Autism is a complex spectrum of behaviors and other distinguishing characteristics across individuals, for which our understanding of continues to unfold. Alongside it’s well documented social and sensory related symptoms, autism also regularly co-occurs with a host of medical complications that impact sleep, eating and digestion, and brain functioning. Recent research suggests that anxiety, ODC, ADHD, sleep disorders, and a range of gastrointestinal challenges are elevated in individuals with autism spectrum disorders. National estimates of children ages 4 to 8 years old with autism found that 95% of children presented with at least one co-occurring condition/symptom (Soke et al., 2018). An earlier study which included both children and adults with autism presented similar findings, and seizures and gastrointestinal symptoms in the autism population greatly exceeded the general hospital population (Kohane et al., 2012). It is unclear if these conditions are directly related to the pathology of autism, if autism itself poses a risk for such disorders, or if the presence of autistic symptomatology simply exacerbates challenges – and such factors vary based on the individual and the condition.
Gastrointestinal (GI) dysfunction is arguably one of the most common co-occurring medical challenges associated with autism. Broad estimates for the prevalence of GI dysfunction in autism vary from 10% to as high as 85%, with some studies suggesting as high as a 95% co-occurrence. The reported problems can range from mild discomfort to more severe and chronic conditions such as constipation, severe abdominal pain, persistent diarrhea or constipation, and chronic reflux (Holinhue et al., 2018). Even though autism is a neurodevelopmental disorder that is assessed and diagnosed based solely on social and behavioral characteristics, our neurobiological and pathophysiological understanding of autism continues to unfold. The observed co-occurrence of gastrointestinal dysfunction alongside a range of other metabolic and immune problems in autism has led researchers to explore the brain-gut connection more thoroughly in this population. It has subsequently been hypothesized that individuals with autism present with altered gut microbiota, which is associated with gastrointestinal dysfunction, in children with a genetic predisposition for autism (Fattorusso et al., 2019). Further, there is a wide body of research to suggest altered maternal gut microbiota and factors in the uterine environment associated with altered gut microbiome in are strongly associated with the presence of autism in mouse models (Afroz et al., 2021; Kim et al., 2022), which has also been observed in human participants; factors including diet can impact the uterine environment and microbiome, linking diet-induced gut dysbiosis to neurodevelopmental disorders and thereby impacting pre- and early postnatal brain development (Gesu et al., 2021). A recent review by Krigsman and Walker (2021) further suggests that gut dysbiosis and systemic immune dysregulation may directly impact neurodevelopment, rather than autism in and of itself predisposing someone with autism to a GI disorder.
Whether the causal factors associated with the increase prevalence of gastrointestinal dysfunction in autism are biological or not, there are many reported behavioral symptoms that accompany this presentation. Atypical and complex feeding and eating related behaviors are often reported, exacerbated by the rigidity and preference for sameness that is seen in autism. Challenges that are commonly in parents of children with autism include extremely limited diets resulting in lower nutritional intake and challenging mealtime behaviors. A review by Pinto-Silva et al. (2022) also found that in addition to food selectivity and problem behaviors at mean time, sensory sensitivity, anthropometric deviations, and nutritional deficits were also commonly reported. Further, inconsistent toileting and self-care routines, paired with limited communication skills, may contribute to or exacerbate these GI challenges. Deficits in socialization and communication skills in children with autism were found to be correlated with adaptive functioning deficits in the areas of communication and daily living skills, which include eating, hygiene, and self-care (Voulgarakis et al., 2021). Other research by Chakraborty et al. (2021) found that of their sample, 93% had at least one gastrointestinal symptom and repetitive behaviors and stereotypies were positively associated with gastrointestinal symptom severity, however, social and communication difficulties were not significantly associated.
In the case of autism spectrum disorders, gastrointestinal dysfunction as well as its other associated medical challenges presents a complex set of barriers for individuals and their families. Behavioral difficulties as well as social and communication skills make it difficult for those with autism to communicate their needs, compounded by genetic and pathophysiological dispositions to gastrointestinal challenges. Various treatments are available that have been found to alleviate GI symptoms specific to those with autism. Recent research has found that probiotic supplementation has been helpful in reducing some of the behavioral symptoms reported, however there is a less stable trend to be seen with respect to changes on the microbiome level (Davies et al., 2021). A similar review by Tan et al. (2021) supports these findings. They also discuss evidence surrounding fecal microbiota transplantation, which has gained much attention as of recently. The review indicates that there is some evidence of efficacy, however the current research available includes small sample sizes and requires more extensive research and replication. Dietary modifications and other approaches to regulate gastrointestinal information has also shown some promise. Psychosocial interventions that support communication, pain management, coping, and medical adherence are also among supports available.
