Quote from : The Ultimate Guide to Kink: BDSM, Role Play and the Erotic Edge Book

Fear triggers the fight-or-flight response, fueled by adrenaline, which, as it turns out, is chemically related to amphetamines. Granted, it's a very different kind of high for mindfuckers: not a mellow, floaty "my vulva is one with the universe" high but a jittery, revved-up "oh fuck oh fuck oh fuck" kind of high. Endorphins are like great downers but adrenaline is uppers all the way. And it's just as addictive. Don't believe me? Go ask anyone who likes to jump off bridges or out of airplanes. - Edge