Multiple sclerosis (MS) is a lifelong condition that affects the brain and spinal cord. It happens when the myelin sheathe, which helps messages travel along the nerves, becomes damaged. People living with MS may experience a range of symptoms, although everyone’s MS is different.
Updated: 2025
Multiple sclerosis (MS) is a condition that affects the central nervous system (CNS). The CNS consists of your brain and spinal cord, and as the name suggests, it plays a central role in the regulation and management of key bodily functions.
Nerve cells in the CNS are covered by a protective layer of fatty protein called the myelin sheath, which is a bit like the insulation which surrounds an electrical cable. MS is an auto-immune condition where the immune system gets confused and attacks the nerve cells. Instead of attacking an infection or virus, it damages this protective sheath. This process is called demyelination. The effect of demyelination is to disrupt the messages that are 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 150,000* people in the UK diagnosed with MS, with around 135 people diagnosed each week. MS is commonly diagnosed in people between the ages of 20 and 40. There are roughly two and a half times as many women with MS as men. MS is also the most common non-traumatic cause of significant neurological disability in people aged under 40.
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, known as relapses, can be followed by periods of time when symptoms improve or disappear altogether, known as remission.
People with a diagnosis of MS will usually experience it very differently. There are so many symptoms which may affect individuals in a variety of ways. No two people are the same.
You can find more information about MS symptoms by visiting our MS Symptoms Choices booklet page.
Although it is not yet certain exactly why people develop MS, research suggests that combinations of genetic, environmental and viral factors are involved. We look at some of those most commonly associated with MS below.
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.
There is a growing body of scientific evidence which suggests that the development of MS may be triggered by infection of the Epstein-Barr virus (EBV). This virus 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 they were unless they had glandular fever and experienced symptoms.
Not everyone with EBV will develop MS. However, given the growing evidence of the link between the virus and MS onset, it is suggested that the development of an EBV vaccine could be beneficial.
Geography is just one environmental factor associated with the onset and progression of MS. Studies have shown that the further north from the equator you live, the more chance you have of being diagnosed with MS. For example, figures reflect a higher rate of MS in the UK, North America and Scandinavia when compared to countries which are very close to the equator. There is a need to gather more information from less developed countries in order to obtain a fuller picture of global MS prevalence
The influence of vitamin D in the health of human immune systems has been proven over time, with scientific studies showing that avoiding deficiency helps to underpin good immune health and reduces susceptibility to autoimmune conditions.
You can find out more about Vitamin D in our dedicated information booklet.
MS is often described in different types, although research suggests it may be one continuous condition. These terms are still used in clinics to help guide treatment.
Relapsing remitting MSThe most common type. People have relapses where symptoms flare, followed by periods of recovery.
Secondary progressive MSSome people move into this stage after living with relapsing remitting MS. Symptoms gradually become more consistent over time, with or without relapses.
Primary progressive MSSymptoms slowly worsen from the start, usually without early relapses. Progression varies widely.
Clinically isolated syndromeA first episode of neurological symptoms caused by inflammation or demyelination. Some people with CIS later develop MS.
Advanced MSA term used when MS has a significant impact on daily life and extra support is needed. It describes severity rather than type.
For more detailed information about types of MS, you can visit our What is MS Choices booklet page.
Only a neurologist, a specialist on central nervous system conditions, is qualified to diagnose MS. A neurologist will perform specific tests to ensure that symptoms are consistent with MS and that all other alternative diagnoses have been excluded.
These are taken to rule out other conditions or nutrient deficiencies being the root cause of undiagnosed health issues. Some of these may have symptoms that are very similar to MS.
This scan is used to identify any areas of the brain and/or spinal cord that may have damage indicative of MS. An MRI scanner consists of a large doughnut-shaped magnet with a tunnel in the centre, which along with radio waves is used to take pictures of the brain or spine.
A lumbar puncture is a procedure where a small sample of cerebrospinal fluid (CSF) is taken from the base of the spine. CSF is the fluid that surrounds and protects the brain and spinal cord. This is then analysed for any abnormalities, such as the presence of certain proteins which can indicate inflammatory activities such as myelin damage.
These are very simple and painless electrical tests which measure the time it takes for the nerves to respond to stimulation. Visual evoked potentials (VEP) are most commonly used in the MS diagnostic process. It involves a conducting gel and electrodes being applied to the head and face. Audio and visual stimuli are then used, and the outcomes are assessed to identify any areas of concern.
A positive diagnosis can take some time and these tests are not always conclusive. You can read more in our Diagnosis information booklet.
Here are some frequently asked questions. If you would like to discuss the topics on this page further or need any support, you can call our MS-UK Helpline free on 0800 783 0518, Monday-Friday, 10am-4pm.
Early signs of MS can vary from person to person. Some people notice changes such as numbness or tingling, vision problems, balance issues or unusual fatigue. Others may feel weakness in a limb or have symptoms that come and go. These early changes can have many causes, so it is always best to speak to a GP or neurologist if you are worried.
There is currently no cure for MS, but there are many ways to treat and manage it. Some people are offered disease modifying therapies that can reduce inflammation and help lower the number of relapses. Many people also use lifestyle approaches, rehabilitation and wellbeing support to help manage their symptoms and live well with MS. MS-UK can help you explore the options that feel right for you.
There is a wide range of support for people living with MS. Many find help through their neurologist, MS nurse or GP, as well as physiotherapy, counselling and rehabilitation teams. Charities like MS-UK offer independent information, emotional support through the Helpline, online activities, Peer Pods and accessible resources to help you understand your options and feel more confident managing life with MS. Support can be tailored to what matters most to you.
Lifestyle changes can be helpful for some people living with MS. Gentle exercise, balanced eating, stress management and good sleep can all support overall wellbeing and may ease certain symptoms. Everyone’s MS is different, so it is about finding what works for you. Many people use a mix of lifestyle approaches alongside treatments or therapies, and MS-UK can help you explore your choices.
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