No one knows for certain what causes M.E. So far scientists have discovered changes in the immune system and nervous system. This is an important start to understanding this illness but much more research must take place before the real cause or causes are found.
What we do know so far is this:
Some people are more likely to develop M.E. than others. Things that make you more likely to suffer from M.E. are called predisposing factors. There is some evidence that some people are more likely to get M.E. because of their genes or family background. It is also thought that perhaps females are more likely to get the illness (although there is nothing girly about having M.E!).
Scientists have identified things that might start the illness. These are called triggering factors. Most often triggers can be infections such as viruses, including the flu and glandular fever. Sometimes bacterial infections or other organisms are thought to start the illness. In very rare circumstances vaccinations are thought to be a trigger as are some toxins found in the environment. Very occasionally people have reported that an accident, operation or other significant childhood illness appeared to start the illness. Major life events such as bereavement or starting a new school are not thought to trigger M.E. These events are more likely to lead to an illness such as depression, which can be misdiagnosed as M.E. Many people do however report that increased stress seems common around the time they first get ill, or when another trigger such as an infection occurs.
There are things that can hold back recovery from the illness. Lack of sleep, being depressed or very anxious, doing too much activity or not enough are all considered factors that can hold back recovery.
More research is needed to find out exactly why people get M.E.
Information produced July 2003
Updated June 2004
