Tag Archives: progressive MS

Suicidal ideation and suicide in MS

Mental health problems and suicide are the underbelly of MS, the elephant in the consulting room. I have attempted to discuss these topics in a way that is not too dark, based on data from a 2026 systematic review. Please be aware, however, that the content may still be upsetting.

Key points

  • The suicide rate among people with MS is roughly twice that of the general population.
  • Several biological, psychological and social factors contribute to suicide risk:
    • depression and anxiety: a biological basis for these comorbidities exists in MS
    • MS disease-related factors: increased disability, disease duration and progression; life-changing symptoms
    • socio-demographic factors: age, male sex, living alone, education level
    • social and existential factors: loneliness, social exclusion and low perceived social support; loss of purpose and meaning; financial strain; fear of stigma.
  • Thoughts of ending one’s life – ‘suicidal ideation’ – precede suicide attempts; effective screening tools exist, are quick to complete and can identify patients at risk of suicide.
  • Systematic screening is not optional but should be part of the basic standard of care.
  • Suicide prevention in MS requires participation by the clinic, the patient (and their family) and the health system.
  • If you or someone you know is having thoughts of suicide, please reach out for help. Support groups are available.

The problem we avoid talking about …

MS is a chronic, unpredictable and often disabling neurological condition. People with MS know this, and as a result they carry a psychological burden that is usually overlooked in a 15-minute annual outpatient appointment. Mental health problems and suicide are the elephant in the MS consulting room. They sit quietly alongside the disability progression conversation, the drug treatment switch discussion, and the “How are things at home?” question that healthcare professionals (HCPs) often forget to ask.

How common are suicidal ideation and suicide in MS?

Suicidal ideation – thoughts of ending one’s life, with or without a plan – is the single most important precursor to suicide attempts, and death by suicide among people with MS is far more common than most HCPs appreciate. A landmark Canadian study in 1991 found that suicide was the third most common cause of death reported in MS clinics.1 The proportion of deaths due to suicide among people with MS (15%) was 7.5 times the proportion in an age-matched general population (2%).

More recent work suggests that the suicide rate among people with MS is roughly twice that of the general population.2 A 2026 systematic review and meta-analysis of suicidal ideation in MS draws on 18 studies and more than 8,000 people with MS to provide a picture of how common it is, what drives it and where the gaps are in MS care.2 From these combined data, the authors estimate that one in five people (20%) in an MS clinic waiting room has considered suicide. This is higher than the 13% figure from a 2020 meta-analysis,3 and the authors suggest two plausible explanations:

  • an expanding evidence base that now includes more diverse settings
  • a real rise in suicidal ideation rates – perhaps linked to the COVID-19 pandemic, growing geopolitical instability and reduced stigma around reporting mental health symptoms.

Individual study prevalence ranged dramatically, from 8% in a Canadian cohort to 36% in an Iranian cohort. This is probably telling us something important about how context, culture, income level and healthcare infrastructure shape suicide risk.

In most high-income countries, lifetime suicidal ideation prevalence in the general population is around 9–10%. The recent 20% figure in people with MS2 is therefore roughly double that seen in the background population – a finding echoed by many independent studies.

Regional and temporal patterns

In the 2026 review, subgroup analysis based on country income level reported a pooled suicidal ideation prevalence of 17% among the 14 high-income countries compared with 32% in the countries with ‘upper-middle’ incomes (three studies from Iran and one from Brazil).2 This aligns with what we know about mental health inequities more broadly – poverty, housing insecurity, financial strain, limited access to psychiatric services, and stigma all worsen outcomes in lower-resource settings. (Please note, the ‘upper-middle income’ data in this review came from just two countries; therefore, we should be cautious about extrapolating to sub-Saharan Africa, South Asia or Latin America as a whole.)

Suicidal ideation prevalence figures published between 19911 and 20262 from many studies conducted across different regions of the world vary widely and may appear inconsistent. The 2026 figure of 20% still means, however, that roughly one in five people with MS has active suicidal thoughts, and global crises in the last five years may be masking an underlying deterioration that will only become visible in the next generation of studies.

