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Cognition and mental health

MS and bipolar disorder: understanding the link

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.

Kynurenic pathway - MS-Selfie gg1

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.

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.

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

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

Key points

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

Background and introduction

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

Anxiety and depression in people with MS

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

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

MH anxiety

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

MH depression

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

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

Psychiatric symptoms versus psychiatric disorders

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

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

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

Other emotional and behavioural changes

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

Cognitive changes

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

Apathy

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

Inappropriate laughing and crying

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

Rare affective changes

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

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

The biological basis of mental illness in MS

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

Anxiety as a manifestation of MS pathology

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

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

Structural and functional brain changes

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

MH limbic system

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

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

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

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

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

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

Neurological versus psychological causes

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

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

Lesion location and emotional symptoms

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

Other contributing factors

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

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

‘Prodromal’ MS and psychiatric symptoms

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

References

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

Male sexual dysfunction in multiple sclerosis

Sexual dysfunction is a common symptom in men with MS, with a prevalence that surpasses that seen in the general population and other chronic disease states. Despite sexual dysfunction being one of the most frequently overlooked and under-addressed MS symptoms, it seldom gets documented and treated in men with MS.

Key points

  • Many men with MS experience some form of sexual difficulty; however, this important aspect of overall well-being is underdiagnosed and undertreated.
  • Such difficulties usually result from a combination of neurological, psychological, social and cognitive factors.
  • Primary dysfunction, caused by damage to the network of signals between the brain, spinal cord and peripheral nerves, can affect the ability to achieve an erection, orgasm or ejaculation; it may also adversely affect libido, sexual desire and genital sensation.
  • Secondary dysfunction results from other MS-related symptoms, including fatigue, spasticity, pain, weakness, bladder dysfunction and bowel dysfunction. Many of the medications used to manage such symptoms may cause or worsen sexual difficulties.
  • Tertiary dysfunction refers to the psychological, emotional and interpersonal challenges of living with MS: depression, anxiety, low self-esteem and impaired body image are among the factors that impact sexual desire and confidence.
  • Management of male sexual dysfunction requires a coordinated, multidisciplinary and personalised approach that involves the MS team, a urologist, physiotherapist, occupational therapist and a psychologist or sex therapist.
  • A wide range of medications, interventions and lifestyle modifications are available that can help couples affected by MS to adapt to the current reality and build a new, satisfying form of intimacy.

An overlooked and distressing symptom

Sexual dysfunction is a common symptom in men with MS, with a prevalence that surpasses that seen in the general population and other chronic disease states. Most studies report that 50–90% of men living with MS will experience some form of sexual difficulty during their disease course. Despite this, sexual dysfunction is one of the most frequently overlooked and under-addressed MS symptoms, and it seldom gets documented and treated in men with MS. This is a clinical paradox, an example of a ‘conspiracy of silence’ where both parties in the clinical encounter overlook a significant issue affecting quality of life.

The main reasons why sexual dysfunction in men with MS is under-recognised, underdiagnosed and undertreated are the taboos of discussing it in the clinic, both from the patient and the HCP perspective. Surveys reveal that the primary barriers to discussing sexual health on the part of HCPs include:

  • time constraints during appointments
  • the major problem that the issue is ‘outside of my role’
  • lack of professional training
  • perceived patient discomfort.

Concurrently, patients are often reluctant to initiate these conversations owing to embarrassment, shame or a deeply held belief that sexuality is somehow incompatible with having a disability. This disconnect between the reality of the patient experience and the focus of the clinical consultation means that a treatable condition that causes significant distress is often left to fester, impacting mental health and relationships. 

Far from being a peripheral concern, sexual function and sexual health are essential components of overall well-being. In men with MS, the onset of sexual dysfunction often precipitates a decline in quality of life, negatively affecting mood, self-esteem and intimate relationships. The distress frequently extends beyond the individual, impacting partners and contributing to marital conflict. The enquiry below illustrates the distress experienced by one man who contacted me for advice; his experience is not uncommon, unfortunately.

