I read a well-stated spiel on the usage of drugs just recently. It was through a fiction novel. James Herbert's Others, to be precise. I do not have an eidetic memory, but I shall attempt to do justice in my retelling. Basically, what he logically surmised was that doing drugs was not a way of opening the consciousness to reality so much as it was to stifle reality for the sake of allowing the delusion to seem real. That is all.
The reality is everything we ingest that we digest contributes to our chemical soup in varying proportions and there is nothing unreal or delusional about the effects.
The trip itself may consists of delusions but that doesn't mean that a psychedelic trip full of weirdness can't open up your consciousness for reality! It can, but it is only the opening up. It is not handing you reality or it's secrets/insights. So some people may steer themselves in some kind of delusion afterwards and some seem to really open up for all kinds of perspectives. The truth rarely fits solely in one perspective.
