our government designed a system of interrogation whose express purpose was to inflict serious psychological damage on people we were interrogating.
This post explains how easy this can be:
sensory deprivation produces psychosis within hours. It's shockingly fast, and can have severe long-term effects after just a day or two. All you have to do is strap somebody down, put on a blindfold, sound-proof earmuffs, and gloves that reduce tactile sensation, and full-blown hallucinations begin in less than a day.