Introduction

Multiple sclerosis (MS) is a chronic neurological condition that affects the central nervous system, causing a range of neurological symptoms such as vision impairment, muscle weakness, cognitive impairment, bladder and bowel dysfunction, etc.¹ In recent years, medical cannabis has been increasingly considered an effective treatment option for managing symptoms of MS. However, medical cannabis, like any treatment, has its pros and cons.² This article discusses MS, medical cannabis, and the benefits and risks of using medical cannabis for treating MS symptoms.

Multiple sclerosis overview

MS is an autoimmune disease that affects the central nervous system, leading to inflammation, demyelination (damage to myelin- the protective sheath around nerve fibres), and neurodegeneration (nerve damage and loss of nerve function). It is a chronic condition that worsens progressively over time.¹

Prevalence

Globally, about 2.5 million people are affected, with a higher prevalence in African-American populations. Women are more affected, with a female-to-male ratio of around 3:1. Typically, it is seen in age groups of 20 to 40. However, it can occur at any age.¹

Types of MS  

Based on disease progression, MS is classified into seven categories. These include:¹

• Relapsing-remitting
• Primary progressive
• Secondary progressive
• Progressive-relapsing
• Clinically isolated syndrome
• Fulminant MS
• Benign MS

Relapsing-remitting MS is the most prevalent type. It is seen in 70-80% of patients with MS. It is characterised by phases of relapse and remission. 

Symptoms

MS presents with a wide range of neurological symptoms, which vary depending on where the damage has occurred in the central nervous system. Some of these symptoms include:¹

• Double vision
• Pain in the eye
• Vertigo
• Difficulty in speaking
• Difficulty in swallowing
• Muscle weakness
• Tremors
• Spasticity
• Fatigue
• Urinary and bowel dysfunction (such as incontinence, constipation, diarrhoea, etc.)
• Difficulty in concentrating
• Depression
• Anxiety

Treatment

There is no treatment available to cure the disease. Treatment consists of various therapies focusing on disease control by managing symptoms, achieving longer remission periods, delaying disease progression, and improving survival. Due to the variability of MS, treatment plans are individualised, and patients usually require lifelong management. Different treatment approaches include:¹

• Disease-modifying therapies (DMTs) include medications like interferons, glatiramer acetate, fingolimod, dimethyl fumarate, natalizumab, and mitoxantrone
• Symptoms are managed using a combination of medications such as muscle relaxants, pain relievers, antidepressants, etc
• Physiotherapy, rehabilitation, and lifestyle adjustments such as exercise and diet are advised for overall health and quality of life

Challenges in treating MS

Various challenges in treating MS include:^{1, 2}

• Even though DMTs manage the disease, they do not provide a cure for MS.
• Managing this condition involves addressing its array of symptoms and disabilities. Taking multiple medications for the long-term often leads to side effects.
• Only limited treatment options are available for the severe forms of MS.
• DMTs are expensive medications. In addition to DMTs, patients incur further costs for symptom management medications, physical therapy, diagnostic procedures, indirect costs, etc., which impact the patient outcome.

Need for alternative therapies

Due to various reasons, such as limitations of conventional treatments, ineffective treatment, side effects, etc., alternative therapies have become increasingly popular. They are supplementary to medical therapies for managing MS symptoms. Common alternative therapies include medical cannabis, acupuncture, diet and nutritional supplements, yoga, etc.³ 

Medical cannabis overview

Cannabis is a plant. It belongs to the genus Cannabis. It is used for various purposes such as recreational, industrial, and medicinal use, etc. Medical cannabis has recently gained attention as an alternative treatment for a wide range of conditions, including MS. This growing interest is driven by increasing evidence that cannabinoids, the active compounds in cannabis, provide therapeutic benefits.²

Key components of medical cannabis

It contains over 100 compounds known as cannabinoids. The two main cannabinoids used for therapeutic purposes are:²

• Tetrahydrocannabinol (THC): It is a Psychoactive component used as an anti-emetic, anti-inflammatory, etc
• Cannabidiol (CBD): Non-psychoactive component, used as a pain reliever and for treating spasticity, etc

Mechanism of action

The mechanism of action of medical cannabis involves its interaction with the endocannabinoid system (ECS) in the human body.

