I think a pretty good anecdotal data point relating "issues due to alcohol" to "issues due to drugs" is the relative lack of injuries and crimes at Burning Man versus, say, Mardi Gras, Coachella, etc. It'll have to stay anecdotal due to such things as self-selection, local support networks, and the environmental hazards in the different situations, but BM still has way less per capita than any similar-or-larger sized festival.