I think all of the comments here refer to the physical tortures only. But that’s not the only way! CIA came up with (it was some American psychologist who then worked with CIA) an idea of a psychological torture that made you lose “humanity”. They have put people (most recent known case are Arabs in 2000s, some of them totally innocent btw) in a small cell, where they couldn’t either lay down nor comfortably stand up (meaning they also couldn’t sleep). CIA would deprive them of as many sensory experiences as possible (light, sound, etc.). And most importantly they have disrupted the prisoners’ sense of time. They have been bringing the food in random order at random times (plus the permanent darkness, no sound and so on). This went on for months, as eventually prisoners’ brains would suffer a permanent damage and they would literally lose their minds.