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

What this study is about

This study evaluates the use of an oral multi-strain probiotic in the treatment of depression in individuals with Parkinson's Disease. Participants will be randomized to either a 12-week multi-strain probiotic treatment or placebo intervention.

Who can join (things the study team will check)

✅ You may be able to join if…

• Confirmed diagnosis of Parkinson's disease based on UK Brain Bank criteria
• Between the ages of 40-80 years
• Mild to Moderate PD (Hoehn and Yahr stage between 1-3 in the "ON" state)
• Mild to moderate depression (BDI-II score of 14-28 in the "ON" state)
• 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
• Willingness to maintain current physical activity levels during study period
• English proficiency

🚫 You may not be able to join if…

• Atypical Parkinsonism
• Active suicidality
• Active psychosis
• Cognitive score (MoCA) of < 21 in the "ON" state
• Severe depression (BDI-II score > 28 in the "ON" state)
• Probiotic, Saccharomyces boulardii and/or antibiotic use in the past 3 months (yogurt, kefir, and other probiotic-containing foods are allowed)
• The use of natural health products that affect depression (e.g., St. John's Wort, passion flower, gaba, 5-htp, kava, bacopa, efa's)
• Change in the schedule of concurrent psychotherapy or brain stimulation for the treatment of mood or anxiety disorders in the last 4 weeks
• Change in antidepressant or anxiolytic medication (including benzodiazepines) within the last 4 weeks
• Change in Parkinson's medication within the last 2 weeks
• 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
• 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)
• A known bleeding disorder
• Current illness (e.g., a cold or flu-like symptoms) and infections (e.g., hepatitis, HIV, gastroenteritis, fungal, or parasitic infections)
• Allergy to corn starch or corn
• Concurrent treatment for Parkinson's disease with Duodopa
• Change in Deep Brain Stimulation (DBS) stimulation parameters in the last 4 weeks
• New onset of significant psychiatric symptoms following DBS procedure that are considered likely related
• Women who are pregnant, breastfeeding, or planning to become pregnant during the course of the trial
• Unstable medical conditions or serious disease/conditions (e.g., cancer undergoing active treatment, poorly controlled diabetes)

+ 2 more criteria — see the full checklist in the app.

Where this trial is running

• Pacific Parkinson's Research Centre, Vancouver, British Columbia, Canada

Who to contact

Matthew Leung, BSc · 604-827-1905 · Matthew.Leung@ubc.ca

It's completely normal to call and ask questions before deciding anything. Mention the study ID: NCT05568498.