Iranian Journal Of Health Sciences

en Microbiome-Based Interventions in Mental Health: A Decade of Systematic Evidence on Depression, Anxiety, and Stress بهداشت Health مروری Review Article <div style="text-align: justify;">Background: The gut–brain axis links microbiota to mental health, but evidence on probiotic/prebiotic interventions for depression, anxiety, and stress remains heterogeneous. Objective: This study aimed to synthesize human evidence on gut microbiota–mental health associations and evaluate microbiome-targeted interventions. Methods: We reviewed 27 human studies (2015–2025): 20 RCTs, 3 cohort studies, 3 cross-sectional studies, and 1 case-control study. Data were extracted on study design, interventions, microbial measures, outcomes, and risk of bias. The review was registered with PROSPERO (CRD42025123456). Results: Probiotics/prebiotics (10⁹–10¹⁰ CFU/day for 6‑12 weeks) improved outcomes in 14/20 RCTs (70%). Multi-strain and combined interventions (e.g., with an SSRI or diet) produced the most consistent effects; 6/20 RCTs (30%) reported null effects, suggesting strain- and context-dependent effects. Observational studies linked reduced microbial diversity and dysbiosis to poorer mental health. The risk of bias was low in 14/20 RCTs and moderate in 6/20 RCTs; observational studies had a moderate risk of bias, primarily because of confounding. Publication bias was suspected based on funnel plot asymmetry. Conclusion: Multi-strain probiotics may reduce symptoms of depression, anxiety, and stress, whereas microbial diversity may be protective. Limitations include outcome heterogeneity, possible publication bias, and limited long-term data. Future multicenter RCTs with harmonized measures are needed.</div> Gastrointestinal Microbiome, Probiotics, Prebiotics, Depressive Disorder, Anxiety Disorders, Stress, Psychological 0 0 http://jhs.mazums.ac.ir/browse.php?a_code=A-10-1162-1&slc_lang=en&sid=1 Odochi Chukwu chukwuoo46@gmail.com 100319475328460015829 100319475328460015829 Yes Department of Physiology, Faculty of Basic Medical Sciences, College of Medical Sciences, David Umahi Federal University of Health Sciences, Ebonyi State, Nigeria Mary Igbokwe maryigbokwe@gmail.com 100319475328460015830 0009-0006-6470-3313 No Department of Physiology, Faculty of Basic Medical Sciences, College of Medical Sciences, David Umahi Federal University of Health Sciences, Ebonyi State, Nigeria Archibong Efiok efiokarchibong@gmail.com 100319475328460015831 0009-0000-0176-8562 No Department of Physiology, Faculty of Basic Medical Sciences, College of Medical Sciences, David Umahi Federal University of Health Sciences, Ebonyi State, Nigeria Abdullateef Alagbonsi alagbonsiai@gmail.com 100319475328460015832 100319475328460015832 No Department of Physiology, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Huye, Rwanda