During the First World War
Military authorities often failed to acknowledge shell shock as an actual affliction. It was not until February 1915 that the term was even accepted by the British military's psychiatric community. Authorities hesitated to recognize shell shock as an injury, because soldiers suffering its effects often appeared physically unharmed.
Symptoms varied from soldier to soldier, but could include the more severe disorders like temporary loss of sight or speech and involuntary spasms or paralysis in limbs. These more severe indicators were classified as symptoms of hysteria, and most commonly affected the ordinary soldiers.
Other more mild symptoms such as headache, exhaustion, stress, and irritation were classified as neursasthenia and tended to affect officers.
The distinction between hysteria and neurasthenia reflected the commonly held belief that mental health issues were an affliction of the lower classes, or a result of weak moral character. The two classifications also meant very different treatment options to cure the afflicted individual.