Parkinson DiseasePhase 2TAPNCT03968133
Treating Anxiety in Parkinson's Disease With a Multi-Strain Probiotic
A Phase 2 study testing Probiotic in people with Parkinson Disease and Anxiety, run by University of British Columbia at 1 site in Canada.
Trial summary
This study evaluates the use of an oral multi-strain probiotic in the treatment of anxiety in individuals with Parkinson's Disease. Participants will be randomized to either 12-week multi-strain probiotic treatment or placebo. Read more about this study
- Who is it for?
- Ages 40 to 80 years
- Conditions the study is for
- Parkinson Disease, Anxiety
- What is being tested?
- Probiotic
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 61 participants
- Where
- 1 siteCanada
- Study dates
- 10 Dec 2020to 1 Dec 2023
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 40 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Confirmed diagnosis of Parkinson's disease based on Queen Square Brain Bank criteria
- Between ages 40-80
- Hoehn and Yahr stage between 1-3 (mild to moderate PD) in the "ON" state
- Anxiety (PAS score ≥14, MDS-UPDRS Part 1.4 score ≥ 2, and/or clinical diagnosis of anxiety based on the MINI clinical interview 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 a negative urine pregnancy test result at screening and baseline
- Willingness to maintain current physical activity levels during study period
Who cannot join
- Atypical parkinsonism
- Active suicidality
- Active psychosis
- Cognitive score (MoCA) of <21 in "ON" state
- BDI-II score above 28 in "ON" state
- Probiotic, sacchromyces boulardii and/or antibiotic usage in the past 3 months
Show all 20Show fewer
- Anti-inflammatory drug usage more than twice a week (e.g. corticosteroids, naproxen, ibuprofen, celecoxib). Use of daily 81 mg ASA permitted
- The use of natural health products that affect depression (e.g. St. John's Wort, passion flower)
- Concurrent psychotherapy or brain stimulation for the treatment of mood disorders
- 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 tumor, progressive supranuclear palsy, seizure disorder, subdural hematoma, multiple sclerosis, or history of significant head trauma
- An immune-compromised condition (e.g. AIDS, lymphoma, patients undergoing long term corticosteroid treatment)
- A bleeding disorder
- Current illness (for example a cold or flu like symptoms) and infections (for example hepatitis, HIV, gastroenteritis, fungal, or parasitic infections)
- Allergy to corn starch or corn
- Concurrent treatment for Parkinson Disease with Duodopa or Deep Brain Stimulation (DBS)
- Women who are pregnant, breast feeding, or planning to become pregnant during the course of the trial
- Unstable medical conditions or serious disease/conditions (e.g. cancer, cardiovascular, renal, lung, diabetes)
- Drug and/or substance abuse
Trial locations and contacts
1 site in 1 country.
Canada1 site
Pacific Parkinson's Research Centre
Vancouver, British Columbia, V6T 2B5
About this study
Official title: Treating Anxiety in Parkinson's Disease With a Multi-Strain Probiotic - a Randomized, Placebo-controlled Trial
This study evaluates the use of an oral multi-strain probiotic in the treatment of anxiety in individuals with Parkinson's Disease. Participants will be randomized to either 12-week multi-strain probiotic treatment or placebo.
Read the detailed description
Parkinson's disease (PD) is a complex condition that carries a high burden of neuropsychiatric comorbidities. About a third of individuals living with Parkinson's disease have one or more anxiety disorders, resulting in lower quality of life, greater care dependency, and increased caregiver burden. Gastrointestinal dysfunction is very common in Parkinson's. Constipation is experienced by the vast majority of patients and often manifests years before onset of motor symptoms, symptoms suggestive of irritable bowel syndrome are also commonly found in PD. Increased intestinal permeability has been demonstrated in PD. Impaired intestinal barrier function can lead to chronic systemic low-grade inflammation, which has been strongly associated with mood disorders. Several lines of evidence suggest a link between the gut microbiome and Parkinson's disease.
The microbiome has been linked to anxiety both in human and animal studies. Several studies have found beneficial effects of probiotics on mood disorders in non-PD populations, including stress and depressive behaviour in animal models, and sad mood reactivity and major depressive disorder in humans. Specifically regarding anxiety, probiotics have shown benefits in several animal models; human probiotic trials have demonstrated improvements in psychological distress and anxiety in healthy controls, in mothers experiencing postpartum depression and anxiety and in individuals afflicted with IBS-related anxiety without PD.
