Deploying troops taking SSRI's could be very dangerous is the reason. You don't need a guy out in the field all of the sudden thinking his platoon is the enemy. Serotonin balance is a very delicate manner not even some physicans take serious enough when writing SSRI scrips. Once it migrates from the stomach to the brain you in effect have a soldier having LSD type experiences.
PTSD requires years of therapy a lot of times which is out of a shrinks area. Sending a soldier with PTSD back into combat is a sure way of complicating the disorder or bringing a relapse. The mind has had enough carnage for years to come.
VEry rarely is a soldier, Marine returned home after War Trauma. Usually they may be given a minor tranquilizer, if that and sent back to “the front” ( whatever that is now)...Most often, troops don’t know themselves they are in shock and most often do not want to leave combat and leave their brothers in arms.
We only have a very very very very small percentage serving now...so there are too many and too long deployments. THAT would be the area to intervene with the least problems...but we can’t cause too many rappers are running arond with their pants hangin low and being tough at the shopping malls!