that's an interesting point to say that the acid is what really sent him over the edge. i had a friend in high school who freaked out pretty hard on acid. they sent him to a mental hospital and when he got out...well...he never came back mentally.
as far as the film, it doesn't show any use of daniel using drugs now. but it does show his pack of KOOL's, not winstons. maybe he's changed since the film. who knows.
good point on the acid though.