PSYCHOACTIVE DRUG-USE IN EVOLUTIONARY PERSPECTIVE

Pure psychoactive drugs and direct routes of administration are evolut ionarily novel features of our environment. They are inherently pathog enic because they bypass adaptive information processing systems and a ct directly on ancient brain mechanisms that control emotion and behav ior. Drugs that induce positive emotions give a false signal of a fitn ess benefit. This signal hijacks incentive mechanisms of ''liking'' an d ''wanting,'' and can result in continued use of drugs that no longer bring pleasure. Drugs that block negative emotions can impair useful defenses, although there are several reasons why their use is often sa fe nonetheless. A deeper understanding of the evolutionary origins and functions of the emotions and their neural mechanisms is needed as a basis Tor decisions about the use of psychoactive drugs.