RESULTS	We found a significant rank order for the sequence of first use : 1 ) alcohol , 2 ) nicotine , 3 ) cannabis , 4 ) LSD , 5 ) psilocybin , 6 ) amphetamine , 7 ) cocaine , 8 ) MDMA , 9 ) gamma-hydroxybutyrate ( GHB ) , 10 ) ephedrine , 11 ) ketamine .\