There is no evidence that trauma directly causes autism. However, autistic children and adults may be more vulnerable to traumatic experiences, and adversity may increase autistic traits.

Autism occurs due to the way the brain develops and is mostly genetic. According to estimates, genes account for 40% to 80% of a person’s likelihood of being autistic.

However, trauma may affect autistic people in unique ways, and people may confuse one for the other.

In this article, we explore the links between autism and trauma and why they may occur together.

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There is no evidence that traumatic events can cause autism in children or adults.

Autism is the result of differences in brain development. It is often present in children from a young age, sometimes as early as 1 or 2 years old.

Some previous studies have found correlations between post-traumatic stress disorder (PTSD) and autistic traits. For example, a 2015 study involving autistic women found that those with the most pronounced autistic traits were more likely to have experienced abuse.

However, this study was retrospective, meaning it used existing data. It did not show that trauma causes autism, only that autistic women often have traumatic experiences.

People cannot develop autism for the first time as adults, whether they have a history of trauma or not. But because the symptoms of PTSD can resemble some of the features of autism, people may confuse one for the other.

Scientists do not fully understand why autism occurs in some people and not others, but there is a strong genetic connection.

Changes in more than 1,000 genes have associations with autism. Many of them play a role in how the brain develops.

Individually, these genes may only have a small effect on a person’s likelihood of being autistic, but cumulatively, they may have a more significant influence. This could explain why autism tends to run in families.

However, not everyone with these genetic differences is autistic. There are some other factors that may play a role, too. These include:

These factors alone probably do not cause autism, but they may make autism more likely. There is no link between any vaccine and autism.

Learn more about what causes autism.

Yes, it is possible to mistake PTSD for autism or vice versa. This is especially the case for young children.

PTSD and autism have some shared symptoms. People with either diagnosis may:

  • seem nervous or anxious
  • not talk much or at all
  • avoid certain places or situations
  • get very upset by certain stimuli, such as loud noises or touch
  • have outbursts of anger or frustration
  • withdraw from others

However, the reason for these behaviors is different in PTSD versus autism. PTSD symptoms are a response to a frightening experience, which may make a child afraid of things that remind them of the event.

In autism, the behaviors may be a product of difficulty communicating and understanding other people or with sensory processing.

It is also possible to be both autistic and have PTSD or other trauma-related mental health symptoms.

Traumatic experiences are generally common. Most people experience at least one traumatic event during their lifetime. Not everyone feels lasting effects from these events. When they do, they may meet the criteria for PTSD.

Autistic people appear to be more likely to have both experienced traumatic experiences and to develop PTSD than nonautistic people.

A 2018 study mentions older research from Istanbul in which children attending an autism clinic were twice as likely to have PTSD symptoms as the larger population. Previous studies have also suggested that autistic children are more likely to experience abuse.

Furthermore, it is possible that the experience of being autistic in a neuronormative world could be traumatic in itself. For example, autistic people may:

  • perceive certain stimuli, such as loud noises, as threatening or physically painful
  • have difficulty identifying when a situation is not safe
  • perceive misunderstandings as potentially dangerous
  • experience bullying

Currently, the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) does not include these experiences under its definition of trauma, which it describes as “exposure to actual or threatened death, serious injury, or sexual violence”.

This may result in people overlooking the ways perception influences the trauma response.

It is possible that traumatic experiences, or adversity in general, may make the core features of autism more pronounced.

A 2019 study found that eye movement desensitization and reprocessing (EMDR) treatment reduced both PTSD symptoms and autism traits in autistic adults with a history of adverse life events. EMDR is a type of therapy that works specifically for PTSD.

These results suggest that trauma-related symptoms may compound autism, but that addressing them may have the opposite effect. However, more research on this is necessary.

Anyone who is experiencing regular distress or feels they may have PTSD should speak with a qualified mental health professional.

It may be helpful to speak with a therapist who has expertise on autism and how it interacts with other conditions.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects if it’s safe to do so.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Find more links and local resources.

There is no evidence that traumatic experiences cause autism. However, trauma-related mental health symptoms can sometimes resemble autism. It is also possible that adverse life events may make autistic traits more pronounced, leading people to notice them more.

Only a qualified mental health professional can assess if a person is autistic, has PTSD, or both. People who think they may have one of these diagnoses can contact a doctor or therapist for support.

More work is necessary to understand how and why trauma affects autistic people and how best to treat it.