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Dissociative states and MS

30/04/2026 Gavin Giovannoni

This MS-related group of symptoms is probably neglected in routine MS neurological practice and may fall through the cracks.

Key points

Dissociative states in people with MS may arise for different reasons: organic (resulting from damage to the temporal and parietal lobes), psychogenic (following psychological trauma) or iatrogenic (induced by drug treatments).
Such states range from transient feelings of unreality to recurring episodes of depersonalisation and/or derealisation. Other presentations may also occur.
Depersonalisation feels like being detached from one’s own body or thoughts, feeling like an ‘outside observer’ of one’s life.
Derealisation feels like being detached from the external world, which may appear foggy, dreamlike, lifeless or two-dimensional.
In MS, dissociation often has a physical (organic) basis in the brain. This article explores the specific effects of damage to each of the four lobes of the human brain.
Managing dissociative states in MS requires a dual approach: biological (treating the underlying MS disease) and psychological.
To differentiate between physical and psychological causes, doctors must consider the possibility of an MS relapse, an infection or the effects of an MS-related treatment. Checks for balance, hearing and psychological screening are also needed.

Causes and range of dissociative states

People with MS have an elevated risk of experiencing dissociative phenomena that give rise to alterations of consciousness, self-perception and reality testing (being able to assess what is real versus what is imagined). These dissociative states − ranging from transient feelings of unreality to chronic depersonalisation−derealisation disorder (DPDR) and non-epileptic seizures − are often undiagnosed. They may arise for different reasons.

Organic dissociation results from damage(lesions)to the temporal and parietal lobes, which can disrupt neural networks responsible for ‘embodied self-awareness’ (the constant experience of oneself through physical sensations, emotions and bodily signals).
Psychogenic dissociative states can occur in people with MS following the psychological trauma of diagnosis and the high prevalence of comorbid post-traumatic stress disorder (PTSD).
Iatrogenic dissociative states can be induced by drug treatments, particularly high-dose corticosteroids and psychoactive symptomatic treatments.

Dissociation is typically characterised by disruption in the normal integration of consciousness, memory, identity, emotion, perception, body representation, motor control and behaviour. The most frequently reported dissociative symptoms in the MS population fall under the spectrum of depersonalisation−derealisation.

Depersonalisation (the fragmentation of self)

Depersonalisation is characterised by a persistent or recurring feeling of being detached from one’s own body or thoughts. People with MS describe this as feeling like an ‘outside observer’ of their life, like watching oneself in a movie, or like a ‘robot’ with no control over their speech or actions. In MS, depersonalisation is associated with damage to the parietal lobe or the spinal cord – areas that help the brain detect body position and movement (proprioception). People with damage to these areas may feel as though a limb does not belong to them. This is not a delusion, because the person may see their limb move and intellectually know it is theirs. Rather, it is a sensory problem with the ‘body schema’ (the brain’s internal map of your body), that no longer matches your physical body.

Derealisation (the distortion of the world)

Derealisation involves a feeling of being detached from your surroundings. The external world may appear foggy, dreamlike, lifeless, colourless or artificially two-dimensional. Objects may appear distorted in size or shape; sounds may seem muted or distant. Derealisation is often worsened by sensory problems in people with MS (affecting sight, sound, touch, taste, smell or movement). Optic neuritis, a common early sign of MS, causes visual blurring, reduced colour intensity and visual field defects (gaps); see Colour vision and Driving at night. When the brain receives unclear visual input, it struggles to construct a vivid, real-feeling model of the environment, which can lead to a secondary sense of derealisation.

Problems with balance (vestibular dysfunction, leading to vertigo, dizziness and gait instability) are often associated with derealisation; conflicting signals from the eyes and inner ear can cause people with MS to feel disoriented.

Non-epileptic seizures

Non-epileptic seizures, also referred to as dissociative seizures, resemble epileptic seizures − involving convulsive movements, apparent loss of consciousness and stiffening of the body. However, they are not caused by abnormal electrical activity in the brain (usually visible on an electroencephalogram) but are psychological, most likely a mechanism for managing distress or trauma. Care is needed to determine the correct cause in each individual because people with MS are actually at increased risk for epilepsy due to brain lesions. Studies of magnetic resonance imaging (MRI) scans suggest that damage in the right brain hemisphere or the frontal lobes may increase the risk of non-epileptic seizures.

Dissociative amnesia and brain fog

Dissociative amnesia is the inability to recall important personal information, far beyond ordinary forgetting. It is usually related to stress or trauma. In MS, this poses a diagnostic challenge because many patients already experience cognitive dysfunction that affects processing speed and working memory. A study differentiating organic (‘true’) memory loss from dissociative amnesia in MS found that people who reported memory problems often had high levels of dissociation and anxiety but did not show major problems on formal memory testing.¹ This implies that the ‘memory loss’ experienced by many people with MS may be an attention problem due to a mild dissociative state or emotional overload, rather than a result of permanent damage to memory structures in the brain.

Dissociative identity disorder

While rare, cases of dissociative identity disorder (DID) have been reported in people with MS. DID is characterised by the presence of two or more distinct personality states. Affected individuals typically have experienced childhood trauma, which makes them more prone to develop dissociation. A diagnosis of MS acts as a further stressor that challenges their sense of identity. Other symptoms of DID may include physical weakness and sensory loss, which can mimic an MS relapse and lead to misdiagnosis.