Limitations of study data

The 2026 review has limitations that need to be acknowledged. Study methodologies vary widely: suicidal ideation is measured with different instruments and at different time points; diagnostic criteria for MS are inconsistently reported; variability between studies is high. The ‘20% prevalence’ figure from 2026 is therefore an estimate with uncertainty. What is not uncertain is that suicidal ideation is substantially more common in MS than in the general population, and that it is driven by modifiable factors and hence is preventable. 

Who is at risk of suicidal ideation among people with MS

No single risk factor predicts suicidal ideation in isolation. Suicide is the final common pathway of several biological, psychological and social factors. Consistent drivers can be grouped into four domains.2

1. Psychiatric comorbidity: depression and anxiety

Depression and anxiety are the most consistently reported risk factors for suicidal ideation in MS.2 Depression affects up to 50% of people with MS at some point, far exceeding the 14–21% figure in the general population. This matters because depression in MS is both more common and more severe than in the general population, and it is driven by a mixture of:

  • neuroinflammation and hormonal factors (depression in MS is not simply a ‘reaction’ to having MS – it has a biological basis)
  • lesion location, particularly in limbic and frontal lobe/cortex pathways
  • disease-modifying therapy (DMT) side effects (particularly with interferon therapy)
  • the psychological burden of uncertainty, disability and loss of role.

Anxiety, which is often under-recognised and under-treated in MS, frequently coexists with depression and independently elevates suicidal ideation risk.

2. Disease-related factors

Several disease features align with suicidal ideation across studies.

  • Greater disability – measured both by clinician-rated EDSS (Expanded Disability Status Scale) scores and by self-reported physical impairment. The latter may be a stronger predictor than EDSS scores, because it captures the subjective experience of living with impairment.
  • Longer disease duration – though this relationship is complex. Study results vary, suggesting that some patients adapt psychologically over time, probably depending how well they adjust to living with MS.
  • Progressive MS – higher suicidal ideation rates are found in people with more advanced MS when compared with the earlier relapsing–remitting phase. Many HCPs and healthcare systems think that once someone with MS becomes disabled, the disease is not modifiable. I hope landmark studies like ocrelizumab in PPMS (O’HAND study), siponimod in SPMS (EXPAND study) and tolebrutinib in non-relapsing SPMS (HERCULES study) change this perspective. 
  • Specific symptoms – fatigue, sleep disturbance, spasms, bladder and bowel difficulties, and speech and swallowing problems also correlate with suicidal ideation. Together, these symptoms erode quality of life.

3. Sociodemographic factors

The evidence here is more mixed.

  • Age – findings are inconsistent. Some studies identify older patients (≥ 65 years) as higher risk; others find younger people with MS more vulnerable. Both extremes carry risk for different reasons; younger recently diagnosed patients face a challenge to their identity and loss of envisioned future; older patients face accumulated disability and social isolation.
  • Male sex – some (but not all) studies find men at higher risk, consistent with general population data on completed suicide.
  • Unmarried status and living alone are both associated with increased suicidal ideation in multiple studies.
  • Education level – most studies suggest that higher educational attainment is protective (better health literacy, coping strategies, economic resources); one Iranian study found the opposite, perhaps reflecting unmet expectations or awareness of prognosis.

4. Social and existential factors

This domain is the easiest to miss in a busy MS clinic but most important to address.

  • Low perceived social support, from family, friends and significant others, is a consistent risk factor.
  • Loneliness and social exclusion – ‘feeling socially excluded’ strongly correlates with suicidal ideation.
  • Hopelessness and loss of purpose – perceived loss of control, loss of masculinity/femininity and failure to achieve an expected role contribute psychologically to suicidal ideation.
  • Challenges to faith or spiritual meaning – having a sense of purpose, comfort in faith, and church membership can all be helpful and protective (in those for whom they are important).  
  • Financial strain and anticipated stigma are particularly important in lower-resource settings.

