Yuuuuup. Rates of suicide and alcoholism skyrocketed amongst the German military in the early days of the Holocaust. It was one of the motivators behind the creation of death camps. They needed a process that would allow them to kill large amounts of civilians but didn't cause mental health problems among the people doing the killing. Or as the Nazis would later figure out, have prisoners carry out different steps of the process so guards only had to threaten people without directly harming anyone. It's why they used the "I was just following orders" defense at Nuremberg when the war was over.

I suspect it's also why US troops have higher rates of PTSD and other problems from conflicts like Vietnam, Iraq, and Afghanistan compared to WWI and WWII, despite the world wars being more traumatic conflicts.