Cannabis and multiple sclerosis
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Multiple sclerosis (MS) is an autoimmune disorder in which inflammation damages nerves in the brain and spinal cord. This neurological damage can give rise to a range of symptoms, including muscle spasms, pain, and fatigue.
Cannabis is a plant humans have used for medicinal and recreational purposes for thousands of years. In recent decades, researchers have been exploring the potential uses of cannabis-based medicines in MS and other diseases.
Research into cannabis and MS is ongoing in many countries.
Potential benefits of cannabis in MS
A number of studies have evaluated whether cannabis-based therapies may help to ease certain symptoms of MS. But most of these studies are small, and the results oftentimes vary from one to another. Moreover, even among participants in the same study, there often is a range of responses to cannabis treatments.
Reviews of the available scientific evidence have generally supported the notion that cannabis-based therapies can help to ease pain and spasticity symptoms in people with MS.
The effect of cannabis on other disease symptoms remains incompletely understood. Following are more details about the use of cannabis for treating specific symptoms.
Muscle spasticity
Multiple clinical trials have tested cannabis products that are eaten or sprayed into the mouth as a potential treatment for spasticity — a symptom characterized by muscle stiffness that’s experienced by as many as 90% of MS patients.
These trials have generally found cannabis-based therapies are not effective for reducing objective measures of spasticity. However, the treatments are consistently effective at reducing patient-reported spasticity symptoms.
In other words, evidence suggests cannabis treatments cannot reduce the physical processes of muscle spasticity, but they can make it less bothersome to deal with this symptom in day-to-day life.
Pain relief
People with MS may experience neuropathic pain — that is, pain caused due to damage in the nervous system. Although effects vary and tend to be small on average, studies have generally been consistent in showing cannabis therapies can help to ease this type of pain in MS. Cannabis products also may help ease pain from muscle spasms.
However, some healthcare professionals remain cautious about the use of medical cannabis, with their main concerns including the absence of robust clinical guidelines, potential misuse of medical cannabis, the risk of psychiatric side effects, and potential interactions of cannabis with other medications. Some of these concerns also have been noted by a columnist with Multiple Sclerosis News Today.
Bladder problems
People with MS commonly experience bladder problems such as frequent urination or incontinence (a loss of control over voluntary urination). Evidence from small clinical studies suggests that a cannabis-based oral spray called nabiximols may help to reduce urinary frequency in some patients. It probably isn’t effective for incontinence, however.
Other effects
Some studies suggest cannabis products can help to improve sleep and reduce fatigue in people with MS. Cannabis also has shown some sleep-related benefits for people with sleep disorders in the general population, though experts say the use of cannabis as a sleep aid requires further study.
Research also has examined whether cannabis can ease tremor in people with MS, but available evidence suggests cannabis therapies are not effective for this symptom.
THC vs. CBD
Cannabis contains more than 100 biologically active compounds called cannabinoids. The two most well-known cannabinoids are tetrahydrocannabinol, or THC for short, and cannabidiol, called CBD.
THC is the primary psychoactive component found in cannabis — meaning this molecule is mainly responsible for the high commonly associated with recreational cannabis use. In addition to its psychoactive effects, THC may promote appetite and reduce nausea. It also may improve muscle control for some patients.
CBD is not psychoactive, so it doesn’t cause a high, but it has a range of other biological effects on the body. For example, CBD is thought to have antioxidant, anti-inflammatory, and anxiety-relieving properties. In certain forms of epilepsy, CBD-based therapies have been shown to be effective for reducing the frequency of seizures. For some patients, it may help with mental health conditions such as anxiety and post-traumatic stress disorder (PTSD).
THC, CBD, and other components of the cannabis plant interact with the body and also with each other. Consequently, the effects of any given cannabis-based product are highly dependent on the specific concentration of these molecules. Additionally, products with different compositions are likely to have different effects.
Cannabis products may contain cannabinoids taken from the plant, or they may use synthetic cannabinoids — lab-made molecules with a similar biological activity. In the U.S., two formulations of synthetic THC are approved to treat chemotherapy-induced nausea and vomiting.
