Tag Archives: neurological

Mental ill-health in MS: prevalence and causes

It is now well established that the burden of MS extends far beyond the purely neurological problems to include mental health.

Key points

  • Many patients with MS experience both anxiety and depression.
  • Other emotional and behavioural changes associated with MS include cognitive changes, apathy, inappropriate laughing and crying, euphoria, mania and bipolar disorder.
  • Physical symptoms like fatigue, sleep disturbances, concentration difficulties, numbness, tingling and dizziness may occur both in MS and in anxiety states, complicating diagnosis.
  • Unless severe anxiety symptoms are formally diagnosed as an anxiety disorder, individuals miss out on targeted treatments.
  • There is growing evidence that MS-related emotional changes are not necessarily a psychological consequence of living with a disability.
    • They may have a biological origin related to structural damage in the brain, caused by the MS disease process.
    • Brain imaging techniques that measure activity reveal how these brain networks function in real time.
  • Emotional changes sometimes occur as a side effect of medications used in the management of MS, including steroids used to treat MS relapses..

Background and introduction

Multiple sclerosis (MS) is a chronic, inflammatory and neurodegenerative disease of the central nervous system (CNS) that is typically defined by its physical manifestations, such as motor weakness, sensory disturbances and fatigue. However, the burden of MS extends far beyond the purely neurological problems to include cognitive changes and mental health disorders such as anxiety, depression, apathy, mania and uncontrolled laughter and crying.

Anxiety and depression in people with MS

Among the most prevalent mental health problems in MS is anxiety, a condition that for many years was overshadowed by the clinical and research focus on depression. Anxiety is not a secondary issue but a core component of the disease experience for many people with MS. Anxiety and depression in MS are closely related, with many patients experiencing both simultaneously. Indeed, the presence of depression in people with MS is a strong predictor of the future development of anxiety, and vice versa. Both conditions share common underlying psychological risk factors such as avoidant coping styles and low optimism as well as unhealthy behaviours like smoking or lack of exercise.

Many large-scale studies have shown that anxiety is more prevalent in the MS population than in the general population. Two meta-analyses published in 2017 and 2023 assessed more than 50 published studies; based on pooled results, they estimated that 22% and 36%, respectively, of people with MS experienced anxiety.1,2 The prevalence rates for depressive disorders in people with MS are about 20−30%. Further research, utilising the UK MS Register, suggests that more than half (54%) of the 4000 patients recorded in the database have experienced clinically significant anxiety and 47% have experienced depression.3

MH anxiety

The proportions of people with different levels of anxiety (normal, mild, moderate or severe) and who have a depression score of 8 or above (N = 1961). Data from UK MS Register.3

MH depression

The proportions of people with different levels of depression (normal, mild, moderate or severe) and who have an anxiety score of 8 or above (N = 2268).  Data from UK MS Register.3

By contrast, the lifetime prevalence of any anxiety disorder in the general population in the USA is around 29% (though the prevalence at a specific point in time is lower). Anxiety is also significantly more prevalent in MS than in many other chronic neurological conditions, suggesting a relationship that may be specific to the pathophysiology or lived experience of MS.

Psychiatric symptoms versus psychiatric disorders

A critical nuance in understanding the epidemiology of anxiety in MS lies in the distinction between clinically significant anxiety symptoms and formally diagnosed anxiety disorders. The two are related but not interchangeable, and the disparity between their prevalence rates reveals a crucial aspect of the clinical challenge. The 2017 meta-analysis that found a 22% prevalence for anxiety disorders also found a substantially higher (34%) prevalence of clinically significant anxiety symptoms. This discrepancy indicates that for every ten patients who meet the formal diagnostic criteria for a specific anxiety disorder, such as generalised anxiety disorder (GAD) or panic disorder, there are approximately 15 patients who experience a level of anxiety that is severe enough to cause distress and impair functioning but is not formally identified and diagnosed in a clinical setting. The result is that these individuals miss out on targeted interventions such as specific psychotherapies or drug treatment that they might otherwise receive.

This large population of symptomatic but undiagnosed individuals may exist for several reasons. First, there is considerable symptom overlap between anxiety and MS itself. Physical symptoms like fatigue, sleep disturbances, concentration difficulties, numbness, tingling and dizziness can be manifestations of either MS or an anxiety state, creating a diagnostic challenge for clinicians and confusion for people with MS. Second, both patients and clinicians may view anxiety as an ’understandable’ or ’normal’ psychological reaction to living with a chronic, unpredictable illness, rather than as a distinct, treatable clinical entity. Finally, the historical research emphasis on depression may have led to less routine screening for anxiety in clinical practice. As an MSologist, it is also essential to differentiate formal depressive disorders from clinically significant depressive symptoms, which are much commoner than disorders.

Among those who do meet the criteria for a formal disorder, GAD appears to be the most prevalent, followed by panic disorder and obsessive-compulsive disorder. Recognising the full spectrum of anxiety, from subclinical symptoms to formal disorders, is essential for developing effective screening protocols and ensuring that all people with MS experiencing anxiety receive appropriate care (see article on management of mental ill-health in MS).

Other emotional and behavioural changes

MS impairs neuropsychiatric function (the interplay between neurological and psychological functioning) in a similar manner to its effects on other neurological functions. Living with MS can result in personality changes and subsequent relationship problems.

Cognitive changes

Cognitive impairment (i.e. dysfunction), particularly slowed information processing speed, is a common, well-documented and debilitating feature of MS. Anxiety has a demonstrably detrimental effect on cognitive domains that are often already compromised in MS, such as attention and executive functions.

Apathy

Apathy, characterised by profound loss of interest, blunted affect and reduced motivation, is also common in MS, particularly advanced MS. It is often misdiagnosed as depression. Apathy is not merely a component of low mood but is linked to executive dysfunction. Predictors identified include depressive symptoms, poor global quality of life, and poor attention and information processing speeds, probably due to MS lesions in the frontal lobe.

