Gut Microbiome and ADHD: A Narrative Review of Clinical Evidence and Practice Implications

Abstract

Objective: This narrative review evaluates the current evidence on the efficacy of probiotic interventions for Attention Deficit Hyperactivity Disorder (ADHD) symptoms in both medicated and drug-naïve paediatric and adult populations and assesses the implications for clinical dietetic practice.

Design: A narrative review synthesizing randomized controlled trials and observational microbiome studies in paediatric and adult populations, specifically distinguishing between probiotic monotherapy and adjunctive protocols.

Results: Observational data confirm gut microbiome alterations in ADHD populations, although specific bacterial signatures vary across studies. Evidence from treatment trials demonstrates that the efficacy of probiotics as monotherapy for core ADHD symptoms remains inconclusive. However, specific adjunctive trials combining probiotics with conventional medication have reported preliminary positive findings on symptom reduction, though results remain heterogeneous. Adult evidence is sparse but indicates potential benefits for emotional dysregulation in specific contexts.

Conclusions: This review concludes that current data do not support universal probiotic supplementation or routine clinical recommendation. However, when families inquire about complementary approaches, the existing literature enables evidence informed guidance within a shared decision-making framework that acknowledges the preliminary nature of current findings and sets realistic expectations.