In some cases yes but there is absolutely PTSD..
Picture a young punk joining the military in the late teens or early 20's sitting in their room playing all the X-box and play stations video shoot em up games.. Thinking it would be cool to shoot up the bad guys, you feel kinda invincible.
Decide one day I can get a job in the military and I wanna go see war and shoot up some enemies.. That sounds cool!!!
You get their in the middle east and are on the front line, bullets flying over your head, could die at any moment, it's hot and you're tired and sweaty but have been trained to move forward and confront the enemy.. You see your best bud in your infantry catch a round in the face and his head gets blown apart.. Your firing on the enemy now and really killing people.. That's war.. It's not easy..
You come back home a different person and have PTSD now.. That's real.. You now have Nightmares, troubled sleep, jumpy as shiit with loud noises, you have visions of dead people next to you that you were friends with, etc. That's PTSD!!
It weighs on the young mind and it begins to break you, your innocence is lost now.. We are all human..