SynthesisPloS one2018
The anxiolytic effect of probiotics: A systematic review and meta-analysis of the clinical and preclinical literature.
Synthesis in PloS one, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers, 8 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
61 citing papers in PubMed, 8 syntheses or guidelines pooled it.
- The Effect of Prebiotics and Probiotics on Levels of Depression, Anxiety, and Cognitive Function: A Meta-Analysis of Randomized Clinical Trials.Brain and behavior · 2025Pooled it
- Understanding the impact of valproate on male fertility: insights from preclinical and clinical meta-analysis.BMC pharmacology & toxicology · 2024Pooled it
- Pooled it
- Pooled it
- Efficacy of probiotics on stress in healthy volunteers: A systematic review and meta-analysis based on randomized controlled trials.Brain and behavior · 2020Pooled it
- Effects of Probiotics on Depressive or Anxiety Variables in Healthy Participants Under Stress Conditions or With a Depressive or Anxiety Diagnosis: A Meta-Analysis of Randomized Controlled Trials.Frontiers in neurology · 2020Pooled it
- Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials.Neuroscience and biobehavioral reviews · 2019Pooled it
- Pooled it
- Probiotic-mediated modulation of gut microbiome in students exposed to academic stress: a randomized controlled trial.NPJ biofilms and microbiomes · 2025Trial
- Efficacy and Safety of Morinda Officinalis Oligosaccharides Combined with Probiotics as a Therapeutic Strategy for Major Depressive Disorder with Gastrointestinal Symptoms: A Randomized, Double-Blind, Controlled Clinical Trial.Neuropsychiatric disease and treatment · 2025Trial
- Exploring the impact of probiotics on adult ADHD management through a double-blind RCT.Scientific reports · 2024Trial
- Colon-delivered short-chain fatty acids attenuate the cortisol response to psychosocial stress in healthy men: a randomized, placebo-controlled trial.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2020Trial
- Effect of Supplementation withNutrients · 2020Trial
- Bifidobacterium longum 1714™ Strain Modulates Brain Activity of Healthy Volunteers During Social Stress.The American journal of gastroenterology · 2019Trial
- Trial
- From Gut to Mind: Impact of Probiotics on Depression, Anxiety, Mood, Gut Microbiota, Sleep and Stress-A Systematic Review of RCTs.Annals of neurosciences · 2026Review
- Plant-derived Natural Products in Neurological and Psychiatric Disorders: Mechanisms of Action and Synergistic Roles with Probiotics.Molecular neurobiology · 2026Review
- Importance of the inflammasome in gut-brain axis: from pathological driver to therapeutic target.Inflammopharmacology · 2026Review
- Probiotic potential of novel Lactobacillus and Limosilactobacillus isolated from Formosan pangolin feces.BMC microbiology · 2026Article
- "Attacking" the Gut-Brain Axis with Psychobiotics: An Umbrella Review of Depressive and Anxiety Symptoms.Pharmaceuticals (Basel, Switzerland) · 2026Review
1 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundProbiotics have generated intensive research interest in recent years as a novel mode of treatment for physical and mental illness. Nevertheless, the anxiolytic potential of probiotics remains unclear. The present systematic review and meta-analysis aimed to evaluate the clinical and preclinical (animal model) evidence regarding the effect of probiotic administration on anxiety.
methodsThe PubMed, PsycINFO, and Web of Science databases were reviewed for preclinical and clinical studies that met the defined inclusion and exclusion criteria. The effects of probiotics on anxiety-like behavior and symptoms of anxiety were analyzed by meta-analyses. Separate subgroup analyses were conducted on diseased versus healthy animals, specific preclinical probiotic species, and clinical versus healthy human samples.
resultsData were extracted from 22 preclinical studies (743 animals) and 14 clinical studies (1527 individuals). Overall, probiotics reduced anxiety-like behavior in animals (Hedges' g = -0.47, 95% CI -0.77 --0.16, p = 0.004). Subgroup analyses revealed a significant reduction only among diseased animals. Probiotic species-level analyses identified only Lactobacillus (L.) rhamnosus as an anxiolytic species, but these analyses were broadly under-powered. Probiotics did not significantly reduce symptoms of anxiety in humans (Hedges' g = -0.12, 95% CI -0.29-0.05, p = 0.151), and did not differentially affect clinical and healthy human samples.
conclusionsWhile preclinical (animal) studies suggest that probiotics may help reduce anxiety, such findings have not yet translated to clinical research in humans, perhaps due to the dearth of extant research with clinically anxious populations. Further investigation of probiotic treatment for clinically relevant anxiety is warranted, particularly with respect to the probiotic species L. rhamnosus.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.