Screening for suicidal ideation in the clinic

If 20% of people with MS experience suicidal ideation but only a small fraction volunteer it spontaneously, systematic screening is not optional but should be part of the basic standard of care. Effective screening tools exist, and they are quick to complete.

The Patient Health Questionnaire-9 (PHQ-9)

The PHQ-9 is the most practical and widely validated mental health tool for neurological conditions, including MS; it is particularly suited to detecting suicidal ideation. Item 9 of this 9-item self-report depression screen specifically asks about thoughts of self-harm or being better off dead. It takes under 3 minutes to complete and can be done in the waiting room or electronically before the clinic. Scores above 10 indicate clinically significant depression warranting action. A positive response to item 9 should trigger a suicide risk assessment. It could be argued that every MS clinic should administer the PHQ-9 at least annually, and at every unscheduled visit where there has been a relapse, a significant disability progression, a DMT change or a major life event.

The Beck Scale for Suicide Ideation (BSI)

The BSI is a 20-item instrument designed specifically for suicide risk. It is more detailed than the PHQ-9 and is better suited to psychiatric follow-up than to first-line screening.

The Beck Depression Inventory-II (BDI-II)

The BDI-II is a broader 21-item depression measure that includes a suicide item. This is often used in research settings but takes longer to complete than the PHQ-9 in a clinic.

The Hospital Anxiety and Depression Scale (HADS)

The HADS is my favoured option that captures both anxiety and depression domains. It does not, however, include a direct suicide item, so a ‘positive’ (i.e. high: 11−21) HADS score should always prompt a follow-up suicide-specific question.

What should you be asked if a screen is positive?

Clinicians often feel awkward asking directly about suicide. Evidence is unambiguous that asking about suicide does not increase the risk. A graded approach works well:

  1. ‘Have you had thoughts that life isn’t worth living, or that you’d be better off dead?’
  2. ‘Have you had thoughts of harming yourself?’
  3. ‘Have you thought about how you might do it?’ (plan)
  4. ‘Do you have access to the means?’ (access)
  5. ‘Have you taken any steps or made any preparations?’ (intent)

Presence of a plan, access to means, or preparatory behaviour indicates a high imminent risk and demands urgent psychiatric referral – ideally, the same day.

Suicide prevention: what can we do?

Suicide prevention in MS operates at three levels: the clinic, the patient and the system.

At the clinical level

  • Screen systematically. A good MS service should embed PHQ-9 into routine MS review and not rely on patients volunteering suicidal ideation. If I were setting up an MS clinic now, I would include PHQ-9 in routine screening and add it to the annual questionnaire that patients must complete before each clinic visit. 
  • Treat depression and anxiety aggressively. Depression and anxiety are the dominant modifiable risk factors. Selective serotonin reuptake inhibitors (SSRIs: sertraline, citalopram, escitalopram) are first-line, well-tolerated drugs and have no meaningful interaction with current DMTs. Cognitive behavioural therapy (CBT) – including web-based models – has a good evidence base in MS. We should reject the dogma that ‘of course they’re depressed, they have MS’ as a reason not to proactively manage depression.
  • Address symptom burden. Fatigue, pain, sleep disturbance, bladder dysfunction and spasticity are not just quality-of-life issues – they are suicide risk factors that need to be treated. Please make sure that your MS care team provides relevant support. 
  • Be alert at transition points. Diagnosis, relapse, disability milestones (losing the ability to walk, work or drive), DMT failure, and being labelled as having secondary progressive MS are all periods of elevated risk. 
  • Assess social support explicitly. Who do you live with? Who helps you? Who would you call at 3 am? Treat loneliness and social isolation as vital potential danger signs.
  • Restrict means where appropriate. Safe storage of medications, particularly in patients with large quantities of prescribed opioids, benzodiazepines or anticholinergics, can save lives. This conversation needs to be had with the patient, their partner and their family. 
  • Document and communicate risk. A named crisis contact, a safety plan, and timely communication with the GP or primary care physician should be standard practice.