Case example

I am a 30-year-old man with relapsing MS. I was diagnosed during my first year of University, aged 18. I presented with transverse myelitis, weakness of both legs and urinary retention. I have been on natalizumab for 12 years and have done very well. However, I have sexual problems with difficulty getting and maintaining an erection. This is affecting my relationship with my wife. Whenever I bring this up with my MS nurse or neurologist, I get dismissed. My GP has given me Viagra, which helps, but its effects are unpredictable, and it often lets me down. I have gotten to the point where I now avoid sexual activity. What advice can you give to help me and others like me?

A complex range of causes

The underlying causes (aetiology) of sexual dysfunction in men with MS are usually complex, variable and dynamic. Some men with MS experience sexual dysfunction as part of a relapse, and they recover with time. However, sexual dysfunction in men with MS usually results from a combination of neurological, psychological, social and cognitive factors. It is therefore vital to approach it from three different perspectives.

  1. Primary dysfunction arises directly from MS lesions within the central nervous system that disrupt the neural pathways governing sexual response.
  2. Secondary dysfunction is the consequence of other MS symptoms, such as fatigue, pain, spasticity, or bladder and bowel issues, which create physical barriers to sexual activity.
  3. Tertiary dysfunction encompasses the psychosocial, emotional and cultural issues that stem from living with a chronic illness, including depression, altered body image and changes in relationships.

Clinical presentations of male sexual dysfunction

Erectile dysfunction

This is the most commonly and widely studied sexual problem in men with MS. Defined as the consistent inability to achieve or maintain a penile erection sufficient for satisfactory sexual performance, erectile dysfunction (ED) affects a large majority of men with MS who report sexual issues, with some estimates as high as 80%. Across the entire male MS population, approximately 70% experience erectile problems at some point after an MS diagnosis.

Ejaculatory and orgasmic dysfunction

While ED receives the most attention, disorders of ejaculation and orgasm are also common and can be even more distressing for patients owing to a lack of effective treatments. Studies estimate that 35–50% of men with MS experience problems with ejaculation. The Male Sexual Health Questionnaire is used as a screen for dysejaculation. Ejaculatory disorders manifest as:

  • delayed ejaculation or anejaculation: difficulty or complete inability, respectively, to ejaculate despite adequate stimulation
  • premature ejaculation: climaxing too rapidly for sexual satisfaction
  • anorgasmia: the failure to reach orgasm
  • altered orgasmic sensation: a less intense or less pleasurable orgasmic experience.

Disorders of libido or sexual desire

A diminished or absent interest in sex is another crucial component of sexual dysfunction in men with MS. Though less rigorously studied than ED, one report suggests that reduced libido affects approximately 40% of men with MS. Loss of libido is particularly complex, often arising from a combination of damage to the brain’s centres that impact desire, the secondary effect of fatigue, and tertiary psychological factors like depression and anxiety.

Altered genital sensation

The direct neurological impact of MS can manifest as abnormal sensations in the genital area, including numbness (decreased sensation), paraesthesias (e.g. pins and needles) or dysaesthesias (unpleasant or painful sensations, such as burning). These sensory disturbances can fundamentally alter the experience of sexual touch, making it less pleasurable or even painful, thereby directly interfering with arousal and orgasm.

The focus on ED in both MS research and clinical practice is driven in part by the availability of effective pharmacological treatments for this issue; this creates an incomplete picture of the patient’s experience. A management plan that successfully restores erectile function, for example, but fails to address a co-existing inability to ejaculate or a profound lack of sexual desire will ultimately fail to improve the patient’s overall sexual satisfaction and quality of life. A thorough clinical evaluation that assesses all phases of the sexual response cycle is therefore needed.

Functional changes underlying male sexual dysfunction in MS

Primary dysfunction

Normal human sexual function is a complex process that requires the integration of signals between the brain, spinal cord and peripheral nerves. MS damages this network in several ways, causing primary sexual dysfunction.

Cerebral and brainstem lesions

MS lesions in the brain and brainstem affect libido, arousal and orgasm.

