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NCT Number: NCT05762887

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

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.

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Key information

Conditions

Bipolar Disorder Bipolar and Related Disorders Mental Disorders Mood Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Sao Paulo

São Paulo, 05403010, Brazil

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Probiotic Group

Other

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 Group

Other

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.

Primary outcomes

  1. 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.

Sponsors and collaborators

Lead sponsor

University of Sao Paulo

Other

Collaborators

  • Baszucki Brain Research Fund
  • Milken Institute

Registry information

Official study title

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

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Mar 10, 2023
Registry last updated
May 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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