Can gut bacteria boost depression treatment? a trial investigates
NCT ID NCT07786285
First seen Aug 25, 2026 · Last updated Sep 01, 2026 · Updated 3 times
Summary
This trial tests whether adding a daily probiotic supplement to standard antidepressant medication can improve depression symptoms and reduce stress. Adults aged 18-65 with a confirmed depression diagnosis and stable antidepressant use will take the probiotic or a placebo for 12 weeks. Researchers will measure changes in mood, stress, and gut microbiome composition to see if the gut-brain connection plays a role in mental health.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- a probiotic supplement containing nine bacterial strains, taken daily for 12 weeks alongside stable antidepressant therapy
- What this could lead to
- If it works, this could point toward a simple, safe add-on to antidepressants that improves mood and reduces stress by balancing gut bacteria.
- What could go wrong
- This is an early-stage trial with a high expected dropout rate, and results may not apply to everyone. Probiotics are generally safe but can cause mild digestive upset.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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About 200 people
The number the study aims to enrol. It can still change while the study runs.
- Expected to start
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Oct 2026
An estimate. Start dates often move.
- Expected to finish
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Oct 2030
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 65 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: \- Age 18-65 years * Confirmed diagnosis of depression according to ICD 11 (International Classification of Diseases) criteria * Written informed consent * Stable antidepressant therapy (same medication for at least 6 weeks to ensure stable clinical response) Exclusion Criteria: * \- Acute suicidality * Severe cardiovascular disease * Pregnancy or breastfeeding * Substance/ alcohol abuse * Severe neurological or systemic disease * Recent antibiotic use * Probiotic use in past year * Treatment resistant depression * Psychotic depression
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Zdravstveni dom Gornja Radgona
Gornja Radgona, 9250, Slovenia
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