The problem is, the claim should be based on data. Not having a good mechanism to explain it is not evidence for it being a mental illness. There is very little

The problem is, the claim should be based on data. Not having a good mechanism to explain it is not evidence for it being a mental illness. There is very little evidence supporting that it's a mental illness. For FM, a thing that has been classified as a mental disorder as late as 2016, spinal fluid pressures may have a role [1]. Medicine is just absolutely littered with these sorts of dismissals. This is why, at any point in time, you can look back 20 years to what was "standard practice", and be shocked. [1] https://www.healthrising.org/blog/2018/02/24/pressure-mounting-fibromyalgia-caused-high-pressure-brain-intracranial-hypertension/ https://www.healthrising.org/blog/2018/02/24/pressure-mounti...