In his memoirs of the Falklands affair a senior officer made comparisons between the Marine Commandos who went home to the UK by ship and the Parachute Regiment who were flown home -- both composed of similar persons.
In his view there were many fewer post-action problems in the Commandos than in the Paras because they had time to talk over the issues and experiences among themselves (it is well known soldiers talk only to other soldiers) before dispersal.
Waiting until the PTSD is well established and manifesting itself is far too late, it must be prevented, and prevention comes from recognition of the inciting factors and the symptoms. If a mandatory buddy system were imposed and supervised this might serve the purpose. In a good military organisation the sergeants know their men and act as their surrogate parents, but are all our military organisations so ordered, and are the men recruited suitable to the stress of the task? Who gets to carry a weapon? The lowest IQ's?