Patients lying about symptoms have been a medical issue for centuries. It is the main topic of Baudrillard's philosophical analysis on simulacra and simulation. Think about it, a soldier who doesnt want to be deployed starts simulating symptoms of a disease to be discharged. How would you catch him, can you? The answer seems straight forward, until you scrutinize it in detail. Neither military or medical knowledge actually have an answer. The kid who doesn't want to go to school says he has a headache and a tummy ache. How do you validate another's conscious and sensory experience? Hypochondriacs affirm to develop every disease they hear about. People under stress feel and have somatic symptoms akin to physical diseases, even when functionally nothing is wrong with them. Etcetera. Disease and diagnosis are not so simple and straight forward, not even when talking about bodily functions.