"Many prisoners find survival in physical exercise, prayer, or plans for escape. Many carry out elaborate mental exercises, building entire houses in their heads, board by board, nail by nail, from the ground up, or memorizing team rosters for a baseball season. McCain recreated in his mind movies he’d seen. Anderson reconstructed complete novels from memory. Yuri Nosenko, a K.G.B. defector whom the C.I.A. wrongly accused of being a double agent and held for three years in total isolation (no reading material, no news, no human contact except with interrogators) in a closet-size concrete cell near Williamsburg, Virginia, made chess sets from threads and a calendar from lint (only to have them discovered and swept away)."
It seems that isolation works like a virus attack, slowly rendering the mind incapable of working properly. Somewhat like a mental Gom Jabbar. Some people at least seem to fight back by consciously creating stimulation. Hack and Counter Hack.