Autism and PTSD: Similarities and Differences

Those who are familiar with the history of autism likely know that in the Diagnostic and Statistical Manual of Mental Disorders, Second Edition (DSM-II), what is now called autism spectrum disorder (ASD) was characterized as "schizophrenia, childhood type." Starting with the DSM-III, ASD and schizophrenia (childhood type) were classified separately, and continue to be characterized separately today.

Perhaps due to this history, there is a great deal of research into the similarities and differences between ASD and schizophrenia in both children and adults. More recently, there has been interest in the similarities between ASD and other disorders such as anxiety, obsessive-compulsive disorder, and ADHD.

One disorder that is rarely considered related to ASD, however, is post-traumatic stress disorder (PTSD). This might be because clinicians did not have a good understanding of PTSD in childhood until relatively recently, and it was largely considered a disorder of adulthood. This month, I want to discuss how ASD and PTSD can co-occur, and/or present diagnostic conundrums for clinicians.

I recently came across this article from Spectrum News, which discusses how having ASD often puts children at risk for trauma (e.g. bullying, being taken advantage of, maltreatment). My colleagues and I recently published a case study about the difficulties of diagnosing ASD versus PTSD in young children. In the past year, we saw two children at our clinic whose parents wanted help differentiating between symptoms of childhood trauma and ASD. In both cases, we saw evidence of trauma (and potential PTSD) rather than ASD, but both cases were complex and required expert consensus.

In both cases, the children had experienced (or witnessed) trauma at a very young age (prior to age 5), which made differential diagnosis difficult. In adults, this is typically not an issue because ASD requires that symptoms were present prior to age 7. However, in children who experience trauma early in life, it can be difficult to separate what symptoms are due to trauma versus due to difficulties with social interactions.

To clarify potential symptom overlap in childhood trauma and ASD, we created the graphic below. On the left, we note symptoms of ASD. On the right, we have symptoms of PTSD. In the middle, we show how symptoms from the two disorders may overlap. For example, in the first bubble, we have "deficits in social-emotional reciprocity" for ASD, and "social withdrawal" for PTSD. However, both may manifest as "lack of interest in peers," which is shown in the middle.

Diagram of symptom overlap in ASD and PTSD (re-printed with permission from Stavropoulos et al., 2018)

Source: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Our case report, along with the Spectrum News piece and many others, highlights the importance of exploring the overlap of PTSD and ASD, especially in young children. Interestingly, it appears that the Spectrum News piece and our study are discussing opposite sides of the same coin. Their article notes how children with ASD may be at increased risk for experiencing traumatic events, whereas we focus on the importance of accurately differentiating between symptoms of ASD and PTSD in children. Both pieces conclude that the prevalence of children with co-occurring ASD and PTSD is likely under-identified and underestimated, and that clinicians, parents, and other professionals need further training around these issues.