I think that's a bit anecdotal. Sure, there is the lore of the systems programmer who took LSD (I wonder if he reads HN :) ) and solved his design task elegantly. But to actually claim that psychedelics makes one more creative would require psychological studies with blinds. You take the sugar pill, I'll eat the mushroom - and vice versa. Which could be done, there are metrics and tests for that - if and when the stuff becomes less controversial.
A lot of people also get new ideas and solutions to problems after a good nights sleep. I knew a person in university who swore hangovers were the most creative period for him. Humans are capable of pretty friggin amazing things au naturel - drugs can modulate performance, but to draw any conclusions in the large would require actual science to draw a distinction between personal learned habits and reproducible effects.
