Abstract

Background Psychosomatic symptoms in children and adolescents are increas- ingly understood to involve the gut-brain axis. Microbiome-based interventions— including probiotics, prebiotics, dietary modifications, and fecal microbiota transplan- tation (FMT)—have been proposed as potential therapies. This systematic review aims to evaluate the comparative efficacy of these interventions on gastrointestinal and non-gastrointestinal psychosomatic symptoms in pediatric populations.

Methods A comprehensive search of PubMed, Embase, Scopus, CENTRAL, and EKB was carried out up to 10 May 2025 for randomized controlled trials (RCT) in- volving participants aged 0–18 years. Eligible studies directly compared the effects of microbiome-targeted interventions on gastrointestinal and non-gastrointestinal psy- chosomatic symptoms, assessed with validated severity scales. Two reviewers inde- pendently selected studies, extracted data, and assessed risk of bias using the RoB 2 tool. Standardized mean differences (SMDs) were pooled using random-effects models in RevMan 5.4.

Results Ten RCTs (n=512) were included, evaluating probiotics, dietary changes, and FMT. Microbiome-based interventions significantly reduced the severity of gas- trointestinal symptoms (SMD -0.52, 95% CI -0.78 to -0.26; I²=62%; 8 studies, using VAS and IBS-SSS). The reductions in non-gastrointestinal symptoms were smaller (SMD -0.38, 95% CI -0.61 to -0.15; I²=55%; 6 studies, using PedsQL and SCARED). Probiotics produced the largest effect sizes. The general certainty of the evidence was low, mainly due to the heterogeneity of the study.

Conclusion Microbiome-based interventions, especially probiotics, appear to re- duce the severity of psychosomatic symptoms in children and adolescents, with more pronounced effects on gastrointestinal symptoms. These findings support further re- search and can inform clinical approaches to pediatric psychosomatic care, while high- lighting the need for more rigorous and standardized trials.

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