The most predominant symptom of ME is that of severe and debilitating fatigue, which feels very different to everyday tiredness or exhaustion, and which doesn't go away with rest or sleep. There are a number of other symptoms too, which are listed below, yet some people experience only a few of them.

• Problems with sleep, speech, memory and concentration.
• Severe headaches (or migraines).
• Dizziness and balance problems.
• Sensitivities to noise and light.
• Difficulty regulating body temperature.
• Digestive problems.
• Tender and swollen lymph nodes.
• Painful/sore throat.
• Painful muscles and joints.

Clinical depression can be a symptom of ME, and can also be associated with the wider issues of living with the condition. Physical exercise tends to worsen the symptoms of the condition, yet any kind of mental or emotional activity can leave people really struggling to function.

Symptoms often fluctuate throughout the day, and they can be mild, moderate or severe. The symptoms can significantly affect a person's ability to cope with daily living, and some people may be housebound or bedbound for months or years.

Studies have shown (Nacul at el, Komaroff et al, Buchwald et al, Schweitzer et al) that the scale of impairment and disability in people with ME can be greater than many other chronic diseases, including cancer. Click here to read about the diagnosis of ME.