Clinical Evaluation of the Antidepressant Effect of the Use of Probiotics in Bipolar Disorder

May 9, 2026 updated by: Beny Lafer, University of Sao Paulo

Clinical Evaluation of the Antidepressant Effect of the Use of Probiotics in Bipolar Disorder and Possible Mediating Effects of Systemic and Intestinal Inflammatory Markers in the Microbiota

Bipolar Disorder (BD) is highly incapacitating and associated with premature mortality. Depressive symptoms and episodes are the most frequent cause of disability in subjects with BD and over half of patients do not respond adequately to approved treatments for this condition, showing the need for new classes of treatments to complement current pharmacotherapy. Previous studies demonstrated that the intestinal flora have potential positive or negative effects on the Central Nervous System and suggest that adding specific strains of bacteria to people's diet may have antidepressant properties.The study proposes to evaluate the clinical benefit of adding probiotics to pharmacological treatments for bipolar depression. This will be a study with 124 subjects (62 receiving probiotics and 62 placebo). The research team in this department has focused especially on non-pharmacological treatments for bipolar disorder (psychotherapy, nutrition and exercise) and is multidisciplinary in scope with psychiatrists, psychologists, nurses, physiotherapists and nutritionists participating in research projects.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

It will test, in a proof-of-concept study, the antidepressant efficacy of adjunctive administration of probiotics in bipolar depression and evaluate potential inflammatory and metabolic markers associated with response to treatment. With this objective, 84 individuals with bipolar disorder type I or type II presenting subsyndromal depressive symptoms or a major depressive episode will be recruited. The study design lasts 12 weeks and is expected to last two years.

Study Type

Interventional

Enrollment (Actual)

141

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Brazil
    • São Paulo
      • São Paulo, São Paulo, Brazil, 05403010
        • University of Sao Paulo

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • BD type I or type II, according to the use of Mini Internacional Neuropsychiatric Interview (MINI)
  • Score on the Young Mania Rating Scale (YMRS) < 8
  • Score on the Montgomery-Asberg Depression Rating Scale (MADRS) > 8
  • Be receiving major guideline-approved treatments for bipolar depression for at least 4 weeks

Exclusion Criteria:

  • Pregnant or lactating women
  • Substance or alcohol dependence
  • Patients on prolonged antibiotic therapy, immunosuppressive therapies
  • A recent introduction of antidepressants in the last 15 days
  • Use of another probiotic, either in the form of food, sachets, capsules and others

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Probiotic group

In addition to the usual medication treatment for bipolar disorder, following the main international guidelines for the treatment of bipolar disorder, subjects will receive food supplementation with a probiotic formulation, twice daily, with food. We will use Pendulum Therapeutics' Glucose Control, probiotic formulation patented in the United States.

Probiotic Ingredients: Clostridium butyricum WB-STR-0006, Clostridium beijerinckii WB-STR-0005, Anaerobutyricum hallii WB-STR-0008, Akkermansia muciniphila WB-STR-0001, and Bifidobacterium infantis.

The product also contains: Chicory inulin and oligofructose (prebiotic fiber), hypromellose (vegetarian capsule), fruit & vegetable juice (coloring agent), magnesium stearate and silica (flow agent for encapsulation)
Other: Probiotic Group
The 124 participants will participate in a randomized, double-blind, placebo-controlled trial in two arms. The probiotic group will consist of 62 patients. These patients will be recruited from the USP Bipolar Disorder Program. This program has an outpatient clinic that offers free medical care to a population of different ethnic groups, with the majority of subjects coming from the middle and lower social classes.
Placebo Comparator: Placebo Group

In addition to the usual medication treatment for bipolar disorder, following the main international guidelines for the treatment of bipolar disorder, the subjects will receive food supplementation with a placebo formulation, twice daily, with food We will use Pendulum Therapeutics' placebo formulation that contains:

Chicory inulin and oligofructose (prebiotic fiber), hypromellose (vegetarian capsule), fruit & vegetable juice (coloring agent), magnesium stearate and silica (flow agent for encapsulation)
Other: Placebo Group
The 124 participants will participate in a randomized, double-blind, placebo-controlled trial in two arms. The placebo group will consist of 62 patients. These patients will be recruited from the USP Bipolar Disorder Program. This program has an outpatient clinic that offers free medical care to a population of different ethnic groups, with the majority of subjects coming from the middle and lower social classes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Outcome
Time Frame: 12 weeks
The Montgomery-Asberg Depression Rating Scale (MADRS) will be used in order to evaluate the reduction of depressive symptoms. Response to treatment at week-12 will be defined as ≥ 50% reduction in total MADRS total score from baseline. Remission will be defined as MADRS total score ≤ 12.
12 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Secondary outcomes
Time Frame: 6 weeks
Analysis of mechanisms -parallel mediation model- will occur from the collection, through peripheral blood, in the sixth week, of inflammatory biomarkers (IL-1β, IL-4, IL-6, IL-10, TNF-α, IFN -γ, LPS, Zonulin and FABP2), to verify whether the antidepressant effect of probiotics is mediated by inflammation.
6 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Sao Paulo

Collaborators

Milken Institute
Baszucki Brain Research Fund

Investigators

  • Principal Investigator: Beny lafer, PhD, University of Sao Paulo

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 9, 2023

Primary Completion (Actual)

March 1, 2025

Study Completion (Actual)

March 1, 2025

Study Registration Dates

First Submitted

January 11, 2023

First Submitted That Met QC Criteria

February 27, 2023

First Posted (Actual)

March 10, 2023

Study Record Updates

Last Update Posted (Actual)

May 13, 2026

Last Update Submitted That Met QC Criteria

May 9, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • U1111-1280-7625

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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