Underlying disease processes in MS

In the general psychiatric population, dissociative disorders are usually regarded as psychological in origin. In MS, however, dissociation often has a physical basis in the brain. MS damages myelin (the protective covering of nerve fibres), severs nerve connections and affects grey matter, all of which disrupts communication between different brain regions. When these connections are broken, the brain cannot integrate sensation, emotion and thought into a conscious experience.

Structure of the brain, showing the left and right cerebral hemispheres (left) and the four lobes (frontal, parietal, temporal and occipital; right) in each cerebral hemisphere. Each individual lobe has particular key roles; however, they do not function in isolation but as part of a wider system of neural networks. From Gemini Pro.

Temporal lobe

The temporal lobes play a central role in processing memory and emotions as well as in combining auditory and visual information. MS-related damage in these areas is associated with psychiatric symptoms, including psychosis and dissociation. The temporal lobe also houses the limbic system, comprising the amygdala (which processes emotion) and the hippocampus (which supports memory). If there is damage to the white matter pathways between the limbic system and the frontal cortex (a region known as the uncinate fasciculus) or to sensory regions, the emotional content of experiences can be lost. For example, when a person with MS sees a familiar object or person, the visual cortex sends information to the limbic system, thus activating the appropriate emotional response (e.g. warmth, recognition). If MS disrupts this connection, the person may recognise the object but feel no emotional familiarity. This mismatch, i.e. recognition without feeling, is central to derealisation and to the jamais vu phenomenon (the strange feeling that something familiar is suddenly unfamiliar or new) that is often reported in temporal lobe disorders.

A sagittal (longitudinal) view of the human brain showing the interconnected network of the limbic system, a key regulator of emotion, memory and spatial navigation. From Gemini Pro 3.0.

Temporal lobe epilepsy

MS lesions in the temporal lobe can sometimes trigger epileptic activity. Even in the absence of full-blown convulsions, abnormal electrical activity there can cause ‘dreamy states,’ profound déjà vu or feelings of unreality similar to the warning phase (aura) of temporal lobe epilepsy. Symptoms of depersonalisation disorder overlap with those experienced in temporal lobe epilepsy, particularly unusual body experiences and memory distortions.

Parietal lobe

The parietal lobe combines sensory information from different sources to form a single perception (cognition) and helps the brain build a map of the body and the world around us. The brain constantly updates this map, or ‘body schema’, using signals from the spinal cord. MS lesions in the parietal lobe or spinal cord can interrupt this information and deprive the brain of body map data.

When the brain ceases to receive reliable input from a limb, because of MS-related damage, it may ‘dissociate’ that body part from its self-image. This can manifest as:

asomatognosia (the inability to recognise a part of one’s own body)
somatoparaphrenia (the delusion that a limb belongs to someone else)
depersonalisation (see above).

Temporoparietal junction

The temporoparietal junction, where the temporal and parietal lobes meet, is a hub for integrating balance, visual and somatosensory signals to locate the ‘self’ in space. Electrical stimulation of this area can cause out-of-body experiences. In MS, lesions affecting the temporoparietal junction or the balance pathways in the brainstem can trigger dissociative events (for example, a feeling of floating above one’s body or viewing oneself from outside. These episodes are often linked to balance problems, suggesting that the brain is trying to make sense of conflicting signals.

Occipital lobe

The occipital lobe is the main visual processing centre of the brain. Damage in this region or in visual pathways can lead to complex visual distortions that trigger derealisation. ‘Alice in Wonderland Syndrome’ is a perceptual distortion in which objects appear much smaller (micropsia) or much larger (macropsia) than they really are. When damage from MS affects the visual association areas, vision may appear two-dimensional, with the world looking ‘flat’ or like a painted backdrop. This loss of depth perception contributes to the feeling of living in a movie or a simulation.

Clinico-radiological paradox

The clinico-radiological paradox refers to the discrepancy between the number and volume of MS lesions seen on MRI and a patient’s level of physical disability. Some people with MS have extensive brain lesions but relatively normal movement and minimal disability scores. While these patients may appear physically ‘fine’, lesions in high-level areas of the cortex (frontal, parietal and temporal lobes) can disrupt cognitive and emotional networks. Such individuals may be at high risk for subjective dissociation − feeling fragmented or cognitively detached − while objective observers (and disability scales) fail to register any deficit. These hidden symptoms can worsen the patient’s sense of isolation and unreality.

Trauma-related causes

Receiving a diagnosis of MS

While localised MS lesions create the ‘hardware failure’ in the brain that enables dissociation, psychological factors often provide the ‘software trigger’. Receiving a diagnosis of MS may be considered a medical trauma, often involving invasive procedures (lumbar punctures), frightening MRI experiences (claustrophobia) and hospitalisations. These repeated exposures to threat and a feeling of helplessness and vulnerability can induce a state of chronic hyperarousal and subsequent dissociation, consistent with the dissociative subtype of PTSD. Many people with MS meet the diagnostic criteria for PTSD specifically related to their MS diagnosis and outlook (please see, How common is post-traumatic stress disorder in people with MS?). Developing an ongoing, incurable and potentially disabling neurological condition can shatter one’s expectations for the future. By detaching from the reality of their diagnosis, people with MS may attempt to shield themselves from overwhelming anxiety and grief. Dissociation serves as an adaptive defence mechanism – a ‘mental flight’ when physical flight is impossible. This sounds dramatic, but it may explain why some people with MS develop dissociative disorders.