The ECS consists of three main components:

Endocannabinoids, receptors, and enzymes that regulate various physiological processes. The active compounds in cannabis (THC and CBD) interact with this system to produce therapeutic and psychoactive effects.⁴ 

Forms of medical cannabis

Medical cannabis is available in various forms.

These include:⁴

• Topical forms- creams, balms, lotions, patches
• Edibles- cannabis-infused gummies
• Oils
• Tinctures- liquid extracts
• Smoking or vaping- dried flower, which can be smoked or vaporised
• Capsules and pills
• Sublingual sprays

Legal status

The legal status of medical cannabis varies significantly across the world, with some countries fully legalising its use for medical purposes while others maintain strict prohibitions.^{2, 5}

• In the United Kingdom, medical cannabis was legalised in November 2018, but its use remains highly restricted
• In Europe, countries like Germany, the Netherlands, and Italy have legalised medical cannabis, though regulations differ widely, with some countries offering easier access than others
• In the United States, medical cannabis is federally illegal under the Controlled Substances Act, but a few states have legalised it at the state level, allowing patients to access it for treating some diseases

Pros of using medical cannabis for MS

• Alleviate muscle spasticity: A retrospective review indicated that cannabinoids are capable of alleviating muscle spasticity in patients with MS²
• Relieves chronic pain: Medical cannabis has proven to be helpful in the pain management of different types of pain associated with MS, such as neuropathic pain, musculoskeletal pain, spasticity-related pain, etc²
• Improves sleep quality: Insomnia and sleep disturbances are common among MS patients. Cannabinoids exhibit sedative effects, which aid in facilitating better sleep²
• Natural alternative: Because cannabinoids are derived from the cannabis plant, medical cannabis is considered a better choice than pharmaceutical products³
• Anti-inflammatory effects: Chronic inflammation is one of the symptoms that is most commonly seen in MS patients. Cannabinoids exhibit immunomodulatory (change the immune system) effects that help reduce inflammation²
• Neuroprotective effects: Cannabis promotes neurogenesis. This allows for better disease control and prevents further nerve damage²
• Reduces dependence on other medications: Patients rely on prescription medications such as opioids, muscle relaxants, and anti-anxiety drugs to get relief from MS symptoms; however, these drugs often lead to dependence. Medical cannabis helps reduce the need for these medications²

Cons of using medical cannabis for MS

• Lack of standardisation and dosing: There are no established universal guidelines for manufacturing, dosing, and prescribing medical cannabis products. Due to the lack of standardisation, it becomes difficult for clinicians to determine the correct dose, leading to inconsistent outcomes and undesirable side effects⁵
• Cognitive impairment risks: Medical cannabis has been shown to cause impaired memory, difficulties in attention and concentration, impaired decision-making, etc. As the patients with MS already have compromised cognitive functioning, medical cannabis can further worsen these symptoms⁶
• Risk of dependency: Long-term use of cannabis can result in addiction⁷
• Adverse effects: Although medical cannabis is generally well-tolerated, it causes side effects when used at high doses. Common adverse effects include dry mouth, urinary tract infection, weakness, fatigue, and headache²
• Drug interactions:  It is a reaction between two or more drugs or herbal products, which can increase or decrease the effects of one or both drugs. Medical cannabis can interact with other medications, potentially leading to adverse effects. Especially those medications that have sedative effects⁴
• Legal and regulatory issues: There is wide variation in the legal status of medical cannabis across different countries and regions⁵
• Limited research: More standardised research is required to fully understand the potential risks and benefits for MS patients² 

Summary

Multiple sclerosis (MS) is a chronic condition causing symptoms like muscle spasms, chronic pain, fatigue, etc. It is an incurable condition. The treatment approach consists of managing symptoms and controlling disease progression. 

Medical cannabis has the potential to alleviate the symptoms associated with MS. It contains compounds such as THC and CBD, which reduce spasticity and pain. 

There are both advantages and disadvantages of using medical cannabis. However, further research will help gain a better understanding of the effects of cannabis. As research progresses, medical cannabis will play a more defined role in managing MS symptoms.