I would love to get on the inside and see how these guys are handled. No, I don't mean the physical torture, I mean the mind shag. I have NO knowledge of how this actually works, but I'm imagining little snatches of fake newscasts that they are allowed to "accidentally" overhear, or fake newspaper headlines they are allowed to glimpse. I don't know if this tactic of constructing a carefully designed alternate reality is even used, but if so the mind reels. I would imagine there may also be a friendly and seemingly gulible guard who they think they are gradually converting to islam. It would be so cool to really see how this is done, but of course it's better not to be known.
For an in-detail description of how the Soviets did it, read the third chapter of Solzhenitsyn's The Gulag Archipelago.
The key piece of breaking someone down mentally seems to be sleep deprivation. Severe sleep deprivation removes your will, your personality, and your grip on reality. It takes you to frightening places that your mind has never seen before.