Not Yet RecruitingNot Applicable

PB-18 Probiotic for Mild to Moderate Depression

88 participantsStarted 2026-05-05

Plain-language summary

The goal of this clinical trial is to learn if Bifidobacterium PB-18 can treat mild to moderate depressive disorder in adults aged 18 to 65 years who are not taking antidepressants or other psychotropic medications during the study. It will also learn about the safety of Bifidobacterium PB-18 and explore its potential effects on the gut-brain axis. The main questions it aims to answer are: Does Bifidobacterium PB-18 increase the response rate at Week 8, defined as a reduction of at least 50% from baseline in the 17-item Hamilton Depression Rating Scale (HAMD-17)? What adverse events occur in participants receiving Bifidobacterium PB-18? How do gut microbiota, metabolite profiles, and related biological markers change after treatment with Bifidobacterium PB-18? Researchers will compare Bifidobacterium PB-18 with a placebo, a look-alike powder that does not contain PB-18, to see if Bifidobacterium PB-18 improves depressive symptoms. Participants will: Be randomly assigned to receive Bifidobacterium PB-18 or placebo in a 1:1 ratio Take the assigned study product once daily for 8 weeks Visit the study site at baseline, Week 4, and Week 8 for symptom and safety assessments Complete study questionnaires, including HAMD-17, HAMA, PSQI, and CBCT Provide blood and stool samples at baseline and Week 8 for exploratory biological analyses

Who can participate

Age range

18 Years – 65 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Outpatient or inpatient participants, aged 18 to 65 years (inclusive), of any sex * Current episode meets Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria for depressive disorder * Baseline score on the 17-Item Hamilton Depression Rating Scale is 7 to 24, inclusive * No concomitant use of antidepressants or other psychotropic medications during the study * Elementary school education or above, able to understand the study requirements and complete the rating scales * Participant personally signs the informed consent form and is willing to complete follow-up according to the study protocol Exclusion Criteria: * Current or past diagnosis, according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria, of bipolar disorder, schizophrenia spectrum and other psychotic disorders, neurocognitive disorders, neurodevelopmental disorders, or substance-related and addictive disorders * Presence of significant psychotic symptoms, such as delusions or hallucinations * Severe or unstable diseases of the central nervous system, cardiovascular system, respiratory system, liver, kidneys, endocrine system, hematologic system, or other systems that, in the investigator's judgment, make the participant unsuitable for the study * Evident suicide risk, defined as a score of 1 or higher on the suicide item of the 17-Item Hamilton Depression Rating Scale * Active inflammatory disease * Gastrointestinal infection, tumor,…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Response Rate at Week 8 Based on the 17-Item Hamilton Depression Rating Scale

Timeframe: Week 8

Trial details

NCT IDNCT07562516

SponsorFirst Affiliated Hospital of Zhejiang University

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2027-01-31

Contact for this trial

Jing Lu, PhD

15858200010 Lujing2016@zju.edu.cn

View on ClinicalTrials.gov More Depressive Disorder trials