Introduction

Multiple sclerosis (MS) is an autoimmune chronic condition that affects the central nervous system (CNS), which consists of the brain and spinal cord. In autoimmune diseases, the body’s immune system mistakenly attacks healthy cells and tissues. In MS, the body attacks the CNS, leading to neuroinflammation. This attack on the CNS leads to both physical and cognitive symptoms, including depression. In the UK, approximately 150,000 people are currently living with MS, with 135 new diagnoses occurring every week.¹

The word ‘sclerosis’ means ‘scarring’ and refers to neuroinflammatory lesions in the myelin, a protective substance that covers the brain and spinal cord. These lesions can affect multiple areas of the myelin, which is where the term ‘multiple’ comes from. Myelin is fatty and normally allows nerve signals to travel quickly. Symptoms of MS develop when myelin is compromised with sclerotic lesions. These include fatigue, bladder control problems, blurry, memory difficulties, uncoordination, muscle cramps, numbness, tingling, stiffness and spasms. 

Understanding depression and MS

Up to 50% of people with MS will experience depression.² This is a rate that is much higher than the rate of depression in the general public. The link between depression and MS is still under investigation and appears to be multifactorial. In 2018, the UK legalised medicinal cannabis to be prescribed by specialist clinicians for certain conditions, including MS.³ There has been increasing interest and research into the use of cannabis for both the physical and psychological symptoms of MS. This article aims to explore the role of cannabis in improving mood and depression for those living with this chronic condition.  

The link between MS and mood disorders

Depression in MS can make the physical symptoms of the condition much harder to manage. It can affect day-to-day functioning and reduce quality of life significantly. Many different factors contribute to the increased prevalence of depression in MS patients. 

• Biological factors: When the immune system mistakenly attacks the myelin, many immune cells, such as pro-inflammatory cytokines, are activated. This inflammation in the brain and spinal cord creates a biochemical environment that can cause feelings of sadness and anxiety
• Psychological factors: MS symptoms are chronic and can be unpredictable. The condition can be ‘relapsing and remitting’ where there are flare-ups and then periods of relative relief. The symptoms affect many bodily systems from eyesight to passing urine. Therefore, managing them and not knowing when they might occur can create a sense of helplessness, further worsening feelings of depression
• Social factors: Some people with MS may socially withdraw due to limitations from their physical symptoms such as fatigue and pain. This can create changes to their relationships and their usual hobbies, which in turn can create feelings of loneliness and isolation

How cannabis works on the brain

Cannabis contains many compounds, with the most researched known as tetrahydrocannabinol (THC) and cannabidiol (CBD). These compounds are known as cannabinoids. These cannabinoids interact with a system in the human body called the endocannabinoid system, which plays a vital role in regulating many bodily functions such as stress, mood, memory, sleep, appetite and emotional responses. Cannabis has been shown to have potent antidepressant effects.⁴

THC and mood enhancement

THC is known for having psychoactive effects as it creates feelings of euphoria and relaxation. These feelings can be beneficial for those experiencing stress and anxiety due to MS. Studies have shown that THC can restore impaired transmission of serotonin, a neurotransmitter (chemicals that allow nerve cells to communicate with each other) linked to mood regulation. Serotonin is the main neurotransmitter targeted with the use of mainstream antidepressants. Additionally, THC may help to alleviate pain and muscle spasms, which can improve overall mood and reduce irritability.⁵

CBD and anxiety relief

CBD, on the other hand, is the non-psychoactive component of cannabis and has been shown to have anxiolytic (anxiety-reducing) properties. Research indicates that CBD can help reduce anxiety and enhance mood without the intoxicating effects that come with using THC. This makes it a far better option for people who might be sensitive to THC or who want to fully avoid any psychoactive effects. Moreover, CBD has anti-inflammatory properties, which can also result in improved mood in a two-fold manner. Firstly by reducing physical discomfort and secondly by reducing the neuroinflammation that created the unfavourable biochemical environment that can cause low mood.⁶

Clinical evidence supporting cannabis use in MS

Many different studies have looked into whether cannabis is effective at managing MS symptoms, especially symptoms related to mood.

1. Pain and quality of life: One study found that cannabis-based therapies can significantly improve pain levels and quality of life in MS patients, indirectly improving mood and emotional well-being.⁷ Improvement in pain symptoms often leads to a better overall emotional state, reinforcing the mind-body connection and holistic view of health
2. Depression and anxiety: Research by Frontiers in Psychiatry shows that cannabis use is associated with lower levels of depression and anxiety, as well as improved sleep and quality of life.⁸ This suggests that cannabis can help alleviate some of the psychological burdens that come with living with a chronic disease

Sativex (nabiximols)

Sativex is a cannabis-based medication that is licensed in the UK to treat spasms and muscle stiffness for those with MS. It is taken as a spray into the mouth and has a mixture of both THC and CBD in equal amounts. Some people also report that it helps with their bladder problems, sleep and tremors. Sativex could (but often does not) result in a far, far milder ‘high’ that smoking illegal cannabis creates due to the psychoactive THC. Smoking illegal cannabis can result in impaired cognition, for example with memory, thinking and executive function. However, this is not the case with Sativex.⁹

FAQ’s

Now that medicinal cannabis is legal, can I go to my doctor to get a prescription for my MS?

Medicinal cannabis can not be prescribed by GPs and can only be prescribed by specialists such as neurologists. Even then, specialists can only prescribe it when other treatments have not been effective and they often require permission from the hospital to be able to prescribe it. The process can take months and although it is now legal, access remains low.

What effects should I be aware of when using medicinal cannabis?

THC, which is the psychoactive component in cannabis, can alter your perceptions and sensations of the world around you. For example, colours and sounds can seem different or more vivid than usual. You may experience sleepiness, a dry mouth or reduced reaction times. 

What other conditions can medicinal cannabis be prescribed for?

Several other conditions in the UK are now eligible for cannabis prescriptions. These include epilepsy, cancer, end-of-life care, HIV and chronic pain. However, the same rules apply; they have to be prescribed by specialists and other treatments must be explored first. 

Summary

As research continues, cannabis has been showing promise as a new tool for improving mood and reducing depression in people living with multiple sclerosis. Cannabis interacts with the body’s endocannabinoid system and influences neurotransmitters such as serotonin that directly impact mood. This makes cannabis a compelling option for many those struggling with depression. However, medicinal cannabis is very regulated and access remains low, likely due to its illegal street drug history. The legalisation of medicinal cannabis occurred relatively recently in 2018 in the UK and research remains in its infancy. As attitudes and laws around cannabis evolve, more patients may find psychological relief and an enhanced quality of life through its use. If you feel like you could benefit from medicinal cannabis, talk to a healthcare provider to discuss your options.