Multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) are both progressive conditions that affect the central nervous system (CNS) and impact a person’s ability to carry out daily tasks.

The effects and symptoms of both conditions can be similar, but the treatment and outlook are different.

This article looks at the similarities and differences between MS and ALS.

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

Both MS and ALS are neurodegenerative conditions that involve the CNS. The National Multiple Sclerosis Society estimates that MS affects nearly 1 million adults in the United States and over 2 million people worldwide, which makes this condition more common than ALS.

According to the Multiple Sclerosis Association of America, researchers updated the statistics of people living with MS to nearly 1 million in 2019. This estimate is nearly 400,000 more than previous estimates.

According to both the ALS Association and the Centers for Disease Control and Prevention (CDC), the exact rate of ALS is difficult to determine. The ALS Association estimates that about 15,000–21,000 people are living with ALS.

According to the CDC, however, an estimated 12,000–15,000 people live with ALS. The CDC also notes that doctors diagnose around 5,000 new cases each year. Both organizations base their estimates on the same information from the National ALS Registry data from 2010–2011.

Symptoms that occur in both MS and ALS include muscle weakness and paralysis. There is currently no cure for either condition, but it is possible to manage the symptoms of both.

In the case of MS, treatments now exist that can prevent flares and slow the progression of the disease.

It is of note, however, that MS and ALS differ in some important ways, which we highlight below.

What is MS?

In MS, the immune system mistakenly attacks myelin, which is the substance that protects the nerves in the CNS. This results in damage and scarring of the myelin sheath that health experts call demyelination.

This can lead to a disruption or distortion of nerve impulses as they travel between the brain and the spinal cord, resulting in a wide range of symptoms.

The impact of these symptoms may vary. In relapsing-remitting MS (RRMS), a person will experience a worsening of symptoms for a while before they make a partial or full recovery. However, the symptoms tend to return.

In progressive forms of MS, the symptoms do not go away but gradually worsen.

Symptoms may be mild, moderate, or severe. Some people will eventually lose their ability to walk and talk, but this is rare.

MS does not usually affect life expectancy.

What is ALS?

ALS, or Lou Gehrig’s disease, is a progressive neurological condition. It prevents the nerves that control muscle movement from working properly.

Over time, damage to the nerves results in muscle weakness and eventually paralysis.

In its late stages, ALS affects breathing, and this can make it life threatening.

Whom do MS and ALS affect?

ALS is 20% more common in males than in females. However, differences in sex even out in more advanced ages. The condition is most likely to start at the age of 40–70 years, but it can develop at any age.

MS is more common in females and typically develops between the ages of 20 and 50 years, but it can also occur at any age.

Other basic differences include the following:

  • ALS often causes paralysis. This is rare with MS.
  • ALS mainly affects physical functions, while MS can lead to problems with memory and thinking. However, more recent data suggest that about half of individuals living with ALS also have issues with thinking and cognition, with about 20% experiencing dementia.
  • ALS is not an autoimmune condition. By contrast, MS probably results from a faulty immune reaction.

The following table summarizes some of the other differences between the two conditions:

MSALS
Autoimmune conditionyesno
Most affected sexfemalesmales
Age range20–50 years40–70 years
Physical symptomsyesyes
Mental symptomsyesno
May be fatalnoyes
Has a curenono

Symptoms of MS and ALS can be similar, but there are some important differences to note.

MS

MS symptoms vary widely from person to person. They can also be unpredictable and change over time. One person may live with mild symptoms for many years, while another may experience a loss of mobility.

Symptoms of MS include:

  • fatigue and weakness
  • difficulties with walking and balance
  • vision problems
  • pain, numbness, or tingling
  • bladder or bowel problems
  • changes in thinking and memory
  • pain
  • depression
  • sexual problems
  • dizziness and vertigo
  • itching

In RRMS, the most common type of MS, symptoms will come and go during periods of flare and recovery.

ALS

ALS symptoms can also vary widely. In ALS, muscles weaken gradually and without pain. Once ALS starts, however, it can take as little as 2–5 years for it to have a significant impact on a person’s life.

Symptoms of ALS can begin in the muscles that control speech and swallowing. In some individuals, symptoms may start in the hands, arms, legs, or feet. However, over time, progressive muscle weakness and paralysis affect almost everyone living with ALS.

