Cited by 254Gut microbiota and healthGastrointestinal motility and disordersTryptophan and brain disorders

The DOI matches its Crossref record; 75 of the 75 references it cites were found in a registry or an index; 1 of the 65 sources its claims cite were checked for support.

Effect of fecal microbiota transplant on symptoms of psychiatric disorders: a systematic review

Open access
Chinna Meyyappan, Arthi, Forth, Evan, Wallace, Caroline J. K., Milev, Roumen·2020·BMC Psychiatry

Published version of a preprint

Abstract

Background: The Gut-Brain-Axis is a bidirectional signaling pathway between the gastrointestinal (GI) tract and the brain. The hundreds of trillions of microorganisms populating the gastrointestinal tract are thought to modulate this connection, and have far reaching effects on the immune system, central and autonomic nervous systems, and GI functioning. These interactions Diagnostic and statistical manual of mental disorders have also been linked to various psychiatric illnesses such as depression, anxiety, substance abuse, autism spectrum disorder, and eating disorders. It is hypothesized that techniques aimed at strengthening and repopulating the gut microbiome, such as Fecal Microbiota Transplant (FMT), may be useful in the prevention and treatment of psychiatric illnesses. Methods: A systematic search of five databases was conducted using key terms related to FMT and psychiatric illnesses. All results were then evaluated based on specific eligibility criteria. Results: Twenty-one studies met the eligibility criteria and were analysed for reported changes in mood and behavioural measures indicative of psychiatric wellbeing. The studies included were either entirely clinical ( n = 8), preclinical with human donors ( n = 9), or entirely preclinical ( n = 11). All studies found a decrease in depressive and anxiety-like symptoms and behaviours resulting from the transplantation of healthy microbiota. The inverse was also found, with the transmission of depressive and anxiety-like symptoms and behaviours resulting from the transplantation of microbiota from psychiatrically ill donors to healthy recipients. Conclusion: There appears to be strong evidence for the treatment and transmission of psychiatric illnesses through FMT. Further research with larger sample sizes and stronger scientific design is warranted in order to fully determine the efficacy and safety of this potential treatment. Registered on PROSPERO, IRD: CRD42019126795.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This systematic review synthesizes preclinical and clinical evidence that fecal microbiota transplant (FMT) can both alleviate and transmit psychiatric symptoms via the gut-brain axis. It reports consistent short-term improvements in depression and anxiety symptoms after healthy-donor FMT, but notes transient effects and major limitations in study design.

Key findings

  • The review reports 28 included studies: 11 entirely preclinical, 9 preclinical with human donors, and 8 clinical; the abstract states 21 studies met eligibility, an internal inconsistency in the paper.
  • All included studies found a decrease in depressive and anxiety-like symptoms/behaviours after transplantation of healthy microbiota, and the inverse was found when microbiota from psychiatrically ill donors was transplanted into healthy recipients.
  • In clinical studies, all eight assessed psychiatric symptoms; all found significant short-term improvement in depression symptoms, but long-term effects were less consistent, with three studies finding return to baseline at week 12, week 20, and month 6, while Xie et al. found persistent decrease up to 17 months.
  • Of four clinical studies assessing anxiety, three found significant improvement; Mizuno et al. found improvement that was not significant, and Mazzawi et al. found improvement insignificant by week 20.

Methods

  • Systematic search of five databases (MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science) using terms related to mood, anxiety, mania, stress, phobia, microbiota transfer, and fecal transplant; November 2019 search yielded 285 studies after duplicates, and an April 2020 update yielded 7 new studies after full-text screening.
  • Eligibility required peer-reviewed English articles with preclinical or clinical samples assessed for changes in psychiatric illness symptoms after endogenous microbe transfer via any route; PRISMA guidelines were followed, and two authors independently screened titles/abstracts and full texts, with disagreements resolved by a third author.
  • Study quality was assessed with the Cochrane Risk of Bias Tool across six domains; non-double-blind randomized studies were included if methodology was comprehensive after review by three authors.

