I think there are legitimate questions about the advisability of marijuana, but this is a claim for which counterexamples are plentiful. Alan Moore springs to mind.
OTOH "you only tell your story once so do it on paper" is also in Dorothea Brandt's "Becoming a Writer".
This is our monthly thread for collecting these little gems and pearls of wisdom, rationality-related quotes you've seen recently, or had stored in your quotesfile for ages, and which might be handy to link to in one of our discussions.