Can gut bacteria boost depression treatment? a trial investigates

NCT ID NCT07786285

What the study statuses mean

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Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting This study
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

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

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

About 200 people

The number the study aims to enrol. It can still change while the study runs.

Expected to start

Oct 2026

An estimate. Start dates often move.

Expected to finish

Oct 2030

An estimate. End dates often move.

Lead sponsor

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

18 to 65 years

Sex

Anyone

Healthy volunteers

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

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.

  1. The places running it

    1 site. The list below names each one and where it is.

  2. 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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  3. A doctor treating you

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Contacts and locations

Locations

  • Zdravstveni dom Gornja Radgona

    Gornja Radgona, 9250, Slovenia

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