Inappropriate laughing and crying

Pathological laughing and crying, also known as pseudobulbar affect (PBA), are common but under-recognised and undertreated symptoms of MS that can be highly distressing and embarrassing for the patient and their relatives. The sudden, involuntary and explosive expressions of laughter or crying characteristic of PBA are often disproportionate or unrelated to the individual’s underlying emotional state.PBA is also associated with cognitive and mood problems, though the sudden and disproportionate emotional reactivity differentiates it from depression. The clinical presentation is due to frontal lobe or brainstem damage resulting from MS, which disrupts motor control pathways for emotional expression.  

Rare affective changes

Euphoria and mania are relatively uncommon in people with MS but are often triggered by high-dose steroids used to treat MS relapses.

Bipolar disorder is significantly more common in people with MS than in the general population; please see the separate post/chapter on this. The diagnosis must be made and treated by psychiatrists and involves lifelong therapy. 

The biological basis of mental illness in MS

MS-related emotional and mood changes are not necessarily a consequence of disability; they are often intrinsic to the MS disease process. This was recognised by the French neurologist Charcot, who, in 1877, noted pathological laughing, weeping, euphoria and depression in his patients who had MS.

Anxiety as a manifestation of MS pathology

While the psychological stress of living with a chronic illness contributes to anxiety in MS, there is growing evidence that anxiety is not solely a reactive or psychological phenomenon. The same autoimmune attack that damages myelin and axons, leading to physical disability, also targets and disrupts the complex neural circuits responsible for mood regulation, threat perception and emotional processing. 

Neuroinflammation and demyelination (damage to nerve insulation) are directly implicated in the development of anxiety and other psychiatric disorders. MS lesions are not confined to areas of the brain responsible for motor and sensory function but also occur within the networks that govern emotion and mood.

Structural and functional brain changes

Research has shown that people with MS can develop gradual grey matter loss in brain regions involved in emotion and motivation, particularly the limbic system and the basal ganglia. The limbic system includes the hippocampus, amygdala and cingulate cortex, and it plays a central role in processing emotions. Changes in the shape of the hippocampus have also been observed.

MH limbic system

Primary components of the limbic system. Modified from Encyclopaedia Britannica Inc.

These structural changes are thought to contribute to the development of mood and anxiety problems in MS. When MS-related inflammation, demyelination (damage to nerve insulation) or atrophy affects these areas, the brain’s ability to regulate fear and emotional responses can be disrupted. This creates a biological vulnerability to anxiety. From a structural perspective, therefore, anxiety in MS can be viewed as a direct consequence of neurological damage, in the same way that damage to the optic nerve causes visual impairment, or damage to the spinal cord leads to motor weakness.

In people with MS, depressive symptoms are consistently correlated with the volume of lesions in the brain and the degree of damage to connections between the cortex and subcortex. Neuroimaging studies show an association between depression and damage in the frontal and temporal areas of the cortex. In contrast, PBA is associated with lesions in the brainstem.

Brain imaging techniques that measure activity, such as functional MRI (fMRI), help to explain how these structural changes translate into anxiety symptoms. Rather than only showing where structural damage exists, fMRI studies reveal how brain networks function in real time. One key process identified in anxious people with MS is ‘fear overgeneralisation’. This occurs when the brain reacts to safe or neutral situations as if they were dangerous. For example, an individual learns to associate a specific signal (e.g. a picture of a circle) with a negative outcome (e.g. a mild electric shock). Anxious individuals tend to ’overgeneralise’ this fear, responding with fear to a similar but harmless signal (e.g. an oval), thus expanding their perception of danger in everyday life.

fMRI studies show that this process mainly involves the hippocampus (which is responsible for comparing incoming new experiences with ‘learned’ memories of danger) and the anterior insula (which plays a key role in generating the physical and emotional feeling of fear). In MS patients with anxiety, the physical pathways connecting these two regions are often disrupted, so that accurate information from the hippocampus is less effectively communicated to the anterior insula. As a result, the anterior insula may generate strong fear responses even when a situation is only mildly threatening or even safe.

fMRI studies have also revealed that many MS patients exhibit greater brain responses or increased recruitment of key emotional regions (e.g. prefrontal cortex and amygdala) compared to healthy controls. This likely reflects compensatory mechanisms the brain deploys to limit the clinical expression of emotional symptoms. The damaged MS brain tries to cope.

Neurological versus psychological causes

MS can trigger primary psychopathology as a result of demyelination and damage to specific functional circuits within the brain, as described above. It can be challenging to differentiate primary organic issues from reactive psychological problems, which is why people with MS may be referred for psychiatric assessments. 

I have, however, also seen patients in whom the initial symptoms were psychiatric, e.g. depression or (rarely) mania, but who were later found to have MS. The link between MS-related CNS damage and emotional symptoms is based on lesion location and lesion burden. For example, MS patients with lesions affecting the functional parts of the brain (rather than the connecting structures) exhibit a higher burden of emotional symptoms than those with lesions confined to the spinal cord. Our emotions are part of brain function in a similar way to motor function. Therefore, it is not surprising that MS impacts emotions. 

Lesion location and emotional symptoms

The evidence for a direct correlation between lesion location and anxiety is inconsistent. Some researchers suggest that, unlike depression, anxiety in MS may be driven more by psychosocial pressures and the psychological reaction to the illness rather than by focal brain damage. This discrepancy does not necessarily invalidate the biological basis of anxiety in MS. It may be that anxiety is related to more diffuse or subtle pathological changes, such as microstructural damage in white matter tracts or widespread neuroinflammation, that are not easily captured by conventional MRI lesion analysis. It is also possible that the broad distribution of the brain’s anxiety circuits means that damage to any number of different locations could produce a similar clinical outcome, making it difficult to pinpoint a single ’anxiety-causing’ lesion location. 

Other contributing factors

Emotional changes may occur as a side effect of medications used in the management of MS, including certain disease-modifying therapies. People with MS are also susceptible to the effects of the menopause, seasonal affective disorder and comorbidities associated with depression and anxiety, such as alcohol and other substance misuse disorders. It is advisable, therefore, to have a complete assessment before having a mood disorder labelled as being due to MS. 

