When a child has one or more developmental delays, one of the challenges practitioners face is determining whether a delay is related to autism or childhood trauma. Making that determination can be challenging because autism and trauma can affect development in similar-looking ways, and because the two can sometimes coexist in the life of a child.

Autistic children have a higher risk of acute stress disorder and post-traumatic stress disorder than their typically developing peers (Li et al, 2024). In addition, diagnostic overshadowing may make it easier to overlook trauma symptoms when autistic features are present, and trauma symptoms may make it harder to notice autistic traits (Stavropoulos et al., 2018).  

Trauma and Autism Both Affect Key Brain Structures

Large brain imaging studies have shown that exposure to trauma during vulnerable developmental periods can change brain structures, including the amygdala, the right putamen, and the frontal and cingulate regions (Jeong et al., 2021). Those brain structures are involved in the development of executive functions like these: 

• Holding information in mind while doing tasks (working memory) 
• Directing attention 
• Concentrating  
• Planning tasks 
• Controlling behaviors and impulses 
• Noticing, naming, and expressing emotions

Variations in brain structure development have also been linked to the expression of some autistic traits (Arunachalam Chandran et al., 2021). Brain imaging studies of autistic infants and toddlers show that many of these structural differences appear during the first two years of life, with some differences visible as early as six months (Girault & Piven, 2020).

In a meta-analysis that explored executive function in preschool children, Chirstoforou et al. (2023) found that autistic children tended to have difficulty with these tasks:

• Inhibition (being able to suppress or control impulses, behaviors, and attention) 
• Set-shifting (changing attention from one task to another) 
• Planning (organizing, prioritizing, and making decisions)

Researchers have also found that autistic preschool children sometimes experience emotional dysregulation that interferes with their ability to function socially and practically in some environments (Davico et al., 2022).  

Trauma Can Lead to Developmental Delays 

Efforts to educate the public about developmental milestones and the need for autism screening have provided many families with good information about the ways autistic traits can show up in infants and toddlers. Information about the impacts of trauma on development aren’t as widely known.

While every child develops in a unique way, skills usually develop along a timeline. The skills a child learns in one phase of development form a foundation for the skills they learn later. Trauma can impact a person’s ability to concentrate, to remember, to think clearly, and to regulate emotions—all of which are abilities children need to learn a new skill.

Children who receive help following a traumatic experience may be able to make use of their resources to recover and to get their development back on track, so to speak. Without support and resilience, however, a child’s developmental path can be changed in important ways: 

• Development could be interrupted or slowed—especially if highly precise learning is involved, such as when a child is building complex motor skills. 
• A child might regress developmentally, losing some previously learned skills. 
• A child might make a developmental leap, learning skills for which they’re not yet mentally or emotionally prepared. This kind of leap is sometimes called precocious acceleration. 

Trauma Effects and Autistic Traits May Look Alike

Autistic traits and the effects of trauma can often present in similar ways (Stavropoulos et al., 2018). Researchers have found that autism and trauma exposure can both lead to:  

• avoidant behaviors; 
• repetitive play; 
• reduced exploration; 
• anxiety or depression symptoms; 
• changes in attention or concentration; 
• difficulty accurately interpreting others’ feelings; 
• emotional dysregulation; 
• developmental language differences; 
• difficulty with change or transitions; 
• sensory over- or under-sensitivities; and 
• sleep disturbances.

There is some evidence that the development of social cognition is also affected by trauma as well as autism. Social cognition is generally defined as the skills we use to perceive, interpret, and respond to social information, including abilities like these:

• Recognizing facial expressions
• Interpreting body language
• Inferring the emotional states of others
• Interpreting social cues
• Taking on or imitating social roles 
• Understanding complex interactions

These skills develop in a fairly predictable progression in most children. Trauma may interrupt the developmental sequence in some children, leading to differences in social cognitive abilities. For example, in a 2023 study involving roughly 4,400 British children, researchers analyzed patterns of childhood maltreatment from birth to age nine. They found that children who experienced abuse between 18 months and 6.75 years were particularly likely to have poorer social cognition later in childhood (Crawford et al., 2023). More exposure to maltreatment generally led to worse social cognition, especially for girls, researchers said.

These differences may emerge very early in development. One of the earliest skills babies learn is known as gaze-following—the ability to look where someone else is looking. In a recent Swedish study, researchers found that ten-month-old infants whose mothers had postpartum depression followed eye gaze less often than babies whose mothers did not have the condition (Astor et al., 2020). Autism also affects early social cognition skills like gaze-following. Researchers have found, for example, that autistic infants often communicate and cooperate less using eye gaze than typically developing infants of the same age (Ellis et al., 2020).

A similar skill, joint attention (two people intentionally paying attention to the same thing), is also affected by both autism and trauma. A delay in joint attention skills at eight months old was linked to autistic traits at 18 months old, one study found (Montagut-Asunción et al., 2022). A Chinese study showed that young children who had experienced parental deprivation, also had differences in the prefrontal cortex which led to joint attention deficits (Ding et al., 2021). 

