Chronic fatigue syndrome - Causes 

Causes of chronic fatigue syndrome 

Exactly what causes chronic fatigue syndrome (CFS) is unknown, but there are several theories.

Some experts think a viral infection such as glandular fever can trigger the condition. Tiredness is normal after a viral infection, but this does not explain why symptoms persist and get worse in CFS.

Also, many cases of CFS do not start after an infection and this theory does not explain why the condition sometimes develops gradually.

Other suggested causes of CFS include:

  • problems with the immune system  
  • a hormone imbalance 
  • psychiatric problems – some cases have been linked to mental exhaustion, stress, depression and emotional trauma
  • genes – some people may have an inherited tendency to develop CFS, as it is more common in some families
  • traumatic events - some cases have been linked to events such as surgery or a serious accident

It is possible that CFS is caused by a combination of factors. Further research is necessary to confirm the cause(s).

Debate over classification

The World Health Organization (WHO) has classified CFS as a chronic (long-term) neurological condition and this classification has been accepted by the Department of Health.

However, the WHO’s decision remains controversial and is not accepted by everyone working in the field.

Members of the team of health professionals who drew up the National Institute of Health and Care Excellence (NICE) guidelines for CFS could not agree that this classification is the right decision, and 84% of members of the Association of British Neurologists surveyed in 2011 said they did not view CFS as a neurological condition.

Page last reviewed: 20/03/2013

Next review due: 20/03/2015


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The 10 comments posted are personal views. Any information they give has not been checked and may not be accurate.

MRAIDANGWALSH said on 19 June 2014

There was just recently a published paper from Tufts University where they are saying that 'systemic

mastocytosis' is playing a role in cfs/fibro, they are calling it 'Spectrum of mast cell activation disorders' I

also found out a person in the U.S.A. who got sick in the 80's has the rarest form of systemic mastocytosis

called Mast Cell Leukemia. the Tufts researchers published I believe May 1st 2014 in Expert Reviews

Clinical Immunology. Some of the authors Petra, Theoharides. I have asked my Doctor and am awaiting to be seen to be possibly evaluated by a

haematologist and I will post if that is found or not. Other research is also leaning towards radiation

sickness and I do know a large co-hort of patients are positives in urine samples on radiation but is still

unproven theories. Also it could be still plausible this is undiagnosed Lyme disease even Myamotoi, the

best success stories I have see thus far are cures from Lyme long term treatments even in M.S. patients

who were previously diagnosed with M.S. who turned out to have all along a wrong diagnosis and it was Lyme. I had a great response from a natural product from Holland & Barret called 'Cats Claw' which is used in Lyme but also works on elastase and is know as a natural anti-leukemic compound I was able to get off all pain medicines including 20 years of steroid prednisone. I am not cured but better than prior use which I took for 6 months daily...

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Snow Cat said on 29 November 2013

1. Boredom.
2. Lack of iron in diet.
3. Unhappiness.
4. Virus.
5. Too much activity/exercise.
6. Stress.
7. Too few calories in diet compared to others in area.
8. Too many calories in diet.
9. Nerve damage.
10. Trauma.
11. Lack of water in diet.
12. Too many carbohydrates in diet.

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CasC said on 21 October 2013

It is appalling that, whilst the Dept. of Health accepts the WHO's classification of CFS as a neurological disease, NICE is allowed to flaunt it. As a result, the psychiatrists at NICE have hijacked the condition for their own ends and refuse to consider it as anything other than a psychological illness. This is preventing proper research into causes and thus a cure of effective treatment.

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PaulaG79 said on 01 March 2013

Great article, from my experience of CFS both personal and from support groups I can see that there are a lot of people who do have stressful/anxious personalities. I'm not one of them, I don't think but there are loads out there. It took ages for me to be diagnoses but I remember that common things are common. It was more likely for me to be diagnosed with something else so I guess my doctor did the sensible thing and investigate that first. I'm glad he did as now there is no doubt what is going on. I'm not sure where these other users get their literature from but its certainly not any registered journals I've read. It can be triggered by viral disease, yes but not specifically caused by them. I think the problem is that many people don't understand what a psychiatric illness actually is? I don't know.

