Not all of the symptoms mentioned need be present in order for a person to have chronic fatigue syndrome. However, fatigue and one or more of the other symptoms must be present continuously for at least six months. This is because many of the symptoms associated with CFS are also extremely common symptoms of mild conditions or other illnesses. The factor that differentiates the symptoms of CFS is the length of time a person has them and the absence of other illnesses. The course of chronic fatigue syndrome varies greatly.
Symptoms can last from several months to as long as a few years.
They are usually most severe during the first year of the illness. They may come and go, but do not worsen over time. If you have symptoms of chronic fatigue syndrome that are severe enough to interfere with your daily life, you should see a doctor. In most cases, diagnosis of chronic fatigue syndrome involves ruling out other illnesses that could be causing the symptoms. Further treatment depends on what diagnosis the doctor makes.