The Rosenhan Experiment

Eight people, none of whom having a history of psychiatric problems, were sent to various mental institutions to lie and say they've been hearing a voice in their heads, repeatedly saying the word "thud." Other than this lie, they were to behave completely as they would normally. All eight participants were diagnosed as clinically insane by the institutions. Seven out of the eight were diagnosed as schizophrenic, the other as bi-polar. They were not allowed to leave and were forced to consume psychotropic drugs. They then realized that the only way they could leave would be to play along and pretend to be insane, and then pretend to be getting better.

Outraged by David Rosenhan's findings, the mainstream psychiatric community reacted aggressively. One major hospital even challenged Rosenhan to reproduce his results by sending more people, vowing not to let them slip through this time. He accepted. After a few months, the hospital proudly announced it had thwarted 41 attempts to sneak sane people into the "mental" hospital. It was at this point that Rosenhan revealed that he hadn't even sent anymore people to the mental institutions. PWNED!