ME/CFS is a complex, debilitating illness. ME/CFS may be diagnosed after six months or more of extreme fatigue that is not improved by bed rest and that may get worse after activities that use physical or mental energy.

Symptoms affect different parts of the body and can include unrefreshing sleep, weakness, muscle and joint pain, problems with concentration or memory, and headaches. Symptoms may be mild to severe. They may come and go, or they may last for weeks, months, or years. They also can happen over time or come on suddenly.

No one knows for sure what causes ME/CFS. Many people say it started after a flu-like illness or other infection, such as a cold or stomach bug. It also can follow infection with the Epstein-Barr virus (the virus that causes mononucleosis or "mono"). Some people with ME/CFS report that it started after a time of great physical stress, such as following surgery.

The symptoms of ME/CFS can come and go or a person may have these symptoms all of the time. At first, one may feel like she has the flu. The main symptoms include:

• Feeling extremely exhausted for more than 24 hours after physical or mental exercise
• Not feeling refreshed after sleeping, or having trouble sleeping
• Having a hard time concentrating, or problems with attention and memory
• Feeling dizzy or faint when sitting up or standing (due to a drop in blood pressure)
• Muscle pain or aches
• Pain or aches in joints without swelling or redness
• Headaches of a new type, pattern, or strength
• Tender lymph nodes in the neck or under the arm
• Sore throat that is constant or goes away and comes back often

Less-common symptoms of ME/CFS include:

• Visual problems (blurring, sensitivity to light, eye pain)
• Psychological symptoms (irritability, mood swings, panic attacks, anxiety)
• Chills and night sweats
• Low grade fever or low body temperature
• Irritable bowel
• Allergies and sensitivities to foods, odors, chemicals, medications, and sound
• Numbness, tingling, or burning sensations in the face, hands, or feet

Symptoms of ME/CFS vary widely from person to person and may be serious or mild. Most symptoms are invisible to others, which can make it hard for friends, family members, and the public to understand the challenges a person with ME/CFS faces. If you think you may have ME/CFS, talk to your doctor.

Experts think ME/CFS affects about 1 million Americans. Many of these cases have not been diagnosed.

Women are two to four times more likely than men to develop ME/CFS. Children do develop ME/CFS, but not as often as adults or adolescents.

Because many symptoms of ME/CFS are also symptoms of other illnesses or side effects of medicine, your doctor will need to do physical exams and tests to help determine if you have ME/CFS. There are no standard lab tests to diagnose ME/CFS.

If you think you may have ME/CFS, see your doctor. Your doctor may:

• Ask you about your physical and mental health.
• Do a physical exam.
• Order lab tests based on your symptoms, such as urine and blood tests, which will tell your doctor if something other than ME/CFS might be causing your symptoms.
• Order tests that check for problems found in people with ME/CFS.
• Classify you as having ME/CFS if:
  1. You have the main symptoms of ME/CFS, including extreme fatigue or exhaustion that does not go away and that prevents you from doing the things you want and need to do for you and your family; exhaustion that comes after mental or physical exercise; sleep problems; and pain; AND
  2. You have had the extreme fatigue and other symptoms for 6 months or longer (3 months or longer for children and adolescents); AND
  3. You and your doctor cannot find another explanation for your symptoms.

The process to make a final diagnosis of ME/CFS can take a long time, so try to be patient. It is usually best to develop a relationship — and follow up often — with one doctor so that he or she can get to know you and see how you respond to treatment over time.

While these tests are being done, talk to your doctor about ways to ease your symptoms. Your doctor may also need to learn more about ME/CFS to help you. If you feel your doctor has doubts about it being a "real" illness, share this document and the links to resources found at the end. If disbelief or doubts continue, consider seeing another doctor for a second opinion. Contact a local university medical school, research center, or one of the resources listed below for help finding a doctor who treats people with ME/CFS.

