Somatic, Psychiatric and Neurodevelopmental Comorbidities in People with Autism Spectrum Disorder (ASD): A Narrative Review

Background/Objectives: Autism spectrum disorder (ASD) is currently singularly described as a behaviourally defined neurodevelopmental diagnosis with symptoms affecting social communication and social understanding alongside the presence of restricted patterns of behaviour. Wide, and often very personal, variations in symptom intensities and differing developmental trajectories, reflective of large heterogeneity, are an important feature of the label. ASD carries enhanced risks for multiple over-represented, sometimes overlapping, comorbidities spanning behavioural, psychiatric and somatic domains. Said comorbidities often have numerous and far-reaching effects on quality of life by way of their impacts and, in extreme cases, their potential effects on life expectancy. It is of paramount importance that data on the risks of such comorbidities are available and, where possible, screening, preventive and/or treatment options implemented. Methods: In this narrative review, the authors searched databases (PubMed/Medline, ScienceDirect, Google Scholar) for papers published between 1 January 2015 and 16 February 2026 that were pertinent to comorbidity and autism. Results: We present data on the frequency of various somatic (gastrointestinal, immunological, metabolic, neurological, motor-sensory disorders), psychiatric (anxiety, mood, schizophrenia spectrum, personality, substance abuse, trauma, feeding and eating, sleeping, self-harm, neurocognitive disorders) and neurodevelopmental comorbidities (intellectual, attentional, speech and language, motor disorders) that can present alongside a diagnosis of ASD. We provide accompanying data on the magnitude of potential risk and, where available, information on comorbidity risks according to sex and age. Conclusions: This review paper deals with an extremely broad field. Limitations of the narrative review strategy are discussed alongside how the variable risk of comorbidity mimics the heterogeneity present in autism, thus inviting further investigations.