Childhood trauma

Research has demonstrated a potential relationship between childhood trauma, dissociation and the development of MS. Severe stress, neglect or abuse in childhood permanently dysregulates the hypothalamic−pituitary−adrenal axis (a system that is crucial for the body’s stress management). It consists of three organs that each release hormones to eventually raise cortisol levels in the body. This results in a chronic proinflammatory state and altered cortisol responses, which may increase biological susceptibility to developing MS later in life. Large-scale cohort studies indicate that women who experienced childhood abuse are significantly more likely to develop MS in the future.²

Treatment-related causes

The management of MS involves disease-modifying therapies (DMTs) and corticosteroids for acute relapse management. Many of these agents have significant neuropsychiatric side effects that can mimic, induce or exacerbate dissociative states.

Corticosteroids. High doses of the intravenous corticosteroid methylprednisolone (e.g. 1000 mg daily for 3−5 days) are the standard of care for speeding up the recovery from acute MS relapses. It is known to cause acute psychiatric adverse effects in many patients (dependent on the corticosteroid dose).Symptoms often begin with insomnia and euphoria but can progress to severe mood lability, anxiety and frank dissociation and delirium. Patients may experience a ‘steroid high’ followed by a crash into depression; some develop acute psychosis with hallucinations and confusion. Corticosteroids enhance dopamine activity. They may cause acute, reversible reductions in hippocampal volume. Their effect on the brain presumably decouples the patient from reality, leading to a temporary dissociative or psychotic state that resolves upon tapering the steroid dosage.

Interferon-beta has a longstanding association with depression and anxiety. Interferons are cytokines that induce a proinflammatory response similar to ‘sickness behaviour,’ which includes social withdrawal, fatigue and anhedonia (inability to feel pleasure in activities that are usually considered to be pleasurable). They may also decrease serotonin levels in the brain.While direct dissociation is less common, the severe anxiety and depression induced by interferons presumably lower the threshold for the onset of stress-induced depersonalisation.

Natalizumab is a highly effective monoclonal antibody, but it carries specific risks. The ‘wearing off’ effect in the week preceding the next infusion can be characterised by intensifying fatigue, cognitive fog and mood instability, which may manifest as a feeling of detachment or unreality.The most severe risk associated with natalizumab is progressive multifocal leukoencephalopathy; this causes extensive, rapid demyelination that can lead to confusion, personality changes and cognitive decline. These symptoms can be misinterpreted as psychiatric dissociation or dementia in the early stages.

Fingolimod, an S1P modulator, has been associated with posterior reversible encephalopathy syndrome. This condition involves swelling in the posterior brain regions (parietal/occipital lobes) caused by leakage of fluid from capillaries. It presents with acute confusion, visual changes, headaches and altered consciousness − a constellation of symptoms that could mimic derealisation and dissociation.

Symptomatic treatments. Abrupt withdrawal of baclofen and tizanidine, which are used for spasticity, can cause severe delirium, hallucinations and dissociation. Similarly, gabapentin and pregabalin, which are often used in people with MS to manage neuropathic pain, can cause sedation and cognitive clouding (‘zombie-like’ feeling) that contribute to depersonalisation.

Diagnosis

When someone with MS develops dissociative symptoms, doctors must first rule out physical (organic) causes before assuming the problem is purely psychological. A diagnostic algorithm should do the following.

1. Rule out an MS relapse
Any new onset of psychiatric or dissociative symptoms warrants an MRI scan with gadolinium. New lesions in the temporal, parietal or frontal lobes can directly cause these symptoms.

2. Rule out infection
Urinary tract infections are extremely common in MS and are the leading cause of acute confusional states (delirium) that can mimic dissociation. A urinalysis and a workup for other infections are mandatory.

3. Review medication
Assess for recent steroid use, cumulative damage from anticholinergic drugs (e.g. for bladder dysfunction) or withdrawal from muscle relaxants (baclofen and tizanidine).

4. Check balance and hearing
‘Neuro-otological examination’ is a specialised assessment for dizziness, vertigo, hearing loss and balance disorders. Checking for nystagmus (uncontrollable eye movements) helps to diagnose balance disorders. Treating vertigo may resolve the derealisation.

5. Carry out psychological screening
Your health professional can use the Dissociative Experiences Scale (DES-II) or the Dissociative Disorders Interview Schedule to quantify symptom severity. People with MS generally score in the normal range on DES-II unless they have comorbid DID or PTSD.

Differentiating organic from psychiatric dissociation is difficult. It may require referral to a neuropsychiatrist. MS-related brain fog or cognitive impairment with an organic basis is characterised by slowed processing speed, word-finding difficulties and fatigue. Patients try to engage but fail. In comparison, psychiatric dissociation is characterised by a subjective sense of detachment (‘I am not here’). Patients may have preserved processing speed but feel emotionally disconnected. As noted above, MS cog-fog often contains a dissociative component driven by anxiety. Treating the anxiety usually clears the ‘cog-fog’ more effectively than cognitive rehabilitation alone.

Management

Managing dissociative states in MS requires a dual approach: biological (i.e. treating the underlying MS disease) and psychological.

Drug treatments

The primary prevention of organic dissociation involves preventing new lesion formation. High-efficacy DMTs are the best way to preserve brain volume and connectivity. Psychotropics such as selective serotonin reuptake inhibitors (e.g. fluoxetine, sertraline) can help manage the anxiety and depression that underlie DPDR. They may also help with MS-related fatigue. Antipsychotics (e.g. quetiapine, olanzapine) may be rarely indicated for managing steroid-induced psychosis or organic paranoia related to temporal lobe lesions. Lamotrigine and other anticonvulsants (e.g. carbamazepine and oxcarbazepine) can be used to treat both seizures and depersonalisation; they are particularly beneficial in patients with temporal lobe pathology.