Right now, there is no cure or FDA-approved treatments for ME/CFS. But, there are things you and your doctor can do to help ease your symptoms. Because the symptoms of ME/CFS vary from person to person, the management plan you discuss with your doctor may look very different from the plan of another person with ME/CFS.

Some people say that complementary or alternative medicine has helped their ME/CFS symptoms. Keep in mind that many alternative treatments, dietary supplements, and herbal remedies claim to cure ME/CFS, but some might do more harm than good. Talk to your doctor before trying alternative therapies to be sure they're safe.

Talking about your feelings with a friend or family member can help. Sometimes it also helps to talk with people who are going through the same thing. Consider joining an ME/CFS support group. See the "ME/CFS Organizations" section at the end of this fact sheet for a list of organizations that offer additional information on ME/CFS and can help you find ME/CFS support groups.

Research shows that about half of people with ME/CFS work part-time or full-time jobs. For some people with ME/CFS, the ability to work is possible thanks to a supportive employer and certain workplace accommodations, including a flexible schedule, a quiet comfortable place to rest, and memory aids.

But, if you can't work because of ME/CFS, you may be eligible for Social Security benefits. Learn more about applying for disability through the Social Security Administration.

If you're uninsured or have been denied coverage in the past for ME/CFS, the Health Insurance Marketplace may be able to provide you with access to affordable coverage. With health insurance plans in the Marketplace, you can no longer be refused coverage just because you have a pre-existing health condition. Medicaid and the Children's Health Insurance Program (CHIP) also can't refuse to cover you or charge you more because of a health condition. They also can't charge women more than men. Learn more about the Affordable Care Act and the Health Insurance Marketplace at Healthcare.gov.

Today, we have a better understanding of ME/CFS, but researchers are still searching for the cause(s). ME/CFS is sometimes seen in members of the same family, perhaps because of a genetic link. Researchers are also testing a variety of treatments for ME/CFS, including anti-viral medications and medications that affect the immune system.

Researchers also are looking at ways to help health care providers identify and diagnose ME/CFS more quickly. HHS currently supports a study led by the Institute of Medicine (IOM) to recommend improved and updated criteria to help physicians make a diagnosis of ME/CFS. The IOM's recommendations may also guide future research.

For more information on ME/CFS, call the OWH Helpline at 1-800-994-9662 or contact the following organizations:

Federal Government

• Agency for Healthcare Research and Quality (AHRQ)
  • Chronic fatigue syndrome/myalgic encephalomyelitis. A primer for clinical practitioners
• Centers for Disease Control and Prevention (CDC)
  Phone Number: 800-232-4636
• Chronic Fatigue Syndrome Advisory Committee, HHS
• Social Security Administration
  • Revised Social Security Ruling about Evaluating Cases Involving Chronic Fatigue Syndrome for Social Security Disability
• Trans-NIH ME/CFS Research Working Group, NIH

ME/CFS Organizations

• International Association for CFS/ME
  Phone Number: 847-258-7248
• Massachusetts CFIDS/ME & FM Association
  Phone Number: 617-471-5559
• New Jersey ME/CFS Association, Inc.
• Email: helpdesk@njcfsa.org
• Bateman Horne Center
• Patient Alliance for Neuro-endocrine-immune Disorders Organization for Research and Advocacy (PANDORA)
  Phone Number: 231-360-6830
• Phoenix Rising
• Rocky Mountain CFS/ME & FM Association
  Phone Number: 303-423-7367
• Solve ME/CFS Initiative
  Phone Number: 704-365-2343
• Wisconsin ME/CFS Association, Inc.
  Phone Number: 608-834-1001

ME/CFS Research Institutes

• Institute for Neuro Immune Medicine at Nova Southeastern University
  Phone Number: 800-541-6682
• ME-CFSCommunity
• Open Medicine Foundation
  Phone Number: 650-351-0310
• Simmaron Research
  Phone Number: 775-298-0030
• Stanford ME/CFS Initiative
• Nevada Center for Biomedical Research
  Phone Number: 775-682-8250