when i was in grade 9 we had a presentation come in and it was just basically them tellin us bad things about weed. this was one of their points. cant remember what else they said.
and weed isnt classified as a halucinigin(sp?). its classified as a Intoxicant; Stimulant; Psychedelic; Depressant.
http://www.erowid.org/plants/cannabis/cannabis.shtml