Earlier quoted context omitted.
> We demonstrate an absence of association between symptom burden and radiographic or biochemical abnormality. We suggest that the phenomenon of Long-COVID may not be directly attributable to the effect of SARS-CoV-2, but rather the neuropsychiatric insults may play a greater role in its aetiology. This is consistent with ME/CFS, which the WHO classifies as a disorder of the nervous system. There are no known diagnos…
That sounds like a rather arrogant assumption that scientists can't figure what the problem is hence the patients are nuts. It could also be the science isn't that good. I had a girlfriend who got ME/CFS. Before she could race me up a 1000 ft hill after she could hardly walk. That change happened in a few days as a result of an infection, and lasted years. Definitely wasn't psychological.
No diagnostic markers have been found (after many decades of seeking them) because CFS is a not a physiological illness. Countless millions of dollars and hundreds if not thousands of doctors and researchers have chased after the holy grail of reliable diagnostic markers for CFS to absolutely no avail because there is nothing to find.
Instead, various MRI studies have shown consistent brain abnormalities in CFS patients. Recently, low dose Abilify (a neurotransmitter modulator typically used for various psychological disorders) has shown some usefulness in CFS patients. And a drug called CT38 that targets receptors involved in managing the stress response has also produced strong results in a small group of CFS patients:
> CT38, a proprietary peptide agonist selective for Corticotropin-Releasing Factor Receptor Type 2 (CRFR2), one of two receptors, or pathways, that control serotonin in the limbic system and cord. In response to any threat to homeostasis, corticotropin-releasing factor (CRF) acts via CRFR1 and CRFR2 to control serotonin. When the threat subsides, these receptors return to their normal configuration – unless permanently upregulated by an intense or prolonged threat. This then dysregulates serotonin, leading to the shared symptoms of many chronic diseases. [1]
> “Once the CRHR2 receptor gets switched on, it's as if it is permanently switched on. When that happens, it has downstream effects on the limbic system and serotonin system.” Then, any stressor the person is exposed to – including exercise, heat or bright lights – is interpreted as being a major stressor. Other potential stressors are mental trauma, physical trauma, viruses and toxins. [1]
And what I've noted is just a small sample of the surfeit of evidence that CFS is a neurological disorder. Unfortunately, the community of CFS patients is more than a little deranged and they're still gunning for a simple answer that doesn't make them feel uncomfortable and that's more amenable to some magic pill solution.
[1] https://www.biospace.com/article/a-different-pathway-to-solv...