APA Dictionary of Psychology

n. a drug, obtained from leaves of the coca shrub, that stimulates the central nervous system (see CNS stimulant), with the effects of reducing fatigue and increasing well-being, followed by a period of depression as the initial effects diminish. The drug acts by blocking the reuptake of the neurotransmitters dopamine, serotonin, and norepinephrine. The psychoactive properties of the coca plant were recognized by the Peruvian Incas before 4000 bce, and in the 1880s the possible therapeutic uses of cocaine were investigated. Sigmund Freud observed that the drug functioned as a topical anesthetic. See also crack; freebase.