How many potential American soldiers, going off to fight in World War II, were rejected because they were thought to be psychopaths? In some places, forty percent. Here's what the military did about that.
In the early 1940s, shipping off men to fight in a global war was not unprecedented, but it was still a massive endeavor. Sinking resources into ineffective or counterproductive soldiers was a waste, and so the military took precautions to make sure that didn't happen. Potential soldiers received a medical check to confirm that they were physically fit for the war effort, but that wasn't enough. World War I showed the nation that war took a mental toll on a person as well as a physical one.
Psychiatry, as a means of helping rational people rather than only treating the dangerously disturbed, had recently gained credibility. It seemed, at first, to the army that there was every reason to take advantage of the science.
Shrinks were (and possibly still are) contentious. There was no one system that all the army psychiatrists used to classify personality. Each psychiatrist had his or her own system. Most of those systems were meant to classify people who were already in institutions, or at least who had urgent need of psychiatric care. This is why draft boards and recruiting offices were alarmed when large percentages of their pool of potential soldiers were classified as having severe personality disorders. For some reason, "psychopathic personality" was a big favorite.
The military had to come up with a solution, and so they recruited William Menninger, a psychiatrist who, by the end of the war, attained the rank of Brigadier General in the army. He came up with a slim book called Nomenclature of Psychiatric Disorders and Reactions. It was more informally known as Medical 203, and was used to evaluate pretty much the entire military. It's a dry-as-dust document, but, then, it wasn't created for entertainment. It was written as a way to carefully and accurately classify the various problems that people have when exposed to war. And it became one of the first official attempts to try to define different types of mental illness.
Image: Wellcome Images