Psychological interventions

Cognitive behavioural therapy is the gold standard for treating DPDR. It helps patients reframe the terrifying sensation of ‘going crazy’ or ‘disappearing’ as a harmless (albeit distressing) symptom of anxiety or the disease. This reduces the catastrophic thinking that perpetuates the dissociation.

Eye movement desensitisation and reprocessing (EMDR) can be effective for MS-related PTSD (medical trauma) or childhood trauma. However, standard EMDR can be overwhelming for patients with dissociation. Modified (e.g. ‘titrated’) EMDR protocols can prevent flooding the patient with traumatic memories before they have stabilisation skills. EMDR is available via some UK NHS psychiatric services.

Grounding and mindfulness techniques (e.g. holding an ice cube, describing the environment) anchor the patient in the present moment and help them to manage acute episodes of derealisation. Mindfulness-based stress reduction has shown efficacy in improving the quality of life and reducing depressive symptoms in people with MS.

Vestibular rehabilitation therapy (VRT) is a specialised, exercise-based physical therapy designed to reduce vertigo, dizziness and imbalance. It should be offered to people with MS where derealisation is driven by vertigo. VRT helps the brain compensate for inner-ear deficits through personalised exercises that focus on gaze stabilisation, balance training and habituation. Physical therapy to improve balance and gaze stability can directly reduce the feeling of unreality.

Conclusions

To self-manage dissociative states effectively, individuals with MS can proactively apply several key principles highlighted above. During acute episodes of derealisation or dissociation, employing practical grounding and mindfulness techniques – such as holding an ice cube or actively describing the immediate environment – can serve as vital tools to anchor oneself in the present moment. Furthermore, individuals can apply cognitive behavioural principles by ‘reframing’ their experiences. Recognising that terrifying feelings of ‘disappearing’ or ‘going crazy’ are often harmless symptoms of anxiety or the disease itself can help reduce the catastrophic thinking that perpetuates dissociation.

Effective self-management also involves staying vigilant about physical triggers (e.g. monitoring for signs of urinary tract infections or medication side effects) and pursuing targeted physical interventions, such as vestibular rehabilitation exercises, if feelings of unreality are driven by dizziness and balance issues. By combining these practical coping strategies with a clear understanding of the biological and psychological origins of their symptoms, individuals with MS can regain a sense of control and significantly reduce the impact of dissociative states on their daily lives.

References

Bruce J, et al. Self-reported memory problems in multiple sclerosis: influence of psychiatric status and normative dissociative experiences. Arch Clin Neuropsychol 2010;25:39–48.
Rehan ST, et al. Association of adverse childhood experiences with adulthood multiple sclerosis: A systematic review of observational studies. Brain Behav 2023;13:e3024.

Cognition and mental health

MS and bipolar disorder: understanding the link

22/02/2026 Gavin Giovannoni

The association between multiple sclerosis (MS) and depression is well-established. Are people with MS also at risk of developing bipolar disorder?

Key points

Bipolar disorder is significantly more common in people with MS than in the general population.
This is not merely a byproduct of the stress of chronic illness; it also has to do with changes in the brain, caused by MS, that affect mood as well as physical function.
Mood symptoms may be caused by MS lesions, disease-related inflammation, or medications (steroids in particular).
Differentiating ‘primary’ (organic) mania from ‘secondary’ (MS-related) mania is crucial to ensure the correct diagnosis and treatment.
Key features that distinguish MS-related mania from organic mania include:
- Late onset, often after age 35–40 years, or onset associated with MS disease progression
- Weak or absent family history of bipolar disorder
- Lack of response to standard treatments for bipolar disorder
Treatment for people with MS who experience bipolar disorder is available and effective. With coordinated care, they can successfully manage their symptoms.

MS affects movement, sensation and other bodily functions, but it also impacts the brain systems involved in thinking, emotions and behaviour. Here, I discuss the relationship between MS and bipolar disorder, a mental health condition that causes episodes of unusually high mood (mania or hypomania) and low mood (depression). Bipolar disorder has received less attention than depression in people with MS, despite its substantial effect on quality of life, treatment adherence and prognosis.

For some people with MS, symptoms of bipolar disorder appear for the first time as their disease develops. In others, existing mood symptoms may be made worse by inflammation, brain lesions or medications used to treat MS. This article explains why bipolar symptoms occur in MS, how they may present, how they can be recognised early and how they can be effectively managed.

How common is bipolar disorder in MS?

Research consistently shows that bipolar disorder is more common in people with MS than in the general population. In the general population, bipolar disorder affects roughly 1–2.4% of people. In MS, studies report current and lifetime prevalence rates of about 3% and 8%, respectively. This means people with MS have approximately double or even treble the usual risk.

Importantly, this increased risk is not simply because people with MS interact with healthcare systems more frequently than the general population, which increases the likelihood of mental health conditions being detected (we call this the ‘admission rate’ bias). Nor is it merely a byproduct of the stress of chronic illness (which might explain depression). Large studies that compare people with MS to similar individuals without MS still show a higher rate of bipolar disorder in the MS group. This suggests the association is real and probably related to changes in the brain caused by MS.

What factors cause MS-related mania?

Researchers believe there are three main mechanisms that drive cognitive and behavioural changes in MS; they can occur alone or together.

