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← Conditions Mental health

Major depression

Compared within 2 studies that had both: 91 people with major depression and 65 healthy people. No microbes less common in people with major depression, and 2 more common.

A difference is an association: it doesn’t mean these microbes cause, prevent or treat major depression.

Phylum

Searching opens both lists and shows only matching rows.

Less common in major depression · 0

Strongest first, then the biggest gap · Each figure is 10 people Strongest first · Each figure is 10 people

None compared.

More common in major depression · 2

Strongest first, then the biggest gap · Each figure is 10 people Strongest first · Each figure is 10 people
  1. Eggerthella lenta in 2 studies Healthy 41% major depression 75%
  2. Eisenbergiella tayi in 2 studies Healthy 9.4% major depression 37%

As many carry these · 1 the amount differs

Strongest first, then the biggest gap · Each figure is 10 people Strongest first · Each figure is 10 people
  1. Ruthenibacterium lactatiformans in 2 studies Healthy 81% major depression 84%

    Carriers have about 5 times as much, in 2 of 2 studies (0.03% → 0.13% of their gut microbes).

Where these numbers come from

Studies
Only GMrepo projects that had people with the condition and healthy people, 10 or more of each. Numbers come from those studies, never from pooling.Sampled in China, Russia.
How common
The share of people whose sample has any of it, in the people with the condition and in the healthy people of those same studies. Tested within studies (Cochran–Mantel–Haenszel, corrected for testing many microbes); a difference counts when it is clear and meaningful (Cohen’s h of 0.2 or more).
Strength word
Counted by code from how many studies point the same way: Seen again and again (3 or more, none clearly the other way), Seen more than once (2, the majority), Seen once (1, listed last). Where studies disagree, a row isn’t listed.
Each study
Tap a row for every study’s own numbers, and for how much carriers have.
Analysis
Our analysis of GMrepo data. GMrepo on Data sources · Read the rules

Also compared · 359 microbes

Compared within studies that had both, but not listed above.

Studies disagree · 1

No meaningful difference · 358
PubMed · human studies and reviews first

Recent research

All research on it
  1. Clinical trial Translational psychiatry · 2026
    Multi-strain probiotic intervention in adults with depressive and anxiety symptoms: A 12-Week pilot study.
    PubMed ↗
  2. Randomized trial BMC psychiatry · 2026
    Exploring brain-gut interaction mechanisms in Transcutaneous auricular Vagus Nerve stimulation for Major Depressive Disorder.
    PubMed ↗
  3. Observational CNS neuroscience & therapeutics · 2026
    Continuous Alterations in the Gut Microbial Landscape Associated With Suicidal Ideation in First-Episode Drug-naïve Major Depressive Disorder.
    PubMed ↗
  4. Observational Journal of affective disorders · 2026
    Integrative multi-kingdom gut microbiome analysis uncovers clinical signatures of major depressive disorder.
    PubMed ↗
  5. Observational mSystems · 2026
    Gut microbiome signatures associated with depression and obesity.
    PubMed ↗

Source: PubMed, U.S. National Library of Medicine · 42 linked papers, last 10 years