Cannabis-Based Medicines May Ease MS Spasticity, but They Are Not a Cure

For people with multiple sclerosis (MS), cannabis-based medicines may offer limited relief from one particularly difficult symptom: muscle spasticity. But the evidence does not support replacing standard MS treatment with cannabis, and the benefits seen in clinical trials have generally involved standardized products—not the wide range of unregulated products sold under state medical-cannabis programs.

MS is an immune-mediated disease of the central nervous system that can cause spasticity, pain, fatigue, weakness, vision problems, balance difficulties and cognitive symptoms. Treatments can help control relapses, slow disease activity and manage symptoms, but no single therapy works for everyone.

What the American Academy of Neurology says

The American Academy of Neurology’s position statement on medical marijuana for neurologic disorders, originally issued in 2014 and updated in 2018, does not endorse cannabis as a routine treatment for MS or other neurologic conditions. Instead, it supports rigorous research and says that cannabis products should demonstrate safety and effectiveness through studies comparable to those required for other medicines.

The AAN acknowledges that some standardized cannabis-based preparations may have therapeutic potential. However, it cautions that results from trials of regulated formulations—many of them conducted in Europe—should not automatically be applied to products that may differ in potency, ingredients, labeling accuracy and quality control. The academy also highlights possible cognitive, psychiatric and neurologic effects, as well as uncertain interactions with prescription medicines.

This is more cautious than the suggestion that the AAN recommended reserving medical cannabis for patients who had failed standard therapy. The AAN’s published position is broader: it does not support prescribing or legalizing medical marijuana for neurologic disorders at this time, while calling for better evidence.

What research in MS has found

Clinical research has focused mainly on spasticity rather than on the underlying disease. In a 2007 randomized trial of 189 people with MS, a standardized THC-and-CBD oromucosal spray improved patients’ self-reported spasticity compared with placebo. Objective measures, including the Ashworth scale, did not show statistically significant improvement, and adverse events led to more withdrawals in the active-treatment group. The trial report is available through PubMed.

Other randomized studies of nabiximols—the standardized spray commonly known by the brand name Sativex—have produced a similar pattern: patients often report that their spasticity feels better, while clinician-measured muscle tone and broader measures of disability may show little or no change. These findings suggest symptom relief, not recovery of nerve function or modification of MS progression.

A 2022 Cochrane review analyzed 25 randomized trials involving 3,763 adults with MS. It concluded that nabiximols probably improves patient-reported spasticity in the short term and may improve patients’ overall perception of well-being. However, the review found no high-quality evidence, limited information about long-term treatment and uncertain benefits for chronic neuropathic pain. Cannabinoid treatment was also associated with a higher likelihood of nervous-system and psychiatric adverse effects in some analyses.

These results do not establish that smoked cannabis, edible products or over-the-counter CBD products work in the same way as a standardized medicine tested in a clinical trial. They also do not show that cannabis prevents relapses, slows disability or treats the immune processes that cause MS.

Why patient surveys tell a different story

Many people with MS nevertheless report using cannabis for symptoms such as spasticity, pain, sleep problems and anxiety. In a 2014 survey of 5,481 NARCOMS registry participants, 26% said they had used marijuana for MS and 16% were current users. The survey measured people’s experiences and beliefs, not the treatment’s effectiveness in a blinded clinical trial. A later NARCOMS survey found that 31% of respondents had ever used cannabis and 20% were current users, while only a small proportion relied on an MS physician as their main source of cannabis guidance. These findings are reported in the 2017 survey study and the 2022 follow-up research.

Such surveys are useful for showing how common cannabis use is and why patients seek it out, but they cannot separate a treatment effect from placebo responses, changes in other medications, differences in symptom severity or the natural fluctuation of MS symptoms.

Potential risks

Depending on the product, dose and THC content, cannabis-based treatments may cause:

• dizziness and drowsiness;
• impaired attention, memory and coordination;
• fatigue and dry mouth;
• changes in mood or perception;
• increased appetite;
• psychiatric or neurologic side effects; and
• problematic use or dependence in some individuals.

Smoking cannabis also exposes the lungs to irritants and combustion products. Products purchased from dispensaries or online retailers may vary substantially in strength and may not contain exactly what their labels claim. In the United States, the Food and Drug Administration explains that it has not approved cannabis to treat MS or any other disease. It has approved specific cannabinoid-related prescription drugs for limited indications, but those approvals do not extend to general medical-marijuana products.

The practical takeaway

For adults with MS whose spasticity remains difficult to control, a standardized cannabis-based medicine may be considered in some health systems as an add-on treatment after other options have been evaluated. The best-supported potential benefit is a modest, short-term improvement in how patients perceive their spasticity—not a cure and not a treatment that has been shown to slow MS.

Anyone considering cannabis should discuss the specific product, THC-to-CBD balance, route of administration, possible drug interactions and personal risk factors with a clinician. It should not be used to replace disease-modifying therapy or other prescribed treatment without medical guidance.