>Pain management, optometry, and many other non-psychiatric disciplines also rely on self-report.

That's just plain wrong on the optometry part. While there is a lot of self-reporting used in optometry because it's faster and easier, it's entirely possible to remove it, because you can't fake not being able to read stuff when your vision is too blurry. How do you think the DMV tests your vision? It's not self-reporting; they show you something that you don't know beforehand and you have to read it. Optometrists also use vision tests to gauge your vision as they try different lenses. If they really wanted to, they could move from static tests that you can memorize to dynamic ones to prevent "cheating", but why would anyone cheat on an optometry exam (like they really would for the DMV)?