Going along with your postulation outright, I'd note that most of the drugs consumed by musicians wouldn't be called "performance enhancing" in the context of g

Going along with your postulation outright, I'd note that most of the drugs consumed by musicians wouldn't be called "performance enhancing" in the context of general terminology - alcohol, grass, hallucinogens, downers, stimulants - pretty much mess with mental capacity and function, not really "enhance" them. A couple cases can be made for certain uppers, but I kind of look at the relationship of drugs and musicians as one rooted in self-medication moreso than performance related. I have heard of orchestra/symphony types using beta blockers.