7 Possible Causes of Chronic Fatigue Syndrome

Those with Chronic Fatigue Syndrome (CFS) bear the unfortunate burden of a condition that though severely debilitating, has no real outward signs and no certain cause. Many are harassed by friends and family that think they are simply depressed or lazy, or that it’s all in their head.  Some look at them and think “They don’t look sick to me!” 

It’s certainly a condition with a lot of confusion around it.

However, I’d like to make it clear that despite uncertainty, CFS is a real condition. A lot of research effort has gone and is going into discovering the possible causes of chronic fatigue.  Though there are no certainties today, there are 7 potential causes that are receiving a lot of attention.

1. Viral Illness and Chronic Fatigue

The idea that a virus may be the cause of chronic fatigue syndrome has some intense interest in the medical community.  Proposed viral causes include:

  • Epstein Barr Virus,
  • Retroviruses,
  • HHV-6  (human herpesvirus type 6),
  • Enteroviruses,
  • Coxsakie B virus,
  • Ross river virus,
  • Borna disease,
  • XMRV (xenotropic murine leukemia virus-related virus )and
  • MLV (murine leukemia virus).

However, none of these have enough evidence linking them to CFS to convince researchers any are the cause at this point.

2. Immune Deficiency and Chronic Fatigue

Researchers have found some small immune differences in patients with CFS, however, the differences are not substantial enough to be thought a significant cause.

3. Endocrine Metabolic-Dysfunction and Chronic Fatigue

Similar to those with fibromyalgia, the following signs of endocrine or metabolic abnormalities have been found:

  • Low Serum Cortisol and Corticotrophin-Releasing Hormone Levels – Can cause fatigue, weakness, low appetite, diarrhea, weight loss, dizziness associated with low blood pressure and reproductive effects. 
  • Increased Serotoninergic Activity - Can cause increased heart rate, shivering, sweating, dilated pupils, tremors or twitching, high blood pressure and fever.  
  • Enhanced Serum Levels of Insulin-Like Growth Factor –  Can cause low blood sugar levels, nausea, hunger, nervousness, cold clammy skin, rapid heartbeat, numbness of the fingertips or lips, trembling, mood changes, confusion, weakness, blurred vision or dizziness, difficulty walking or talking, fatigue, weight gain and other effects on the metabolism.

However, because these findings are not unique to CFS, being shared by people with fibromyalgia and some syndromes with atypical depressive features, it is felt some other factors must come into play.

4. Neurally-Mediated Hypotension (The Fainting Reflex) and Chronic Fatigue  

A few studies show an overwhelming majority of patients with CFS have neurally mediated hypotension, a condition which causes blood pressure to drop inappropriately causing dizziness, nausea and fainting. However, these studies were not placebo controlled, blinded or randomized , so the role of neurally-mediated hypotension remains uncertain.

5. Depression and Chronic Fatigue

Depressions link to CFS is a topic of intense debate.  People with CFS are understandably up in arms as they have long been battling the idea that they are just depressed and that the physical weakness and fatigue they experience is “all in their heads”. With studies showing 2 out of every 3 paitients meet depression criteria however, there is a clear link between depression and CFS. Yet, whether this is a cause or an effect of CFS remains to be seen.

6. Sleep Dysfunction and Chronic Fatigue

The results of one small study showed that people with CFS had significantly different polysomnographic findings (results from a machine which monitors  brain waves, eye movements, muscular/skeletal movement and heart rhythm during sleep) than a control group after a night’s sleep.

Compared with the control, CFS paitients had less rapid eye movement (indicating deep, restorative sleep), lower sleep efficiency and less time sleeping overall. To make things even more interesting, these finding could not be linked to any known sleep disorders or fibromyalgia.

7. Genetics and Chronic Fatigue

CFS has been linked to certain genes dealing with immune and stress response.  Findings suggest that trouble managing stress may be linked to the development of CFS.

Though we cannot know  which of these factors, if any, are the real cause of Chronic Fatigue Syndrome today, new findings and continued studies bring great hope to the 1% of the population living with CFS and to the doctors awaiting better, more focused, CFS specific treatments to provide their patients with.

Stay Healthy,

Dr. Jeff M.D.


Gluckman, MD, Stephen J. "Clinical Features and Diagnosis of Chronic Fatigue Syndrome." UpToDate. Web. 14 Sept. 2011.

"What Are The Effects Of Low Cortisol Levels? | LIVESTRONG.COM." LIVESTRONG.COM - Lose Weight & Get Fit with Diet, Nutrition & Fitness Tools. Web. 14 Sept. 2011.

Staff, Mayo Clinic. "Low Blood Pressure (hypotension): Causes - MayoClinic.com." Mayo Clinic. Web. 14 Sept. 2011.

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