In summary, given the high rate of anxiety in PD, the growing evidence that probiotics may improve anxiety and mood disorders in non-PD populations, and the strong links between the gut microbiome and PD, we will carry out a randomized, blinded, placebo-controlled study into the use of a multi-strain probiotic to improve anxiety and Parkinson's disease.
Recruitment: Approximately 72 participants will be randomized to either the probiotic intervention arm or placebo treatment. Participants will mainly be recruited from the Pacific Parkinson's Research Centre movement disorder clinic at the University of British Columbia in Vancouver.
Participants will receive a detailed description of the study and will need to provide informed consent for participation in the study. Participants will be screened for inclusion and exclusion criteria.
Assessments: Clinical assessments of motor function, cognition and neuropsychiatric symptoms will be done before the 12 week intervention phase as well as following after the 12 week intervention with regular check ins during the course of the intervention. Blood samples and stool samples will be collected before and after the intervention.
The primary outcome will be the difference between the probiotic vs. placebo groups in mean Parkinson's Anxiety Scale (PAS) score pre/post-intervention. The primary analysis will be based on intention-to-treat. Secondary analyses for anxiety will include assessing the proportion of participants with a post-intervention PAS of ≤13 in each group. For other secondary outcomes, the between-group difference analysis will be applied to the fatigue, depression, PD motor function, severity (UPDRS I-III) and quality of life scores pre/post intervention, respectively. Adverse events, tolerability and drop-out rates will be registered and overall rates compared between the intervention groups. Furthermore, differences and changes in blood markers and microbiome composition will be assessed.
- Conditions
- Parkinson Disease, Anxiety
- Being tested
- Probiotic, Placebo
- Keywords
- probiotic, mood
- Medical subject headings
- Parkinson Disease, Anxiety Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ProbioticDietary supplement
Also called Ecologic® BARRIER 849
Oral probiotic delivered in powdered form.
PlaceboDietary supplement
Oral placebo delivered in powdered form.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic | Experimental | Ecologic® BARRIER 849 (Maize starch, maltodextrin, vegetable protein, potassium chloride, +/- probiotic bacteria (B. bifidum W23, B. lactis W51, B. lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, Lc. lactis W19, Lc. lactis W58; ≥ 2,5*10^9 colony forming unit (CFU)/g), magnesium sulphate, manganese sulphate.) sachet, two times daily dosing for a total of 2 grams (viable cell count of 2.5 × 10^9 CFU/gram) per day. Receives: Dietary Supplement: Probiotic |
| Placebo | Placebo comparator | Placebo (maize starch, maltodextrin, vegetable protein, magnesium sulphate, manganese sulphate) Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Parkinson's Anxiety Scale (PAS)
The PAS is a self reported 12-item scale that has three subscales: persistent anxiety, episodic anxiety, and avoidance behavior; It is rated using a Likert scale (0-4).
Measured: 13 weeks
Secondary outcomes (5)
Beck Depression Inventory (BDI)
The BDI is a self reported 21-question multiple-choice self-report inventory on a scale from 0-3.
Measured: 13 weeks
Parkinson's Disease Quality of Life Questionnaire (PDQ-39)
The PDQ-39 is a self reported questionnaire that assesses how often people affected by Parkinson's experience difficulties across 8 dimensions of daily living.
Measured: 13 weeks
Fatigue Severity Scale (FSS)
The Fatigue Severity Scale is a self reported 9-item scale which measures the severity of fatigue and its effect on a person's activities and lifestyle in patients with a variety of disorders on a scale from 1 (strongly disagree) to 7 (strongly agree).
Measured: 13 weeks
Montreal Cognitive Assessment
The MoCA test is a one-page 30-point administered assessment used for detecting cognitive impairment.
Measured: 13 weeks
Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS)
The MDS-UPDRS is a clinical assessment of motor and non-motor symptoms in individuals with Parkinson's Disease. It consists of four subscales. Subscales 1, 3, and 4 are administered by a trained individual with subscale 2 being self reported. Each item is rated from 0 to 4.
Measured: 13 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 May 2019
- Study start10 Dec 2020
- Primary completion1 Dec 2023
- Study completion1 Dec 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Parkinson DiseaseStudies of the same condition, open and under way.