MS lesions that affect mood-regulating circuits
inflammation and immune changes
treatment-related factors.

Understanding these mechanisms allows clinicians to distinguish MS-related mania from ‘primary’ (organic) psychiatric illness and to deliver appropriate management.

MS lesions that affect mood-regulating circuits

This mechanism disrupts the ‘hardware’ that controls mood. MS causes inflammation and lesions (scarring) in the brain. Areas that are especially important for controlling emotions and behaviour include:

the right orbitofrontal cortex (OFC) – involved in regulating social behaviour, judgement and impulse control
the temporal lobes – important for memory and emotional processing
the white-matter pathways that connect these regions with deeper emotional and reward centres such as the amygdala and thalamus.

If MS lesions interfere with these circuits, the balance between emotional impulses and rational control can be disrupted. This may lead to behaviours that are characteristic of mania, including disinhibition (reduced ‘internal brakes’), uncontrolled emotions, euphoria (unusually elevated mood) and impulsivity. This pattern is sometimes called secondary mania (mania caused directly by a brain condition such as MS).

There is evidence that right-sided frontal or temporal injury leads to mania-like behaviours in other conditions (e.g. stroke, traumatic brain injury, tumours).

Understanding right- and left-sided brain functions

Consistent with literature on secondary mania from stroke or tumours, MS-associated mania is most often associated with right-sided brain lesions. The right hemisphere is dominant for processing negative emotions and withdrawal behaviours, while the left hemisphere processes positive emotions and approach behaviours. A lesion in the right hemisphere may impair the processing of negative emotions, leading to an unopposed ‘positive’ or euphoric affect (‘highs’) driven by the intact left hemisphere.

Inflammation and immune changes

During MS relapses or periods of immune activation, inflammatory molecules disrupt how brain cells communicate (think of it as a disruption to the brain’s ‘software’). One important system involved is the kynurenine pathway, which controls how the body uses tryptophan (an amino acid essential for the creation of compounds such as serotonin and melatonin).

Inflammation increases the activity of an enzyme called indoleamine 2,3-dioxygenase. This shifts tryptophan away from serotonin production towards production of quinolinic acid, a substance that overly stimulates nerve cells through NMDA receptors (N-methyl-D-aspartate receptors). This ‘excitatory overload’ can lead to symptoms like those seen in primary mania, such as agitation, mood instability, sleep disturbance and racing thoughts.

The kynurenine pathway in inflammation-induced pathology of the central nervous system. Activation of IDO in peripheral immune cells (e.g. macrophages) or in the brain leads to production of kynurenine. This is converted to kynurenic acid in astrocytes and to quinolinic acid in microglia. Kynurenic acid can block the release of glutamate and dopamine, contributing to cognitive dysfunction. Quinolinic acid, by contrast, can increase glutamate release, which contributes to neurodegeneration. Figure modified from Haroon et al.

3-HAO, 3-hydroxy-anthranilic acid oxygenase; IDO, indoleamine-2,3-dioxygenase; KAT II, kynurenine aminotransferase II; KMO, kynurenine-3-monooxygenase; NMDA, N-methyl-D-aspartate.

This pathway is one of the clearest biochemical links between MS inflammation and bipolar-type symptoms.

Treatment-related factors

Some medications used in MS influence mood and may contribute to manic symptoms.

Steroids

High-dose intravenous methylprednisolone, typically 1000 mg/day for 3–5 days, is the most common cause of drug-induced mania in MS. Up to 12% of people treated with corticosteroids experience symptoms of mania, and nearly 65% of those with psychiatric side effects present with a mix of mania and psychosis.

A history of prior steroid-induced mood changes, female sex, older age and higher steroid doses increase risk. Steroid-induced mania typically appears 3 − 4 days after starting treatment (median 11 days in some studies) and may involve:

severe insomnia
pressured speech
irritability or agitation
grandiosity
psychosis in severe cases.

Symptoms usually resolve when the dose is tapered (within roughly 3 weeks), but they can persist longer in individuals with underlying bipolar disorder. I therefore try to avoid treating MS relapses with steroids. However, this is not always possible.

Other agents that may cause mania

Amantadine, used for fatigue, can trigger mania in susceptible individuals.
Modafinil and methylphenidate, also used for fatigue, have been linked to sudden switching between manic and depressive symptoms.
Cannabinoids may destabilise mood or cognition.
Interferons more commonly cause depression than mania, but irritability, aggression and mania have been reported. The risk of new psychiatric symptoms is low, and patients with stable mood disorders can usually tolerate interferons with careful monitoring.
Fingolimod is linked to mood changes; severe rebound inflammatory activity after discontinuation could theoretically trigger mania.

Diagnosis of MS-related mania

Distinguishing between primary bipolar disorder, secondary MS-related mania and steroid-induced mania can be difficult. Accurate diagnosis is essential for effective management, as treatment for one form may exacerbate another. Below are some of the ‘atypical’ features of MS-related mania that deviate from classic bipolar disorder.

Late onset of symptoms

Primary bipolar disorder usually begins in adolescence or early adulthood. In contrast, secondary mania associated with MS can appear later, often after age 35–40 or during disease progression. A manic or psychotic episode may sometimes be the first manifestation of MS, occurring months or years before a neurological diagnosis.

Mania coinciding with an MS relapse

A sudden change in mood, sleep or behaviour that coincides with new neurological symptoms (e.g. numbness, vision changes, weakness) may indicate that inflammation or new lesions are affecting mood circuits. There may also be evidence of disease progression from MRI scans.