Different strains
The cannabis plant is originally native to central Asia, but over the millennia humans have cultivated it across the world. Selective breeding practices have produced more than 700 different strains of cannabis, each with unique botanical and biochemical features. There is some debate among botanists as to whether or not some strains of cannabis should be classified as separate species.
As of now, cannabis strains are mostly grouped into two subspecies — Cannabis sativa and Cannabis indica — based on the makeup of the cannabinoids and the effect on the body. A third group includes strains resulting from combinations of indica and sativa strains. Their characteristics each are unique:
- Indica strains usually have a higher ratio of CBD to THC, and are commonly described as causing a “body high,” with feelings of relaxation and sleepiness.
- Sativa strains generally have a comparably higher ratio of THC to CBD, and are often described as causing a “head high,” with feelings of energized stimulation, alertness, and creativity.
- Hybrid strains are generally somewhere between indica and sativa in terms of cannabinoid profile and effect.
Notably, the individual cannabinoid profiles and effects can vary substantially among strains in the same group, and even among plants from the same strain.
Also, because each patient has a unique combination of disease symptoms, preferences, and lifestyle, there is no strain, or group of strains, that is overall better as a treatment for people with MS. Patients should talk with their doctors to determine what could work best given their individual circumstances.
Cannabis treatment options for MS
Cannabis products can be consumed in a number of ways: smoked or vaporized and inhaled, eaten, sprayed in the mouth, or applied to the skin. Several formulations have been explored in MS.
Inhaled
While a few studies have examined smoked or vaped cannabis products as a potential therapy in MS, smoking anything can cause lung damage. Thus, inhaled formulations are not generally recommended for medical purposes.
Edibles
As the name suggests, “edibles” refer to forms of cannabis that are meant to be eaten or swallowed. These can take many forms, including gummies, candies, baked goods, or capsules. A number of clinical trials have examined the effects of using an oral cannabis extract (OCE) — an edible formulation with specifically controlled concentrations of cannabinoids — for treating MS. OCEs have been demonstrated to ease patient-reported symptoms of spasticity and pain in MS.
Oral sprays
A cannabis oral spray called nabiximols, which contains a nearly equal mixture of THC and CBD, has been studied in numerous MS clinical trials — and found to significantly ease symptoms such as spasticity, pain, and bladder problems. The therapy is approved in Canada and most of Europe to treat MS-related spasticity, but it is not approved for use in the U.S. It is marketed under the brand name Sativex, by Jazz Pharmaceuticals.
Risks of cannabis use in MS
Using cannabis products can cause unwanted and unpleasant side effects. In rare cases, these effects can be dangerous. The specific safety profile of each depends on the particular product, dose, and method of administration. Common side effects associated with cannabis products that have been reported in MS clinical trials include:
- dizziness or lightheadedness
- diarrhea, nausea, and/or vomiting
- urinary tract infection
- dry mouth
- fatigue or drowsiness
- headache
- disorientation or impaired attention
Cannabis use may interfere with neurological development in children and adolescents. Among people with MS, studies have shown an association between regular cannabis use and poorer performance on tests of cognition and memory.
Taking cannabis can increase the risk of developing psychosis in at-risk individuals, such as those with a family history of schizophrenia, especially when the product is used at high doses. Cannabis products also can cause an increase in heart rate, and there is evidence suggesting cannabis can raise the risk of heart attack, stroke, and other cardiovascular complications, particularly in individuals with underlying heart conditions.
People who use cannabis regularly typically develop a tolerance to it, meaning that a larger amount is needed to induce the same effect. About 9% of cannabis users develop physical dependence, where stopping cannabis use can cause withdrawal symptoms like irritability, hot flashes, nausea, and insomnia. These symptoms are generally mild but can be more intense for heavy users.
The estimated lethal dose of cannabis is so high it is considered practically impossible to overdose on such products. However, in addition to the effects from cannabis itself, these plant products may interact with other medications and increase the risk of unwanted symptoms or toxicity.
For example, the same liver enzyme that metabolizes THC also metabolizes a number of common medications, from antidepressants to heart medications. Taking cannabis with any of these drugs may lead to too much or not enough of the drug in the body. It is recommended people with MS should always talk to their doctor before using any new cannabis product.
Beyond biological effects, using cannabis also may risk legal and employment repercussion, depending on the legality of cannabis where a patient lives.
