It was probably built on Pavlov's experiments with dogs and bells. And, yes, the Russians, Chinese and, I think, the North Vietnamese have all used it.
I once read a novel that was so far out I only finished it because I was familiar with the author. It was all about American brainwashing using hypnosis and psychedelic drugs. I got to the end and was still a little disappointed but when I turned the last page to the author;s note it read something like, "So you think all this is impossible. Log into the Internet and Google "MK Ultra".
I'd invite you to do the same. It was all real, and one of the more disgraceful projects undertaken by the CIA.