If such cases occur often enough, then the list of symptoms is not particularly useful. It can only have some use as a warning, if there are non-symptomatic tes

If such cases occur often enough, then the list of symptoms is not particularly useful. It can only have some use as a warning, if there are non-symptomatic tests available, but such is not the case here - you can't lab test your brain cells for the source of your opinions. What you seem to suggest is looking for more symptoms if you already experience some - but that "method" is flawed, and known as medical student's disease: http://en.wikipedia.org/wiki/Medical_students_disease http://en.wikipedia.org/wiki/Medical_students_disease . In any case, if someone could reasonably check off all the items on the list, but be a very objective person; or respond to none of the items, and base his opinions entirely on groupthink; then I maintain my belief that the list is useless.