- More trials run by University of British ColumbiaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomized, triple-blind, placebo-controlled study
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 61 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of British Columbia
- Sponsor type
- University, hospital or other
- Collaborators
- The W. Garfield Weston Foundation
- Responsible party
- Principal investigator, Silke Cresswell, University of British Columbia
- Investigators
- Silke Appel-Cresswell, MD, Principal investigator, University of British Columbia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03968133
- Sponsor's protocol ID
- H18-03083
- Acronym
- TAP
- Status last verified
- May 2026
- First submitted
- 28 May 2019
- Last updated
- 6 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Lam JST, Tosefsky KN, Ainsworth NJ, Meng D, Uzelman P, Zhu J, Cirstea MS, Pio F, Vila-Rodriguez F, Howard AK, Finlay BB, Appel-Cresswell S. Probiotic supplementation for anxiety symptoms in people with Parkinson's disease: a randomized, double-blind, placebo-controlled trial. NPJ Parkinsons Dis. 2026 Apr 25;12(1):104. doi: 10.1038/s41531-026-01364-1.
PubMed 42034654Lam JS, Tosefsky KN, Zhu J, Meng D, Uzelman P, Pio F, Ainsworth NJ, Vila-Rodriguez F, Howard AK, Appel-Cresswell S. Anxiety is associated with increased risk of suicidality in Parkinson's disease. J Parkinsons Dis. 2026 Mar;16(2):285-297. doi: 10.1177/1877718X251410887. Epub 2026 Jan 6.
PubMed 41493876
Study at a glance
From the registry record, last updated by the sponsor on 6 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Treating Anxiety in Parkinson's Disease With a Multi-Strain Probiotic - a Randomized, Placebo-controlled Trial
- ClinicalTrials.gov ID
- NCT03968133
- Acronym / sponsor ID
- TAP / H18-03083
- Conditions
- Parkinson Disease, Anxiety
- Keywords
- probiotic, mood
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 61 participants (actual)
- Lead sponsor
- University of British ColumbiaUniversity, hospital or other
- Collaborators
- The W. Garfield Weston Foundation
- Study start
- 10 Dec 2020 (actual)
- Primary completion
- 1 Dec 2023 (actual)
- Study completion
- 1 Dec 2023 (actual)
- First posted
- 30 May 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study evaluates the use of an oral multi-strain probiotic in the treatment of anxiety in individuals with Parkinson's Disease. Participants will be randomized to either 12-week multi-strain probiotic treatment or placebo.
Detailed description
Parkinson's disease (PD) is a complex condition that carries a high burden of neuropsychiatric comorbidities. About a third of individuals living with Parkinson's disease have one or more anxiety disorders, resulting in lower quality of life, greater care dependency, and increased caregiver burden. Gastrointestinal dysfunction is very common in Parkinson's. Constipation is experienced by the vast majority of patients and often manifests years before onset of motor symptoms, symptoms suggestive of irritable bowel syndrome are also commonly found in PD. Increased intestinal permeability has been demonstrated in PD. Impaired intestinal barrier function can lead to chronic systemic low-grade inflammation, which has been strongly associated with mood disorders. Several lines of evidence suggest a link between the gut microbiome and Parkinson's disease.
The microbiome has been linked to anxiety both in human and animal studies. Several studies have found beneficial effects of probiotics on mood disorders in non-PD populations, including stress and depressive behaviour in animal models, and sad mood reactivity and major depressive disorder in humans. Specifically regarding anxiety, probiotics have shown benefits in several animal models; human probiotic trials have demonstrated improvements in psychological distress and anxiety in healthy controls, in mothers experiencing postpartum depression and anxiety and in individuals afflicted with IBS-related anxiety without PD.
In summary, given the high rate of anxiety in PD, the growing evidence that probiotics may improve anxiety and mood disorders in non-PD populations, and the strong links between the gut microbiome and PD, we will carry out a randomized, blinded, placebo-controlled study into the use of a multi-strain probiotic to improve anxiety and Parkinson's disease.
Recruitment: Approximately 72 participants will be randomized to either the probiotic intervention arm or placebo treatment. Participants will mainly be recruited from the Pacific Parkinson's Research Centre movement disorder clinic at the University of British Columbia in Vancouver.
Participants will receive a detailed description of the study and will need to provide informed consent for participation in the study. Participants will be screened for inclusion and exclusion criteria.
