Deconditioning is more of a psychological issue rather than a physical one.
This is contrary to all the science I have ever read on deconditioning. There is, in extreme cases (and yes, extreme cases do exist) a big impact from extreme deconditioning. Take someone in a limb cast that needs to keep it on for many months. The brain loses the connectivity to move those muscles. The brain adapts. So when the cast comes off it takes a long while to get the brain to adapt to moving the limb again.
This is not psychology. Its brain physiology. The psychology is about how the patient
feels about that. Its about coping style.
In ME there is physiological impact on the brain. Neurological functioning is dependent on energy supply. If the speech regions are compromised then someone may have trouble speaking, or even find it impossible. Again, physiology not psychology.
Psychology can have some impact on physiology, but most of the claims of such impact are exaggerated unproven hypotheses. In the case of broad and complex diseases, especially multisystem diseases, I find biological hypotheses far more plausible.
Who agrees with this statement? In the absence of a proven biological mechanism for disease, the disease must be psychological!
Let us use the same logic the other way around. In the absence of a proven psychological mechanism for disease, the disease must be biological. Kaboom!!! There goes the entirety of psychiatry.
This tells us the reasoning is unsound. The unknown is the unknown. What we can say is that in the history of medicine no distinct disease that was claimed as psychiatric was ever proven to be psychiatric. None. That does not mean such disease does not exist. It means that psychiatry has not yet established its scientific basis. That means that treating such things has to be done with caution and an awareness that you could be wrong about even the most fundamental things, including diagnosis.
Now there is clearly a psychological disorder that does exist and does not have physiological causation. That is false belief systems. That is however a big problem in society, and is cultural as well as personal in scope. Its also a big issue to medicalize it. Who are the ones with false beliefs? Democrats or Republicans? How do you justify your answer? What if both views are wrong to some extent? Who is provably right, athiests or the religiously devout? How do you justify your answer? These are social and cultural issues, though individuals can and do develop unjustified belief systems, and we are even taught them in school.
Again, my position is a moderate one compared to those extreme positions.
I had a chuckle at
@TiredSam 's reply to this. Taking the average is not guaranteed to be the right position. If some doctor decided someone needed a heart and lung transplant, and one doctor thought that they did not, would you give them a transplant of one lung and half a heart? There are some kinds of questions in which this moderate view heuristic is useful, and others where it is a nonsense. If one doctor decided someone needed that transplant NOW, and another thought putting it off for a year would be a good idea, then there is some scope for considering an in-between position depending on the evidence.