Weak family history

Primary bipolar disorder often runs in families; the absence of a family history suggests a secondary cause (i.e. MS-related pathology).

Disproportionate cognitive decline

Impulse control and executive functions, such as planning, organising and paying attention, are impaired – possibly reflecting frontal lobe involvement.

Mania as an MS relapse

A minority of patients present with isolated psychiatric symptoms (mania, psychosis, delirium) as the only manifestation of a relapse. MRI often reveals new frontal or temporal lesions, even when motor or sensory signs are absent.

Lack of response to standard treatments

Failure to respond to standard mood stabilisers, or paradoxical worsening with antidepressants, warrants a re-evaluation for organic causes.

Genetic considerations

Is the risk solely environmental (inflammation/lesions), or do MS and bipolar disorder share a genetic root? The Major Histocompatibility Complex (MHC) on chromosome 6 is the primary genetic risk factor for MS (specifically the HLA-DRB1*15:01 allele). Interestingly, Genome-Wide Association Studies have suggested that the MHC region is also involved in bipolar disorder and schizophrenia.
There is some evidence that, in certain familial clusters, a gene located near the HLA locus (possibly involving the HLA-DR2 antigen) could confer susceptibility to both autoimmune demyelination and bipolar disorder. Other studies have indicated the opposite: that specific MS risk alleles in the HLA region are associated with decreased schizophrenia risk. The results are therefore mixed; some haplotypes may increase the risk of severe mental illness, while others appear protective against it. It is likely that environmental factors (inflammation, lesion burden) play a greater role than genetics in most cases.

There is some evidence that, in certain familial clusters, a gene located near the HLA locus (possibly involving the HLA-DR2 antigen) could confer susceptibility to both autoimmune demyelination and bipolar disorder. Other studies have indicated the opposite: that specific MS risk alleles in the HLA region are associated with decreased schizophrenia risk. The results are therefore mixed; some haplotypes may increase the risk of severe mental illness, while others appear protective against it. It is likely that environmental factors (inflammation, lesion burden) play a greater role than genetics in most cases.

Management

Treatment of MS-related mania depends on the cause.

Steroid-induced mania

If steroids triggered the symptoms, the steroids should be tapered or discontinued if safe.
Short-term antipsychotic medications, such as quetiapine, olanzapine or risperidone, can help stabilise mania symptoms. Quetiapine has the added benefit of aiding sleep, which is commonly disrupted in people with MS. Use of low-dose benzodiazepines during the steroid course can help to reduce the insomnia that often precedes or triggers mania.

Mania caused by MS inflammation

If mania is part of an organic, MS relapse, treating the inflammation is important. High-dose steroids may then be necessary, even though they can in other circumstances cause mania.
This crucial distinction underscores the need for close coordination between neurology and psychiatry.

Mood swings

Lithium is still the gold standard mood stabiliser and is generally safe for psychiatric management in MS. The anticonvulsants valproate, lamotrigine and carbamazepine are useful alternatives in people with MS; they treat both the mania and other MS-related comorbidities, such as neuropathic pain and trigeminal neuralgia.

Managing future steroid treatment

People with a known history of bipolar disorder or steroid-induced instability may benefit from:

starting a low-dose mood stabiliser (e.g. lithium) before the steroid course
adding an antipsychotic temporarily (e.g. olanzapine)
using sleep support (e.g. low-dose benzodiazepines) to prevent insomnia (a common trigger for mania).

Long-term management

Any MS patient presenting with new-onset mania requires a comprehensive workup, including MRI (to check for new frontal/temporal lesions) and a review of recent medication changes, rather than a direct referral to psychiatry. Ongoing coordination between neurologists and psychiatrists is, however, essential. A neurologist might misinterpret mania as ‘euphoria’ related to frontal lobe damage (pseudobulbar affect), while a psychiatrist might miss the neurological signs of an MS relapse that is driving the mood change. Screening tools (e.g. Mood Disorder Questionnaire) may help identify individuals at higher risk but should not replace clinical judgement.

Recognising the distinguishing features of MS-related mania allows clinicians to intervene promptly, reduce misdiagnosis and optimise care. With integrated neurological and psychiatric management, most people with MS experiencing bipolar symptoms can achieve stable, effective control of their mood and maintain a high quality of life.

Reference

Haroon, E et al. Psychoneuroimmunology meets neuropsychopharmacology: translational implications of the impact of inflammation on behavior. Neuropsychopharmacology Rev; 2011:1–26.

Cognition and mental health

Mental ill-health in MS: prevalence and causes

08/02/2026 Gavin Giovannoni

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

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

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.

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

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.
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.
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.
Ruiz-Algueró, M et al. Health care use before multiple sclerosis symptom onset. JAMA Netw Open 2025;8:e2524635.

DMTsSafety, Monitoring MS

How can I reduce my chances of adverse events on specific DMTs?

10/01/2023 Gavin Giovannoni

The complications associated with immunosuppression vary from DMT to DMT. You will find it helpful to understand what investigations to expect before and during treatment and how these may vary depending on the DMT(s) you are considering.

Key points

Numerous tests are carried out at the start of your treatment (baseline); these include blood, urine and tests for a range of infections.
Some patients will need tests or procedures specific to their DMT that are inappropriate for everyone with MS – for example, vaccination against some infections; pregnancy and/or genetic counselling; prevention of cardiovascular complications; and management of infusion reactions.
Ongoing monitoring is required for many but not all of the above factors.
All licensed MS DMTs have had a thorough risk ̶ benefit assessment, and their benefits are considered to outweigh the potential risks.