Anxiety in MS may also be caused by high-dose corticosteroids, which are the standard treatment for MS relapses. Steroids have significant neuropsychiatric side effects, including anxiety, mania, insomnia and psychosis. For someone with MS already dealing with the stress of a relapse, the addition of steroid-induced anxiety can be particularly distressing.

‘Prodromal’ MS and psychiatric symptoms

Psychiatric comorbidities, such as anxiety and depression, have historically been viewed as consequences that follow the diagnosis of MS. Recent research, however, points to the existence of an ‘MS prodrome’, during which anxiety and depression occur years before the first classical neurological event.4 Increased rates of anxiety are a significant feature of this prodromal phase, suggesting that anxiety and/or depression may be early signs of MS, not merely a consequence. This body of recent research supports the idea that psychiatric symptoms in MS have a biological origin. This is most likely driven by the same low-level, diffuse neuroinflammatory and neurodegenerative processes that are smouldering away in the CNS long before the first eloquent MS lesion.

References

  1. Boeschoten, RE et al. Prevalence of depression and anxiety in multiple sclerosis: A systematic review and meta-analysis. J Neurol Sci 2017;372:331−341.
  2. Zhang X et al. The prevalence and risk factors of anxiety in multiple sclerosis: A systematic review and meta-analysis. Front Neurosci 2023;17:1120541.
  3. Jones KH, et al. A large-scale study of anxiety and depression in people with multiple sclerosis: a survey via the web portal of the UK MS Register. PLoS ONE 2012;7:e41910.
  4. Ruiz-Algueró, M et al. Health care use before multiple sclerosis symptom onset. JAMA Netw Open 2025;8:e2524635.

What should I expect during the diagnostic consultation?

The practice of neurology and medicine varies worldwide, so I will explain what to expect if you were to consult me. 

Key points

  • The principles of diagnosing MS are to show the dissemination of lesions in space and time and to exclude alternative diagnoses that mimic MS.
  • Diagnosing MS takes time and should not be rushed; do not be afraid to ask questions.
  • Most patients diagnosed with MS have an emotional response similar to the five stages of grief – Denial, Anger, Bargaining, Depression and Acceptance (DABDA). Additionally, many patients experience Anxiety about the future (DABDA+A).
  • Newly diagnosed patients should avoid overloading themselves with information about MS; much of the online information can be misleading and anxiety-provoking. Guidance is provided below about reliable information sources.
  • Counselling, cognitive behavioural therapy and the support of an MS ‘buddy’ can help patients adjust to a diagnosis of MS, which is a serious condition and should be respected.
  • You should be aware that medical ‘gaslighting’ may happen and know how to deal with it.

Tests to exclude other diagnoses

MS is a clinical diagnosis and a diagnosis of exclusion. Therefore, I would take a detailed medical and neurological history and examine you for neurological signs. Finding signs of involvement in a particular neurological pathway is important for fulfilling the criteria for dissemination in space. MS must involve at least two neuronal pathways. To be confident that no alternative diagnosis could explain your presentation, a full work-up will likely include magnetic resonance imaging (MRI) of the brain and spinal cord, evoked potentials, a lumbar puncture and blood tests. In addition, I would need to show dissemination in time, involving two or more structures separated in time by at least 4 weeks.

The diagnosis of MS is not trivial and should not be rushed. If I doubted the diagnosis, I would wait. The old maxim ‘time is often the best diagnostician’ is as pertinent today as it was in the past. Despite this, the misdiagnosis rate remains stubbornly high. I recommend you read some of the posts that cover the diagnosis of MS in more detail, such as Am I sure that I have MS? and Do I have active MS?

Time to adjust to a diagnosis of MS

You should not expect too much from the initial consultation. The second consultation, once all the diagnostic tests are back, will be the difficult one. Before COVID-19, an MS diagnostic workup in the NHS would take about 6 ̶ 8 weeks. Due to COVID-19-related delays in getting MRI scans and evoked potentials, it currently takes up to 4 months. Occasionally, patients with possible MS are admitted to the hospital because of a disabling attack. This allows us to make a more rapid diagnosis. 

Being diagnosed with MS or any other chronic and potentially disabling disease is distressing. In my experience, patients’ responses are highly variable, including relief about finally getting a diagnosis, surprise, shock, anger or blaming the messenger for the bad news. Some question my judgement and refuse to accept the diagnosis; they may accuse me of being wrong and seek a second, third or fourth opinion. Many are devastated and expect the worst: how long before I need a wheelchair? Rarely patients are uninformed, have little or no idea about MS and ask about the disease. 

Examples of some responses to a diagnosis of MS

I always try and be reassuring and tell patients that MS is now a treatable disease. If we manage their MS actively, we can prevent or at least delay the development of disability for many decades.

Emotional response

I also warn patients about the emotional reaction they will likely have to being diagnosed with MS. The psychological impact of an MS diagnosis and the uncertainty associated with having a potentially disabling disease should never be underestimated. Elisabeth Kübler-Ross in 1969 described five common stages of grief, best known by the acronym DABDA:

Denial, Anger, Bargaining, Depression, Acceptance

We have added an extra A – for Anxiety about the future – to expand this to DABDA+A. People diagnosed with MS may go through these stages in order of the pneumonic, but some will jump around, and others go through some stages many times. Although the Kübler-Ross stages have been criticised in the psychological literature, they provide a valuable framework for discussing a patient’s emotional journey. Being diagnosed with MS is a marathon, not a sprint, and it will take time to come to terms with it.

It is important for healthcare professionals (HCPs) to be there for the journey and to make sure that newly diagnosed patients have access to their MS team and high-quality information about MS. 

Step-wise approach to understanding MS

In the modern era, most patients I diagnose as having MS are aware of the disease and suspect they have MS before I tell them so. I say this because Dr Google, Dr ChatGPT and Dr Bing are only keystrokes away, and their answers are very credible. 

Because of their anxiety, most newly diagnosed patients only take away one thing from the consultation: they have MS.  Almost everything else they hear is forgotten. I encourage patients to record the consultation or bring a partner, friend or family member who can be their backup memory. 