At the patient and family level

  • Psychoeducation. Many people with MS don’t know that depression is a common and treatable part of MS – they assume sadness and hopelessness are inevitable. Naming and confronting depression and suicidal ideation helps.
  • Normalise help-seeking. The stigma of psychiatric care in MS remains real. Framing mental health as part of MS care, not something separate, reduces that barrier.
  • Involve family. Family members are often the first to notice a change – withdrawal, giving away possessions, changes in sleep. They need to be taught about what to watch for.
  • Build purpose and connection. Peer support groups (e.g. MS Society, Shift.ms, MS Trust, MS International Federation resources, National MS Society [US]), vocational rehabilitation, social prescribing, church attendance, volunteering and hobbies all buffer against hopelessness. Having a purpose in life and being productive reduce the likelihood of suicidal ideation.
  • Safety planning. A written safety plan – warning signs, coping strategies, people to call, reasons for living, means restriction – is a simple but evidence-based self-administered intervention. The Stanley-Brown Safety Plan is freely available online.

At the system level

  • Integrate mental health into MS services. A neuropsychologist or clinical psychologist embedded in an MS service should not be a luxury; it is the minimum standard for a condition where one in two patients develops depression. That said, most NHS MS clinics don’t employ a neuropsychologist, and referring people with MS for assessment and management takes time.
  • Address inequity. The doubled suicidal ideation prevalence in upper-middle-income countries2 is not inevitable. It reflects under-resourced mental health services, stigma, and financial barriers to care – all modifiable at a policy level.
  • Research under-represented populations. The Bazmi review2 of 14 high-income and three upper-middle-income countries openly discusses its limitations: it includes no data from low-income countries and none from most of Asia, Africa or Latin America, beyond a single Brazilian study. MS care cannot be evidence-based at a global level if the evidence is dominated by findings from high-income countries. More research is needed. 

The bottom line

If you are an HCP and are reading this, please remember that roughly one in five of your MS patients has had thoughts of suicide. Most of them have not told you. The dominant drivers – depression, anxiety, disability, symptom burden, loneliness, hopelessness – are either treatable or modifiable, and the screening tools are simple, brief and validated. Although suicidal ideation is common in people with MS, it is driven by modifiable factors and hence is preventable. Suicide in MS is not inevitable. It is, however, easy to miss. Every person with MS deserves a clinician who asks directly, listens without flinching, and acts on what they hear.

If you or someone you know is having thoughts of suicide, please reach out for help.

In the UK, Samaritans are available 24/7 on 116 123.

In the US, the 988 Suicide and Crisis Lifeline is available by call or text.

In other countries, the International Association for Suicide Prevention (IASP) maintains a directory of crisis services at iasp.info/crisis-centres-helplines/

You are not alone, and help is available.

References

  1. Sadovnick AD, et al. Cause of death in patients attending multiple sclerosis clinics. Neurology 1991;41:1193. doi.org/10.1212/WNL.41.8.1193.
  2. Bazmi E, et al. Global prevalence and risk factors of suicidal ideation in multiple sclerosis: a systematic review and meta-analysis. Health Sci Rep 2026;9:e72331. doi: 10.1002/hsr2.72331.
  3. Kouchaki E, et al. Prevalence of suicidal ideation in multiple sclerosis patients: meta‐analysis of international studies. Soc Work Pub Health 2020;35:655–63.

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

How do I want my MS to be treated?

What is the difference between a maintenance ̶ escalation DMT and an immune reconstitution therapy (IRT)? Why is it important to understand the distinction?

Key points

  • Maintenance–escalation and immune reconstitution therapy (IRT) are two approaches to MS treatment currently favoured.
  • IRT is a one-off, short course which acts on immune system cells in three stages: reduction, repopulation and reconstitution.
  • Maintenance–escalation is given continuously without interruption. If it does not work well, the treatment is changed to a more effective DMT (known as ‘escalation’).
  • Additional future approaches are likely to include induction ̶ maintenance and/or combination therapy.

If I had MS, how would I want to be treated? This is a difficult question, and one that many of my patients ask me. The answer depends on your life stage, what risks you are prepared to take, personal factors such as family planning considerations and the extent of your understanding of MS and how we approach its treatment.

