Tag Archives: anxiety disorder

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.

Intimate issues: bowel disorders

Here I discuss why people with MS develop problems with their bowel function and I offer straightforward advice on how to manage constipation, diarrhoea and other MS-related bowel problems.

Key points

  • Many people with MS experience a bowel disorder as a result of changes within the central nervous system that may affect the rectal and anal muscles.
  • Agents that increase the muscular action of the bowel can help to treat constipation.
  • Medications for some MS symptoms can increase constipation and may need to be reviewed.
  • Faecal impaction associated with constipation is a serious problem that may need hospital treatment.
  • Small intestinal bacterial overgrowth (SIBO) from faecal impaction may occur if the bacteria of the small intestine increase above normal values, producing harmful toxins.
  • SIBO is associated with unpleasant symptoms including abdominal bloating, pain, anaemia, irritable bowel syndrome, constipation, diarrhoea and faecal impaction.
  • Bowel hypomobility and any faecal impaction underlying SIBO need to be addressed, and antibiotics may be required to reduce the abnormal bacteria in the bowel. A gut health programme and dietary review are important for long-term management.
  • Being incontinent of faeces in public is highly embarrassing and may lead to severe anxiety and social isolation.
  • Faecal urgency or incontinence are best treated by developing a bowel routine and trying to evacuate your bowels in a controlled environment and at a regular time of day.
  • Regular rectal or transanal irrigation can significantly improve the quality of life in such cases.
  • MS should be treated early with effective DMTs, to avoid or delay damage to the neuronal pathways that control bowel function.

Many people with MS experience bowel disorders, including constipation, faecal hesitancy (difficult initiating a bowel action), incomplete emptying, faecal urgency, urgency incontinence, overflow diarrhoea, excessive bloating and excessive flatus. Understanding the causes of rectal and anal dysfunction in patients with MS can help us to select the most relevant therapies to target specific symptoms.

People with MS who experience constipation generally have a loss of sphincter tone (strength) at rest and during contraction compared with non-MS patients. In faecal incontinence, rectal sensitivity threshold is reduced, meaning that when faeces enter the rectum the threshold at which the defaecation reflex is triggered is lower than normal. There is also evidence that the coordination of the pelvic floor following contraction of the anal sphincter is abnormal in people MS. Pelvic floor exercises may help with this.

Management of constipation

Bowel dysfunction, particularly constipation, is common in MS. Constipation occurs because the MS bowel is sluggish due to reduced motility (i.e. the muscles or nerves do not work as they should). The management aim is usually to encourage regular bowel action, either daily or at least every two days.

Prokinetic agents that increase the muscular action of the bowel can help to treat constipation. The prokinetic agent I prescribe most often is senna. If this fails, other options include bisacodyl, co-danthrusate, sodium picosulfate or prucalopride; these agents work by stimulating the nervous system in the bowels. Prokinetic agents often need to be taken with bulking (fibre) and loosening (liquid) agents. Bulking agents include methylcellulose, psyllium or ispaghula husks, and sterculia granules. Loosening agents keep liquid in the bowel, causing water to be retained with the stool; examples include lactulose, polyethylene glycol (Movicol), magnesium hydroxide and magnesium sulphate (Epsom salts).

Cyclical use of laxatives can contribute to ongoing constipation: you use laxatives to treat your constipation, the laxatives cause diarrhoea, so you stop taking them. You then become constipated again, and the cycle repeats itself. 

If you experience bladder incontinence, dehydrating yourself to control your bladder problems can make constipation worse; you must drink adequate quantities of water throughout the day. Similarly, anticholinergic drugs used for treating urinary frequency and urgency and treatments for pain and spasticity may all make constipation worse. Therefore, if you are constipated your medications for other symptoms of MS need to be reviewed. 

Faecal impaction

Over time, the bowels may become impacted with faeces, and a hard, stony mass of compacted faeces forms (known as a faecolith). The gut bacteria may then overgrow and liquefy the stool above this impacted faecolith, bypass the impaction and cause diarrhoea. A typical history of faecal impaction includes periods of constipation punctuated by episodes of diarrhoea. If you suffer from chronic constipation and intermittent diarrhoea, you should contact your health team for help. Faecal impaction is a serious problem and often warrants treatment in hospital.

