Evolutionarily speaking, social isolation is more stressful than violence
Soldiers develop mental health issues more often when they return home and become socially isolated than when they are at war, surrounded by their brothers
I was no "real" soldier but due to some weird circumstances I fought in a war. The difficult part of returning home is everything is so low stakes, the freedom to ride around on a Hilux living by your wits and a rifle turns into a world where you can easily survive flipping burgers and you have a toddler screaming at you because you selected the wrong color cup and the HOA has a meltdown because they decided the wrong species of plant is growing on your yard. Boring.
Sometimes you dream of the war because life is so simple and the goal is obvious, and every decision seems impactful to your survival.
There's a section of Gustav Hasford's 'The Short Timers' that describes this well. Two soldiers have recently returned from the front lines and hitch a lift to a base, or PX, or something of that nature. The gate guard - some fat fuck who's clearly never seen the enemy face to face - won't let them in because they're Marines and Marine day is Tuesday, or something of that nature, so our man just cocks his rifle and sticks it in the guy's stomach, finger on the trigger, and looks the guy in the eye.
It's a very well written book.
I don't know really whether I should recommend war stories to a guy who's been to war but if you do enjoy reading that sort of stuff, both of his novels (The Short Timers - which turned into Full Metal Jacket - and the sequel 'The Phantom Blooper' are excellent.)
Soldiers develop mental health issues more often when they return home and become socially isolated than when they are at war, surrounded by their brothers