Neurocognitive Effects of FMT in MDD Patients With and Without IBS

March 16, 2026 updated by: Valerie Taylor

Understanding the Neurocognitive Effects of Fecal Microbiota Transplantation in Major Depressive Disorder Patients With and Without Irritable Bowel Syndrome

This study is a phase 2/3 open-label controlled trial (CT) in which adults with Major Depressive Disorder (MDD) and adults who have MDD plus comorbid Inflammatory Bowel Syndrome (IBS) will be assigned to either receive oral Fecal Microbiota Transplantation (FMT) or to continue with the treatment they are currently receiving in a Treatment As Usual (TAU) arm. An IBS alone group receiving TAU will be recruited as a clinical control group.

The primary goals of this study are to determine effectiveness, safety and tolerability of oral FMT in adults with MDD and in MDD who have comorbid IBS. Additional goals are to characterize patterns and progressions of cognitive and neural correlates associated with MDD and with MDD + IBS and to determine if they improve with FMT. It is known that both, individuals with MDD and those with MDD and IBS show cognitive alterations as well as changes in neural structures, but this study is designed to see if those are changed with treatment response to FMT. Additionally, trial feasibility will be monitored via recruitment rate, study visits adherence and participant retention to inform future trial scalability."

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

133

Phase

  • Phase 2
  • Phase 3

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

  • Canada
    • Alberta
      • Calgary, Alberta, Canada, T2N 4Z6
        • University of Calgary, TRW building

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 60 years (Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Between 18-60 years of age:

    Participants should be at least 18 years old and not older than 60 years at the day of screening

  2. Have a primary diagnosis of MDD as assessed/confirmed by the M.I.N.I. International Neuropsychiatric Interview (MINI)
  3. Have had a well-documented inadequate response to at least 2 approved antidepressants
  4. A MADRS score of ≥ 19 at screening and visit 2a
  5. Have a comorbid diagnosis of IBS. IBS patients can include any of the following: diarrhea predominant IBS (IBS-D), constipation predominant IBS (IBS-C), IBS with mixed bowel habits (IBS-M), or unclassified with IBS (IBS-U) as confirmed by the referring doctor using ROME III criteria
  6. Moderate-to-severe IBS symptoms, as indicated by a score of ≥175 on the IBS Severity Scoring System (IBS-SSS)

Exclusion Criteria:

  1. Participant meets Diagnostic and Statistical Manual of Mental Disorders (DSM-5)[1] Criteria for the following conditions according to the M.I.N.I:

    1. Substance Use Disorder within the last 3 months. *(Criteria should include Alcohol and non-alcohol substances except Cannabis)
    2. Moderate or severe substance use disorder for Cannabis use the last 3 months
    3. Active Anorexia Nervosa or Bulimia nervosa
    4. Schizophrenia, schizoaffective or bipolar disorder
    5. Active suicidality
  2. Regular intake of non-steroidal anti-inflammatory drugs, antibiotics, or iron supplements for medical purposes in the three (3) months prior to study entry
  3. Use of prebiotics or probiotics for medical purposes for more than two (2) weeks within the last three (3) months
  4. Conditions causing immunosuppression
  5. Women who are breastfeeding, pregnant or seeking to get pregnant during the course of this study. Not using an acceptable method of birth control (implants, injectable, combined oral contraceptives, IUDs, sexual abstinence or a vasectomized partner)

