What is MS? Choices booklet

Multiple sclerosis (MS) is a disease of the central nervous system (your brain and your spinal cord). The central nervous system cells are covered in a protective layer of fatty protein called the myelin sheath (a bit like the insulation on an electrical cable). MS is an auto-immune disease, where the immune system gets confused and instead of attacking an infection or virus, the immune system turns on itself and attacks the nerve cells, damaging this protective sheath. This process is called demyelination. The demyelination disrupts the ‘messages’ being transmitted from and to the brain, causing them to slow down, become distorted or not get through at all.

The term ‘sclerosis’ is a Greek word that means scarring. Demyelination causes many scars or lesions in different places within the central nervous system. The symptoms that occur depend on the site and severity of the lesions and this is why people with MS experience different symptoms at different times.

It is estimated that there are more than *150,000 people in the UK diagnosed with MS. MS is commonly diagnosed in people between the ages of 20 and 30. There are roughly three times as many women with MS as men.

In the early stages of MS, the central nervous system can sometimes repair the damaged myelin or use different pathways for the signals. This is why episodes of symptoms (relapses) can be followed by periods of time when symptoms improve or disappear altogether (remission).

Common symptoms at diagnosis

  • Fatigue
  • Optic neuritis (loss of vision in one eye, blurred or double vision)
  • Weakness of limbs
  • Reduced co-ordination
  • Balance problems
  • Numbness
  • Pins and needles
  • Unexplained pain

What causes MS?

Although it is not yet certain exactly why people develop MS, research suggests that combinations of genetic, environmental and viral factors are involved.


MS is not directly inherited. However, there does appear to be a genetic component, possibly a combination of certain genes which makes people more susceptible. Family members of someone diagnosed with MS have a slightly higher chance of developing MS themselves.


Studies have found that the further north from the equator you live, the higher the chance of developing MS. It appears that there is a higher rate of MS in the UK (MS is more common in Scotland than in the rest of the UK), North America and Scandinavia but a very low chance in countries like Malaysia which are very close to the equator.

Some research suggests that there is a link between MS and vitamin D deficiency. Vitamin D mostly comes from exposure to sunlight so this could be a factor. Research on this matter is ongoing.

You can find out more in our Choices booklet, Vitamin D.

Epstein-Barr virus (EBV)

Studies suggest that the development of MS may be triggered by a viral infection. EBV causes glandular fever, usually in teenagers and young adults. Up to 95 per cent of all adults have been exposed to the virus but not all will know unless they had glandular fever and experienced symptoms.

Not everyone with EBV will develop MS which shows it is not the only factor, however, studies state that a high percentage of people with MS have previously had the EBV infection. The findings of a study suggest that a vaccine against EBV could help to prevent MS, and researchers are working to develop one.

Common misconceptions about MS

We asked people affected by MS what were the most common misconceptions they have heard from others about MS.

Below are our findings and explanations.

‘I am going to lose my independence’

MS impacts everyone in different ways. Many people with MS continue to enjoy an active life for several years after they are diagnosed, although others may require increasing levels of support over time.

‘My children will get MS’

MS is not an inherited condition. In children of people with MS, it is thought there is a genetic susceptibility towards developing MS in the future, but it is not directly inherited as many other factors come in to play. The origin of MS is not fully understood. For a child of a person with MS, the chance of that child developing MS in the future is 1 in 48, or less than two per cent over that child’s lifetime.

‘MS is a terminal illness and I am going to die early’

Most people with MS live just as long as anyone else. Although MS cannot yet be cured, it is not a life-threatening or terminal illness but what is known as a chronic long-term health condition. This means that once you have it, you have it for life.

‘Everyone ends up in a wheelchair’

MS can indeed impact how, and how well people with the condition walk. One of the most common aspects of MS is that everyone’s MS is different. People will experience different disease progression at different times and so it is impossible to say what support needs or disability will be accrued by MS disease activity.

‘You look ok, you must be better!’

We know that MS is a lifelong condition and cannot be cured. There will be good days as well as bad and others will notice this. MS can fluctuate. Many symptoms are invisible and not obvious to others.

‘People with MS cannot work’

People with MS can be valuable members of the workforce. Some people with MS will face barriers, challenges, and obstacles and might eventually need to retire on the grounds of ill health, but this is not inevitable for everyone.

‘Being fatigued’ is the same as being tired’

People feel judged and labelled as lazy, unfit or malingering. Fatigue is not a symptom that can be solved by having a good night’s sleep. Fatigue can feel like ‘bone weariness’, ‘feeling lead-like’ etc. There are management strategies for people with fatigue such as pacing tasks (and counter-intuitively) and regular exercise.

‘Exercise will make your MS worse’

Because chronic fatigue is so common in people with MS, clinicians and the medical community used to advise that people avoided activity and exercise. There is now strong evidence that says that regular, planned, moderate exercise can significantly reduce the impact of fatigue for people with MS.

‘You look or / sound like you are drunk’

MS can impact speech and balance. People with MS have sometimes been told they appear drunk by the sound of their voice, perhaps they may experience slurring of words. This can be heightened when fatigued. Balance issues can impact how a person walks and again others may think this is due to alcohol rather than MS. This is generally due to a lack of understanding of the condition.

Although there is currently no cure for MS there are ways to manage the disease, including drug therapies, complementary therapies, dietary changes and various aids to give you relief from your symptoms. We have a range of Choices booklets which go into each of these in more detail.

MS does not need to be as devastating a diagnosis as it may first seem. If you have access to good information, the right treatments and support from both your family and healthcare professionals, you can still live a happy and fulfilling life.

For more information on all of the above conditions please see the following links. If you would like to discuss anything mentioned in this booklet then please call our helpline on 0800 783 0518. If you would like a plain text version of this booklet please email info@ms-uk.org

Further information

MS-UK Choices booklets

Is it MS? Diagnosis, Types of MS, MS symptoms


* ‘MS Society Multiple Sclerosis Incidence, and Prevalence in the UK’. 2024. The Health Improvement Network (THIN) Database (A Cegedim Proprietary Database). This work uses data provided by patients and collected by the NHS as part of their care and support.