I try to avoid overloading patients with information early on. Instead, I provide links to online resources about having MS. We arrange a follow-up session with the MS nurse specialist in the next 10 ̶ 14 days so that they can ask questions.

Guidance about what information to trust

I counsel patients to stay away from Dr Google, Dr ChatGPT and Dr Bing until they have come to terms with having MS. Much of the MS-related content available on the web is misinformation and disinformation; until you understand the disease, it is difficult to know what information is valid, reliable and helpful and what is quackery. Many patients ignore this advice and overwhelm themselves with information, which can worsen anxiety. 

I don’t introduce recently diagnosed patients to MS-Selfie initially. MS-Selfie is written at too high a level for the average person who is newly diagnosed. If patients want more information, I direct them to the MS Trust, the MS Society and ‘MS Brain Health: time matters’ (for more detail, see Resources and hot topics).  

Counselling, support and respect

Depending on a patient’s response to the diagnosis, we may refer them for counselling, cognitive behavioural therapy and/or mindfulness therapy to help them come to terms with having MS and to help manage their anxiety. Most patients are receptive to these psychological therapies. 

Many people with MS are traumatised by their diagnostic consultation and may experience symptoms of post-traumatic stress disorder from the event. This should not happen in the modern era. In my experience, gestures such as having tissues on hand for a distressed patient or holding their hand are ways that HCPs can demonstrate their empathy.

On rare occasions, particularly for patients who are alone and socially isolated, we may buddy them up with another carefully chosen patient to ask questions and learn about MS. These MS buddies need to be optimistic, able to communicate well and not overwhelm the recently diagnosed patient with information. I work closely with the charity Shift.ms, which does a similar thing. 

In the diagnostic consultation, I avoid too much detail about treating MS and the specific DMTs. These are best discussed at the next visit. With some patients, however, the discussion gets to treatments very quickly. In such cases, I tailor the consultation to the individual’s needs. 

During the diagnostic consultation, I also show patients their MRI scans. Seeing your brain, spinal cord and MS lesions provides an objective way of helping you to visualise the disease. 

Recently diagnosed patients must be given time to ask questions and even to sit in silence. MS is a serious disease, and informing someone about the diagnosis must be done carefully. After more than 30 years as a neurologist, I still find telling my patients they have MS challenging. The patient being diagnosed with MS, as well as the disease, must be respected. 

What if a doctor belittles my concerns?

The term ‘medical gaslighting’ describes a scenario where health professionals dismiss or downplay a patient’s real symptoms, leading to an incorrect diagnosis. Now that we have recognised medical gaslighting as a significant problem in MS, please don’t allow a neurologist to gaslight you. There are things you can do to prevent this. 

  • Keep detailed notes and records. Patient-held notes transform consultations and allow you to become a partner in your healthcare.
  • Ask to record the consultation. Many HCPs don’t like this; just tell them you must listen to the conversation again to ensure you don’t forget things or miss important information. You will be surprised how this changes the HCP’s behaviour. 
  • Ask questions. Then ask some more. And don’t be fobbed off; if you are dissatisfied with the answer, ask the question again. 
  • Take someone with you for support. Having a witness during the consultation has a similar effect to recording the conversation or documenting it with notes. 
  • Focus on your most pressing issues to make the best use of your consultation time. If your HCP is pressed for time, say you understand, but you would like to prioritise the following issues today. This helps you to frame the limits of the consultation and promote a two-way discussion. Also, don’t expect the HCP to have all the answers at their fingertips, but do expect them to come back to you later with the answers.
  • Try and pin down the next steps for your problem; ask what the action points are. For example, if the MRI shows this, how will that change my management? Do I need further investigations? How soon should I switch treatments?

If you still feel that you are being ignored, here are some of your options.

Some courses of action open to you if you experience medical gaslighting.

Abuse, manipulation, gaslighting and delaying a diagnosis are potentially reportable events which HCPs need to know about. Therefore, make your healthcare system aware of the problem rather than suffer in silence. 

What is multiple sclerosis?

This is the first of a series of basic lessons to help you understand multiple sclerosis (MS).

Key points

  • MS is an autoimmune disease in which the immune system attacks the central nervous system.
  • Its exact cause is unknown; some contributory environmental factors are outlined.
  • Common manifestations of MS include lesions, relapses and intermittent symptoms, which often worsen with fatigue.
  • Early treatment is important to help prevent the damage that occurs with MS.

Multiple sclerosis (MS) is an organ-specific autoimmune disease. Autoimmune simply means that the immune system, whose primary role is to fight infections and cancers, goes awry and attacks itself. Organ-specific means that a disease is limited to one organ. So, in the case of MS, the immune system attacks the central nervous system (CNS), which consists of the brain, spinal cord and optic nerves.

Every organ in the body has its specific autoimmune disease. For example:

  • joints: rheumatoid arthritis
  • skin: psoriasis 
  • insulin-producing cells of the pancreas: type 1 diabetes
  • intestines: inflammatory bowel disease
  • kidneys: autoimmune nephritis (interstitial or glomerulonephritis).

The cause of MS

At present, the exact cause of MS is unproven. MS is a complex disease that occurs due to the environment’s interaction with inherited or genetic factors.1 Some of the main environmental factors are:

  • low vitamin D levels or a lack of sunshine
  • smoking 
  • Epstein–Barr virus (EBV), the virus that causes infectious mononucleosis (glandular fever) 
  • obesity, particularly in adolescence.

What we don’t know is how these genetic and environmental factors interact to cause MS. There are many genetic variants that predispose someone to get MS, but only a minority of people who have these variants will get the disease. Similarly, only a minority of people exposed to environmental risk factors get the disease.

Mechanisms that underlie the common manifestations of MS

Lesions

MS is characterised by inflammatory lesions – areas of damage or scarring (sclerosis) in the CNS – that come and go. The clinical manifestations of MS depend on where these inflammatory lesions occur. If, for example, a lesion involves the optic nerve, it will cause impaired vision; if it involves the brain stem, it causes double vision, vertigo or unsteadiness of gait; a spinal cord lesion leads to loss of feeling, limb weakness or bladder and bowel problems.  

