A chemical signature of Chronic Fatigue Syndrome suggests the disease may be caused by the body going into a semi-hibernation state, a study has said.

Around 250,000 British people are affected by CFS, also known as ME.

The disease causes the carrier to suffer from extreme exhaustion, and can strike suddenly, with no clear cause and few effective treatments.

Suggested explanations range from bacterial or viral infections to psychiatric issues.

In a previous study, scientists said the best treatments for ME were cognitive behaviour therapy or exercise, but these were criticised by sufferers for trivialising their condition and ignoring possible biological causes.