Except there is obviously a psychological component to the triggering of CFS/ME symptoms. Just consider how in many of us mental exertion can cause post-exertional malaise. It's not like we have to completely wipe out our thoughts in order to not have post-exertional malaise. There are clearly some types of thoughts, or quantity, that eventually have a physical affect on our bodies. This is just an example.
I wouldn't say its "some kind of thoughts" that can trigger mental exertion-derived PEM. "Some kind of thoughts" suggests that the subject matter of the thoughts plays a role, which don't think is the case in any ME/CFS patient I have talked to about this issue.
I have had quite a bit of discussion with members of this forum regarding what types of mental exertion triggers PEM, and it seems that many ME/CFS patients find socializing (talking and chatting) with friends is a major cause of PEM derived from mental activity. I get this type of PEM myself, and it in fact significantly limits my social life.
After pondering upon this phenomenon for many years, I finally came up with a theory to try to explain it, which is outlined in
this post. Basically, my theory is that mental exertion-derived PEM from socializing is caused by
brain arousal.
Arousal is a physiological state in the brain which involves the reticular activating system (RAS). As we get more excited by stimuli (and a good chat or discussion is very mentally stimulating), arousal increases. I suspect that some physiological response connected to arousal (such as the increase in norepinephrine) then drives the PEM.
But you wouldn't call arousal "some kind of thoughts"; arousal is just the level of excited alertness of the brain.
I was able to notice several times when my anxiety popped up, either in response to social stress or sometimes seemingly out of nowhere, but probably caused certain anxious/negative thoughts I was just having, it was directly tied to extreme discomfort in my shoulder and/or chest.
This chicken and egg etiology can be hard to fathom. I had a similar issue when I noticed that as my anxiety levels rose, so would my level of nasal / sinus congestion and inflammation.
From your perspective, you might assume that my rising anxiety was causing this congestion and inflammation.
However, I had a theory that it was the other way around. To test this theory, I starting using topical nasal sprays and treatments that would reduce my nasal / sinus congestion and inflammation. Sure enough, when I did this, I found my anxiety levels dropped also. So this indicated that the nasal / sinus congestion and inflammation was a factor causing my anxiety symptoms, and not the other way around. (Inflammation is increasing being linked to mental conditions such as anxiety, depression, schizophrenia, and so forth, so it is not surprising that sinus inflammation might lead to anxiety).
Psychiatry is brim full of these unproven ideas that anxiety symptoms in the mind can lead to physical symptoms.
For example, anxiety often arises with IBS, and some psychiatric researchers have come to the conclusion that the gut symptoms are a result of the anxiety; ie, they posit that the gut symptoms are psychosomatic, caused by the anxious mental state.
However, IBS often arises from a gut infection, and in this case, the anxiety comes after the IBS has been triggered by the infection, indicating that that anxiety is a consequence of the IBS, and not the other way around.
So if you use a bit of detective work, you can figure out which is primary and which is secondary.