Currently, there are two main philosophies regarding the treatment of MS with DMTs: maintenance/escalation versus immune reconstitution therapies (IRTs). 

What is an immune reconstitution therapy?

By definition, an IRT is given as a short course, i.e. as a one-off treatment in the case of autologous haematopoietic stem cell transplantation (AHSCT) or intermittently in the case of alemtuzumab, cladribine or mitoxantrone. IRTs are not given continuously, and additional courses of the therapy are given only if there is a recurrence of MS inflammatory activity. IRTs can induce long-term remission and, arguably, in some cases a potential cure.

IRTs have three phases to their mode of action, which I refer to as the ‘three Rs’.

  1. Reduction, or depletion, when we try to kill the autoimmune cells that cause MS.
  2. Repopulation, when the immune system recovers from stem cell transplantation and, hopefully, the autoimmune cells don’t return.
  3. Reconstitution, when the immune system is recovered and fully competent. The recovered immune system following treatment with an IRT is different from what was there before. Some people like to think of an IRT as a reboot of the immune system, but without MS.
Slide1

The three Rs of immune reconstitution therapy: reduction, repopulation and reconstitution. From Giovannoni, Curr Opin Neurol.1 

What is an MS ’cure’?

One attempt at a definition describes an MS cure as no evidence of disease activity (NEDA) 15 years after the administration of an IRT. I justify using 15 years because it is the time-point most accepted for defining ‘benign MS‘ and is also beyond the average time to onset of secondary progressive MS in natural history studies.

What is a maintenance therapy?

A maintenance therapy is given continuously without an interruption in dosing. Although maintenance therapies can induce long-term remission (i.e. NEDA), they cannot result in a cure. The recurrence or continuation of inflammatory disease activity with maintenance therapies is an indication of a suboptimal response to treatment and typically results in a treatment switch. Ideally, this switch should be to a more effective class of DMTs – hence the term ‘escalation’. 

What would I recommend?

I can’t choose for you. The debate is complex and depends on many factors. One important consideration is vaccine readiness: will I be able to mount an adequate immune response to a vaccine? IRTs have the advantage that they allow reconstitution of the immune system; once it recovers, vaccine responses are restored, and even live vaccines can be given.

The table below highlights key differentiators. Further, detailed information about most of the products listed in the Table can be accessed through the DMT comparison tool available at ClinicSpeak or via the Multiple Sclerosis Trust MS Decisions aid.

Similarities and differences between maintenance treatments and immune reconstitution therapies. Registered trade names (UK market) of the generic drugs listed are shown in brackets. *How to define a ‘cure’ in MS is controversial. Modified from Giovannoni, Curr Opin Neurol.1
DMT, disease-modifying therapy; HSCT, haematopoietic stem cell transplant; IRT, immune reconstitution therapy.

The future

I envisage two more treatment strategies emerging.

  • One approach is induction ̶ maintenance therapy, using an IRT followed by an immunomodulatory therapy rather than an immunosuppressive DMT (which is a safer option) the aim is to keep MS in long-term remission. This approach is used in oncology, where the cancer is hit hard with induction chemotherapy and then kept at bay with a well-tolerated maintenance therapy (e.g. antihormonal therapies in breast cancer).
  • Another approach is combination maintenance therapy; the aim would be to combine an anti-inflammatory therapy with, say, neuroprotective therapies to target smouldering MS.

The diagram below illustrates the scheduling of the four approaches discussed in this section. You may like to try out the DMT comparison tool to find out how some of the drugs listed in the comparison Table above align with your personal life choices and priorities.

Slide5

Four approaches discussed in this section. The white panels illustrate the two approaches currently available; the shaded panels illustrate two strategies that may emerge in the future. Modified from Giovannoni, Curr Opin Neurol.1


References

  1. Giovannoni G. Disease-modifying treatments for early and advanced multiple sclerosis: a new treatment paradigm. Curr Opin Neurol 2018;31:233 ̶ 43.

Am I eligible for an MS disease-modifying therapy?

