Unless you're a pilot, try using good a VR airplane simulator for a while (DCS World for example), getting a feel for the airplane and then push it until you crash into the ground. The moment you loose control and start falling towards the ground, you start panicking, even though you know it's a game.
While not PTSD, I can totally imagine you can find ways of using VR to cause PTSD or similar. Like forcing someone to have a VR headset on with disturbing experiences for a long time and the person would surely eventually go insane.