What Is Multiple Sclerosis (MS)?

Multiple Sclerosis is a chronic disease of the brain and spinal cord that makes up the central nervous system. Multiple sclerosis is an autoimmune disease, an unpredictable condition that can be relatively benign, disabling or even devastating. Some people with MS may be mildly affected, while others may lose their ability to see clearly, write, speak or walk when communication between the brain and other parts of the body becomes disrupted.

With MS, the immune system attacks healthy myelin, a fatty tissue that surrounds and protects the nerve fibers. Damage to and loss of the myelin tissue forms scar tissue called sclerosis. These areas are also called plaques or lesions. When damaged in this way, the nerves are unable to conduct electrical impulses to and from the brain.

How Common Is Multiple Sclerosis (MS)?

In the U.S., approximately 400,000 people are affected by MS, with multiple sclerosis symptoms developing, on average, between 20 and 40 years of age—although symptoms can begin as early as age 10 and as late as age 80. There is not enough known about what causes MS to definitively say why a particular person develops the disease. Although researchers believe genetic factors, autoimmune disorders, certain infectious viruses and environmental factors can play a role.

What Are the Types of Multiple Sclerosis?

The four main types of multiple sclerosis can present symptoms differently. The types of MS include:

  • Clinically isolated syndrome (CIS): An initial episode of MS symptoms shows early signs of MS, but it may not necessarily develop into multiple sclerosis
  • Relapsing-remitting MS (RRMS): The most common type of MS, RRMS patients have flare-ups of new or worsening symptoms that may subside and go into remission
  • Primary progressive MS (PPMS): Patients with PPMS have symptoms that gradually intensify and don't offer times of remission
  • Secondary progressive MS (SPMS): As symptoms grow more severe, nerve damage can worsen. RRMS patients may eventually develop into SPMS and as the disease intensifies, times of remission dwindle or cease

What Causes Multiple Sclerosis?

Scientists do not yet know the cause of MS. The autoimmune disease comes on during inflammation of cells in the body, which could be based on environmental factors (such as receiving less sun), genetics or infections and viruses. The study of MS causes is ongoing.

What Are Risk Factors for Multiple Sclerosis?

While the definite cause of MS isn't known, key risk factors for multiple sclerosis include:

  • Family history: Parents or siblings of MS patients have an increased chance of developing MS themselves. Even though the disease is not inherited, the genetic risk for it can be
  • Age: The onset of signs of MS commonly happens between age 20 and 40, but is not solely limited to that timeframe
  • Sex: Women develop MS as much as three times as often as men
  • Climate and Vitamin D: Countries with a temperate climate, such as in the northern United States, and people with low levels of Vitamin D due to low sunlight exposure are at higher risk
  • Race: Northern European races have the highest risk of MS, whereas those with Native American, Asian or African descent face the lowest risk
  • Smoking: Smoking increases a person's risk of developing MS and can lead to more severe cases of the disease and rapid progression
  • Autoimmune diseases: Individuals with certain autoimmune disorders, such as thyroid disease, psoriasis, and type 1 diabetes, have shown a higher chance of developing MS
  • Previous viral infections: Epstein-Barr virus, which causes mononucleosis, has been linked to the development of MS. Research is ongoing to determine links between other viral infections and the development of MS

Symptoms of Multiple Sclerosis

Multiple Sclerosis symptoms are not the same in all people with the disease. They can be mild or severe and can last a long or short time. Also, depending on what areas are affected, they can present in many different combinations.

What Are the Early Signs of MS?

The early signs of MS vary based on the location of the affected nerves. Often, the first symptoms of MS impact vision. Both the CIS and MMRS types of MS present initial MS signs. The most common symptoms of MS that a patient may notice first are:

  • Blurred or double vision
  • Visual color distortion
  • Pain and loss of vision
  • Difficulty walking
  • Sensations of pain, numbness, or “pins and needles”

Other Multiple Sclerosis Symptoms

Multiple sclerosis complications and symptoms can increase as the area of affected nerves grow and the disease develops. Other symptoms that can develop include:

  • Muscle weakness in the limbs
  • Difficulty with coordination
  • Impaired walking or standing
  • Partial or complete paralysis
  • Muscle stiffness
  • Involuntary muscle spasms
  • Fatigue
  • Speech difficulty
  • Tremor
  • Dizziness
  • Hearing loss
  • Bowel and bladder disturbances
  • Depression
  • Changes in sexual function

Many MS patients experience some form of cognitive impairment, sometimes mild and only detectable through testing and at other times readily apparent. Common cognitive impairments include:

  • Concentration
  • Attention
  • Memory
  • Poor judgment

MS Symptoms in Women vs Men

Women are up to three times more likely than men to develop the RRMS type of MS, the most common form of MS. Men are more likely to develop PPMS than women. While the symptoms of MS are similar in women and men, women may have more hormonal-related symptoms that impact menstruation and menopause, including irregular periods and flare-ups during a period. Men with PPMS may see MS progress faster with a quicker degeneration of disability.

