Gut microbiome differences in children with Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder and effects of probiotic supplementation: A randomized controlled trial.
A twelve-week probiotic lifted gut diversity in kids with autism but not in kids with ADHD.
01Research in Context
What this study did
Novau-Ferré et al. (2025) gave kids with autism or ADHD a daily probiotic pill for twelve weeks.
They tracked gut bacteria before and after to see if the bugs changed differently in each group.
What they found
The autism group gained more kinds of good gut bugs.
The ADHD group only lost some harmful bacteria.
Same pill, different outcomes—autism guts responded, ADHD guts mostly ignored it.
How this fits with other research
Arnold et al. (2026) sketched a brain-gut loop that says tummy bugs can tweak sensory issues in autism.
Nil’s trial is the first real test showing you can steer those bugs with a simple pill, so the loop now has a steering wheel.
Greer et al. (2014) remind us that ADHD and autism traits overlap; Nil shows their gut worlds do not, so one-size probiotic plans won’t fit both.
Why it matters
If you serve kids with autism, you can now add “gut check” to your list. Ask the doctor about probiotic brands used in the study. Track any changes in picky eating, sleep, or sensory meltdowns. Share the data with the team—tiny bugs might boost your behavior plan.
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02At a glance
03Original abstract
BACKGROUND: Emerging evidence suggests a significant role of gut microbiota on neurodevelopmental disorders, including Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD). AIMS: Our study aimed to compare gut microbiota composition between these disorders and evaluate the effect of probiotic supplementation. METHODS: We conducted a 12-week randomized, double-blind, placebo-controlled trial with 80 children aged 5-14 years (39 with ADHD, 41 with ASD). Baseline and post-intervention fecal samples were analyzed using 16S rRNA gene sequencing to identify changes in gut microbiota composition. RESULTS: We identified 22 taxa differentiating ADHD and ASD (AUC = 0.939), characterised by increased presence of Clostridia, Ruminococcaceae, and Lachnospiraceae in ADHD, and Bacteroides, Bacilli and Actinobacteria in ASD. These differences remained after accounting for potential confounders. ASD children receiving probiotics had significant increases in Chao 1, Fisher's alpha, and Shannon indices whereas no significant differences in α and β-diversity were found in ADHD. In ADHD, bacteria with potential adverse effects were under-represented. In ASD, the abundance of Eggerthellaceae, and other taxa associated with gastrointestinal problems and anxiety was decreased. CONCLUSION: Variations in gut microbiota may influence responses in ADHD and ASD. Probiotic supplementation favorably altered gut microbiota composition, offering insights for future therapeutic strategies targeting the microbiome in neurodevelopmental disorders. WHAT THIS PAPER ADDS: Recent research underscores the role of gut microbiota in ADHD and ASD, indicating that diet can significantly influence microbiota composition and potentially manage these neurodevelopmental disorders. This study reveals distinct differences in gut microbiota composition between children with ADHD and ASD and demonstrates that probiotic supplementation can modulate specific microbial genera in each disorder. These findings pave the way for the development of innovative microbiome-targeted therapies, offering a new avenue for the treatment of neurodevelopmental disorders. Understanding this relationship is crucial for designing future interventions.
Research in developmental disabilities, 2025 · doi:10.1016/j.ridd.2025.105003