Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are increasingly conceptualized as multisystem neurodevelopmental conditions involving behavioral, gastrointestinal, immune, and metabolic alterations. The microbiota-gut-brain axis (MGBA) has been proposed as a key framework linking these systems, although evidence from human studies remains heterogeneous and inconclusive. We conducted a structured narrative review of pediatric human studies investigating the…
