughts.
Broader Range of Potentially Traumatic Events
Autistic individuals may also interpret a broader range of life events as being traumatic, extending beyond the events typically categorised as trauma under DSM-5’s Criterion A for PTSD. This broader interpretation is supported by findings that even non-DSM defined traumatic events can precipitate PTSD symptoms in autistic individuals (Rumball et al., 2021). The propensity to perceive various adverse experiences as traumatic necessitates specialised screening and intervention strategies tailored to the autistic population, who are likely to benefit from approaches that consider their unique sensory and cognitive processing traits.
A Different Neurology for Emotional Processing
The interaction between PTSD and autism characteristics highlights neurobiological and cognitive overlaps that influence how autistic individuals experience and express symptoms. Variations in key neural circuits, particularly in the amygdala and prefrontal cortex, are crucial in emotion regulation and the processing of fear and threats. The amygdala’s role in emotional responses may be hyperreactive in autistic individuals, leading to heightened responses to stress and potentially traumatic events. Conversely, the prefrontal cortex, which modulates amygdala activity and is vital for executive functions and emotional regulation, often exhibits varied or reduced activity or connectivity in both PTSD and autism.
The Role of Hormones
Both PTSD and autism are associated with differences in the functioning of the hypothalamic-pituitary-adrenal (HPA) axis, the core of the body’s stress response system. In autistic individuals, this axis may activate chronically or inadequately, leading to atypical cortisol patterns that impair the body’s ability to manage stress effectively (Taylor & Corbett, 2014). These differences can make stressful events more impactful and overwhelming, heightening the risk of PTSD following traumatic experiences.
Different Sensory and Social Processing
The neurobiological traits of autism, such as enhanced sensory sensitivity and varied processing of social cues, further complicate these interactions. Autistic individuals often perceive a world where sensory stimuli are amplified and social communications are difficult to interpret, increasing their vulnerability to traumatic experiences (Haruvi-Lamdan et al., 2018; Hoover, 2015). Challenges in integrating personal experiences within a coherent narrative can affect how memories of trauma are processed and recalled, often leading to more vivid and distressing trauma memories (Rumball et al., 2021).
Where to From Here?
When we understand the association of autism with trauma, in terms of both the increased vulnerability to autistic people experiencing traumatic events and developing PTSD, we are better informed to be able to protect autistic people from experiencing trauma, recognise and treat PTSD, and support a loved one who is autistic and has PTSD.
To further understand the association of autism with trauma we have developed two brand new events: Trauma and Autistic Children and Teens and Trauma and Autistic Adults. Within these events you will learn:
- why the effects of trauma can be missed in autistic people and autism can be missed in traumatised people
- about the types of events that can cause trauma for autistic people
- the recent research on the association of trauma and autism.
- the similarities and differences between autism and trauma
- the impacts of trauma for an autistic person.
- strategies that can help the person, their partner and/or family
- when to seek professional help and the types of assistance available to help resolve and heal from trauma/s.
Whilst the themes and content description for these events are similar, please note that we have divided the content by age because the research, case examples, impacts, types of support and strategies for each age group differ. As a result, the events are quite different from each other.
References:
Haruvi-Lamdan N., Horesh D., & Golan O. (2018). PTSD and autism spectrum disorder: Co-morbidity, gaps in research, and potential shared mechanisms. Psychological Trauma: Theory, Research, Practice, and Policy, 10(3), 290–299. https://doi.org/10.1037/tra0000298
Ilen, L., Delavari, F., Feller, C., Zanoletti, O., Sandi, C., & Schneider, M. (2024). Diurnal cortisol profiles in autistic adolescents and young adults: Associations with social difficulties and internalizing mental health symptoms. Autism Research : Official Journal of the International Society for Autism Research, 17(8), 1601–1615. https://doi.org/10.1002/aur.3184
Rumball, F., Brook, L., Happé, F., & Karl, A. (2021). Heightened risk of posttraumatic stress disorder in adults with autism spectrum disorder: The role of cumulative trauma and memory deficits. Research in Developmental Disabilities, 110, 103848. https://doi.org/10.1016/j.ridd.2020.103848
Hindera, O. (2023). 33.4 PTSD and ASD: Illuminating Diagnostic Overshadowing. Journal of the American Academy of Child & Adolescent Psychiatry, 62(10), S51. https://doi.org/10.1016/j.jaac.2023.07.293
Kildahl, A. N., Bakken, T. L., Iversen, T. E., & Helverschou, S. B. (2019). Identification of Post-Traumatic Stress Disorder in Individuals with Autism Spectrum Disorder and Intellectual Disability: A Systematic Review. Journal of Mental Health Research in Intellectual Disabilities, 12(1-2), 1–25. https://doi.org/10.1080/19315864.2019.1595233
Briere J, Agee E, Dietrich A. Cumulative trauma and current posttraumatic stress disorder status in general population and inmate samples. Psychol Trauma. 2016 Jul;8(4):439-46. doi: 10.1037/tra0000107. Epub 2016 Jan 11. PMID: 26752099.
Brewin, C. R., Dalgleish, T., & Joseph, S. (1996). A dual representation theory of posttraumatic stress disorder. Psychological Review, 103(4), 670-686.
Haruvi-Lamdan, N., Horesh, D., & Golan, O. (2018). PTSD and autism spectrum disorder: Co-morbidity, gaps in research, and potential shared mechanisms. Psychological Trauma: Theory, Research, Practice, and Policy, 10(3), 290-299.
Hoover DW, Kaufman J. Adverse childhood experiences in children with autism spectrum disorder. Curr Opin Psychiatry. 2018 Mar;31(2):128-132. doi: 10.1097/YCO.0000000000000390. PMID: 29206686; PMCID: PMC6082373.
Kerns, C. M., Newschaffer, C. J., & Berkowitz, S. (2015). Traumatic childhood events and autism spectrum disorder. Journal of Autism and Developmental Disorders, 45(11), 3475-3486.
Lai, M. C., Lombardo, M. V., & Baron-Cohen, S. (2014). Autism. The Lancet, 383(9920), 896-910.
McManus, S., Meltzer, H., Brugha, T. S., Bebbington, P. E., & Jenkins, R. (2009). Adult psychiatric morbidity in England, 2007: Results of a household survey. The NHS Information Centre for Health and Social Care.
Rumball F, Happé F, Grey N. Experience of Trauma and PTSD Symptoms in Autistic Adults: Risk of PTSD Development Following DSM-5 and Non-DSM-5 Traumatic Life Events. Autism Res. 2020 Dec;13(12):2122-2132. doi: 10.1002/aur.2306. Epub 2020 Apr 22. PMID: 32319731.
Suliman S, Mkabile SG, Fincham DS, Ahmed R, Stein DJ, Seedat S. Cumulative effect of multiple trauma on symptoms of posttraumatic stress disorder, anxiety, and depression in adolescents. Compr Psychiatry. 2009 Mar-Apr;50(2):121-7. doi: 10.1016/j.comppsych.2008.06.006. Epub 2008 Aug 23. PMID: 19216888.
Taylor JL, Corbett BA. A review of rhythm and responsiveness of cortisol in individuals with autism spectrum disorders. Psychoneuroendocrinology. 2014 Nov;49:207-28. doi: 10.1016/j.psyneuen.2014.07.015. Epub 2014 Jul 22. PMID: 25108163; PMCID: PMC4165710.
