White Torture in Iran prisons

I'm not sure what do they do to journalist/writer prisoners in Iran that when they come out, they are completely different people. Most of them, not only stop writing, but also loose the sense of enthusiasm they used to have toward life and joy. For example Sina Motallebi has not written a single piece anywhere since then. Also I've heard that Kambiz Kahe, the pro-active film critic, is now a depressed and silent man.

This kind of white torture, as it's sometimes called, is much worse that ordinary ways of physical torture. Because in the latter, you'll proudly carry signs of your braveness and their crudeness on your body until you die. Moreover, you can show it to other people what they did to you because of your writings or activities. But when they break you down and make a silent, hopeless, and suicidal person of you, who doesn't have any bruise to be proud of or to show off, you'll be dead; in a way that costs the minimum political price for them.