To determine whether an apparent developmental delay is linked to autism, trauma, or both, it’s important to consider a child’s family history, cultural background, and developmental history—including a careful look at what developmental tasks could have been disrupted by an adverse event. 

Learn more: Autism is Cross-Cultural. Shouldn’t Your Assessments Be, Too?  

Key Messages 

Trauma and autism can both affect the way a child develops, sometimes leading to delays that pause, regress, or advance the development of important skills. It’s important to conduct a holistic evaluation that includes validated autism and trauma assessments, an analysis of cultural factors that could affect how either is expressed, and information gleaned from multiple sources and varied settings. It will take extra attention to determine the origin of a developmental delay when a child’s life has included trauma, but your time and care will enable you to plan supports that better meet a child’s needs. 

Learn more: The WPS Guide to Autism Assessment 

Research and Resources:

Arunachalam Chandran, V., Pliatsikas, C., Neufeld, J., O'Connell, G., Haffey, A., DeLuca, V., & Chakrabarti, B. (2021). Brain structural correlates of autistic traits across the diagnostic divide: A grey matter and white matter microstructure study. NeuroImage: Clinical, 32, 102897. https://doi.org/10.1016/j.nicl.2021.102897

Astor, K., Lindskog, M., Forssman, L., Kenward, B., Fransson, M., Skalkidou, A., Tharner, A., Cassé, J., & Gredebäck, G. (2020). Social and emotional contexts predict the development of gaze following in early infancy. Royal Society Open Science, 7(9), 201178. https://doi.org/10.1098/rsos.201178

Christoforou, M., Jones, E. J. H., White, P., & Charman, T. (2023). Executive function profiles of preschool children with autism spectrum disorder and attention-deficit/hyperactivity disorder: A systematic review. JCPP advances, 3(1), e12123. https://doi.org/10.1002/jcv2.12123

Crawford, K. M., Choi, K., Davis, K. A., Zhu, Y., Soare, T. W., Smith, A. D. A. C., Germine, L., & Dunn, E. C. (2022). Exposure to early childhood maltreatment and its effect over time on social cognition. Development and Psychopathology, 34(1), 409–419. https://doi.org/10.1017/S095457942000139X

Davico, C., Marcotulli, D., Cudia, V. F., Arletti, L., Ghiggia, A., Svevi, B., Faraoni, C., Amianto, F., Ricci, F., & Vitiello, B. (2022). Emotional dysregulation and adaptive functioning in preschoolers with autism spectrum disorder or other neurodevelopmental disorders. Frontiers in Psychiatry, 13, 846146. https://doi.org/10.3389/fpsyt.2022.846146

Ding, K., Wang, H., Li, C., Liu, F., & Yu, D. (2021). Decreased right prefrontal synchronization strength and asymmetry during joint attention in the left-behind children: A functional near-infrared spectroscopy study. Frontiers in Physiology, 12, 759788. https://doi.org/10.3389/fphys.2021.759788

Ellis, K., Lewington, P., Powis, L., Oliver, C., Waite, J., Heald, M., Apperly, I., Sandhu, P., & Crawford, H. (2020). Scaling of early social cognitive skills in typically developing infants and dhildren with autism spectrum disorder. Journal of Autism and Developmental Disorders, 50(11), 3988–4000. https://doi.org/10.1007/s10803-020-04449-9 

Girault, J. B., & Piven, J. (2020). The neurodevelopment of autism from infancy through toddlerhood. Neuroimaging Clinics of North America, 30(1), 97–114. https://doi.org/10.1016/j.nic.2019.09.009

Jeong, H. J., Durham, E. L., Moore, T. M., Dupont, R. M., McDowell, M., Cardenas-Iniguez, C., Micciche, E. T., Berman, M. G., Lahey, B. B., & Kaczkurkin, A. N. (2021). The association between latent trauma and brain structure in children. Translational Psychiatry, 11(1), 240. https://doi.org/10.1038/s41398-021-01357-z 

Li, S. T., Chien, W. C., Chung, C. H., & Tzeng, N. S. (2024). Increased risk of acute stress disorder and post-traumatic stress disorder in children and adolescents with autism spectrum disorder: a nation-wide cohort study in Taiwan. Frontiers in Psychiatry, 15, 1329836. https://doi.org/10.3389/fpsyt.2024.1329836

Montagut-Asunción, M., Crespo-Martín, S., Pastor-Cerezuela, G., & D'Ocon-Giménez, A. (2022). Joint attention and its relationship with autism risk markers at 18 Months of Age. Children, 9(4), 556. https://doi.org/10.3390/children9040556

Stavropoulos, K. K., Bolourian, Y., & Blacher, J. (2018). Differential diagnosis of autism spectrum disorder and post traumatic stress disorder: Two clinical cases. Journal of Clinical Medicine, 7(4), 71. https://doi.org/10.3390/jcm7040071