Yes.
Hell the title itself is brillant comment on drug addiction (if you know what trainspottiing is). That’s what we should be telling kids…how boring it is.
And the scene where…well…THE scene shudder where the mother is screaming. And the other junkies are just wishing she’d shut up. But Ewan, being compassionate, does the right thing and gives her a shot.
Right after he gives himself one.
Oh yes. Rang true that.
And then there’s…no, I don’t want to revisit this any farther.
That film is exactly the reason I opened this thread.
Hunter S. Thompson/Terry Gilliam/Johnny Depp portrayed one’s behaviour on acid so accurately it was amazing. I believe there are many scenes and thoughts in that movie that cannot be fully understood unless you at one point had the mentality of being on acid.
Having spent a little time wandering around Las Vegas on acid, there are a number of impressions in that film that stuck me as astonishingly accurate representations of that experience.Conspicuously colourful kalaidoscopic casino carpeting keeps coming constantly kinesthetically combining with cacophonous clanging… 
Yeah, but I’m talking about things other than visuals. For example, when Duke is in the hotel room tripping his brain out, and Lacerda comes in, and he’s hiding behind the table and crawling his hand like a spider. Then he talks about the giant monster outside his window, though the book does a better job of describing it, it’s great. In the book he describes how he’s studying it’s movements, definitely a thing that an experienced acid taker would do.
Huh. (Sorry to continue this non-addiction hijack, but) I took large quantities of LSD a couple of times per week between 1989 and 1998 with very few breaks, and only became significantly confused about what was real and what wasn’t once, (which was a bad night in 1990 when I first learned that that tolerance goes away if you lay off for a month) – and one other time when I plugged an anime tape I hadn’t seen in at a random spot and my cats’ reaction to the projected video image (A multi-tentacled Lovecraftian horror rising up out of the ground, as both of my cats ran up to the wall and stood on their hind legs with their forepaws at the base of the projected image, interested in the apparent motion, while the protagonist screamed “That’s their god!” and continuing chaos and panic went on onscreen) convinced me in a matter of seconds that the alien deity Bubastis had returned after an aeon and that I was lucky I had housecats and could continue to live as their servant, because people without cats were all going to be eaten. That probably lasted for less than a minute, though, until I got it together enough to press “stop” on the remote, and look out the window to confirm that the sky hadn’t cracked open or anything.
So I don’t really agree that an experienced LSD user would typically have a true hallucination – although it certainly fits with someone who gobbles handfuls of drugs indiscriminately, and also has a headful of acid. (Hunter S. Thompson was definitely not the sort of person I would want to be high around, or have high around me. Very entertaining when it’s remote, though, as in a book or on the screen.)
In the movie they don’t actually show the monster floating around outside, and I agree with you that it’s very hard to get full open eye hallucinations, but I’m not talking about visuals like I mentioned before. Just the very idea that he sees or imagines this monster (I’ll bet you know how easy it is to create an image in your mind and have it be so vivid it’s as though your eyes were open) and then decides to study its movements. From my experience with acid and the observation of other people, it’s very common for people under the influence to be very analytical and to examine everything, as he was doing.