[fjsolwmv]

In the US there was an experiment where a bunch of healthy people were sent for a temporary hold and evaluation, and something like half of them were declared insane for refusing to admit they were insane, and trapped until the experimenters intervened.

[ThrowawayR2]

That's the Rosenhan experiment: https://en.wikipedia.org/wiki/Rosenhan_experiment

Rosenhan's paper itself ("On Being Sane In Insane Places") also makes for fascinating reading and is very readable even for laypeople.