A needle and syringe programme (NSP), syringe-exchange programme (SEP), or needle exchange program (NEP) is a social service that allows injecting drug users (IDUs) to obtain hypodermic needles and associated paraphernalia at little or no cost. It is based on the philosophy of harm reduction that attempts to reduce the risk factors for diseases such as HIV/AIDS and hepatitis. While NSPs provide most or all equipment free of charge, exchange programmes require service users to return used syringes to receive an equal number of new syringes.
A comprehensive 2004 study by the World Health Organization (WHO) found a "compelling case that NSPs substantially and cost effectively reduce the spread of HIV among IDUs and do so without evidence of exacerbating injecting drug use at either the individual or societal level." WHO's findings have also been supported by the American Medical Association (AMA), which in 2000 adopted a position strongly supporting NSPs when combined with addiction counseling.
Needle-exchange programmes can be traced back to informal activities undertaken during the 1970s. The idea is likely to have been rediscovered in multiple locations. The first government-approved initiative (Netherlands) was undertaken in the early to mid-1980s, followed closely by other initiatives. While the initial programme was motivated by an outbreak of hepatitis B, the AIDS pandemic motivated the rapid adoption of these programmes around the world.
Harm reduction begins with the assumption that it is not reasonable to assume that individuals make healthy decisions. Advocates hold that those trapped in dangerous behaviors are often unable and/or unwilling to break free of them, and should at least be enabled to continue these behaviors in a less harmful manner. A tendency in the medical profession has been to treat drug dependency as a chronic illness like diabetes, hypertension and asthma, to be treated, evaluated and even insured in like manner. Treating drug dependency as an illness absolves drug users of responsibility for their condition.