Relapses

A new MS lesion in a site that is eloquent will cause symptoms and neurological signs; if these last for at least a day, they are called an attack or a relapse. If a lesion occurs in a site not associated with overt symptoms, this is often referred to as a subclinical or asymptomatic relapse. Subclinical relapses can be detected using magnetic resonance imaging (MRI). It is said that for every clinical attack there are 10 or more sub-clinical attacks (new MRI lesions).2 

Damage frequently occurs at the site of MS lesions. The inflammation strips the myelin covering the nerve processes and may cut through axons. Axons are the nerve processes that transmit electrical impulses or signals. When the axons are stripped of their myelin sheath, and/or are cut, they can’t transmit electrical signals. This causes loss of function, which manifests with specific symptoms.

Demyelination: loss of the myelin sheath that insulates nerves, leading to disruption of electrical signals. Image courtesy of Timonina/shutterstock.com

Intermittent symptoms

Surviving axons that pass through the lesion are able to recover function, by synthesising and distributing so-called ion channels across the demyelinated segment or by being remyelinated. Both these processes are not perfect. For example, the new sodium channels may not function normally, so they sometimes fire spontaneously. The spontaneous firing of axons may cause positive symptoms, for example, pins and needles, pain or spasms. The new myelin is typically thinner and shorter than normal and is temperature, fatigue and stretch sensitive. 

Stretch sensitivity

If someone with MS has a lesion in their spinal cord, electric shock-like sensations may occur when they stretch the spinal cord by bending or flexing their neck; this is known as Lhermitte’s sign.  

Temperature sensitivity

Recurrent symptoms may occur when body temperature rises, for example following fever, exercise or a hot bath. The MS symptoms (which may vary among individuals) disappear when the fever resolves or the body cools down. The temperature sensitivity is often referred to as Uhtoff’s phenomenon

Fatigue

Symptoms tend to worsen with physical and/or mental fatigue; for example, someone with MS may begin dragging a leg or dropping their foot after 20–30 minutes of walking. This is because the transmission in the functioning nerves, which have been previously damaged, begins to fail. This failure may be related to a lack of energy and/or to temperature changes that occur with exercise. 

Worsening MS (also called progressive MS)

If the axons, or nerve processes, above and below an MS lesion die off, the surviving axons may sprout to take over the function of the axons below the lesion. This puts an unnecessary strain on the surviving axons, which makes them vulnerable to die off in the future. A reduction in the number of nerves in a neuronal system reduces the neurological reserve of that system, making it more vulnerable to future attacks. In other words, the ability to recover from future attacks is reduced, and the neuronal pathway is susceptible to delayed degeneration and premature ageing. Clearly, if no treatment is given and focal inflammatory lesions continue to come and go, this will cause worsening of the disease. If enough damage is allowed to accrue, even switching off new inflammatory lesions may not prevent the so-called delayed neurodegeneration. This is why one of the primary principles of managing MS is early treatment to prevent damage from occurring in the first place. We have also discovered that the neuronal systems with the longest nerve fibres, in particular the bladder and legs, are much more susceptible to damage. We think this is simply because the longest pathways provide the greatest scope to be hit by multiple MS lesions.

Ageing and MS

As we get older our nervous systems degenerate. If we live long enough, we will all develop age-related neurological problems, such as unsteadiness of gait, loss of memory, reduced vision, loss of hearing, and poor coordination. 

What protects people with MS from becoming disabled and developing age-related neurodegeneration are brain reserve and cognitive reserve. Brain reserve is simply the size of your brain or the number of nerve cells you have. Cognitive reserve, in comparison, relates to how well these nerves function; it is associated with your level of education and how well you enrich your life by using your brain. From about 35 years of age, our brains start to shrink. In MS, this brain shrinkage is in general much greater than normal, and the resulting reduction in brain and cognitive reserve almost certainly primes the nervous system to age earlier. This is one of the reasons why people with MS continue to develop worsening disability later in the course of their disease. This insight is one of the main reasons why we promote early effective treatment of MS to protect and maintain brain and cognitive reserves.  


References

  1. Olsson T, et al. Interactions between genetic, lifestyle and environmental risk factors for multiple sclerosis. Nat Rev Neurol 2017;13:25–36.
  2. Gafson A, et al. The diagnostic criteria for multiple sclerosis: From Charcot to McDonald. Mult Scler Relat Disord 2012;1:9–14

Am I sure that I have MS?

The multiple sclerosis misdiagnosis rate is around 5% and this has major implications for individuals and the treatment of MS.

Key points

  • A wrong diagnosis of MS may have financial, social and psychological consequences for the individuals concerned, affecting major life decisions.
  • Some MS treatments have life-threatening complications and should only be prescribed for people with a clear diagnosis of MS.
  • Some of the diseases that mimic MS can be made worse by disease-modifying treatments for MS.
  • Diagnostic criteria for MS have evolved and now take account of clinical, electrical, laboratory and magnetic resonance imaging findings.

A case study

She had been diagnosed with multiple sclerosis 8 years ago and had been taking interferon-beta since her diagnosis. I told her that I didn’t think she had MS and that her diagnosis was almost certainly complicated migraine with aura. The lesions on her magnetic resonance imaging (MRI) scan were non-specific white matter lesions and not inflammatory. Her neurological examination, spinal fluid analysis and evoked potentials (EPs) were normal. What clinched the non-MS diagnosis for me was the history of neurological events, which were too short-lived and migratory to be MS attacks. The final piece of the jigsaw was that a special MRI sequence showed none of her white matter lesions had a central vein, which told me that none of her white matter lesions was an MS lesion.  Her anger was palpable. She was angry because she had decided not to start a family and had changed her career because of the fear of becoming disabled in the future and not being able to work or look after a child.  This case illustrates why I always try to review the diagnosis of patients referred to me with MS and why it is important to answer this question before starting a disease-modifying therapy (DMT).   

Making a diagnosis of MS

Unfortunately, there is no single test to diagnose MS. Rather, MS is diagnosed by combining a set of clinical and MRI findings, electrical or neurophysiological investigations and laboratory tests. If these tests fulfil a set of so-called MS diagnostic criteria, the healthcare professional (HCP) or neurologist makes a diagnosis of MS. 

