“Channel 13: More than 20,000 Israeli soldiers have been injured, 56% of whom suffer from psychological disorders and traumas. The total number of wounded has risen to 80,000, including 31,000 cases of post-traumatic stress disorder, and estimates indicate reaching 100,000 injured by 2028.”
The transition in Nazi Germany from shooting to gassing happened partly because of the effect it has on the psyche of the perpetrators.
https://en.wikipedia.org/wiki/Einsatzgruppen
“The historian Christian Ingrao notes an attempt was made to make the shootings a collective act without individual responsibility. Framing the shootings in this way was not psychologically sufficient for every perpetrator to feel absolved of guilt.”This isn’t the best evidence, but it shouldn’t be too hard to find, if wants to look more deeply into it.