Multiple SclerosisPhase 2NCT06261489
Cannabis (THC vs. CBD) in Multiple Sclerosis
A Phase 2 study testing THC and CBD in people with Multiple Sclerosis, run by University of Calgary at 2 sites in Canada.
Trial summary
The goal of this clinical trial is to examine the effect of Cannabis components, THC and CBD, on cognition and bladder symptoms in people with Multiple Sclerosis (MS). Participants will complete questionnaires and cognitive tests. Read more about this study
- Who is it for?
- Ages 26 to 59 years
- Conditions the study is for
- Multiple Sclerosis
- What is being tested?
- THC and CBD
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 2 sitesCanada
- Study dates
- 5 Dec 2025to 30 Sep 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
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 26 to 59 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Age between 26 and 59 years inclusive.
- Confirmed diagnosis of Multiple Sclerosis as per McDonald criteria (any type) [12]
- Symptoms of neurogenic lower urinary tract dysfunction (NLUTD) as measured by neurogenic bladder symptom score (NBSS), with a minimum score of 7.
- If already on a medication for NLUTD, must be stable on this medication for at least 4 weeks.
- Sexually active men and women of child-bearing potential must agree to use adequate contraception.
- Written informed consent.
Who cannot join
- Major psychiatric disorder such as schizophrenia or bipolar disorder
- Major neurological disorder which could affect cognition such as dementia, traumatic brain injury.
- Seizure disorder
- Use of antipsychotic medication
- Use of benzodiazepines other than exclusively at night/bedtime
- Experienced a MS relapse in the last ninety (90) days.
Show all 12Show fewer
- Current use of cannabis or CBM greater than 3x/week.
- Currently using cannabis/CBM less than 3x/week and being unwilling to abstain for the duration of the study.
- Visual acuity (binocular) worse than 20/70 (in order to complete the cognitive outcomes)
- Significant upper extremity disability that would interfere with the cognitive tests battery.
- Indwelling catheter use/urinary diversion
- Pregnant or Breastfeeding
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Canada2 sites, 2 recruiting
- Recruiting
University of Calgary Foothills Medical Center
Calgary, Alberta
- Recruiting
University of Calgary
Calgary, Alberta
Sarah A Morrow, 1-403-9444241, sarah.morrow@albertahealthservices.ca
About this study
Official title: The Differential Effects of THC vs. CBD on Cognition in Persons With MS
The goal of this clinical trial is to examine the effect of Cannabis components, THC and CBD, on cognition and bladder symptoms in people with Multiple Sclerosis (MS).
Participants will complete questionnaires and cognitive tests. They will be randomly assigned to receive either CBD or THC oil and will take the study drug for 15 weeks.
Read the detailed description
Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system.
Cannabis and cannabis-based medicines (CBM) are often used by persons with MS (PwMS).
Cannabis research to date indicates that its use worsens cognitive function in PwMS. Additionally, cognitive impairment (CI) is already a frequent consequence of MS, with a significant negative impact on quality of life (QOL).
This is pilot randomized, double blinded, double arm clinical trial of Tetrahydrocannabinol (THC) 25 mg or Cannabidiol (CBD) 50 mg orally for 15 weeks in people with MS trial.
The investigators will recruit PwMS with symptoms of neurogenic lower urinary tract dysfunction (NLUTD). These participants can either be on a treatment that has been only partially effective (as per patient report) or has never tried an intervention for their NLUTD symptoms.
The primary aim is to evaluate the differential effect of the tetrahydrocannabinol (THC) and cannabidiol (CBD) on cognitive outcomes in persons with Multiple Sclerosis (PwMS) using cannabis for NLUTD.
The results of our proposed study will better inform both healthcare practitioners and patients with respect to the potential risks of treatment with cannabis-based products and any difference with respect to THC vs. CBD-based products.
- Conditions
- Multiple Sclerosis
- Being tested
- THC, CBD
- Keywords
- Cannabis, Cognitive Function
- Medical subject headings
- Multiple Sclerosis, Marijuana Abuse
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
THCDrug
Also called Tetrahydrocannabinol
Participants will be randomly assigned to the study treatment. THC dose will be gradually increased until 25 mg. Treatment will be taken orally at bedtime for 15 weeks.
