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. Furthermore, 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.
Due to no single cause has been identified, and because many other illnesses produce the same symptoms, CFS can be a challenge to diagnose. There are no tests for CFS, so your doctor will have to rule out other causes for your fatigue.