Chronic Fatigue Syndrome Fast Facts

Chronic fatigue syndrome (CFS) is a condition where a person experiences long-lasting tiredness, pain, mental fogginess, and/or other symptoms that don’t have an identifiable cause.

CFS is sometimes called myalgic encephalomyelitis (ME), and the disorder may also be referred to as CFS/ME.

Up to 2.5 million Americans are thought to be affected by CFS, but most cases go undiagnosed.

CFS is most common in adults between 40 and 60, and many more women than men are diagnosed with the disorder.

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Up to 2.5 million Americans are thought to be affected by CFS, but most cases go undiagnosed.

What is Chronic Fatigue Syndrome?

Chronic fatigue syndrome (CFS) is characterized by long-term, unexplained tiredness, body pain, mental fogginess, dizziness, and other physical and neurological symptoms. The symptoms commonly worsen after physical activity but are not improved by rest or sleep.

CFS is thought to be common, affecting anywhere from 800,000 to 2.5 million American adults. However, the condition is not well understood, and it’s estimated that as many as 90% of cases go undiagnosed.

Symptoms of Chronic Fatigue Syndrome

The specific symptoms of CFS vary from case to case, and they may come and go or change over time. Common symptoms of CFS include:

  • Persistent fatigue that lasts at least six months
  • Sleep that doesn’t replenish energy
  • Insomnia
  • Worsening of fatigue after physical or mental activity (called post-exertional malaise or PEM)
  • Impaired concentration
  • Impaired memory
  • Dizziness or lightheadedness, especially after sitting or standing from a prone position
  • Muscle aches and pains
  • Joint pain
  • Headaches
  • Sore throat
  • Swollen lymph nodes
  • Chills or sweating
  • Low-grade fever
  • Digestive problems
  • Mood swings
  • Depression
  • Heartbeat irregularities
  • Sensitivity to light

What Causes Chronic Fatigue Syndrome?

Scientists don’t know what causes CFS. However, the disorder likely occurs because a combination of factors merge to trigger the symptoms. Some possible risk factors being considered by researchers include:

  • Viral infections: Some viruses linked to CFS include the Epstein-Barr virus and human herpes virus 6. However, no conclusive viral link has been determined.
  • Immune system problems: Impaired immune systems appear in patients suffering from CFS, but it’s unclear if this impairment is enough to cause the disorder.
  • Hormonal imbalances: abnormal blood levels of hormones produced in the hypothalamus, pituitary glands, or adrenal glands are sometimes found in persons with CFS. The significance of these abnormalities is still unknown.
  • Physical or emotional trauma: Some people report that they experienced an injury, surgery, or significant emotional stress shortly before their symptoms began.

Is Chronic Fatigue Syndrome Hereditary?

Studies have suggested some people may be at increased risk of developing CFS because of inherited mutations (abnormal changes) in their genes. Researchers have discovered that CFS sometimes runs in families, and studies of identical twins have suggested that at least some of the family-history risk may be due to genetics. However, researchers have not yet identified any specific genes or gene mutations conclusively associated with CFS.

Some scientists believe that the inherited risk of CFS is due to the disorder’s association with depression, which is also known to run in families.

How Is Chronic Fatigue Syndrome Detected?

CFS can be difficult to detect early on because its symptoms tend to be non-specific and similar to many other disorders. By definition, the symptoms must last at least six months to qualify as CFS, so early symptoms are often overlooked or dismissed.

Unexplained symptoms that last for a prolonged time or get worse are reasons to consult with your doctor or medical professional.

How Is Chronic Fatigue Syndrome Diagnosed?

A doctor may suspect CFS if a person presents with otherwise unexplainable symptoms that are characteristic of the disorder. If this is the case, the doctor will conduct exams and tests to rule out other possible causes of the symptoms. The diagnostic process may include:

  • Physical exams and neurological exams to rule out other possible causes of the symptoms
  • Laboratory tests to look for possible causes such as thyroid dysfunction, anemia, or diabetes

Your doctor may consult with other specialists to look for possible underlying causes of the symptoms, including:

  • A sleep specialist to rule out problems such as sleep apnea
  • A rheumatologist to rule out immune system dysfunction
  • A neurologist to rule out brain- or nervous system-related causes
  • A psychologist or psychiatrist to rule out mental health-related issues such as depression

To meet the diagnostic criteria for CFS, a patient must experience:

  • Problems with memory, focus or concentration, and/or dizziness that worsens when sitting or standing
  • Symptoms interfering with the level of function the patient was capable of before the illness.
  • Symptoms that are new since the start of the illness.
  • Symptoms that do not improve with rest.
  • Symptoms that get worse after exertion, either physical or mental.

The symptoms must persist for at least six months and occur at least half the time during that period.


How Is Chronic Fatigue Syndrome Treated?

There is no cure for CFS. Treatment typically focuses on improving symptoms so the patient can function as well as possible.

Possible treatments include:

  • Antidepressants
  • Over-the-counter pain medications
  • Medications such as pregabalin, duloxetine, amitriptyline, or gabapentin for more severe pain
  • Low-dose corticosteroids
  • Dietary supplements
  • Improvement of sleep habits
  • Psychotherapy for depression
  • Low-intensity exercise (in exercise programs tailored for people with PEM)

How Does Chronic Fatigue Syndrome Progress?

Left untreated, CFS can lead to serious complications and impairments, both physical and social. Long-term complications can include:

  • Depression
  • Inability to carry out daily routines
  • Social isolation
  • Problems at work
  • Relationship problems
  • Nutritional problems
  • Problems related to inactivity

How Is Chronic Fatigue Syndrome Prevented?

Because the origin of CFS is unknown, there is no known way to prevent the disorder.