Assessments: Clinical assessments of motor function, cognition and neuropsychiatric symptoms will be done before the 12 week intervention phase as well as following after the 12 week intervention with regular check ins during the course of the intervention. Blood samples and stool samples will be collected before and after the intervention.
The primary outcome will be the difference between the probiotic vs. placebo groups in mean Parkinson's Anxiety Scale (PAS) score pre/post-intervention. The primary analysis will be based on intention-to-treat. Secondary analyses for anxiety will include assessing the proportion of participants with a post-intervention PAS of ≤13 in each group. For other secondary outcomes, the between-group difference analysis will be applied to the fatigue, depression, PD motor function, severity (UPDRS I-III) and quality of life scores pre/post intervention, respectively. Adverse events, tolerability and drop-out rates will be registered and overall rates compared between the intervention groups. Furthermore, differences and changes in blood markers and microbiome composition will be assessed.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized, triple-blind, placebo-controlled study
| Arm | Type | Receives |
|---|---|---|
| Probiotic | Experimental | Dietary Supplement: ProbioticEcologic® BARRIER 849 (Maize starch, maltodextrin, vegetable protein, potassium chloride, +/- probiotic bacteria (B. bifidum W23, B. lactis W51, B. lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, Lc. lactis W19, Lc. lactis W58; ≥ 2,5*10^9 colony forming unit (CFU)/g), magnesium sulphate, manganese sulphate.) sachet, two times daily dosing for a total of 2 grams (viable cell count of 2.5 × 10^9 CFU/gram) per day. |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboPlacebo (maize starch, maltodextrin, vegetable protein, magnesium sulphate, manganese sulphate) |
Who may qualify
- Ages
- 40 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Confirmed diagnosis of Parkinson's disease based on Queen Square Brain Bank criteria
- Between ages 40-80
- Hoehn and Yahr stage between 1-3 (mild to moderate PD) in the "ON" state
- Anxiety (PAS score ≥14, MDS-UPDRS Part 1.4 score ≥ 2, and/or clinical diagnosis of anxiety based on the MINI clinical interview 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 a negative urine pregnancy test result at screening and baseline
Key exclusion criteria (20 listed)
- Atypical parkinsonism
- Active suicidality
- Active psychosis
- Cognitive score (MoCA) of <21 in "ON" state
- BDI-II score above 28 in "ON" state
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ProbioticAlso: Ecologic® BARRIER 849Oral probiotic delivered in powdered form. | Dietary supplement | Probiotic |
| PlaceboOral placebo delivered in powdered form. | Dietary supplement | Placebo |
Primary outcome
Parkinson's Anxiety Scale (PAS)
Time frame: 13 weeks
The PAS is a self reported 12-item scale that has three subscales: persistent anxiety, episodic anxiety, and avoidance behavior; It is rated using a Likert scale (0-4).
5 secondary outcomes
Beck Depression Inventory (BDI)
Time frame: 13 weeks
Parkinson's Disease Quality of Life Questionnaire (PDQ-39)
Time frame: 13 weeks
Fatigue Severity Scale (FSS)
Time frame: 13 weeks
Montreal Cognitive Assessment
Time frame: 13 weeks
Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS)
Time frame: 13 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Nov 2026.
- Derived from this study: PubMed 42034654Lam JST, Tosefsky KN, Ainsworth NJ, Meng D, Uzelman P, Zhu J, Cirstea MS, Pio F, Vila-Rodriguez F, Howard AK, Finlay BB, Appel-Cresswell S. Probiotic supplementation for anxiety symptoms in people with Parkinson's disease: a randomized, double-blind, placebo-controlled trial. NPJ Parkinsons Dis. 2026 Apr 25;12(1):104. doi: 10.1038/s41531-026-01364-1.
- Derived from this study: PubMed 41493876Lam JS, Tosefsky KN, Zhu J, Meng D, Uzelman P, Pio F, Ainsworth NJ, Vila-Rodriguez F, Howard AK, Appel-Cresswell S. Anxiety is associated with increased risk of suicidality in Parkinson's disease. J Parkinsons Dis. 2026 Mar;16(2):285-297. doi: 10.1177/1877718X251410887. Epub 2026 Jan 6.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Silke Appel-Cresswell, MD principal investigator
University of British Columbia
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Probiotic in people with Parkinson Disease and Anxiety, run by University of British Columbia at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 20 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Parkinson's Anxiety Scale (PAS) (time frame: 13 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03968133, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Nov 2026.