What an interesting topic! The American Civil War was where post traumatic stress disorder was first recognized. Dr. Jacob Da Costa was an army surgeon at the 1900s or so, and began to recognize a large number of his patients had a variety of symptoms but no illness he could detect. Irritability, heart palpitations, insomnia, and a whole host of things. As noted, a good many of these men were also troubled by feelings of having been a coward, questions about the morality of the war, being on the losing side and other psychological issues. He was the first to connect it to hard service during the war. It was called Da Costa Syndrome, 'soldier's heart', shell shock, combat fatigue and some other terms until PTSD was arrived at. The disorder had actually been noted as far back as Roman times, particularly so during the Napoleonic wars, but no one had associated it with combat before.
I think there was a really high number of suicides connected with wartime service among the survivors. Major Berry, who led the NC brigade who fired on Stonewall Jackson, committed suicide not long after the war - he had given the order. There were also a large number of soldiers who were committed to asylums and institutions for mental health problems. (A good many were also confined who were not insane but had head injuries or severe chronic pain, like Thomas Benton and William Cushing.) Wonder if there are any statistics to look at for those types of admissions to institutions?
There were also a really big number of men who were addicted to drugs because of their war injuries. Cushing was one of those, which is what led to his being committed. During his famous attack on the Albemarle, he didn't clear the blast and broke his back and hip. It never healed and he was never pain free. The only management for that condition was morphine - he became addicted. Since things like this, drug addiction or alcoholism, etc., were considered moral failings at that time, I think there were men who exited rather than live with that 'failing'. Sometimes I wonder if this is where America's problem with drugs really began.