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Brain fog

“Brain fog” is a term people often use to describe a range of symptoms. It is not a medical term or a diagnosis, but it is a very real issue. People with ME/CFS, Long COVID or Post Viral Fatigue often describe brain fog as: 

  • Difficulty concentrating, especially for longer periods 
  • Sluggish or muddled thinking 
  • Forgetfulness 
  • Word finding difficulties 

There is a strong link between brain fog and fatigue, poor sleep, depression, anxiety and stress. People with ME/CFS find that PESE/PEM leads to increased brain fog. In the Primary Fatigue Service, we often hear from our patients that their brain fog improves when their fatigue and sleep are better managed. People also often report that, as they learn to cope with it better, their anxiety levels can reduce and this can also improve some brain fog. 

If you think you might be suffering from brain fog please read the website sections on Fatigue, Sleep and ME/CFS, Long COVID or Post Viral Fatigue. Work on these areas if you can. If you see no impact on your brain fog, or are still concerned, speak to your GP so that they can consider a referral to the Primary Fatigue Service.  


More information on brain fog:  

Our specialists have checked this information and it is equally applicable for people living with ME/CFS or Post Viral Fatigue.

Cognitive dysfunction - MEpedia (
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