Chronic Fatigue Syndrome Caregiver Tips

Many people with CFS also suffer from other brain and mental health-related issues, a situation called co-morbidity. Here are a few of the disorders commonly associated with CFS:

Chronic Fatigue Syndrome Brain Science

While the cause of CFS remains unclear, scientists are looking for clues in the brains of people with the disorder. One study at Stanford University discovered key differences between the brains of people with CFS and those of healthy people.

The brains of people with CFS showed an overall lower-than-normal volume of a type of tissue called white matter. White matter consists of nerve cells covered in a fatty substance called myelin, which protects the cells and helps them to send signals to one another. White matter is sensitive to inflammation, and because CFS might be associated with chronic inflammation or viral infections, an overall reduction in white matter is not surprising.

The study also found that CFS patients showed abnormalities in a part of the brain called the right arcuate fasciculus. It’s a bundle of nerve cells connecting two parts of the brain (the frontal lobe and temporal lobe). The CFS brains also showed a thickening of the areas connected by the right arcuate fasciculus.

In right-handed people, the left arcuate fasciculus connects brain areas associated with language comprehension, but the function of the right arcuate fasciculus is not as well known. Some scientists think that it is involved in producing emotional expression in speech or interpretation of facial expressions. Research has also shown that right arcuate fasciculus abnormalities may be associated with autistic spectrum disorder.

It’s not yet clear how these findings are connected to CFS symptoms, but they do suggest the brain’s structure and function might play a role in the disorder.

Chronic Fatigue Syndrome Research

Title: Assessment of N-Acetylcysteine as Therapy for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (NAC ME/CFS)

Stage: Recruiting

Principal investigator: Dikoma Shungu, PhD

Weill Cornell Medicine 

New York, NY

Chronic fatigue syndrome/myalgic encephalomyelitis (ME/CFS) is an unexplained multisystem disorder for which there are currently no validated treatments. The present exploratory clinical trial aims to advance the understanding of the mechanisms of in situ GSH synthesis control through the assessment of the response of brain GSH and plasma markers of oxidative stress to different doses of NAC in comparison to the placebo, as a potential treatment for ME/CFS that would provide neuroprotection against oxidative stress by restoring cortical GSH reserves. If successful, this exploratory clinical trial would address a significant public health concern by shedding new light on the mechanisms of action of NAC in brain GSH restoration, which could open a new avenue for the development of potentially effective treatments for a disorder, ME/CFS, that currently has none.

This phase two, single-site study will utilize a double-blind, placebo-controlled, randomized, pre-/post-treatment design to investigate the effect of NAC dosing on brain GSH levels and measure temporally concordant plasma levels of several established circulating markers of oxidative stress. Three study groups of 20 subjects each (for a total of 60 who completed all components of the study) will be administered a different dose (0 mg/day, 900mg/day, 3600mg/day) of the study intervention over four weeks; N-acetylcysteine (NAC) treatment. Subjects receiving a 0 mg/day dose will be administered a placebo. Baseline visit assessments will include blood collection, survey questionnaires, MRI, and MRS imaging. Subjects whose initial screening confirms low GSH level at baseline will be provided with a 4-week supplement of anonymized NAC or placebo caplets. After four weeks, subjects will undergo a follow-up visit to repeat the baseline assessments.


Title: Analysis of Post-exertional Malaise Using a Two-day CPET in People With ME/CFS

Stage: Recruiting

Study Director: Betsy Keller, PhD

Ithaca College  

Ithaca, NY

This study aims to collect and identify key outcome measures or disease parameters in ME/CFS that are altered during elevated symptoms relative to baseline by gathering information before and after symptom provocation using a two-day cardiopulmonary exercise test.

The phenomenon of post-exertional malaise (PEM), in which an ME/CFS patient’s symptoms are elevated following even low-level exertion, is a hallmark feature of the disease. The cause of PEM, like the cause of ME/CFS, is not understood. This study aims to utilize a two-day CPET to invoke PEM. This provides a unique opportunity to collect data on how key outcome measures or disease parameters are altered during elevated symptoms relative to baseline within each patient by gathering information before and after symptom provocation.

A total of 90 participants and 90 controls will undergo CPET testing. Participation will be split among three sites (Ithaca, NY, New York, NY, and Los Angeles, CA). Subjects will be located in urban and rural areas to establish relatively diverse study populations.

This study is a component of the Cornell ME/CFS Collaborative Research Center (CRC). Blood samples taken before and after CPET will be utilized in associated projects with the Cornell ME/CFS CRC. CPET data, along with the analysis of blood samples, has great potential to reveal why exercise negatively affects ME/CFS patients and thus perhaps why patients are also impaired even before increasing their activity level.


Title: Does a Technology Enabled Multi-disciplinary Team-based Care Model for the Management of Long COVID and Other Fatiguing Illnesses Improve Clinical Care of Patients and Represent a Sustainable Approach Within a Federally Qualified Health Center? (LC&FIRP)

Stage: Recruiting

Principal Investigator: Christian Ramers, MD

Family Health Centers of San Diego

San Diego, CA

The primary objective of the present research is to determine the effectiveness of the Family Health Center of San Diego’s Long COVID and Fatiguing Illness Recovery Program (LC&FIRP) on clinician- and patient-level outcomes. LC&FIRP is comprised of a teleECHO program focused on multi-specialty case consultation and peer-to-peer sharing of emerging best practices to support the management of complex cases associated with PASC, ME/CFS, and OPIFI. Our secondary objective is to determine the feasibility, acceptability, and sustainability of LC&FIRP. Our findings should provide a fuller understanding of the potential impact of innovative technology-enabled multi-disciplinary team-based care models in low-resource, community-based primary care settings.

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