Standard tests … and why we do them

If you have read the article on immunosuppression, you will know that immunosuppressive DMTs may reduce white blood cell counts and antibody responses to vaccines and increase the likelihood of some infections and cancers. However, we can reduce the risk of many complications associated with long-term immunosuppression (we use the shorthand ‘de-risk’). This article explains what needs to be done at the start of DMT administration (baseline) and during subsequent monitoring. The specifics, however, vary from DMT to DMT.

Baseline tests

Tests at baseline (before starting DMT administration) include full blood count, platelets, liver, kidney and thyroid function tests, and a urine screen. Recording baseline immunoglobulin levels is particularly important if you are about to start an anti-CD20 therapy (ocrelizumab, ofatumumab or rituximab) so that we have a reference level for future comparisons.

Serum protein electrophoresis is done for patients considering starting interferon-beta; having a so-called monoclonal gammopathy (an abnormal immunoglobulin) is a contraindication to starting an interferon-beta formulation in people with MS. The drug has been associated with a form of capillary leak syndrome, leading in rare cases to death from an adult respiratory distress syndrome.

The table below summarises the routine investigations required at baseline; subsequent sections provide further detail.

Tests routinely carried out at the start of treatment (baseline).
AHSCT, autologous haematopoietic stem cell transplantation; CMV, cytomegalovirus; CSF, cerebrospinal fluid; DMT, disease-modifying therapy; EBV, Epstein ̶ Barr virus; ECG, electrocardiogram; FBC, full blood count; HIV, human immunodeficiency virus; HPV, human papillomavirus; JCV, JC virus; LFTs, liver function tests; MMR, measles/mumps/rubella; MRI, magnetic resonance imaging; PCP, pneumocystis pneumonia; PML, progressive multifocal leukoencephalopathy; TB ELISpot, tuberculosis enzyme-linked immune absorbent spot; TFTs, thyroid function tests; U&E, urea and electrolytes; VZV, varicella zoster virus.

Infection screening

At our centre, we screen for a relatively large number of infectious diseases so that we can treat any subclinical infection before starting a DMT. This is particularly relevant for HIV-1 and 2, hepatitis B and C, syphilis and tuberculosis (TB).

Screening for the JC virus (JCV), which causes progressive multifocal leukoencephalopathy (PML), is only really needed for people with MS considering starting natalizumab. Even if you are JCV positive, you can be treated with natalizumab for 6 ̶ 12 months and sometimes longer if you are prepared to take on the risk of PML and the extra monitoring required to detect PML early.

We only check measles/mumps/rubella (MMR) status in patients without documentation of full vaccination as children. We check varicella zoster virus (VZV) status before starting immunosuppression and vaccinate seronegative individuals. Currently, we are still using the live VZV vaccine. This will change, and we will likely be offering all people with MS in the UK the component inactive VZV vaccine (Shingrix, that has had its licence extended) to reduce the chances of zoster reactivation in all adults starting immunosuppression. This new Shingrix indication is similar to the pneumococcal vaccine (Pneumovax). Our centre is only recommending Pneumovax in patients about to start an anti-CD20. However, when Shingrix becomes available on the NHS, it will make sense to bundle this with the Pneumovax and make it routine for all people with MS before starting immunosuppressive therapy. Please check with your healthcare team which products are available locally.

Routine tests and monitoring for Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are only needed for subjects undergoing autologous haematopoietic stem cell transplantation (AHSCT), which causes profound short-term immunosuppression that can result in CMV and EBV reactivation. CMV reactivation also occurs with alemtuzumab, so this needs to be considered when investigating patients who develop complications after receiving alemtuzumab (please see Opportunistic infection in MS).

For patients starting long-term immunosuppression, it is advisable to screen for active human papillomavirus (HPV) infection (by cervical smear or vaginal swab) and for warts or active infection with molluscum contagiosum. Warts are caused by HPV skin infection; molluscum contagiosum is due to a relatively benign pox virus that typically affects young children but occasionally affects adults. Warts and molluscum contagiosum can spread rapidly in patients receiving alemtuzumab, so I recommend treating these skin infections before starting immunosuppression for MS.

Vaccinations

We encourage all patients to be vaccinated against COVID-19 and seasonal flu; outside the flu vaccine season, we remind people to get vaccinated during the next vaccine season.

Hepatitis B, meningococcal and Haemophilus influenzae vaccines are considered only for people with MS who are at high risk of infection and have not had these vaccines as part of a national vaccine programme, i.e. healthcare and laboratory workers for hepatitis B, school and university students and military recruits for meningococcal vaccine and paediatric patients for Haemophilus influenzae.

The issue around having the HPV vaccine as an adult is more complex. For example, in the UK, the NHS does not cover the cost of the vaccine for people over 25. In addition, most people have only had the quadrivalent vaccine (Gardasil-4), which covers about two-thirds of the strains that cause cancer. Some people with MS may want to upgrade their immunity with the polyvalent vaccine (Gardasil-9) that covers over 95% of the cancer-causing strains of HPV. For more information on HPV vaccination, please see Case study: cervical intraepithelial neoplasia (CIN) and ocrelizumab.

