Getting slightly more modern, we come to the Bergonic chair. During the First World War, soldiers came back from battle with what was called shell shock, which we now know as PTSD. Back then, no one understood PTSD or how to cure it, though various methods were employed, including the Bergonic chair, which delivered strong electric shocks to different parts of the body.
It didn't work (seriously, who thought it was good idea?), and shock therapy still isn't fully understood, though has resulted in brain or muscle damage.