Do you think philosophers like Descartes, Plato, etc. were on drugs when they had their famous works like Descartes' Meditations?
EDIT: Word choice
In his book Cogito Ergo Sum: The Life of Rene' Descartes (which I have not read; I'm just looking at passages from Google Books), author Richard Watson states that it is likely that Descartes smoked pot while he was a soldier in Breda. Watson's logic is as follows: we have evidence (such as the recent study in the South African Journal of Science) that marijuana was smoked in conjunction with tobacco in the early 17th century (Descartes was in Breda during the Thirty Years' War in 1618). At the time, tobacco use was fairly prolific throughout Europe and 17th century Dutch art often depicts its subjects using tobacco, so there is a pretty high likelihood that Descartes would have come into contact with tobacco while he was in Breda. Watson then connects the ubiquity of tobacco use in the Netherlands to the evidence that marijuana was occasionally smoked with tobacco in order to argue that Descartes probably smoked pot at some point. I think this is an extrapolation, but I definitely haven't researched this as much as Watson has.
That being said, Descartes later became a tobacco critic, and as such it's next to nil that he was using marijuana while he wrote Meditations around two decades after his time in Breda.
The rest of your question is pretty broad, and I'm sure at least some philosophers were using psychoactive substances while they wrote famous pieces (Sartre stated that his experience with mescaline influenced some of his works and Henry James wrote an essay on nitrous oxide), but probably not the majority of them.
Sources: http://www.sajs.co.za/sites/default/files/publications/pdf/SAJS%20111_7-8_Thackeray_Sci%20Corr.pdf
https://www.lib.umn.edu/bell/tradeproducts/tobacco
https://www.jstor.org/stable/25617422?seq=1#page_scan_tab_contents (unfortunately I can't find any database of all of the paintings, but you can google Dutch Golden Age Tobacco paintings for some examples)
http://www.nytimes.com/2009/11/15/weekinreview/15grist.html
https://www.theatlantic.com/magazine/archive/1996/05/the-nitrous-oxide-philosopher/376581/