MMR is a live vaccine given in childhood (see MMR vaccine: to vaccinate or not? ). Owing to vaccine hesitancy, however, many people do not receive this vaccine as children. Therefore, if an adult with MS is about to start immunosuppressive therapy and has not been vaccinated against MMR, we advise them to do so. This is particularly important for people about to start natalizumab because these viruses are neurotropic and can infect the brain. Natalizumab blocks immune response within the brain; hence, exposure to a neurotropic virus could cause serious infection, similar to what we see with the JC virus – which causes PML.

Travel vaccines for people who travel as part of their work or plan to travel shortly need to be considered. In particular, the yellow fever vaccine is a live vaccine (made from a weakened yellow fever virus strain) and it should ideally be given before someone starts on immunosuppressive therapy.

Cardiovascular screening

You may need an ECG (electrocardiogram), to rule out an abnormal heart rhythm or electrical conduction abnormality and to check your left ventricular function (ejection fraction). These abnormalities are a relative contraindication to using the S1P modulators (fingolimod, siponimod, ozanimod, ponesimod), which may affect the conduction of the heart. In patients treated with mitoxantrone, the left ventricular ejection fraction (LVEF) must be done at baseline and regularly monitored because mitoxantrone is toxic to the heart. If the LVEF drops significantly, further dosing of mitoxantrone is contraindicated.

Pregnancy, family planning and genetic testing

Many chemotherapy agents used in AHSCT for ablating (extracting) the bone marrow are toxic to the ovaries and testes. Therefore, patients receive counselling before treatment and can have eggs (oocytes) or sperm banked for future use. Egg banking is also a consideration for women with MS being treated with mitoxantrone. Men receiving mitoxantrone do not need to bank sperm, however, because mitoxantrone does not cross the testes ̶ blood barrier.

Genetic testing is only required at present if you wish to receive siponimod. Siponimod is metabolised by a specific liver enzyme (biological catalyst) with two functional variants – slow metabolising and fast metabolising. People who carry two slow-metabolising variants of the enzyme cannot receive siponimod. Intermediate metabolisers (those that carry one slow- and one fast-metabolising version of the enzyme) receive low-dose siponimod, while those with two fast-metabolising enzymes receive high-dose siponimod.

Protecting against progressive multifocal leukoencephalopathy

I have included magnetic resonance imaging (MRI) and lumbar puncture with cerebrospinal fluid (CSF) testing for JCV among the baseline tests. This is specific to patients at high risk of developing PML who are switching from natalizumab to a depleting immune reconstitution therapy such as alemtuzumab or another therapy that depletes their immune system (e.g. cladribine or an anti-CD20 therapy). These tests are done to exclude asymptomatic PML, which will otherwise be carried over to the new treatment. The effects of these immunosuppressive therapies on your immune system cannot be rapidly reversed, which is a problem because immune reconstitution is needed to clear PML. Most MS centres do not mandate CSF testing in this situation because it does not always reveal the presence of PML. However, I still request this test on my patients to gain as much information as possible on which to base potentially life-changing decisions.

Prophylactic antivirals and antibiotics

Patients in our centre undergoing AHSCT or receiving alemtuzumab will be given antivirals and antibiotics to reduce the likelihood of certain infections. This is particularly relevant for listeriosis, which is a rare infection transmitted via food. We also encourage all our patients to start and maintain a specific diet to reduce the chances of listeriosis. The risk of listeriosis is only present for a short period when both the adaptive and innate immune systems are compromised, that is, for 4 weeks after receiving alemtuzumab, so we recommend antibiotic prophylaxis for 4 weeks. Our online resource provides more information about listeriosis. If you live in the UK, you can order our free listeriosis prevention kit, which contains a booklet (also downloadable) and various practical items to help keep you safe.

Strategies for limiting the risks from immune reconstitution therapies and infusion DMTs.

Infusion reactions

When you use agents that cause cell lysis (breakdown), such as alemtuzumab and intravenous anti-CD20 therapies, the contents of cells cause infusion reactions. To prevent such reactions or reduce their severity, we pretreat patients with corticosteroids, antihistamines and antipyretics. The exact protocols for each DMT differ; for example, ocrelizumab infusion reactions are generally only a problem with the first and second doses; therefore, many centres don’t give steroids with the third and subsequent infusions. The latter was particularly important during the COVID-19 pandemic when it was shown that the recent administration of high-dose steroids increased your chances of severe COVID-19.

Ongoing monitoring

Once someone has been treated with a DMT, ongoing monitoring is required. What gets monitored and how frequently depends on the individual DMT. For a list of DMTs associated with important adverse events, please see our summary Table in ‘De-risking’ guide: monitoring requirements of individual DMTs.

The regulatory authorities usually put in place specific monitoring requirements, which can differ worldwide. It is important that you also enrol in your national cancer screening programmes. Being on chronic immunosuppression increases your chances of developing secondary malignancies, so please remain vigilant.

Tests carried out regularly as part of ongoing monitoring.
FBC, full blood count; LFTs, liver function tests; MRI, magnetic resonance imaging; PML, progressive multifocal leukoencephalopathy; TFTs, thyroid function tests; U&E, urea and electrolytes.

I want to reassure you that all licensed MS DMTs have undergone a thorough risk ̶ benefit assessment by the drug regulators, and the benefits of these treatments are considered to outweigh the potential risks. On balance, the level of immunosuppression associated with MS DMTs is typically mild to moderate; hence, the complications are relatively uncommon. MS is a serious disease and, if left to run its natural course, would result in most patients becoming disabled. To learn more about the natural course of MS, please read the section entitled What are the consequences of not treating MS?