Key points

Do you know the eligibility criteria for MS disease-modifying therapies? And who decides what drugs can be prescribed for your MS?

  • Disease-modifying treatments (DMTs) change the long-term trajectory of MS and protect the central nervous system from further damage.
  • Regulators such as the European Medicines Agency (EMA) and the Federal Drug Administration (FDA) decide in which group(s) of patients a particular drug can be used, based on the results of clinical trials.
  • Once a drug has been licensed in your region, local payers decide whether to make it available within your country, based on cost-effective assessments.
  • If you have active MS, your level of disease activity, its severity and speed of development will determine which DMTs you can be offered.
  • In some countries, ocrelizumab has been approved for the treatment of active primary progressive MS (PPMS) and siponimod has been approved for the treatment of active secondary progressive MS.
  • Protecting upper limb function has been a neglected area; studies are now ongoing, however, with a view to finding DMTs that limit the progression of upper limb disability.

What do disease-modifying drugs do?

Disease-modifying therapies (DMTs) are treatments that change the natural history – that is, the long-term trajectory – of the disease. They reduce the rate of disability worsening and so protect the end-organ (in the case of MS, this is the central nervous system). To simplify, let’s say that a person with MS on no treatment may manage for an average of 18-20 years before needing to use a walking stick (corresponding to Expanded Disability Status Scale [EDSS] 6.0), while someone on treatment might manage without aid for 24 years, i.e. a 4-6-year delay, then the treatment can be called disease-modifying. (Please note, the treatment effect or 4-6-year delay in reaching EDSS 6.0 is an average and some people with MS will do better than others. Conversely, some will do worse than average.) 

Is interferon a DMT?

In the early days of interferon therapy, there was debate about whether simply reducing the relapse rate by 30% relative to placebo treatment, without slowing down the worsening of the disease over 2 years, was disease-modification. However, subsequent trials and follow-up of people with MS treated with interferon-beta showed a slowing down of disease worsening, delays in developing secondary progressive MS and a favourable impact on survival.1 

Do symptomatic treatments modify the disease?

Symptomatic treatments improve the symptoms associated with MS without affecting the natural history. Treatments are classified as symptomatic in relation to their mode of action; but some classes of treatment may yet prove to be disease-modifying. For example, we often use sodium channel blocking agents, such as phenytoin, carbamazepine, oxcarbazepine and lamotrigine, for MS-related neuralgia and other pain syndromes. However, there is evidence that this class of therapy may be neuroprotective and hence disease-modifying. 

Who decides on eligibility for a licensed DMT?

Regulators decide in which group of people with MS the DMT can be used, and they grant a licence for its use. Regulators include the EMA, the FDA and the Medicines and Healthcare products Regulatory Agency (MHRA in the UK).

Payers hold the purse strings and decide which licensed drugs to make available. They makecost-effectiveness assessments to try and optimise the use of the drug in clinical practice. Payers include medical insurance companies and the NHS in the UK. 

Guidelines are formulated to help healthcare professionals use DMTs in the most appropriate way within a particular healthcare system. Guidelines often go much further than the regulators and payers, in that they try to address potential ambiguities in the prescribing of DMTs. National, regional or local guidelines that provide expert clinical guidance include the UK NICE (National Institute for Health and Care Excellence) MS management guidelines and the Association of British Neurologists guidelines. 

In the NHS in England, we must abide by NHS England’s algorithm that is predominantly based on NICE technology appraisals, NICE standards of care and the Association of British Neurologists guidelines. To navigate the specifics of the eligibility criteria is quite complex. However, a simpler way of looking at this is to start by defining how active your MS is. 

How does disease activity affect my treatment options?

To be eligible for DMTs, you must have active MS. A summary of the four categories of disease activity is given below. Further details can be found in the section entitled Do I have active MS?

  1. Inactive MS – you are not currently eligible for DMTs.
  2. Active MS – you should be eligible for a so-called platform therapy (interferon-beta, glatiramer acetate, teriflunomide, dimethyl fumarate or ponesimod) and ocrelizumab or ofatumumab.
  3. Highly active MS – you are eligible for all therapies except natalizumab. Please note in England fingolimod can only be used as a second-line therapy (after another DMT has failed).
  4. Rapidly evolving severe MS – you should be eligible for all DMTs.

