Hallucinogens, also referred to as psychedelics, are a broad range of agents that alter perception in different ways. An estimated 1.3 million Americans are current (past month) users of hallucinogens. Hallucinogen use is highest among young adults; 3,4-methylenedioxymethamphetamine (MDMA) is the most commonly used agent, followed by lysergic acid diethylamide (LSD) and phencyclidine (PCP)....