what medical conditions can not be proven or disproven by medical means, and what are their symptoms?

Answer 1

Alzheimer's is a disease that doctors still have difficulty diagnosing, but they're coming closer to exact diagnosis and treatment every day. Only a few years ago, Alzheimer's Disease could only be determined through autopsy, when, of course, it was too late to help the victim!

Answer 2

if a condition cannot be proven by medical means then it is not a medical condition. Medicine pretty much limits itself to those things it can identify, or at least make an educated guess about.