An occupational therapy lens on microbiota-gut-brain modulation in ASD and ADHD.

Research on the microbiota gut brain axis has expanded rapidly, with growing interest in its potential relevance to neurodevelopmental conditions such as autism spectrum disorder and attention-deficit hyperactivity disorder. Systematic reviews increasingly report associations between gut microbial alterations and behavioral features in these populations, yet causal mechanisms remain unconfirmed and translational relevance for rehabilitation remains limited. Much of the existing literature prioritizes microbial composition, inflammatory markers, and neurochemical correlates, with comparatively little attention to everyday functioning, participation, and lived experience. This Perspective argues that microbiota gut brain interactions should be conceptualized within rehabilitation sciences as contextual physiological modulators, referring to internal bodily processes that shape readiness and engagement without determining occupational performance outcomes, and influencing occupational readiness and regulatory capacity rather than acting as etiological drivers of participation restrictions. Drawing on ecological and occupation-centered models of function, including the International Classification of Functioning framework and occupational therapy theories of performance and participation, we propose a reframing that preserves functional orientation while integrating emerging neurophysiological insights. The paper outlines implications for rehabilitation assessment, intervention planning, and interdisciplinary collaboration, and advances programmatic directions for future research that prioritize participation-based outcomes and ecological validity, defined here as the extent to which outcomes reflect real-world participation and everyday functioning rather than laboratory-based or symptom-only change. Repositioning microbiota gut brain research within a participation-focused rehabilitation framework may enhance translational value and support function-oriented, interdisciplinary care for children with autism spectrum disorder and attention-deficit hyperactivity disorder.