  • Libido and arousal: Sexual desire is not merely a hormonal process; it originates in the brain. Lesions in higher cortical areas, particularly the limbic system (the brain’s emotional centre) and the hypothalamus, can diminish libido and impair the capacity to process sensory or psychological cues as erotic. MRI studies have correlated dysfunction in arousal and erection with lesions in specific brain regions, including the frontal lobe, prefrontal cortex, temporal lobe, insula and hippocampus.
  • Orgasm: Orgasm is also vulnerable to cerebral damage, and orgasmic dysfunction is associated with lesions in the pons (part of the brainstem), left temporal lobe and right occipital areas.

Spinal cord lesions

The spinal cord relays neuronal signals from the brain to the genitals and transmits sensory information back up to the brain. Lesions along the spinal tracts are the leading cause of ED and ejaculatory disorders.

  • Erectile function: Penile erection is a neurovascular phenomenon mediated by two distinct pathways, both of which can be compromised by MS. A psychogenic erection, initiated by erotic thoughts or sensory stimuli processed by the brain, depends on intact nerve signals travelling down the spinal cord to the pelvic organs. A reflexogenic erection, triggered by direct physical touch to the genitals, relies on a reflex arc located in the sacral segments of the spinal cord (S2−S4). MS lesions can disrupt these pathways individually or in combination. Consequently, depending on the specific location of the spinal damage, a man might be able to achieve an erection from direct touch but not from psychological arousal, or vice versa.
  • Ejaculation: Ejaculation is a far more complex reflex than erection, involving the coordinated contraction of multiple pelvic muscles and requiring precise, intact communication between the brain and the entire length of the spinal cord. This complexity makes it exceptionally vulnerable to disruption by MS lesions, which helps explain why ejaculatory problems in MS are so common and difficult to treat.

Autonomic and hormonal factors

The autonomic nervous system, which controls involuntary bodily functions, plays a pivotal role in regulating erection and ejaculation. MS can cause autonomic dysfunction, further contributing to these problems. Additionally, emerging evidence suggests that chronic inflammation associated with MS, as well as hypothalamic lesions, can disrupt the hypothalamic-pituitary-gonadal axis. This can lead to altered levels of sex hormones, such as testosterone, and has even been linked to impaired sperm quality.

Secondary dysfunction

Secondary sexual dysfunction arises from other MS-related symptoms and the side effects of medications used to treat these symptoms.

  • Fatigue: Fatigue is one of the most common and disabling MS-associated symptoms that directly undermines sexual function by reducing the physical energy and motivation required for intimacy. When daily life is already exhausting, sexual activity can feel like an insurmountable task.
  • Spasticity, pain and weakness: Spasticity, chronic pain, and muscle weakness can make movement difficult and some sexual positions uncomfortable or impossible. Painful muscle spasms can be triggered by the movements of sexual activity, leading to a conditioned avoidance of sex.
  • Bladder dysfunction and bowel dysfunction: The fear of urinary or faecal incontinence during sexual activity is a potent psychological deterrent. With more than 50% of people with MS experiencing bladder and bowel issues, this is a widespread concern. The anxiety and embarrassment associated with a potential accident can cause individuals and their partners to avoid physical intimacy altogether.
  • Side effects of medication: Many of the medications prescribed to manage the symptoms of MS can, ironically, cause or exacerbate sexual dysfunction. Antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants, are well known for causing decreased libido, ED and anorgasmia. Similarly, medications for spasticity, neuropathic pain and urinary frequency can also interfere with sexual responses.

Tertiary dysfunction

Tertiary dysfunction refers to the complex web of psychological, emotional and interpersonal challenges that arise from living with a chronic, unpredictable illness like MS. These factors can be just as debilitating to a person’s sexual health as any physical symptom.

