Thanks for this. These diagnostic mysteries are not uncommon enough. Suffering from illness is bad enough. Adding "frustrating dismissal by physicians" makes it nearly intolerable, especially since so many people place physicians in such high regard.
"One doctor suggested Knapp’s problems might be psychological."
Gaslighting by people such as those from "science-based" or "evidence-based" medicine is such a demoralizing and psychologically abusive experience, particularly as these "experts" have self-appointed "skeptic" coattail-riders who heap abuse on sick people online and irl.
Stories like this man's should help us understand that with all the scientific progress that has been made, our experts are still human beings with incomplete information and imperfect knowledge.