APA Dictionary of Psychology

a form of drug use in which the substance is injected directly into a vein with a hypodermic needle and syringe to speed up and maximize the effect. This typically involves self-administration of a psychoactive drug, often an opioid and especially heroin. Sharing or reusing needles or syringes increases the risk of acquiring and transmitting serious blood-borne infections, including hepatitis and HIV. See also needle exchange program.