Chronic fatigue syndrome (CFS) is a debilitating disorder characterized by extreme fatigue or tiredness that doesn’t go away with rest, and can’t be explained by an underlying medical condition. CFS can also be referred to as myalgic encephalomyelitis (ME) or systemic exertion intolerance disease (SEID).
The causes of CFS aren’t well-understood. Some theories include viral infection, psychological stress, or a combination of factors. Because no single cause has been identified, and because many other illnesses produce similar symptoms, CFS can be difficult to diagnose. There are no tests for CFS, so your doctor will have to rule out other causes for your fatigue.
While CFS has in the past been a controversial diagnosis, it’s now widely accepted as a real medical condition. CFS can affect anyone, though it’s most common among women in their 40s and 50s. There is no current cure, so treatment for CFS focuses on relieving your symptoms.