  • Depression and anxiety: There is a strong, two-way, destructive relationship between MS, depression and sexual dysfunction. Depression affects 30–50% of individuals with MS, and it is an independent predictor of sexual dysfunction. The experience of sexual failure can, in turn, trigger or worsen feelings of depression, despair and isolation, creating a vicious cycle that is difficult to break.
  • Body image and self-esteem: The physical changes brought on by MS – such as a limp, the need for a cane or wheelchair, weight gain from steroids or inactivity, or tremors – can profoundly damage a man’s body image and sense of masculinity. This may lead to feelings of being ‘flawed’, ‘broken’ or ‘unattractive’ that erode self-esteem and sexual confidence.
  • Relationship dynamics and role changes: MS does not just affect the individual; it impacts the entire relationship. Performance anxiety and fear of rejection can lead to avoidance of intimacy. A particularly challenging dynamic arises when an intimate partner must assume significant caregiving responsibilities. This ‘role reversal’ can blur the lines between lover and caregiver, disrupting the emotional foundation of the sexual relationship. The partner’s own sexual satisfaction and quality of life are also frequently diminished, highlighting the two-way nature of sexual dysfunction.

Management of male sexual dysfunction in MS

A single treatment approach towards sexual dysfunction in MS often fails because it is a multifactorial problem that requires a coordinated, multidisciplinary approach. This includes the MS team, a urologist, a physiotherapist, an occupational therapist and a psychologist or sex therapist. Failure to implement an interdisciplinary approach is usually because the MS team is reluctant to initiate the conversation about sexual health or lacks knowledge.

Before any medication or therapy is initiated, it is essential to break the ‘conspiracy of silence’ and create a safe, confidential environment for open communication between the patient, their partner and the healthcare provider. For the MS HCP, this involves routinely and proactively asking about sexual health as part of a holistic review of systems, often alongside questions about bladder and bowel function. For the patient, having ‘permission’ to discuss these sensitive issues can be profoundly therapeutic, reducing shame and ‘validating’ their experience as a legitimate medical concern.

Management of primary sexual dysfunction

Pharmacotherapy for erectile dysfunction

  • Oral phosphodiesterase-5 (PDE-5) inhibitors: Medications such as sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) and avanafil (Spedra) are the first-line pharmacological treatments for ED in men with MS. Vardenafil is generally not available on the NHS, and avanafil is prescribed via specialist sexual dysfunction clinics. Sildenafil (Viagra) has a short half-life and needs to be taken before intercourse is planned. In comparison, tadalafil (Cialis) has a long half-life and is called the weekend Viagra. Some men with MS find that combining the two drugs is synergistic. Please note that they come in different doses, so you will need to titrate the dose to find the one that works best for you. These drugs do not create an erection spontaneously; they work by enhancing the natural erectile process, increasing penile blood flow in response to sexual arousal. Clinical trials have demonstrated their efficacy, but they may be effective in only about 50% of men with MS (a lower rate than in the general population), likely due to the underlying neurological deficits. These drugs are contraindicated in men taking nitrate medications for heart conditions.
  • Injectable and intraurethral medications: For men who do not respond to or cannot take oral PDE-5 inhibitors, these locally administered medications are highly effective second-line options. Alprostadil, a synthetic prostaglandin, can be injected directly into the erectile tissue of the penis (intracavernosal injection) or inserted as a small suppository into the urethra. These methods induce an erection directly and are often successful when oral agents are not.

Management of ejaculatory and orgasmic disorders

This remains an area of unmet clinical need, as there are currently no medications specifically approved or consistently effective for treating delayed ejaculation or failure to reach orgasm (anorgasmia) in MS. Some antidepressants (e.g. SSRIs) may be used ‘off-label’ to treat premature ejaculation thanks to their side effect of delaying orgasm. For delayed ejaculation or anorgasmia, the focus shifts to enhancing stimulation through manual or oral techniques or with the use of assistive devices like penile vibrators.

Addressing low libido and sensory changes

A review of the patient’s current medications is needed because many drugs, especially SSRIs, can suppress libido. Switching to an alternative antidepressant with a more favourable sexual side effect profile, such as bupropion or certain SNRIs (serotonin and norepinephrine reuptake inhibitors), may be beneficial. If blood tests reveal low testosterone levels, hormone replacement therapy may be considered to improve desire and energy. For altered genital sensation, the goal is to compensate for the diminished nerve signals by increasing the intensity and focus of stimulation using vibrators, different types of touch, or other sexual aids.

