My understanding of "being gassed" during WW I : while fighting in dug out trenches in Europe, a type of gas (probably nerve gas) was used as a weapon by Germany. As a result some of our soldiers were permanently affected. I remember as a high school student in the 1940's I had a teacher who was supposedly "gassed" and he, in mid sentence, would walk out the open classroom door and continue down the hallway, still lecturing. That was as strange as he ever acted. For better understanding, Molly Ball Stoddard