10 Heroin Heroin is an opiate processed directly from the extracts of the opium poppy. It was originally created to help cure people of addiction to morphine. Upon crossing the blood-brain barrier, which occurs soon after introduction of the drug into the bloodstream, heroin is converted into morphine, which mimics the action of endorphins, creating a sense of well-being; the characteristic euphoria has been described as an “orgasm” centered in the gut. One of the most common methods of heroin use is via intravenous injection. 9 Cocaine Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. It is both a stimulant of the central nervous system and an appetite suppressant, giving rise to what has been described as a euphoric sense of happiness and increased energy. It is most often used recreationally for this effect. Cocaine is a potent central nervous system stimulant. Its effects can last fr...