The underlying principles of diagnosing MS are to show the dissemination of lesions in space and time and exclude possible mimics of MS. The diagnostic criteria have evolved over time from 1) being based purely on clinical attacks,1 to 2) include electrical and spinal fluid tests as well as clinical attacks,2 and 3) to add on the use of MRI to help confirm dissemination in time and space.3–6  

Dissemination in time 

This means that two attacks or MS lesions must occur at least 30 days apart or that oligoclonal bands (OCBs) of immunoglobulins can be detected in the spinal fluid.

Dissemination in space 

This requires MS lesions to occur in different locations, for example, the optic nerve and the spinal cord. 

Electrical tests

The electrical or neurophysiological tests are called evoked potential (EPs) and test electrical conduction in a particular pathway. They can show lesions in nerve pathways that are not evident on the neurological examination or seen on MRI. The EPs can also show slow electrical conduction, which is one of the hallmarks of diseases that affect myelin, the insulation around nerves that is responsible for speeding up the electrical conduction of nerve impulses.

Laboratory tests

The laboratory tests are typically done to exclude other diseases that can mimic MS. Examining the spinal fluid for the presence of OCBs is useful in helping to make an MS diagnosis. OCBs are the fingerprint of a specific type of immune activation within the central nervous system (CNS). The OCB fingerprint is relatively specific for the diagnosis of MS in the correct clinical context. (OCBs are also found in CNS infections and other autoimmune diseases, but these are relatively easy to differentiate from MS.)

Please be aware that you may have MS according to the latest diagnostic criteria when you could not be diagnosed with MS using past criteria.

Why is a correct diagnosis important?

Neurologists get the diagnosis wrong in approximately 5% of people with MS. In other words, one in 20 people who have a diagnosis of MS in life does not have MS when their brain is studied post mortem. This data is based on a large study in a region of Denmark.7 More recently, a study from a specialist MS centre in the United States reported a misdiagnosis rate of approximately 15% in patients with presumed MS referred to their centre for treatment.8 

Why is getting the diagnosis of MS correct so important? Firstly, some MS treatments have life-threatening complications; you don’t want to expose people without MS to these complications. More concerning is that some of the diseases that mimic MS can be made worse by MS DMTs. Finally, a diagnosis of MS has many psychological, social, financial and economic implications. Even if you turn out to have ‘benign disease’, just having a diagnosis of MS, has implications for your life choices and may impact your ability to get insurance cover, to name obvious examples. I, therefore, advise you to make sure you have MS and not an MS mimic.

Common MS mimics

References

  1. Schumacher GA, et al. Problems of experimental trials of therapy in multiple sclerosis: Report by the Panel on the Evaluation of Experimental Trials of Therapy in Multiple Sclerosis. Ann N Y Acad Sci 1965;122:552–68.
  2. Poser CM, et al. New diagnostic criteria for multiple sclerosis: guidelines for research protocols. Ann Neurol 1983;13:227–31.
  3. McDonald WI, et al. Recommended diagnostic criteria for multiple sclerosis: guidelines from the International Panel on the diagnosis of multiple sclerosis. Ann Neurol 2001;50:121–7.
  4. Polman CH, et al. Diagnostic criteria for multiple sclerosis: 2005 revisions to the “McDonald Criteria”. Ann Neurol 2005;58:840–6.
  5. Polman CH, et al. Diagnostic criteria for multiple sclerosis: 2010 revisions to the McDonald criteria. Ann Neurol 2011;69:292–302.
  6. Thompson AJ, et al. Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria. Lancet Neurol 2018;17:162–73.
  7. Engell T. A clinico-pathoanatomical study of multiple sclerosis diagnosis. Acta Neurol Scand 1988;78:39–44.
  8. Kaisey M, et al. Incidence of multiple sclerosis misdiagnosis in referrals to two academic centers. Mult Scler Relat Disord 2019;30:51–6.

What are the consequences of not treating MS?

Are there valid reasons not to treat MS with a disease-modifying therapy? What are the consequences of not treating MS? Is watchful waiting justified?

Key points

  • Untreated MS will, given time, result in physical disability, impaired quality of life and ‘hidden’ problems such as cognitive impairment, anxiety and depression.
  • Brain atrophy, or shrinkage, occurs at a faster rate in people with MS than in healthy individuals.
  • Optic neuritis, inflammation or destruction of nerve fibres in the brain and spinal cord, and extensive damage to the cerebral cortex (grey matter) are some consequences of MS lesion development.
  • Quality of life impacts may include reduced mobility, relationship difficulties, increased likelihood of unemployment and memory impairment.
  • Without treatment, the life expectancy of people with MS is reduced by about 6 ̶ 8 years.
  • There are, however, several valid reasons why some people with MS prefer not to receive disease-modifying treatments.

Risks from no disease-modifying treatment

Many patients ask me what will happen to their MS if they don’t take a disease-modifying treatment (DMT) and how effective DMTs are at preventing negative outcomes. Here I try and address questions you need to ask yourself before starting a DMT.

If you are an individual with MS, predicting your disease course is difficult. However, many studies monitoring groups of people with MS show patterns in relation to the progression of the disease and its outcome, with various data sets being consistent.

Given sufficient time, most people with MS who are not treated will become disabled. Most people focus on physical disability, but MS causes many hidden problems, such as cognitive impairment, anxiety and depression.

How untreated MS can progress – headline results

The slides below summarise some of the outcomes of untreated MS; these include brain changes (atrophy), further MS lesion development, reduced health-related quality of life, long-term impact on physical and mental health and shorter life expectancy. (To enlarge an individual slide, click on the arrow at the top right.)

Brain changes
MS lesion development
Quality of life impact
Long-term outlook

DMTs have changed the landscape

It is important to note that these outcomes are from the pre-DMT era and don’t apply to populations of people with MS treated with DMTs. New real-life data indicate that DMTs, particularly high-efficacy DMTs, are preventing many of these problems. By not being on a DMT, if you have active MS, you are at risk of acquiring damage from focal inflammatory lesions. Early in the disease course, you may not be aware of this damage because of the remarkable capacity of the nervous system to compensate for damage (neurological reserve). However, once the compensatory mechanisms have been exhausted, further damage results in overt disability. It is important to regard DMTs as preventive treatments, i.e. their aim is to delay, and hopefully prevent, future disability.

