I think it's possible. In feb 2007, I took an OD that nearly killed me, it was very frightening. For about a year or so afterwards, I would have flashbacks of drinking the activated charcoal. It would happen randomly but I truly believe I could taste. I was once in a shop and a smell must have triggered off something in my brain and I vomitted after I ran out of the shop.
I'm ok with it now. It got easier as I was able to reassure myself that I wouldn't be forced to drink it in the middle of a shop!
