World War I brought mental illness to the public’s attention when it became obvious that “shell shock,” known as PTSD today, was a problem among troops returning from combat. Which is the MOST LIKELY reason this issue became obvious after World War I?

Other wars were very mild and not nearly as traumatizing as World War I.

So many men fought in World War I that it made the condition obvious.

There was a lot of treatment for mental illness but not this kind of trauma.

Mental health issues are the result of the pressure of modern society and did not exist in previous eras.