I do have a strong opinion on this. I unintentionally offended a lady on another thread by sharing it and I really am not taking pride in causing offence to others like her.
But this is my honest opinion:
CFS/ME/Fibromyalgia are NOT medical conditions. They are not diagnosable by any tests.
They are synonymous with "we've excluded all causes, and have no answers"
It's a functional syndrome.
Research shows your typical sufferer is a middle aged female without higher education with concomitant depression or anxiety. That's not a sneer. It's a fact. It does not mean ALL sufferers will fit this.
Drs realise that many people for whatever reason do not like a mental health diagnosis for many different reasons. Stigma still exists with these diagnoses. So, they give the patient a physical syndrome, which validates them , and also makes them go away from the drs office.
I believe the symptoms absolutely. I believe depression better explains them. That's also not a sneer. I've suffered depression in the past, and it's a visceral reaction I feel when I imagine being back in that hell hole. When I think back, I had so many IBS like symptoms (I don't now), I had aches and pains in my arms and legs. The tiredness was all consuming, I'd spend my days off just sleeping in the late mornings, sometimes for 3 hours and still feel shattered. But when I treated the depression, these symptoms more or less resolved. Depression is very real and it causes all manner of physical symptoms. You're hyper aware of pain etc. i never sought help for those symptoms as I knew deep down it was depression related and I'd given up caring much at the time anyway. But, if I had sought help and denied I was in mental distress, no doubt I'd have been diagnosed with fibromyalgia.
Furthermore, CFS/ME/fibromyalgia/long COVID/depression/health anxiety/IBS often co -occur...
On another note, I have seen (middle aged women) palmed off with 'fibromyalgia' when they've later turned out to have rheumatoid arthritis or lupus or worse. I think these subjective functional syndromes do no favours to the sufferer.
One last point. It does causes cognitive bias in healthcare professionals. If you have fibromyalgia on your past history, any future complaints of pain are likely to be taken less seriously and attributed to 'fibromyalgia'. You could be less likely to be investigated.