Cannabinoids for Multiple Sclerosis Symptoms: Evidence Review

How to read this page

This page summarizes research on cannabinoids for symptoms of multiple sclerosis (MS). It does not recommend cannabis or CBD for MS, gives no amounts, and does not apply to treatments that change the course of MS. Never stop or change an MS medicine because of this page. Evidence labels used: approved medicine, promising but limited, mixed, insufficient evidence and evidence of harm. "Spasticity" means muscle stiffness and spasms. "Nabiximols" is a prescription mouth spray with plant-derived THC and CBD in a 1:1 combination. [1]

The short answer

Cochrane review (2022)

This review included 25 randomized trials with 3,763 adults, lasting 3 to 48 weeks. Thirteen trials tested nabiximols, seven a synthetic THC-like cannabinoid, two an oral THC extract and one inhaled herbal cannabis. [1]

• Spasticity. Compared with placebo, nabiximols probably increases the number of people who report an important reduction in spasticity severity (odds ratio 2.51, moderate certainty), about 216 more per 1,000 people. [1]
• Overall improvement. Cannabinoids probably increase the number of people who report being "much" or "very much" improved (moderate certainty). [1]
• Quality of life. Cannabinoids may have little to no effect. [1]
• Harms. They may slightly increase stopping treatment because of side effects, and may increase nervous system and psychiatric disorders (low certainty). [1] Serious adverse events may not differ from placebo. [1]
• Limits. The review says certainty is limited because studies were short. [1]

Other reviews

NCCIH summarized a review of 17 studies (3,161 people) in which cannabinoids gave a small improvement in patient-rated spasticity, pain and bladder problems, but not in objective spasticity tests. [2] The American Academy of Neurology (2014) concluded that nabiximols is probably effective for subjective spasticity, probably ineffective for objective spasticity measures or bladder incontinence, and possibly ineffective for tremor. It judged data on smoked cannabis inadequate. [2]

A 2024 review of 31 studies, only six of them randomized, found nabiximols (the most common product) lowered spasticity scores, but results varied widely between studies (97% inconsistency). [3] We therefore treat it as supportive, not conclusive. A 2015 JAMA review also found moderate-quality evidence for spasticity, with more short-term adverse events. [4]

Where nabiximols is approved

Approval rules change. Check the current regulator.

Risks and special groups

Dizziness, dry mouth, nausea and sleepiness were more common in MS trials in a 2023 BMJ umbrella review. [9] NICE notes breastfeeding is a contraindication for nabiximols and nabilone, and that limited evidence exists for pregnancy. [6] The FDA warns CBD can cause liver injury, drowsiness and interactions with other medicines. [10] NCCIH links cannabis use with more motor vehicle crashes. [2]

Store-bought oils and flower are not the studied preparations. In one US sample, 74% of CBD products missed their labeled CBD amount by at least 10%. [11]

Where to read next

Approved cannabinoid medicines, cannabis and CBD medicine interactions, impairment and driving and pregnancy and breastfeeding. For chronic pain more broadly, see the chronic pain evidence review.