Advanced or progressive MS

Ocrelizumab and siponimod are now approved in several countries for the treatment of active PPMS and active SPMS, respectively. A classification of active PPMS requires recent MRI evidence of disease activity, that is, the formation of new T2 lesions and/or the presence of gadolinium-enhancing lesions in the last 3 years. Active SPMS is confirmed by the occurrence of superimposed relapses and/or the presence of new T2 lesions and/or gadolinium-enhancing lesions in the last 2 years. Based on these very narrow definitions, most patients with PPMS and SPMS will not be eligible for ocrelizumab or siponimod, respectively. The differences between the MRI criteria for active PPMS and active SPMS reflect the reality that people with PPMS are less likely to be having regular monitoring MRI scans.

Stages of MS currently not eligible for treatment

In the UK, people with MS who are wheelchair users are not eligible for DMTs. The reason for this is that patients with more advanced MS have generally been excluded from phase 3 clinical trials; hence there are no data to show whether licensed DMTs are effective in this group.

There is a long-held view that inflammation is reduced or absent in advanced MS. However, clinical, imaging and pathological data show that inflammation still plays a large, and possibly a major, role in advanced MS. Therefore, not targeting more advanced MS with an anti-inflammatory is counterintuitive.

The importance of upper limb function

In 2016, the #ThinkHand campaign was launched to raise awareness of the importance of hand and arm function in people with MS and the need for clinical trials in this population. Studies currently ongoing that focus on limiting upper limb disability progression include ChariotMS (oral cladribine)2 in people with advanced MS (UK only) and the global, multicentre O’HAND trial  (ocrelizumab)3 in participants with PPMS. 

Once someone with MS becomes a wheelchair user, they still have neuronal systems that are potentially modifiable – for example, upper limb, bulbar (speech and swallowing), cognition and visual function. There is an extensive evidence base showing that several licensed DMTs can slow the worsening of upper limb function despite subjects having advanced MS. Now that ocrelizumab and siponimod have been licensed for active primary and secondary progressive MS, respectively, these DMTs may form the platform for future add-on trials. 


References

  1. Goodin DS, et al. Survival in MS: a randomized cohort study 21 years after the start of the pivotal IFNβ-1b trial. Neurology 2012;78:1315 ̶ 22.
  2. National Institute for Health and Care Research (NIHR). MS clinical trial to focus on people who can’t walk. November 2020. Available at https://www.nihr.ac.uk/news/ms-clinical-trial-to-focus-on-people-who-cant-walk/26227 (accessed June 2022).
  3. US National Library of Medicine. A Study to Evaluate the Efficacy and Safety of Ocrelizumab in Adults With Primary Progressive Multiple Sclerosis (O’HAND). First posted July 2019. Available at https://clinicaltrials.gov/ct2/show/NCT04035005 (accessed June 2022).

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. 

Do I have active MS?

Before deciding to start a disease-modifying therapy you need to know if you have active MS.

Key points

  • To qualify for a disease-modifying treatment for MS you must have active disease.
  • Active MS is characterised by relapses (new symptomatic or asymptomatic lesions); the clinical diagnosis of relapse may be supported by MRI or CSF evidence of activity.
  • Different levels of disease activity qualify for different types of DMT.
  • Diagnostic criteria for MS have evolved considerably over the past two decades; this has helped to make treatment decisions earlier and easier, both for MS neurologists and for people with MS.

To be eligible for disease-modifying therapy (DMT) you must have ‘active MS’. This term is increasingly used to refer to current or recent evidence of focal inflammatory activity, i.e. new lesions on magnetic resonance imaging (MRI) or a relapse. Inflammation damages axons, or nerve processes. When a lesion develops, the effects of inflammatory mediators can cut (transect) axons, demyelinate them or stop them from working.

