A disease characterized by profound fatigue, sleep abnormalities, pain, and other symptoms that are made worse by exertion. Chronic fatigue syndrome occurs more commonly in women. The cause of this condition is unknown, but may include environmental or genetic factors. The main symptom is fatigue for over 6 months. The fatigue often worsens with activity, but doesn't improve with rest. Many symptoms can be treated or managed with a multidisciplinary approach.