My point is just that I think pathogens undoubtedly play a role, as do life circumstances. There are likely several other factors as well - maybe various genetics, physical injury, childhood experiences, and so forth.
I take a strong counter-view to the theory that serious mental illness is triggered by adverse life events, because such views are so prevalent amongst psychiatrists and mental health care professionals. If this view were not so prevalent (and largely erroneous in my view), I would not feel the need to try to counter it.
ME/CFS patients feel strongly that their illness is biological, and have fought against the idea it is psychological.
I feel exactly the same about psychiatric symptoms: I believe these are largely biologically caused, not psychological.
The argument against adverse life circumstances (psychological factors) playing a role in triggering mental health conditions is that no psychological therapies have ever cured serious mental health conditions such as bipolar, schizophrenia, autism, etc.
If psychological factors were able to push you into a state of mental ill health, then logically, psychological therapy (ie, talk therapy on the couch, art therapy, or what have you) should be able to reverse that ill health. But it does not.
Freud himself admitted that he never cured one patient with the psychoanalysis therapy he invented. But back in those days, treatments which target the physical brain were very limited, so talk therapy on the couch was about the only thing on offer.
Psychological therapies are effective in cases where depression is caused by life events though. Depression is one mental condition which can have biological causes, but can also be caused by life events (or a combination of both).
Mental health can be some of the worst suffering inflicted on human beings. The only comparable suffering is perhaps those who live in constant terrible pain (which includes some ME/CFS patients with severe body pains).
We need to figure out what causes mental ill health, we need to determine the root cause, because it's a torture no human being should go through.
Personally, even after my ME/CFS, I kind of loved professional stress and mentally thrived on it but physically suffered. I was still able to keep that up for over a decade until a further decline made it so even though I still thrived on the professional stress, the crashes became unbearable. Even now I love the 'idea' of professional stress, but I'm aware of the toll it will take (only took a couple decades to learn).
Presumably you do not have an anxiety disorder, as you were enjoying the stress and excitement, but then suffered the next few days due to PEM. But at the time, the excitement was fun.
However, if you had generalised anxiety disorder, even the the most minor stresses can feel overwhelmingly tense and very unpleasant.
The analogy I often give to explain the mental tension of generalised anxiety disorder is that it's like you are walking down the street a night, and suddenly you are pulled into a dark alleyway by a mugger, and gun is pointed to your head. At that very moment, you feel extreme anxiety and mental tension. Your brain automatically turns your anxiety circuits on to the maximum for survival reasons, because your life now depends on your next actions.
Generalised anxiety disorder (GAD) is like the anxiety you would feel with that gun pointed to your head, except that there is no gun. There are no external causes for your anxiety; the anxiety is there because of a dysfunction in your brain: your anxiety circuits have been mistakenly permanently switched on, due to some malfunction of the brain. Wirth GAD, even if you are in the most relaxing of circumstances, you still will feel as tense as you would be if a gun were pointed to your head.
Now take someone with generalised anxiety disorder, who is constantly in this heightened state of anxiety 24 hours a day, and then in addition, apply an external stressor in their life.
That external stressor is going to be interpreted as 10 times more stressful than it actually is, because the brain is already super hyped up with anxiety. In this way, people with anxiety can not longer handle ordinary life stressors.