It is critical for families, clinicians, educators, and providers alike to remain abreast of these developments and continue to implement strategies to mitigate these challenges. Educational programs that focus on self-help and independence are beneficial for those who have more impaired adaptive skills as they transition to adulthood. Psychosocial research supporting individuals and their families with autism and other complex medical challenges should continue, as well as biomedical research to understand the brain-gut connection among neurodevelopmental disorders. Finally, gastrointestinal challenges co-occur alongside a host of other medical complications that remain under-researched in autism and other neurodevelopmental disorders, and research and continue to explore the biological in medical factors that are intertwined with autism’s complex social presentation.
Harry Voulgarakis, PhD, BCBA-D, is an Assistant Professor of Child Study at St. Joseph’s University, New York. As a Licensed Psychologist and Behavior Analyst, he maintains a private practice in New York City, specializing in psychological and neuropsychological assessment and consultation. You can read more about Dr. Voulgarakis and his practice at drharryv.com.
Afroz, K.F., Reyes, N., Young, K. et al. (2021). Altered gut microbiome and autism like behavior are associated with parental high salt diet in male mice. Scientific Reports, 11, 8364.
Davies, C., Mishra, D., Eshraghi, R., Mittal, J., Sinha, E. B., Mittal, R., & Eshraghi, A. Altering the gut microbiome to potentially modulate behavioral manifestations in autism spectrum disorders: a systematic review, Neuroscience & Biobehavioral Reviews, 128, 549-557.
Chakraborty, P., Carpenter, K. L. H., Major, S., Deaver, M., Vermeer, S., Herold, B., Franz, L., Howard, J., & Dawson, G. (2021). Gastrointestinal problems are associated with increased repetitive behaviors but not social communication difficulties in young children with autism spectrum disorders. Autism, 25(2), 405–415.
Fattorusso, A., Di Genova, L., Dell’Isola, G.B., Mencaroni, E,, Esposito, S. (2019). Autism spectrum disorders and the gut microbiota. Nutrients, 11(3), 521.
Gesu, C., Matz, L., & Buffington, S. (2021). Diet-induced dysbiosis of the maternal gut microbiome in early life programming of neurodevelopmental disorders. Neuroscience Research, 168, 3-19.
Holingue, C., Newill, C., Lee, L., Pasricha, P.J., Fallin, M. D. (2018). Gastrointestinal symptoms in autism spectrum disorder: a review of the literature on ascertainment and prevalence. Autism Research.
Krigsman, A., & Walker, S. J. (2021). Gastrointestinal disease in children with autism spectrum disorders: Etiology or consequence?. World journal of psychiatry, 11(9), 605–618.
Kohane, I.S., McMurry, A., Weber, G., MacFadden, D. Rappaport, L., Kunkel, L., et al. (2012). The co-morbidity burden of children and young adults with autism spectrum disorders. PLoS ONE 7:e33224.
Pinto-Silva, R., Margarida Nunes Costa, A., & Tello-Rodrigues, I. (2022) Feeding problems in children with autism spectrum disorders: a systematic review. Speech, Language and Hearing.
Soke, G. N., Maenner, M. J., Christensen, D., Kurzius-Spencer, M., & Schieve, L. A. (2018). Prevalence of co-occurring medical and behavioral conditions/symptoms among 4- and 8-year-old children with autism spectrum disorder in selected areas of the united states in 2010. Journal of Autism and Developmental Disorders, 48(8), 2663–2676.
Tan, Q., Orsso, C.E., Deehan, E., K, J., Tun, H., Wine, E., Madsen, K., Zwamigenbam, L., & Haqq, A. (2021). Probiotics, prebiotics, synbiotics, and fecal microbiota transplantation in the treatment of behavioral symptoms of autism spectrum disorder: A systematic review. Autism Research, 14(9), 1820-1836.
Voulgarakis, H., Saulnier, C. A., Bendell-Estroff, D., Bush, P., & Field, T. (2021). Deficits in socialization and daily living skills associated with gastrointestinal symptoms in children with autism spectrum disorder. Children’s Health Care, 50(4), 398-412.