At the beginning of the First World War, mental illnesses and nervous conditions were believed to result from an individual’s “weak” mind or character, rather than a legitimate reaction to an overwhelming event. The evolution of the conflict and its mechanization and brutalization added a different dimension to the understanding and treatment of what was known among soldiers as “shell shock”. By the end of the war, over 10,000 Canadian soldiers would be diagnosed with a “war neurosis” — what we know today as Post-traumatic stress disorder — and many more suffered without ever receiving an official diagnosis.