Limitations

  • Stated: there is no agreed definition of a “healthy microbiome”; clinical studies had small sample sizes and lacked large-scale double-blind randomized controlled trials; most clinical studies assessed psychiatric symptoms in individuals with IBS rather than exclusively psychiatric disorders, so improvement may be secondary to GI symptom improvement.
  • Stated: preclinical human-donor studies mostly used only male donors or mice, some donors took medications including antidepressants, and variability in antibiotics for germ-free mice and FMT administration protocols limits translation and comparability.
  • Evident: the abstract reports 21 eligible studies while the Results section reports 28 included studies; allocation concealment was not assessed because no studies concealed treatment allocation, and blinding failures were rated as high bias.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1186/s12888-020-02654-5

Cites

75 of 75 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Figures

Fig. 1 Flow chart showing literature search and screening process using PRISMA process
Fig. 1 Flow chart showing literature search and screening process using PRISMA processCC BY · PubMed Central

Verification

Claims the paper makes

46 Not checked yet · 24 Own interpretation · 13 Own result · 13 No basis given · 9 Own method · 1 Partly supported · accuracy not yet measured

Verify all 64 references — free account

Show all 52 claims

  • It may state two separate claims as one. 35
  • Probably not a substantial claim. 27
  • The quote only partly states this claim. 1
54 of 54
  • The paper relies on this without support.

    Many people with Major Depressive Disorder or anxiety disorders deny pharmacological treatment due to side effects or stigma-related reasons, or are treatment-resistant and unable to find an effective way to improve their symptoms.

    “While there are pharmacological treatments available for both disorders, many people deny treatment due to side effects or stigma-related reasons or are treatment-resistant and unable to find an effective way to improve their symptoms.”
  • The paper relies on this without support.

    There are few studies on FMT in humans as a treatment method in the context of psychiatric disorders.

    “However, as this is a relatively novel area of research, there are few studies on FMT in humans as a treatment method in the context of psychiatric disorders.”
  • The paper relies on this without support.

    The gut-brain axis is a bidirectional signaling pathway between the gastrointestinal tract and the brain.

    “The Gut-Brain-Axis is a bidirectional signaling pathway between the gastrointestinal (GI) tract and the brain.”
    “The GBA consists of bidirectional biochemical and neural signalling between the gastrointestinal (GI) tract and the brain.”
  • The authors state this as an assumption.

    One transplant is sufficient for therapeutic benefits lasting up to 6 months.

    “Assuming one transplant is sufficient for therapeutic benefits lasting up to 6 months”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

2 of 2

Citations

Cites

Research works printed but not linked: 1

  1. Petrakis IL, Gonzalez G, Rosenheck R, Krystal JH. Comorbidity of alcoholism and psychiatric disorders. Alcohol Res Health. 2002;26(2):81–9.

Cited by

Sorted by citations

See all 254

Metadata

Authors
Chinna Meyyappan, A., Forth, E., Wallace, C. J. K., & Milev, R.
Affiliations
Queen's University (CA)
Venue
BMC Psychiatry
Published
2020-06-15
Volume
20
Issue
1
Pages
299-299
ISSN
1471-244X (ISSN-L)
OpenAlex
W3035496405
Cited by
254
References
75
Citations by year
2026: 31 · 2025: 53 · 2024: 41 · 2023: 37 · 2022: 44 · 2021: 43 · 2020: 5
FWCI
3.09
Type
journal article
Language
en
Open access
Locations
  • BMC Psychiatry (publishedVersion, cc-by)
  • Research Square (acceptedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
Canadian Institutes of Health Research
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Gut microbiota and health
  • Health Sciences › Medicine › Gastroenterology › Gastrointestinal motility and disorders
  • Life Sciences › Neuroscience › Biological Psychiatry › Tryptophan and brain disorders
Keywords
fecal microbiota transplantation, gut-brain axis, mental illness, depression, anxiety, gut microbiota, autism spectrum disorder, eating disorders, substance abuse
MeSH terms
Autism Spectrum Disorder, Gastrointestinal Microbiome, Fecal Microbiota Transplantation, Anxiety, Humans, Microbiota

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-10-09, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

A second model labelled each claim on 2026-10-09 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).

Cited sources are checked with a language model’s help (gpt-6-sol).

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review