CBDDrug
Also called Cannabidiol
Participants will be randomly assigned to the study treatment. CBD dose will be gradually increased until 50 mg. Treatment will be taken orally at bedtime for 15 weeks.
| Study group | Role | What they receive |
|---|---|---|
| Tetrahydrocannabinol (THC) 25 mg | Experimental | THC oil will be administered orally once a day for 15 weeks. Receives: Drug: THC |
| Cannabidiol (CBD) 50 mg | Experimental | CBD oil will be administered orally once a day for 15 weeks. Receives: Drug: CBD |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cognitive outcome: The Differential Effect, if any, of THC and CBD in MS Cognition will be measured by Symbol Digit Modality Test (SDMT).
Symbol Digit Modality Test (SDMT) is an assessment of the information processing speed. It consists of the presentation of a standard letter sized paper (8.5 × 11 in.) that contains the numbers and symbols to be processed. At the top of the page is a key where nine symbols are each paired with a single digit. The remainder of the page has a pseudorandomized sequence of these symbols. In the oral version of the SDMT, adapted for the MS population by Rao, the subject responds orally with the digit associated with each of the symbols as quickly as possible, and is scored as the total number of correct responses in 90s.Participants will be evaluated at baseline, week 10 and week 15.
Measured: 15 weeks
NLUTD outcome: The Differential Effect, if any, of THC and CBD on Neurogenic lower urinary tract dysfunction (NLUTD) symptoms will be measured by Neurogenic Bladder Symptom Score (NBSS).
Neurogenic Bladder Symptom Score (NBSS) is a validated measure of bladder symptoms and QoL. It is scored from 0 (no symptoms) to 74 and has 3 domains: incontinence; storage, voiding, and consequences; and a single overall QOL question. Participants will be evaluated at baseline, week 10 and week 15.
Measured: 15 weeks
Secondary outcomes (1)
Blinding feasibility: The ability to blind the administration of THC vs CBD in PwMS will be evaluated based on participants and investigators report.
The investigators will ask subjects at each visit to try and identify which arm they were randomized to. If participants feel they are able to determine which group they were assigned to, they will be asked to identify how/why. This data will help investigators to develop better masking in our subsequent study.
Measured: 15 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Feb 2024
- Study start5 Dec 2025
- Primary completion30 Sep 2027 (estimated)
- Study completion30 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Multiple SclerosisStudies of the same condition, open and under way.
- 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
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Calgary
- Sponsor type
- University, hospital or other
- Collaborators
- Multiple Sclerosis Society of Canada
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06261489
- Sponsor's protocol ID
- REB23-1128
- Status last verified
- Sep 2026
- First submitted
- 10 Jan 2024
- Last updated
- 15 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 15 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Differential Effects of THC vs. CBD on Cognition in Persons With MS
- ClinicalTrials.gov ID
- NCT06261489
- Acronym / sponsor ID
- REB23-1128
- Conditions
- Multiple Sclerosis
- Keywords
- Cannabis, Cognitive Function
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- University of CalgaryUniversity, hospital or other
- Collaborators
- Multiple Sclerosis Society of Canada
- Study start
- 5 Dec 2025 (actual)
- Primary completion
- 30 Sep 2027 (estimated)
- Study completion
- 30 Sep 2027 (estimated)
- First posted
- 15 Feb 2024 (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.
The goal of this clinical trial is to examine the effect of Cannabis components, THC and CBD, on cognition and bladder symptoms in people with Multiple Sclerosis (MS).
Participants will complete questionnaires and cognitive tests. They will be randomly assigned to receive either CBD or THC oil and will take the study drug for 15 weeks.
Detailed description
Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system.
Cannabis and cannabis-based medicines (CBM) are often used by persons with MS (PwMS).
Cannabis research to date indicates that its use worsens cognitive function in PwMS. Additionally, cognitive impairment (CI) is already a frequent consequence of MS, with a significant negative impact on quality of life (QOL).
This is pilot randomized, double blinded, double arm clinical trial of Tetrahydrocannabinol (THC) 25 mg or Cannabidiol (CBD) 50 mg orally for 15 weeks in people with MS trial.
The investigators will recruit PwMS with symptoms of neurogenic lower urinary tract dysfunction (NLUTD). These participants can either be on a treatment that has been only partially effective (as per patient report) or has never tried an intervention for their NLUTD symptoms.