Possible reasons for not receiving a DMT

Many people with MS will not be on a DMT, for a variety of reasons. The list below is probably not extensive; if you know of other reasons why someone who qualifies is not taking a DMT, please let me know.

Inactive MS

Someone with inactive MS will not be eligible for a DMT. There is no standard definition of active MS. To me, active MS is recent evidence of focal inflammatory disease activity, defined as:

  • clinical relapse(s) in the last 2 years
  • OR magnetic resonance imaging (MRI) activity in the last 12 ̶ 36 months (new or enlarging T2 lesions or T1 Gd-enhancing lesions)
  • OR a raised cerebrospinal fluid (CSF) neurofilament light chain level in the last 12 months.

Worsening disability in MS without focal inflammatory disease activity is not active disease. It can be due to damage caused by past inflammation, smouldering MS or the effects of premature ageing; anti-inflammatory DMTs can’t address this problem. We need different types of DMTs to address these mechanisms – for example, neuroprotective and/or remyelination therapies and anti-ageing therapies.

Watchful waiting

In many situations, some neurologists think someone with MS will end up having benign disease, so they are not prepared to start treatment until the patient develops some overt disability. I abhor this practice and it is one of the reasons I spend so much of my time disseminating knowledge and getting involved with health politics. Watchful waiting, in terms of treating MS, is not supported by data. The earlier and more effectively you treat MS, the better the outcome. The only situation I could condone watchful waiting in someone with active MS is when the diagnosis of MS is in question. Sometimes in neurology, time is the best diagnostician. If the person has MS, it will declare itself with further disease activity, and this would be the trigger to start a DMT.

Family planning

Trying to fall pregnant, pregnancy or breastfeeding are common reasons to interrupt or stop DMTs. Please note that most neurologists now have options to treat MS during pregnancy and while breastfeeding, so this is becoming a less common reason for not taking a DMT.

Risk aversion

Some people with MS are not prepared to take the potential risks associated with DMTs.

Personal reasons

Some people with MS don’t believe in having their MS treated, preferring to try alternative medicines and turn down traditional DMTs. If you are one of these people, I would recommend you continue to interact with your MS team and have regular monitoring of your MS (clinical, MRI, patient-related outcome measures [PROMS] and possibly CSF analyses). Then, if these alternative strategies don’t work, you will keep open the option of treatment with a ‘traditional DMT‘. Most alternative treatment strategies for MS are compatible with DMTs and hence should be viewed as complementary. Understanding the difference between complementary and alternative treatments is important. Complementary treatment strategies are part of the holistic management of MS.

Financial constraints

In some parts of the world, MS treatment is not covered by a national health service or medical insurance scheme and some people with MS simply can’t afford DMTs. Even in rich countries, people with MS who are disenfranchised don’t have access to treatment; these may include illegal immigrants, refugees and asylum seekers waiting for their applications to be processed.

Progressive or more advanced MS

In most countries, neurologists don’t initiate treatment in patients with more advanced MS. This approach is based on a lack of evidence of the effectiveness of DMTs in this population. However, we are increasingly offering ocrelizumab (for active primary progressive MS), siponimod (for active secondary progressive MS) or off-label therapies on a compassionate basis to people with more advanced MS. In addition, there is also the potential to participate in clinical trials of new treatments for more advanced MS.

Ageism

Some healthcare systems and some neurologists are reluctant to start DMTs in people with MS who are over a certain age. This is based on a lack of evidence of the effectiveness of DMTs in this population, and it is why we need to do clinical trials in older people with MS.

Comorbidities

Many people have other medical problems for which the treatment takes priority over the treatment of MS. For example, a patient of mine was diagnosed with stage four bowel cancer. After her surgery, she started an intensive period of chemotherapy during which we stopped her DMT.

References

  1. Fisher E, et al. Gray matter atrophy in multiple sclerosis: a longitudinal study. Ann Neurol 2008;64:255–65.
  2. Barkhof F, et al. Imaging outcomes for neuroprotection and repair in multiple sclerosis trials. Nat Rev Neurol 2009;5:256–66.
  3. Simon JH. Brain atrophy in multiple sclerosis: what we know and would like to know. Mult Scler 2006;12:679–87.
  4. Ziemssen T, et al. Optimizing treatment success in multiple sclerosis. J Neurol 2016;263:1053–65.
  5. Hickman SJ, et al. Detection of optic nerve atrophy following a single episode of unilateral optic neuritis by MRI using a fat-saturated short-echo fast FLAIR sequence. Neuroradiology 2001;43:123–8.
  6. Trapp BD, et al. Axonal transection in the lesions of multiple sclerosis. N Engl J Med 1998;338:278–85.
  7. Peterson JW, et al. Transected neurites, apoptotic neurons, and reduced inflammation in cortical multiple sclerosis lesions. Ann Neurol 2001;50:389–400.
  8. Orme M, et al. The effect of disease, functional status, and relapses on the utility of people with multiple sclerosis in the UK. Value Health 2007;10:54–60.
  9. Pfleger CC, et al. Social consequences of multiple sclerosis (1): early pension and temporary unemployment – a historical prospective cohort study. Mult Scler 2010;16:121–6.
  10. Kobelt G, et al. Costs and quality of life of patients with multiple sclerosis in Europe. J Neurol Neurosurg Psychiatry 2006;77:918–26.
  11. Feuillet L, et al. Early cognitive impairment in patients with clinically isolated syndrome suggestive of multiple sclerosis. Mult Scler 2007;13:124–7
  12. Confavreux C and Compston A. Chapter 4. The natural history of multiple sclerosis. In: McAlpine’s Multiple Sclerosis, Fourth Edition, 2006; 183 ̶ 272. Churchill Livingstone.
  13. Weinshenker BG et al. The natural history of multiple sclerosis: a geographically based study. I. Clinical course and disability. Brain 1989;112:133 ̶ 46.
  14. Torkildsen GN, et al. Survival and cause of death in multiple sclerosis: results from a 50-year follow-up in Western Norway. Mult Scler 2008;14:1191–8.
  15. Kingwell E, et al. Relative mortality and survival in multiple sclerosis: findings from British Columbia, Canada. J Neurol Neurosurg Psychiatry 2012;83:61–6.
  16. Sadovnick AD, et al. Cause of death in patients attending multiple sclerosis clinics. Neurology 1991;41:1193–6.
  17. Brenner P, et al. Multiple sclerosis and risk of attempted and completed suicide – a cohort study. Eur J Neurol 2016;23:1329–36

What type of MS do I have?

