From my perspective psychological torture in no way harms their physical body. However if the interrogator is smart they can do the following:
Block or obscure the detainee’s vision and lay them down on the ground face up in an open area. Then bring a vehicle nearby and start the engine. At that point in time another interrogator will take an empty tire and begin rolling it closer to the detainee’s head while the nearby vehicle increases is RPM’s.
As the engine make more noise and the empty tire gets closer the detainee will be quite certain the interrogator is about to smash their head with a vehicle. In this case the interrogator only needs to keep repeating the question, calmly, and without emotion.
Another one is to tie the detainee to a chair while blind folded. Then take them to a slightly elevated location about 2–3 ft. above ground. Place a mattress at the bottom of it for safety. Then position the detainee with them facing the edge. Tie the back of the chair to a rope and tie that rope so there is only about 3–4 inches of slack, anchor the rope. Then slowly inch the detainee towards the edge. As the interrogator slowly inches the detainee closer to the edge the detainees feet will notice that the floor is giving out. A great way to add to this experience is if it’s very windy, or you have a speaker playing sounds that sound far away.
As the chair finally takes all the slack ensure the interrogator has a hand on the back of the chair the entire time. That hand when removed this will throw the detainee into a frenzy of panic. If the interrogator is feeling very mean they will give the rope extra slack and let the chair fall a bit then grab back onto it arresting the decent.
Bear in mind at no point in time is the detainee in any real danger, its their perception of their environment crafted to generate fear by the interrogator that is terrifying.