Other symptoms of ALS include:

  • tripping when walking
  • abnormal fatigue of the arms, legs, or both
  • slurred speech
  • uncontrollable laughing or crying
  • dropping objects
  • muscle cramps and twitches

As ALS advances, it can affect the respiratory muscles, making it difficult to breathe. For this reason, a person may need to use a ventilator.

It is rare for a person with ALS to experience remission.

MS and ALS appear to have different causes.

MS

Experts do not know exactly why MS develops. It is possible that a combination of factors, including genetics, immune responses, infections, and environmental triggers, may contribute to the development of the condition.

The following may play a role:

  • Immunological factors: There may be a link between MS and other autoimmune conditions.
  • Environmental triggers: Smoking, having low vitamin D levels, and living in a colder climate are common risk factors.
  • Infectious diseases: Certain viral infections may play a role.
  • Genetic factors: These might increase a person’s risk of developing the condition.

ALS

Most cases of ALS have no clear cause, but genetic and environmental factors appear to play a part. Researchers have found several different genes with mutations in cases where two family members develop ALS.

In addition, environmental factors, such as exposure to toxins, may also influence the ALS development.

ALS does not seem to involve unusual immunological activity.

There is currently no cure for either MS or ALS, but treatment is available to help slow progression of these conditions and manage their symptoms.

MS treatment options

Disease-modifying therapy (DMT) has a long history of use for long-term treatment of MS and prevention of flares. These drugs are for regular use, whether symptoms are present or not.

A person typically injects the medications at home, although a doctor may recommend or prescribe oral or intravenous (IV) DMT instead. A person receives IV medication into a vein and directly into the bloodstream.

DMT can reduce the risk of flares and may slow the progression of the condition. A person should speak with a doctor about the best drug for their situation.

Medications such as Avonex, Betaseron, and Copaxone have been helping people with MS since the early 1990s, while newer medications, such as Kesimpta, are recent additions to the treatment of MS.

Other treatment options can help manage flares and treat symptoms.

Some options include:

  • Corticosteroid injections: These reduce nerve inflammation and can reduce the impact of a flare and help manage severe symptoms. A doctor will give these only when necessary.
  • Plasma exchange: This involves taking blood from a person’s body, removing certain substances from the blood, and returning it to the body. This is suitable for people with severe symptoms and when other medications prove ineffective.
  • Lifestyle remedies: Exercising when possible, avoiding smoking, eating a balanced diet, and taking doctor-recommended supplements may help.
  • Physical therapy: Various types of therapy can help a person maintain strength and flexibility and find new ways to carry out tasks as their abilities change.
  • Other treatments: A doctor can recommend a variety of treatments for symptoms such as depression, constipation, pain, and itching.

ALS treatment options

Several types of drugs are available to slow disease progression and help a person manage their symptoms.

Individuals may also wish to try different therapy types or make some lifestyle changes:

  • Riluzole (Rilutek or Tiglutik) and edaravone (Radicava): Riluzole is a drug that may reduce damage to the muscles and nerves, although it cannot reverse the existing damage. Edaravone may slow the progression of ALS.
  • Other medications: Medications are available that can help alleviate symptoms such as:
    • fatigue and pain
    • muscle cramps
    • spasms
    • involuntary displays of emotion
    • excess saliva and phlegm
  • Condition management strategies: Trying physical and speech therapies, communication therapy, assistive technology, feeding tubes, ventilators, and occupational therapy can help improve quality of life. Counseling may help with depression and sleep issues.

MS and ALS have symptoms that can appear similar, but key differences do exist. One major difference between the two conditions is the outlook.

Both are degenerative conditions that can progress over time. However, it is possible for a person with MS to live for many years with only mild symptoms. According to the NINDS, a person with MS will have roughly the same life expectancy as a person without MS.

ALS, on the other hand, is more likely to progress rapidly and become life threatening due to the respiratory failure that accompanies it.

According to the ALS Association, the life expectancy of a person with ALS is 2–5 years following diagnosis. However, some individuals will live for 10 or more years past their initial diagnosis.

Many treatment options and lifestyle strategies can help improve the quality of life of a person with either MS or ALS. Ongoing research may help improve the outlook in the future.

Some scientists believe that over time, regenerative therapies, such as stem cell therapy, may be able to reverse or repair neurological damage. This could mean a cure for conditions such as MS and ALS.