1. Madness
(source)
A Shell Shocked soldier in a trench during the Battle of Courcelette in mid-September 1916. Shell shock was the reaction of soldiers in World War I to the trauma of battle. It has been described as a reaction to the intensity of the bombardment and fighting that produced a helplessness appearing variously as panic, or flight, an inability to reason, sleep, walk or talk. "Simply put, after even the most obedient soldier had enough shells rain down on him, without any means of fighting back, he often lost all self control."