Below are some tips for managing MS-related constipation.

  1. Optimise your diet by eating lots of fibre.
  2. Don’t dehydrate yourself. Drink plenty of water; be aware that caffeine and alcoholic beverages are not hydrating. Both cause the kidneys to make more urine (diuresis) and are dehydrating.
  3. Try to eliminate the concurrent use of medications that exacerbate constipation (anticholinergics and opioids).
  4. Exercise regularly; the anticipation of exercise and exercise itself stimulate a defaecation reflex.
  5. If you need to use laxatives, start with a prokinetic agent that stimulates the bowel to move, such as senna; then add in bulking agents (e.g. psyllium husks or other fibre substitutes) followed by liquifying agents (lactulose or polyethylene glycol).
  6. Don’t suppress the need to go to the toilet; many people with chronic constipation have learnt bad habits (such as not using toilets that are unfamiliar to them).
  7. Try to develop a daily bowel routine, for example, by having a bowel movement at a particular time (ideally in the morning). This may require you to stimulate a bowel movement, perhaps by eating something, drinking a caffeine-containing drink, anal stimulation (anal plug), using glycerine suppositories, mini-enemas or (if necessary) an anal irrigation system. An anal plug is used to stimulate the colonic emptying reflex and is removed before you have bowel action.

These final recommendations may sound extreme, but they are essential steps to prevent faecal impaction. They may also give you the confidence to go out knowing that you can avoid faecal urgency and incontinence.

Small intestinal bacterial overgrowth (SIBO)

People with MS with bowel dysfunction may develop small intestinal bacterial overgrowth (SIBO), which is defined as an increase in the bacterial content of the small intestine above normal values. Some studies show that four in every 10 people with MS have SIBO; it is also detected in approximately one-third of patients with gastroenterological complaints who undergo a breath test. Proton pump inhibitors (omeprazole and related drugs) and smoking are risk factors for developing SIBO. The risk of SIBO increases with age and does not depend on gender or race.

SIBO is associated with dyspepsia, abdominal bloating, abdominal pain, anaemia, irritable bowel syndrome, functional constipation, diarrhoea and faecal impaction. A slowdown in your bowel transit time with SIBO decreases the normal clearance of bacteria from the small intestine. This slowdown is due to changes in the motility of the intestine, which is almost universal in people with MS.

Risks from SIBO

SIBO may damage the intestinal surface or mucosa of the bowel, because the bacteria can produce harmful toxins. This can result in leaky gut syndrome and acquired lactose intolerance. The leaky gut syndrome is controversial and associated with many symptoms that may overlap with MS-related symptoms. Leaky gut syndrome is not medically defined, and no specific tests or treatments are available. In comparison, acquired lactose intolerance occurs when someone loses the ability to digest lactose, the main sugar in milk, which causes them to develop diarrhoea, gas and bloating after eating or drinking dairy products. If you have lactose intolerance, you quickly learn to avoid lactose-containing products or use lactase preparations that help digest lactose. Please note that cheeses and yoghurt are generally tolerated because the bacteria used in the culturing process to produce these dairy products break down the lactose.

We know that many bacterial overgrowth products can impact human metabolism and behaviour. For example, people with liver dysfunction can’t metabolise these bacterial toxins and they develop hepatic encephalopathy. People with neurological disorders with reduced brain and cognitive reserve tend to be more susceptible to the effects of these bacterial metabolites, which are thought to upregulate innate immunity in the nervous system. This is why I try to stress to my patients that they should manage their constipation to prevent this from happening. Severe constipation and faecal impaction should be viewed as a chronic infection and managed and treated.

Diagnosis of SIBO

A breath test is most commonly used to diagnose SIBO. This noninvasive test measures the amount of hydrogen or methane you breathe out after drinking a mixture of glucose and water. A rapid rise in exhaled hydrogen or methane indicates bacterial overgrowth in the small intestine. Although widely available, breath testing is less specific than other tests for diagnosing bacterial overgrowth.

