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PTSD and autism: Are autistic people more likely to develop post-traumatic stress disorder?

It’s a fairly well-known fact in the autism community and in autism scholarship that if you’re autistic you probably also have PTSD or a considerable history with PTSD. And I’m not using PTSD as a euphemism for having a bit of trauma; I’m talking about the real, clinical diagnosis of post-traumatic stress disorder and all that that entails.

So, what does PTSD entail?

There are four categories of PTSD symptoms and, to receive a formal diagnosis, you need one or more symptoms from each of the four categories. The first category is intrusive symptoms such as unwanted memories or thoughts, recurrent nightmares about the trauma, reliving the trauma experience over and over again and not being able to control it, distress or troubling body sensations when reminded about aspects of the trauma, and so on. In short, there’s a real lack of control and it’s almost like the trauma is controlling you.

The second category is avoidance symptoms such as trying really hard to avoid thoughts, feelings, or memories related to the trauma, or refusing to talk to or even go anywhere near people who remind you of the perpetrator, if a person was the cause of the trauma.

The third category is negative changes in thinking or mood. This can include forgetting or blocking memories of the trauma, very negative beliefs about oneself and distorted beliefs about the trauma (such as, “It’s all my fault,” or “I caused this,” — really beating yourself up with these thoughts), decreased interest in activities that you’d normally find interesting, feeling detached and distant, and so on.

The fourth and final category is hyperarousal. This can include having outbursts at really little things, being easily startled, trouble sleeping, trouble concentrating, etc.

For autistic people, PTSD is extra-complicated. For us, PTSD is also associated with an increase in autism-related symptoms and traits such as an increase in stimming, an increase in meltdowns or shutdowns, an increase in self-injurious behaviour (or maybe we’ve never self-injured before but suddenly start to once PTSD sets in), increased hyperactivity, loss of self-care skills, and sometimes a loss of communication abilities. This can make it challenging to get the social support that we need. Social support is helpful in the prevention, management, and alleviation of PTSD.

Complex PTSD and autism

Also, even when autistic people are successfully treated for PTSD, they often develop it again. For many of us, trauma can build on trauma, on trauma, on trauma, for several years or decades leading to what has been called complex PTSD (C-PTSD), which has some differences in symptoms compared to PTSD, and is believed to be more difficult to treat.

Complex PTSD is typically associated with repeated or ongoing trauma. It’s important to note that C-PTSD is not yet a formal diagnosis in the DSM-5 — the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, which is what’s used to diagnose mental illness in North America. Many experts think it will be added to a future edition of the DSM, and C-PTSD has already been added to the International Classification of Diseases, 11th edition (ICD-11).

From what I know about C-PTSD, it’s almost like the symptoms of PTSD turn into a kind of personality type. The trauma symptoms are so deeply ingrained and have been a part of the person’s life for so long that they become deeply foundational to the person’s psychological makeup and, I’d even say, to their physiological makeup. It really covers everything about their lives and their ability to trust others, relate to the world, be in touch with themselves and their own bodies — It’s a condition that affects the entire person.

I think that the existence of co-occurring autism and C-PTSD can lead to that common confusion between autism and PTSD. It’s really common for people on their journey to diagnosis — in other words, the prediagnosis stage of late-diagnosed autism — to wonder, “Hey, I have these symptoms and traits. Is it autism or is it PTSD?”

My answer? It’s probably both!

In this world (which is designed to best accommodate the neurotypical brain) and with our brains, I think it’s very unlikely to be autistic and not have some experience with PTSD.

Brain differences make it more likely that autistic people will develop PTSD

Do autistic people experience more trauma or are they more susceptible to developing PTSD as a result of trauma? It’s likely a combination of both. Autistic people and other neurodivergent individuals are more likely to be abused and bullied compared to neurotypicals, we’re often seen as easy targets by the predatory type, we’re often naïve and overly trusting (especially as children and teens), and this is the case whether or not other people know we’re autistic and whether or not we ourselves know we’re autistic.

Interpersonal trauma, like bullying and abuse, is associated with the development of PTSD, but not all who experience these things go on to develop PTSD. In fact, only about 20% of people who experience trauma develop PTSD.

Why do most autistic people develop PTSD in response to trauma? The answer appears to be in our brains.

The connection between our right and left hemispheres is smaller or doesn’t operate the same as it does in the neurotypical brain. This means that information, including trauma, does not get processed as quickly. While this attribute is associated with some of the best aspects of autism, such as being able to really deeply focus on certain subjects or tasks, it’s not great when it comes to trauma.

And, if you think about it, a lot of the autistic traits that we experience are, in part, associated with this fact. We are bombarded by external stimuli and information that comes in from our senses, we’re overwhelmed by our own thoughts and processes in our own minds, and when you combine these two attributes and the fact that the brain is trying to process all this information, it just gets stuck! There’s a bottleneck of information. Things don’t get processed properly or quickly enough.

Also, we autistics have more connectivity between neurons in each brain hemisphere, which can lead to fixating or perseverating on traumatic events initially, usually right after they happen and then continuing to do so long after the trauma has ended. This “looping” of the event — replaying and re-examining it over and over again in the mind — is one of the necessary conditions for developing PTSD in the first place.

In short, the above brain-based attributes create a fertile ground for PTSD to take root and grow.

If you’d like to know more about this topic, check out:

PTSD and autism.

Complex post-traumatic stress disorder.

Complex PTSD and autism.

Traumatic stress disorder fact sheet, Sidran Institute.

Post traumatic stress disorder, Anxiety Canada.

The autistic brain and PTSD, Embrace Autism.

Relations between social support and PTSD symptoms.

Meltdowns and shutdowns, Embrace Autism.


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