I stumbled across this question pretty randomly on this site and immediately knew I had to create a post about it.
Personally, I’ve never mixed drugs/alcohol with writing. If I’m drinking, then it’s something I’m doing with friends. I’ve never really thought about drinking at home and seeing how that helped or hindered my writing. That said, I know a lot of great writers are very well known for drinking and writing. The quote “write drunk and edit sober” speaks magnitudes.