By contrast, the gradual worsening of disability that occurs in people with more advanced MS (which may, or may not, occur in the presence of focal inflammatory activity) has many potential causes, only one of which is focal inflammation.

Signs of active MS

Relapses

When a new MS lesion occurs in an eloquent part of the central nervous system it causes new symptoms or exacerbates old ones – this is usually interpreted as a relapse. Relapses, by definition, last at least 24 hours in the absence of infection or fever.

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 more when assessing MRI activity. There is no international consensus on the gap between the baseline and new MRI scan to define active disease.

Asymptomatic lesions

Most focal MS disease activity does not cause any overt symptoms because the brain has a way of compensating for damage. For every clinical relapse, there are at least 10 or more lesions on MRI. Therefore, what we see clinically in terms of relapses is the tip of the iceberg. Even standard MRI is relatively insensitive in detecting and monitoring MS disease activity; it misses new lesions that are smaller than 3 ̶ 4 mm in size and does not detect most lesions that occur in the grey matter of the brain (cortex and deep grey matter nuclei, e.g. thalamus and basal ganglia). Therefore, MRI scans also reveal just the tip of the iceberg. This is one of the reasons we also use cerebrospinal fluid (CSF) neurofilament levels as a marker of this microscopic activity.

Disease activity levels

Inactive MS

Many people with MS experience frequent intermittent symptoms or ‘pseudorelapses’ that come on when they are tired, after exercise or have a raised body temperature from a fever, exercise, hot bath or a warm environment. These intermittent symptoms are usually quite stereotyped and last minutes to hours. They are indicative of a previously damaged pathway but do not represent a relapse or disease activity.

Active MS

Most neurologists require evidence of disease activity in the last 12 months, with some of us accepting a 24-month or 36-month window if there is no serial or regular MRI support. However, if you have had no relapses or MRI evidence of new lesions in the last 24 months, then your MS is defined as inactive. (This does not mean your MS is necessarily stable; you could have worsening disability as part of the progressive or smouldering phase of the disease.) Inactive MS needs to be monitored in case it reactivates, in which case you could become eligible for treatment.

Inactive MS - format updated 180625 SS

Schematic showing different levels of MS disease activity.
*Some neurologists accept MRI activity in the last 24 months, 36 months or even longer as a criterion for active MS.

Highly active MS and rapidly evolving severe MS

Active MS has been divided into an additional two categories that have implications for DMT prescribing (depending on where you live).

  • Highly active MS describes MS with unchanged or increased relapse rates, or ongoing severe relapses compared with the previous year, despite treatment with beta-interferon or another so-called first-line therapy. In England, patients in this subgroup are eligible for natalizumab, alemtuzumab, fingolimod and cladribine.
  • Rapidly evolving severe MS (RES) is defined as two disabling relapses and MRI evidence of activity within a 12-month period. In England, patients in this subgroup are eligible for natalizumab, alemtuzumab and cladribine.

Evolution of diagnostic criteria

In the early 2000s, disease activity was defined using clinical criteria only; you needed at least two documented relapses in the last 2 years to be eligible for DMT.1 This meant that a neurologist had to examine you to confirm abnormalities compatible with a relapse. However, many people with MS without rapid access to a neurologist would recover before being assessed, meaning that their relapses often could not be documented. This was very frustrating for someone wanting to start a DMT. If patients had MRI evidence to support recent disease activity, how could we deny them access to a DMT because they were not seen in a timely way to have their relapse documented in the clinical notes?

In 2009, the criteria for diagnosing MS incorporated MRI into the definition to allow us to treat so-called high-risk patients with CIS (clinically isolated syndromes compatible with demyelination). These criteria required patients with CIS to have nine or more T2 lesions on MRI or at least one gadolinium-enhancing lesion. These MRI criteria were based on the McDonald diagnostic criteria at the time.2 These eligibility criteria evolved further in 2014, once alemtuzumab was licensed, to include clinical or MRI activity.


References

  1. 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.
  2. Polman CH, et al. Diagnostic criteria for multiple sclerosis: 2010 revisions to the McDonald criteria. Ann Neurol 2011;69:292–302.

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.