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Ola09 said on 07 May 2012

I absolutely agree with all of the other comments! OK, I will accept that stress might make it worse - but then stress will make every other condition worse. But as for the mental problems - depression and anxiety - they are definitely the effect (and not the cause!!!) of chronic fatigue! And pushing yourself, or being pushed to keep going (I feel for you andiforest) is the stupidest approach, because it really does make you much much worse. It is so sad that most people with chronic fatigue have to result to the internet and other sufferers' experiences to try to help themselves, and there is so little help from the very people who are supposed to be there to help us - the doctors of the NHS - please take us seriously! This is a debilitating illness which is making our lives and the lives of those around us unbearable!

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ab73 said on 20 December 2011

There is no "debate" about the WHO classification except in the UK. Over 30 other countries including the US and Australia accept that ME is a neurological condition.

The UK medical community is at best lagging behind the latest research, and at worst arrogant in being the only country not to recognise this disease for what it is: a seriously debilitating - physical - illness.

Consider why there is no UK biomedical research??

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nobodysfool said on 21 July 2011

It is well established that this condition is caused by infections, without any pscycholigical factors being indicated. It is outragous for the author of this information page to suggest that psycholigical factors are implicated in the vast majority of cases.

Post-polio syndrome has long been accepted medical science and has identical symptoms to ME/CFS. The only difference is that the specific trigger for the syndrome in the patient is more certain. It seems utterly nonsensical to accept polio as a cause of such a syndrome, but then dismiss every other virus as a possible trigger

The initial symptoms of ME/CFS also do not differ from the symptoms of all Post-Viral Fatigue. The difference is that the symptoms are chronic and the chronocity is the likely causal factor in the presentation of further symptoms.

There is a general concesus amongst the leading experts that ME/CFS is caused by an overactive immune system, triggered in most cases by a non-specific viral infection. This is the only coherent explaination which so far fits the scientific evidence and it also matches with patients experiences.

The triggering infection does not need to have been as severe as glandular fever, it may have presented as nothing more than a common cold.

Whilst viral infections are clearly the most likely trigger in the majority of cases, it has to be accepted that anything that activiates the immune system might be implicated in a small minority of cases. This could include prolonged stress, polutants, other parasites, certain toxins and brain injury.

Patients with a clear viral trigger appear to relapse more frequently than the small minority that are suspected to have another trigger implicated. This is consistant with a viral infection being the far more likely trigger in the majority of cases.

The syndrome is consistant with the immune system remaining on red alert having been triggered. The pschological explanations are proposterous

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Janan said on 18 May 2011

I don't know what information the NHS use as a basis for their list of factors which contribute towards the likelihood of developing CFS. I have spent many hours reading accounts of this illness. In my experience, the vast majority of patients are neither depressed, mentally or physically stressed, anxious or traumatised prior to becoming ill.
The emphasis on psychological and psychiatric factors is unhelpful and is the main reason why we are no nearer having any real understanding of this disease.

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habardfoster said on 03 May 2011

I didn’t have an abusive childhood .I had a totally unremarkable ordinary childhood .My abuse was down to doctors who sent me to school when I became ill with ME at eleven.
My problems started with ME . I fell ill before my family .When I fell ill my parents were not supported in any way by d doctors or experts in the health care world. my mother though suspecting something wasn’t right was ignored .I was sent to school on there advice and pressure and became worse and worse .The teachers wanted me to leave because I was collapsing in class upsetting the other pupils ,but the doctors psychiatrists kept forcing me back..When my family fell ill six years later they realised how ill I was. My mother felt guilty for believing the doctors and not following her own instincts about my health . It took the rest of the family to fall ill to take ME seriously .I have an older brother and Father who are not ill. Most of the stress I have experienced in life is not coming from inside but the pressure of being disbelieved by the world outside and the stress of not feeling you have any say in your own health .I grew up from eleven with the rest of my family fearing that we would end up in a psychiatric ward if we challenged the so called experts or complained to much . I am now 37 years old and fell that NHS CHOICES is a strange title for this website . Your health your choice? is even more ironic .It is no longer your health or your choice if you are forced to except the treatments devised by psychiatrists who have tried and succeeded to hijack this disease .The NHS should be ashamed of its involvement in the psychiatrists power struggle over the ill.

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conkerama said on 08 December 2009

The recent discoveries and continuing research around the XMRV retrovirus should be mentioned here. As a long-term CFS/ME sufferer, I am already taking reasonable steps to protect others around me from transmission of the virus 'just in case'. Others may wish to take similar precautions.

The psychological make-up and life events of a person will affect the outcome of ANY disease. Why does the NHS make such an issue of it with CFS?

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