MS has historically been classified into different subtypes, and this subdivision dictates what treatments you are eligible for. These MS disease subtypes are not supported biologically, however, and many MS neurologists are of the opinion that MS is one disease.1

Key points

  • The difference between relapsing MS and non-relapsing progressive MS is explained.
  • The stages of MS have different labels, for historical development and reimbursement reasons, but biologically MS is one disease.
  • From a treatment perspective, the key thing is to know if your MS is active or inactive.
  • Active MS can be differentiated from inactive MS by relapses, MRI evidence of disease activity and raised neurofilament levels in the cerebrospinal fluid.

Type of MS

You should be able to classify yourself as having either relapsing MS or non-relapsing progressive MS. Knowing what type of MS has been diagnosed and whether your MS is active or inactive will allow you to ask your MS neurologist questions about the MS treatments available to you. 

Around 85–90% of people with MS start with so-called relapse-onset MS, i.e. they have a definite attack of symptoms that is usually followed by a period of complete or incomplete recovery. A single attack may be labelled as a clinically isolated syndrome (CIS): it does not fulfil the current diagnostic criteria for full-blown MS, but it means someone is at risk of further attacks and hence of developing MS in the future.

EDSS, Expanded Disability Status Scale score
EDSS, Expanded Disability Status Scale score

Once you have more attacks, either clinically in the form of relapse or subclinically with new lesions on magnetic resonance imaging (MRI), then you are usually diagnosed as having MS. The diagram below illustrates the typical course of repeated relapses and remissions, with worsening disability over time, that characterises so-called relapsing–remitting MS (RRMS).

After a variable period, people with relapse-onset MS may notice worsening neurological function without improvement. This is called secondary progressive MS (SPMS) and it can occur with superimposed relapses (so-called relapsing SPMS [RSPMS]) or without relapses.

EDSS, Expanded Disability Status Scale score
EDSS, Expanded Disability Status Scale score

A small number of people with MS (10–15%) will present with worsening neurological function without a prior history of relapses; this is called primary progressive MS (PPMS).

Interestingly, some people with PPMS go on to have relapses, and this is referred to as progressive relapsing MS (PRMS).

EDSS, Expanded Disability Status Scale score
EDSS, Expanded Disability Status Scale score

Rarely, someone may present with worsening neurological function, similar to PPMS, but have a prior history of just one relapse. This is referred to as single-attack progressive MS (SAP), but most MS specialists classify these patients as having SPMS

In summary …

  • Relapsing MS captures all people with MS who are still having relapses, i.e. within the last 2 years, and includes RRMS, RSPMS and PRMS.
  • Non-relapsing progressive MS refers to SPMS and PPMS: these latter two groups should have no history of recent relapses, i.e. in the last 2 years.

To further confuse things, non-relapsing progressive MS used to be referred to as chronic progressive MS (see below). 

Why is this important?

Different DMTs are licensed for different types of MS, and many treatment guidelines specifically state the type of MS for which a particular drug can be used.

Is MS one or more diseases?

In the past, MS was regarded as one disease: either you had MS, or you did not. The stages were referred to as early relapsing MS or chronic progressive MS, but MS was still one disease. 

When disease-modifying therapies (DMTs) were developed, MS was split into multiple sub-types. This categorisation was driven by commercial considerations, and it allowed interferon-beta to be licensed in the US under the Orphan Drug Act. The classification of orphan disease in the US requires there to be fewer than 200,000 people with that diagnosis. Dividing MS into RRMS, SPMS, PPMS and later CIS ensured that each category met this criterion. 

Since then, PRMS and radiologically isolated syndrome (RIS) have been added as potential subtypes. These classifications tend to be arbitrary and overlap, but there is no biological basis to support MS being more than one disease. 

Is your MS active or inactive?

From a treatment perspective, it is important to know if your disease is active or inactive. In active MS, there is evidence of ongoing inflammation in the brain and spinal cord. If you are having relapses, are developing new lesions on MRI or have raised neurofilament (NFL) levels in your cerebrospinal fluid (CSF) or blood, your MS is active. 

Active MS responds to anti-inflammatory treatments; inactive MS is less responsive to currently licensed DMTs. 

Criteria for ‘active’ MS accepted by many MS health professionals. CSF, cerebrospinal fluid; NFL, neurofilament light.
*Some neurologists accept 24 months, 36 months or even longer when assessing MRI activity. There is no international consensus on the gap between the baseline and new MRI scan to define active disease.

The term progressive MS refers to the stage of MS when your disability gets worse – independent of relapses, and possibly of focal inflammatory lesions. I say ‘possibly’, because our current MRI scans don’t show new or enlarging microscopic lesions but only those that are larger than ~3–4 mm. NFL measurements in either the CSF or blood have the advantage of being additive and integrating inflammatory activity. In my experience, about one in ten patients classified as ‘inactive’ based on clinical and MRI activity is found to have active MS when CSF NFL levels are analysed. Unfortunately, however, many MS neurologists, regulators and payers do not accept this latest definition of MS disease activity because tests for NFL levels are currently not widely available. 

In conclusion, knowing the type of MS you have and whether your disease is active or inactive will allow you to discuss with your MS specialist the kinds of treatment available to you

References

Giovannoni G, et al. Smouldering multiple sclerosis: the ‘real MS’. Ther Adv Neurol Disord 2022;15:17562864211066751.