The gold standard for diagnosing SIBO is a small intestine aspirate and fluid culture. The fluid sample is obtained as part of a small bowel endoscopy. Other tests can include abdominal X-rays or CT scans. Faecal impaction resulting from constipation can also be diagnosed from spinal MRI scans of people with MS.

Management of SIBO

The initial way to treat bacterial overgrowth is to manage the underlying bowel hypomobility problem and clear any faecal impaction. In parallel, a course of antibiotics may be needed to reduce the number of abnormal bacteria in the bowel. However, unless you deal with the underlying problems, the bacteria will repopulate the bowel when the antibiotics are discontinued. This is why some people with SIBO may require long-term antibiotics. Switching between different antibiotics helps prevent bacterial antibiotic resistance from emerging. Please be aware that antibiotics wipe out most intestinal bacteria, both normal and abnormal; hence, they are not an ideal long-term solution to SIBO.

Starting a gut health programme is an essential part of treating SIBO. You will need a nutritional review, possibly with a dietitian, and you may need to change your diet to prevent constipation and/or faecal impaction. In some cases, you may require supplements. particularly if you are vegan.

Management of faecal incontinence

Being incontinent in public is one of the most embarrassing things that can happen to someone with MS, and it may result in social isolation to avoid experiencing the embarrassment again. Many patients with MS describe their experience of being incontinent of faeces and/or urine in public as the worst thing that has happened to them. It doesn’t have to happen; there are many ways to prevent it.

Faecal urgency needs attention (as does urgency incontinence – see section on bladder disorders). It is best treated by developing a bowel routine and trying to evacuate your bowels at a regular time of day, typically in the morning. This can be aided by using something to stimulate the bowels. I usually start by prescribing glycerine suppositories or mini-enemas. If the latter fails, I may elect to use transanal irrigation.

Transanal irrigation may sound drastic, but it often makes a massive difference to the quality of life in people with MS who need it and helps them to tackle a problem that can otherwise leave them stranded at home. I regularly refer patients for assessment to use the commercial rectal irrigation system, Peristeen, mainly because of the psychological benefits they derive from it.

The biggest problem with poor rectal compliance and faecal urgency is the odd occasion when you have diarrhoea due to gastroenteritis. With diarrhoea, whatever the cause, your rectum fills multiple times during the day and hence you are more likely to be incontinent. In this situation, you may need to use incontinence pads.

Faecal incontinence is not necessarily linked to disability. Why not? The reason is that a strategically placed MS lesion in the spinal cord can impact bowel function without causing other disabilities. I have patients who have had spinal cord relapses that leave them with faecal urgency and episodes of faecal incontinence, but very little other disability.

Case example

One patient of mine developed a severe anxiety disorder following an episode of faecal incontinence in public. She had intrusive thoughts and unpleasant flashbacks, reliving the episode repeatedly. After referral to a psychiatrist, she was diagnosed as having post-traumatic stress disorder. It took several years of counselling for her to overcome the social phobia associated with her anxiety and start going out again.

She now ventures out only after having an enema to clear her lower colon and rectum; she never eats when she is out, so as not to stimulate the reflex urge to defaecate that follows eating. She wears pads and carries a change of clothing. Her faecal incontinence emergency pack contains wet wipes, clean underwear, spare continence pads and poo bags to dispose discreetly of any used items – the same items I packed when I went out with my daughters before they were potty trained.

The importance of managing bowel dysfunction

Bowel dysfunction is one of the hidden symptoms of MS. To assess whether or not you have a bowel problem, and its severity, you can complete the Wexner Incontinence Score. Over the lifetime of the disease, most people with MS develop bowel problems, so it is important to realise that much can be done to help you. Please discuss these symptoms with your neurologist or MS clinical nurse specialist. 

On the positive side, if MS is treated early and effectively before the neuronal pathways that control bowel function are damaged, these issues can usually be avoided or delayed. Preventing disability, such as bowel dysfunction, is better than treating it. This is another critical reason to manage your MS actively with DMTs.