I absolutely know I chew ice in part due to an enlarged thyroid. I go back and forth between hyper and hypo-thyroidism. When I'm hypo, my thyroid swells up and my windpipe gets constricted, and as odd as it sounds, food goes down fine, coffee, milk and carbonated drinks, fine...but water seems to come back up. So I find chewed-up ice to be easier to get down. If I am able to drink water, it has to be room temperature...and I could never drink water with ice in it...but I can get a few cupfuls of pure ice down no problem! I don't get it.