The primary aim is to evaluate the differential effect of the tetrahydrocannabinol (THC) and cannabidiol (CBD) on cognitive outcomes in persons with Multiple Sclerosis (PwMS) using cannabis for NLUTD.
The results of our proposed study will better inform both healthcare practitioners and patients with respect to the potential risks of treatment with cannabis-based products and any difference with respect to THC vs. CBD-based products.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Tetrahydrocannabinol (THC) 25 mg | Experimental | Drug: THCTHC oil will be administered orally once a day for 15 weeks. |
| Cannabidiol (CBD) 50 mg | Experimental | Drug: CBDCBD oil will be administered orally once a day for 15 weeks. |
Who may qualify
- Ages
- 26 to 59 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Age between 26 and 59 years inclusive.
- Confirmed diagnosis of Multiple Sclerosis as per McDonald criteria (any type) [12]
- Symptoms of neurogenic lower urinary tract dysfunction (NLUTD) as measured by neurogenic bladder symptom score (NBSS), with a minimum score of 7.
- If already on a medication for NLUTD, must be stable on this medication for at least 4 weeks.
- Sexually active men and women of child-bearing potential must agree to use adequate contraception.
Key exclusion criteria (12 listed)
- Major psychiatric disorder such as schizophrenia or bipolar disorder
- Major neurological disorder which could affect cognition such as dementia, traumatic brain injury.
- Seizure disorder
- Use of antipsychotic medication
- Use of benzodiazepines other than exclusively at night/bedtime
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 |
|---|---|---|
| THCAlso: TetrahydrocannabinolParticipants will be randomly assigned to the study treatment. THC dose will be gradually increased until 25 mg. Treatment will be taken orally at bedtime for 15 weeks. | Drug | Tetrahydrocannabinol (THC) 25 mg |
| CBDAlso: CannabidiolParticipants will be randomly assigned to the study treatment. CBD dose will be gradually increased until 50 mg. Treatment will be taken orally at bedtime for 15 weeks. | Drug | Cannabidiol (CBD) 50 mg |
Primary outcome
Cognitive outcome: The Differential Effect, if any, of THC and CBD in MS Cognition will be measured by Symbol Digit Modality Test (SDMT).
Time frame: 15 weeks
Symbol Digit Modality Test (SDMT) is an assessment of the information processing speed. It consists of the presentation of a standard letter sized paper (8.5 × 11 in.) that contains the numbers and symbols to be processed. At the top of the page is a key where nine symbols are each paired with a single digit. The remainder of the page has a pseudorandomized sequence of these symbols. In the oral version of the SDMT, adapted for the MS population by Rao, the subject responds orally with the digit associated with each of the symbols as quickly as possible, and is scored as the total number of correct responses in 90s.Participants will be evaluated at baseline, week 10 and week 15.
NLUTD outcome: The Differential Effect, if any, of THC and CBD on Neurogenic lower urinary tract dysfunction (NLUTD) symptoms will be measured by Neurogenic Bladder Symptom Score (NBSS).
Time frame: 15 weeks
Neurogenic Bladder Symptom Score (NBSS) is a validated measure of bladder symptoms and QoL. It is scored from 0 (no symptoms) to 74 and has 3 domains: incontinence; storage, voiding, and consequences; and a single overall QOL question. Participants will be evaluated at baseline, week 10 and week 15.
1 secondary outcome
Blinding feasibility: The ability to blind the administration of THC vs CBD in PwMS will be evaluated based on participants and investigators report.
Time frame: 15 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Sep 2026.
- Individual participant dataSharing planned: Undecided
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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.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing THC and CBD in people with Multiple Sclerosis, run by University of Calgary at 2 sites 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 12 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: looking for participants now, as of the sponsor's last update on 15 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites 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. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sarah A Morrow, MD, MS, FRCPC, FAAN (1-403-9444241, sarah.morrow@albertahealthservices.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cognitive outcome: The Differential Effect, if any, of THC and CBD in MS Cognition will be measured by Symbol Digit Modality Test (SDMT). (time frame: 15 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 15 Sep 2026; AzTrials last refreshed its copy on 30 Oct 2026.