Management of secondary sexual dysfunction

  • Fatigue: Energy conservation is paramount. This involves planning sexual activity for times of day when energy is highest (often the morning), taking a nap beforehand, and collaborating with a partner to find less physically demanding sexual positions, such as spooning.
  • Spasticity: Proactive management can prevent painful muscle spasms from disrupting intimacy. This may include gentle stretching or massage before sex, taking an antispasticity medication like baclofen approximately 30–60 minutes before sexual activity, and/or experimenting with positions that minimise muscle tightness and discomfort.
  • Bladder and bowel issues: Careful planning can alleviate the anxiety surrounding potential incontinence. Strategies include restricting fluid intake for a few hours before sex, ensuring the bladder and bowel are emptied immediately beforehand and using intermittent self-catheterisation if needed. Using a condom can also provide a sense of security against urinary leakage.
  • Cognitive changes: For individuals whose concentration is affected by MS, creating an environment conducive to focusing is helpful. This means minimising external distractions, such as television or phones, and maximising sensual stimuli, including lighting, music and scent, to help maintain focus on the intimate experience.

Psychological counselling and sex therapy are the cornerstone of a holistic management plan and include cognitive behavioural therapy (CBT). CBT can be effective for challenging and reframing the unhelpful thoughts and beliefs that fuel performance anxiety and negative body image. Couples counselling provides a structured forum to improve communication, openly discuss fears and frustrations, and collaboratively explore the changes MS has brought to the relationship, including the sensitive shift from partner to caregiver.

Sensate focus and body mapping are specific sex therapy techniques that are particularly valuable for couples affected by MS. These exercises involve non-demand, non-goal-oriented sensual touching, shifting the focus away from intercourse and orgasm and toward the rediscovery of pleasure. This is especially important when genital sensation has been altered, as it helps couples identify new erogenous zones and broaden their definition of intimacy.

Rehabilitation and lifestyle interventions

These approaches focus on improving physical function and overall health to support sexual well-being.

Pelvic floor exercises are crucial for maintaining erectile rigidity and for the muscular contractions associated with ejaculation. A specialised physiotherapist can design an exercise programme (for example, Kegel exercises) to strengthen these muscles, potentially improving erectile and ejaculatory control. While much of the research into pelvic floor training has focused on women, the principles are also directly applicable to men.

General health has a direct impact on sexual function. Lifestyle modifications such as adopting a heart and brain-healthy diet, engaging in regular physical activity as tolerated, maintaining a healthy weight and quitting smoking can all improve vascular health.

Assistive devices for erectile dysfunction

For men with ED that is refractory to medication, mechanical aids are an important and effective option. Vacuum constriction devices consist of a plastic cylinder placed over the penis, a hand-held pump that creates a vacuum to draw blood into the penis, and a constriction band that is slipped onto the base of the penis to trap the blood and maintain the erection for up to 30 minutes.

Vacuum constriction device operated by a hand-held pump.

Penile prostheses or penile implants are a surgical solution for severe, intractable ED. A device is surgically implanted into the penis that allows the man to create a rigid erection mechanically. This uses saline to inflate the cylinder that is implanted in the penis. The saline can be pumped from a reservoir into the prosthesis or erectile cylinder to mimic an erection. The saline can then be pumped from the cylinder back into the reservoir to cause detumescence. This is typically considered a third-line treatment when all other options have failed.

Penile implant for severe erectile dysfunction

Education, education, education ….

Providing clear, accurate information to the patient and their partner about how MS can affect sexual function helps to demystify the problem, correct common misconceptions (e.g. that sexual activity will worsen the disease), and empower the couple to explore solutions collaboratively.

A management plan for male sexual dysfunction needs to be personalised to address specific primary, secondary and tertiary factors. The goal is often not just to restore previous sexual function but to help the man with MS to adapt to a new reality, encouraging him and his partner to build a new, satisfying form of intimacy.

This calls for improved clinical education of MS healthcare professionals, the integration of standardised screening tools into routine care, and a fundamental shift in clinical culture toward a more holistic model of well-being that values sexual health as a core component of MS management.