Multiple Sclerosis Diagnosis

While many advancements have been made in MS, there is still no definitive test available on how to diagnose MS. Currently, a multiple sclerosis diagnosis is based on clinical attacks—the sudden appearance of symptoms—and magnetic resonance imaging (MRI) showing evidence of lesions, plaques and scarring on the nerve fibers. MRI technology has evolved as a valuable tool used to establish an early diagnosis and monitor disease progression.

Multiple Sclerosis Treatment

At Brigham and Women’s Hospital, MS experts develop individualized multiple sclerosis therapy and plans for how to treat MS based on:

  • Age
  • Overall health
  • Medical history
  • Extent of the disease
  • Tolerance for specific medications or procedures
  • Expectations for the course of the disease

Because there currently is no cure for MS, current treatments focus on easing symptoms and making life more manageable for patients. Over the past 15 years, there has been considerable progress in multiple sclerosis treatments, which may include medication with supportive services such as psychiatry services, therapy services, and nutrition and wellness plans. Learn more about our Brigham and Women's Hospital treatment options.


Possible medications used to treat MS include:

  • First-line injectable therapies, including interferons and glatiramer acetate
  • Oral medications including fingolimod, teriflunomide, and dimethyl fumarate

In some cases, first-line therapy with disease-modifying treatments may not adequately control disease and second-line options are used as well, including:

  • Natalizumab
  • Anti-CD20
  • Cyclophosphamide

A variety of other medications have been shown to have some effect in reducing MS relapses or lesion formation in small studies. These medications are approved for use in other diseases and are occasionally used “off label” in the treatment of MS.

Psychiatry Services

Living with MS does have an impact on mental health and often can lead to depression. At Brigham and Women’s Hospital, MS patients have access to the services they need to cope with the challenges they face.

Specialists within the Department of Psychiatry at Brigham and Women’s Hospital provide a broad range of programs, including specialized services that address the unique needs of patients living with chronic conditions, such as MS.

Therapy Services, Nutrition and Wellness Plans

An integral part of MS is ensuring that each patient receives all the support services they need to help manage the impact the disease has on their overall health and well-being.

Part of the multidisciplinary care provided at Brigham and Women’s Hospital, many patients with MS also benefit from:

  • Speech therapy
  • Physical therapy
  • Occupational therapy
  • Nutrition counseling
  • Exercise plans

Multiple Sclerosis Treatment at Brigham and Women’s Hospital

The Multiple Sclerosis Center, located at Brigham and Women’s Hospital, is world-renowned for providing the most advanced management and multiple sclerosis treatment options for patients with MS, bolstered by a clinical research program that is leading the way in the latest discoveries. Since its creation in 1999, the Center—led by Howard L. Weiner, MD—has been at the forefront of MS patient care and research, including the landmark CLIMB MS cohort that has provided many insights into genetics, immunology imaging, and treatment of MS.

MS is one of the many diseases and conditions that form the focus of our Neurosciences Center. Our multidisciplinary team of neurologists, neurosurgeons, psychiatrists and radiologists offers the most innovative and advanced treatments and therapies for MS and all diseases of the nervous system. Our dedication to discoveries and research in these areas has made us the choice for patients from the region and around the world.

To learn more about Multiple Sclerosis, watch this video of Dr. Howard L. Weiner discussing BWH research focused on improving MS treatment and finding a cure.

Multiple Sclerosis FAQs

What Effects Does Multiple Sclerosis Have on the Body?

A disease that impacts the central nervous system, the effects of MS can be seen throughout the body, both from a cognitive and functional standpoint. MS patients may have a range of symptoms that include vision problems, muscular changes, mood shifts, depression, fatigue and more.

Can MS Be Hereditary?

The cause of MS isn't fully known, and while it isn't believed to be directly inherited, those closely related to someone with MS are more likely to develop MS.

How can Multiple Sclerosis be Prevented?

There is no known prevention for MS, but for those who do have early signs of MS, a healthy lifestyle can prove beneficial in reducing symptoms and slowing the progression of the disease. Doctors recommend eating a healthy diet without smoking and with limited alcohol, getting regular, varied exercise and reducing stress.

Multidisciplinary Care

Brigham and Women’s Hospital provides a multidisciplinary approach to patient care, collaborating with colleagues in other medical specialties. If your neurologist or neurosurgeon discovers an underlying illness or concern, you will be referred to an appropriate Brigham and Women’s Hospital physician or allied health professional for an expert evaluation.

Additional Resources

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