Legal status
Internationally, the legality of cannabis differs from country to country — and that status can even vary within some countries. In the U.S., cannabis is illegal federally, but many states have passed laws that have made it legal to use cannabis products for medicinal and recreational purposes within their borders.
In U.S. states where medical cannabis is allowed, there are specific requirements and approved conditions for its use; these often vary from state to state. Cannabis is legally available for MS patients in most states. Some don’t specify MS or any MS-associated symptom in their list of approved conditions, but allow the use medical cannabis products for conditions associated with symptoms that are common in MS, such as chronic pain.
| States | Status of medical cannabis for MS |
|---|---|
| Alabama, Arkansas, Delaware, Mississippi, Missouri, North Dakota, South Dakota | Available for spasms and spasticity in MS |
| Alaska, Arizona, California, Colorado, District of Columbia, Montana, Nevada, Oregon, Rhode Island | Available for spasms and spasticity in MS, also legal for recreational use |
| Florida, Hawaii, Louisiana, Minnesota, New Hampshire, Ohio, Pennsylvania, Utah | Available for MS |
| Connecticut, Illinois, Maine, Massachusetts, Michigan, New Jersey, New Mexico, New York, Vermont, Washington | Available for MS; recreational use is also legal |
| Maryland, West Virginia | Available for severe or persistent muscle spasms |
| Oklahoma | Available at the discretion of the prescribing clinician |
| Virginia | Available at the discretion of the prescribing clinician, also approved for recreational use |
| Georgia | Low-THC products available for severe MS through a state registry |
| Iowa | Medical cannabidiol (CBD) products are available for MS with severe muscle spasms |
| Texas | Low-THC products available for MS through a compassionate use program |
| Idaho, Indiana, Kansas, Kentucky, Nebraska, North Carolina, South Carolina, Tennessee, Wisconsin, Wyoming | Not legalized or not available for MS |
To date, three cannabis-based therapies have been approved by the U.S. Food and Drug Administration (FDA), although none have regulatory approval for MS or its symptoms.
These include a CBD-based medication called Epidiolex (cannabidiol), and two synthetic formulations of THC called Cesamet (nabilone) and dronabinol (sold as Marinol and Syndros).
Nabiximols, an oral spray containing both THC and CBD, has been approved under the brand name Sativex to treat MS-related spasticity in at least 29 countries, including Canada, Australia, and most European nations. However, this medication is not approved in the U.S.
Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
FAQs about cannabis and MS
Evidence from clinical trials suggests that cannabis products can help to ease some symptoms of multiple sclerosis (MS), particularly pain and spasticity. There is some data that cannabis-based therapies may help manage other symptoms, such as frequent urination and sleep problems, but these effects are less well-studied. For other MS symptoms, like tremor, cannabis therapies are considered unlikely to be beneficial.
Like most other medicinal products, cannabis products may cause adverse reactions; common side effects reported in multiple sclerosis (MS) clinical trials include dry mouth, disorientation, dizziness, and nausea. Cannabis products also can interact with medications, and may pose additional risks to people with certain psychiatric histories or heart conditions. It is generally advised that people with MS should talk with their healthcare team about whether and how it would be safe for them to use cannabis products.
Cannabidiol or CBD is one of the main biologically active compounds in cannabis, though it does not produce a “high” like the other main component, tetrahydrocannabinol (THC). The effects of cannabis products depend largely on the relative amounts of CBD and THC in them. It’s generally recommended that people with multiple sclerosis who are trying cannabis products for the first time should start with a CBD-dominant or balanced product to minimize the likelihood of unwanted effects.
The legality of cannabis use, for recreational or medicinal purposes, varies by country, and within the U.S., cannabis laws differ from state to state. In most states, medical cannabis can be prescribed to ease symptoms of MS, but there are about 10 states in which medical cannabis products are not legal or authorized for use by patients with this neurodegenerative disorder.
Nabiximols is a cannabis-based oral spray that is approved to treat spasticity related to multiple sclerosis (MS) in Canada, Australia, and much of Europe, where it is marketed as Sativex. The therapy, however, is not approved for use in the U.S. Other cannabis products have been evaluated in MS clinical trials, but at present none are widely approved for MS treatment.
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