Torture does work in cases where the information is verifiable. Consider for example that the interrogator has an encrypted file and a subject that knows the key.
Torture is morally abhorrent, but it's not necessarily ineffective.
"What's the decryption key?"
"I don't know."
I thought the placebo affect can still work (to some degree) even if you knew you were given a placebo.
https://www.health.harvard.edu/blog/placebo-can-work-even-kn...
Either way, it's inadmissible in court. It's a technique for aiding in interrogation (like torture would be, if it worked), not a forensic technique for producing evidence.