that's bullshit and hearsay. the only one who was really into drugs was syd barrett and they kicked him out relatively early on.
thats true, while floyd is "trippy" and "progressive" and may have been doing a lot of psychedelics around the time of 'saucer full of secrets' and 'piper at the gates of dawn'
roger waters was known to take music composition VERY seriously, likewise gilmour.........by the time they hit 'dark side', 'the wall', 'wish you were here', 'animals'.........they were not known to be one of those bands that were fucked up all the time
they were trying to compose material that was a whole encompassing sensory experience, as evinced by the album art, ultra-forward-thinking, stage shows, ect.........while drugs might be viewed by some as a facilitator for the enjoyment of floyd's music.......they certainly are not a prerequisite.......not for the band itself either