Probiotics for depression and mood problems in Parkinson's disease

Probiotic Treatment for Depression and Associated Mood Disorders in Parkinson's Disease

This trial will test whether a 12-week oral multi-strain probiotic can improve depressive symptoms in people with Parkinson's disease.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 60 (estimated)
• Ages: 40 Years to 80 Years
• Sex: All
• Sponsor: University of British Columbia (Academic / other)
• Drugs / interventions: chemotherapy
• Locations: 1 site (Vancouver, British Columbia)
• Trial ID: NCT05568498 on ClinicalTrials.gov

What this trial studies

Participants with Parkinson's disease and mild-to-moderate depression are randomized in a triple-blinded, placebo-controlled design to receive either a multi-strain probiotic or placebo for 12 weeks. Eligibility includes ages 40–80, Hoehn and Yahr stage 1–3 in the ON state, and a BDI-II score of 14–28, with exclusions for recent probiotic or antibiotic use and significant cognitive impairment. Mood outcomes are measured with standard clinical scales and participants maintain their usual activity levels during the intervention. The trial is conducted at the Pacific Parkinson's Research Centre, affiliated with the University of British Columbia.

Who should consider this trial

Good fit: Ideal candidates are English-speaking adults aged 40–80 with clinically confirmed Parkinson's disease (Hoehn and Yahr 1–3) and mild-to-moderate depression (BDI-II 14–28) who have not used probiotics or antibiotics in the past three months.

Not a fit: People with severe depression, active suicidality or psychosis, atypical parkinsonism, marked cognitive impairment (MoCA <21), or recent probiotic/antibiotic use are unlikely to qualify or benefit from this intervention.

Why it matters

Potential benefit: If successful, the probiotic could reduce depressive symptoms in people with Parkinson's and improve quality of life.

How similar studies have performed: Previous studies in non-Parkinson populations and animal models have shown mood benefits from some probiotics, but randomized evidence specifically in Parkinson's disease is limited, so this trial builds on encouraging but not definitive prior work.

Eligibility criteria

Inclusion Criteria:

1. Confirmed diagnosis of Parkinson's disease based on UK Brain Bank criteria
2. Between the ages of 40-80 years
3. Mild to Moderate PD (Hoehn and Yahr stage between 1-3 in the "ON" state)
4. Mild to moderate depression (BDI-II score of 14-28 in the "ON" state)
5. Women of childbearing potential must agree to use a medically approved method of birth control (e.g., hormonal contraceptives, intrauterine devices, vasectomy/tubal litigation, barrier methods and double barrier method) and must have negative pregnancy test results at screening and baseline
6. Willingness to maintain current physical activity levels during study period
7. English proficiency

Exclusion Criteria:

1. Atypical Parkinsonism
2. Active suicidality
3. Active psychosis
4. Cognitive score (MoCA) of \< 21 in the "ON" state
5. Severe depression (BDI-II score \> 28 in the "ON" state)
6. Probiotic, Saccharomyces boulardii and/or antibiotic use in the past 3 months (yogurt, kefir, and other probiotic-containing foods are allowed)
7. The use of natural health products that affect depression (e.g., St. John's Wort, passion flower, gaba, 5-htp, kava, bacopa, efa's)
8. Change in the schedule of concurrent psychotherapy or brain stimulation for the treatment of mood or anxiety disorders in the last 4 weeks
9. Change in antidepressant or anxiolytic medication (including benzodiazepines) within the last 4 weeks
10. Change in Parkinson's medication within the last 2 weeks
11. Neurological disease other than PD, including Alzheimer's disease, multi-infarct dementia, Huntington's disease, normal pressure hydrocephalus, a brain tumour, progressive supranuclear palsy, seizure disorder, subdural hematoma, multiple sclerosis, or history of significant head trauma
12. A significant immune-compromised condition due to either a health condition or use of an immune suppressant (e.g., AIDS, lymphoma, chemotherapy treatment, patients undergoing long-term systemic corticosteroid or immunosuppressant treatment)
13. A known bleeding disorder
14. Current illness (e.g., a cold or flu-like symptoms) and infections (e.g., hepatitis, HIV, gastroenteritis, fungal, or parasitic infections)
15. Allergy to corn starch or corn
16. Concurrent treatment for Parkinson's disease with Duodopa
17. Change in Deep Brain Stimulation (DBS) stimulation parameters in the last 4 weeks
18. New onset of significant psychiatric symptoms following DBS procedure that are considered likely related
19. Women who are pregnant, breastfeeding, or planning to become pregnant during the course of the trial
20. Unstable medical conditions or serious disease/conditions (e.g., cancer undergoing active treatment, poorly controlled diabetes)
21. Drug and/or substance abuse
22. The patient, in the opinion of the Investigator, is unable to adhere to the requirements of the study. This includes any patient who, in the judgment of the Investigator, is likely to be noncompliant during the study, or unable to cooperate because of a significant language barrier or cognitive impairment

Where this trial is running

Vancouver, British Columbia

• Pacific Parkinson's Research Centre — Vancouver, British Columbia, Canada (Recruiting)

Study contacts

• Study coordinator: Matthew Leung, BSc

Conditions Parkinson Disease; Depression; PARKINSON DISEASE; Parkinsons Disease; Probiotics; Gut Microbiome