CBD and multiple sclerosis: what 25 trials actually tested

Research on multiple sclerosis involves three families of products, and confusing them causes most of the misunderstandings.

Cannabidiol (CBD) does not produce the psychoactive effect of THC, as our article on the differences between THC and CBD explains. On its own, a result obtained with a THC-containing spray tells you nothing about a CBD oil.

Multiple sclerosis is a common disease. Inserm, the French medical research institute, counts about 110,000 people affected in France, with 4,000 to 6,000 new cases a year and an average age of onset around 30. In young adults, it is the leading cause of severe disability not due to injury. Spasticity, an involuntary stiffness of the muscles, is a frequent complication.

Sativex received its French marketing authorisation on 8 January 2014. The authorisation covers moderate to severe spasticity caused by multiple sclerosis in adults who have not responded well enough to other antispastic drugs, as an add-on to their usual treatment.

The medicine has still never been sold in France. In an answer to a written parliamentary question published on 28 February 2023, the government explains that price negotiations have been failing since 2015, although the product is authorised in 17 other European countries. It puts the number of patients who could benefit at 5,000.

The Transparency Committee of the Haute Autorité de santé issued its opinion of 22 October 2014 after a hearing with the manufacturer. It rated the medical benefit as low and the added benefit as non-existent (level V), and found no demonstrated impact on quality of life.

That verdict rests on the three pivotal trials:

• Trial GWMS 0106, 189 patients: at six weeks, a gap of 0.52 points on a 0 to 10 spasticity scale, smaller than the protocol had planned for.
• Trial GWCL 0403, 337 patients: no difference from placebo on the main outcome at fourteen weeks.
• Trial GWSP 0604: 572 patients were first treated openly, and only the 241 who responded were randomised, a preliminary sort that favours the product.

Patients scored their own spasticity in these trials. The first trial had originally taken the Ashworth scale, scored by the doctor, as its main outcome, then replaced it. In the results reported by the HAS, the Ashworth scale shows no difference from placebo. The committee judged the benefit clinically relevant in 10 to 20% of patients who respond poorly to their usual treatment.

Published on 5 May 2022, the Cochrane review on cannabinoids in multiple sclerosis pools 25 randomised trials and 3,763 participants, of whom 2,290 received a cannabinoid. Trial length ranges from 3 to 48 weeks.

For perceived spasticity, nabiximols probably raises the number of people reporting a clear improvement, with an odds ratio of 2.51 (95% confidence interval 1.56 to 4.04) and moderate certainty. In absolute terms, the gain is 216 people per 1,000 compared with placebo.

The effect on quality of life is small or nil, with a standardised difference of -0.08 (-0.17 to 0.02) and low certainty. Adverse effects probably increase: the odds ratio is 2.41 for withdrawals due to an adverse effect, 2.61 for nervous system disorders and 1.94 for psychiatric disorders. The authors point out that most trials were short.

A trial run in Mashhad, Iran, published in 2025 in Naunyn-Schmiedeberg's Archives of Pharmacology, assigned 49 patients to CBD drops (24 patients) or a placebo (25). Over two weeks the dose went from 5 mg to 70 mg a day, then rose to 80 mg until the fourth week.

Spasticity, the target outcome, did not differ between the groups at 4 weeks or at 8 weeks. In the CBD group, the authors report a slightly faster 7.6-metre walking test and slightly lower peak pain scores. Those are secondary outcomes from a single centre, in 49 people over one month, and they raise a question they cannot answer.

The first concerns disease progression. The CUPID trial, published in 2013 in The Lancet Neurology, gave 498 patients with a progressive form either dronabinol, a synthetic THC, or a placebo for 36 months. The hazard ratio for progression was 0.92 (0.68 to 1.23), p = 0.57, and the authors conclude that there was no overall effect on progression.

The second concerns stiffness as measured by the doctor. The RELEASE MSS1 trial, published in 2024, tested nabiximols in 68 patients using the lower-limb Ashworth scale. It missed its main outcome, with a difference from placebo of 0.04, p = 0.7152.

Launched in 2021, the French medical cannabis experiment covered five indications, one of them painful spasticity in multiple sclerosis or other central nervous system diseases. According to the minutes of the ANSM scientific committee, 246 of the 1,683 patients still treated on 27 February 2025 were followed for spasticity linked to multiple sclerosis.

Enrolment of new patients stopped on 27 March 2024, and the permanent framework is still awaiting the HAS opinion. Our article on medical cannabis in France in 2026 tracks that timetable.

Freely sold CBD is not a medicine, and it may not claim any effect on a disease. Epidyolex, the only authorised medicine based on cannabidiol, is indicated for rare forms of epilepsy (Lennox-Gastaut and Dravet syndromes, tuberous sclerosis complex). Multiple sclerosis is not among its indications.

If you are followed for multiple sclerosis and use CBD, let your neurologist know. CBD is processed by the same liver enzymes as many medicines, a point covered in our article on interactions between CBD and medicines. For an overview of the evidence, read what clinical studies say about CBD.