What causes M.E?

The cause or causes of M.E. are not fully understood. It often develops after a virus, like flu or glandular fever, but it can also happen gradually for no obvious reason. People with M.E. have been found to have abnormalities in the nervous system, including part of the brain called the hypothalamus. The hypothalamus regulates sleep, temperature control and appetite. Abnormalities have also been found in the immune system. More research is needed before these abnormalities and their impact are properly understood.

Predisposing factors

It is thought that women are more prone to developing M.E. Some studies have suggested that genetics may have a role to play as the illness may be more common in certain families.

Triggers for the illness

Often it is not possible to identify what has triggered your M.E.

Around two-thirds of cases of M.E. are triggered by an obvious viral infection, including glandular fever, viral meningitis, viral hepatitis, and, less commonly, infection with bacteria or other organisms. Many of the infections triggering M.E. seem to be ordinary flu-like infections, from which some people don't recover in the normal way.

Other possible triggers include:
Vaccinations or toxins in the environment. These are very occasionally identified as possible triggers for the illness.
Physical injury or trauma such as an accident or operation very occasionally appear to trigger M.E.
The evidence that life events such as bereavement can trigger M.E. is weak. Major life events are more likely to lead to a mood disorder such as depression, which can be misdiagnosed M.E. Many people with M.E. do however report that increased stress seems common around the time they first get ill, or when another trigger like an infection occurs.

Factors that can hold back recovery

Doing too much or being too active or lurching between over and under activity, which is otherwise known as ‘boom and bust’.
Sleep problems, which are very common with M.E., reduce energy levels even further.
Mood disorders such as depression and anxiety reduce a person's ability to cope with the illness.
Whilst rest is very important, doing too little or being inactive may be detrimental. Prolonged inactivity can cause muscle wasting and weakness. However, in the early stages of the illness or during a relapse, a period of inactivity may help.

Real experiences

Laura
'As a teenager, I suffered from constant colds, which floored me for weeks at a time. When I started university, a number of allergies became apparent.
I was constantly nauseated, which later developed into irritable bowel syndrome.
I remember a friend being very concerned at how exhausted I'd become if I walked quickly. Then followed a very nasty throat infection. Several months later, working as a nursing student, I was given my Hepatitis B vaccination, and I subsequently developed symptoms that suggested a virus. I became exhausted and had to leave my course due to excruciating back and hip pain. I got progressively worse, with disturbed sleep and aching muscles, and after six months required a wheelchair to get around. It can take some time to chart the backward path that led to illness, and for me there were several triggers.'

Information first produced November 2003. Currently under review.