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: Other
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: Participants with a confirmed diagnosis of MDD receiving TAU
Eligible and consenting patients will be assigned 1:1 to receive either FMT from a healthy donor or continuing on their usual medication for MDD, i.e., treatment as usual (TAU). This arm will continue to receive their usual anti-depressant.
Active Comparator: Participants with a confirmed diagnosis MDD who will receive FMT + TAU
Eligible and consenting patients will be assigned 1:1 to receive either FMT from a healthy donor or continuing on their usual medication for MDD, i.e., treatment as usual (TAU). This arm will be assigned to receive FMT provided by healthy donors.
Biological: Fecal Microbiota Transplantation
FMT is a technique in which intestinal microbiota are transferred from a healthy screened donor to a patient, with the goal being to introduce or restore a stable microbial community in the gut.
Other Names:
  • FMT
No Intervention: Participants with a confirmed diagnosis of MDD + IBS assigned to continue with TAU
Active Comparator: Participants with a confirmed diagnosis of MDD + IBS assigned to receive FMT + TAU
Biological: Fecal Microbiota Transplantation
FMT is a technique in which intestinal microbiota are transferred from a healthy screened donor to a patient, with the goal being to introduce or restore a stable microbial community in the gut.
Other Names:
  • FMT
No Intervention: Participants with a confirmed diagnosis IBS only receiving TAU
No Intervention: Healthy Controls
Data from healthy comparison (HC) participants will be drawn from another completed research study. Healthy comparison participants who will best match the patient population enrolled in the current trial and who consented to data sharing will be selected.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The Montgomery-Åsberg Depression Rating Scale (MADRS)
Time Frame: Baseline to week 13

a 10-item questionnaire which psychiatrists use to measure the severity of depressive episodes in patients with mood disorders. This will be used to evaluate the effectiveness of adjunct oral FMT as compared to TAU with currently accepted approved therapy for MDD.

The MADRS overall score ranges from 0 to 60. Each item yields a score of 0 to 6 and Higher MADRS score indicates more severe depression
Baseline to week 13
IBS Symptom Severity Scale (IBS-SSS)
Time Frame: Baseline to week 13

The IBS-SSS is a 5-item questionnaire that is used to assess the severity and frequency of abdominal pain, severity of abdominal distention, dissatisfaction with bowel habits, and interference with quality of life over the past 10 days.

Scores on the IBS-SSS can range from 0 to 500 with higher scores indicating more severe symptoms. Subjects can be categorized as having mild (75-175), moderate (175-300), or severe (>300) IBS.
Baseline to week 13

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Toronto Side Effect Scale (TSES)
Time Frame: Baseline to Week 13
The TSES is a 32-item instrument that is designed to establish incidence, frequency, and severity of CNS, GI, and sexual side effects. For each side effect, frequency and severity are measured on a 5-point scale. intensity is measured by multiplying frequency and severity.
Baseline to Week 13
IBS specific Quality of Life (IBS-QoL)
Time Frame: Baseline to Week 13

is a self-report 34-item instrument used to assess the impact of IBS and its treatment. used to examine GI tolerability in patients with IBS.

The individual responses to the 34 items are summed and averaged for a total score and then transformed to a 0-100 scale for ease of interpretation with higher scores indicating better IBS specific quality of life.
Baseline to Week 13
nuclear magnetic resonance (NMR) spectrometry
Time Frame: Baseline to Week 13
To assess the effect of FMT on microbiome profile (community structure and functional metagenome).
Baseline to Week 13

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
structural and functional neuroimaging
Time Frame: Baseline to week 13
fMRI to examine brain imaging changes in response to FMT
Baseline to week 13
Number of participants recruited, and completed the study visits
Time Frame: From Baseline to week 13
trial feasibility will be monitored via recruitment rate, study visits adherence and participant retention to inform future trial scalability
From Baseline to week 13

Collaborators and Investigators

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

Sponsor

Valerie Taylor

Investigators

  • Principal Investigator: Valerie Taylor, MD, PhD, University of Calgary

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)

April 6, 2022

Primary Completion (Actual)

October 21, 2024

Study Completion (Estimated)

October 21, 2026

Study Registration Dates

First Submitted

December 13, 2021

First Submitted That Met QC Criteria

December 13, 2021

First Posted (Actual)

December 30, 2021

Study Record Updates

Last Update Posted (Actual)

March 19, 2026

Last Update Submitted That Met QC Criteria

March 16, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IMA-FMT-MDD/IBS-2020

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

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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