Heroin (diacetylmorphine (INN)), also known as diamorphine (BAN), or, especially in older literature, as morphine diacetate, is a semi-synthetic opioid drug synthesized from morphine, a derivative of the opium poppy. It is the 3,6-diacetyl ester of morphine (di-acetyl-morphine) and a morphine prodrug. The white crystalline form is commonly the hydrochloride salt diacetylmorphine hydrochloride, though, when supplied illegally, it is often adulterated, thus dulling the sheen and consistency from that to a matte white powder, which diacetylmorphine freebase typically is. 90% of illicit diamorphine (heroin) is thought to be produced in Afghanistan.

Diacetylmorphine, in non-medical settings called heroin, is used as a recreational drug for the transcendent relaxation and intense euphoria it induces. Anthropologist Michael Agar once described heroin as “the perfect whatever drug.” Tolerance quickly develops, and users need more of the drug to achieve the same effects. Its popularity with recreational drug users, compared to morphine, reportedly stems from its perceived different effects. In particular, users report an intense rush, an acute transcendent state of euphoria, that occurs while diacetylmorphine is being metabolized into 6-monoacetylmorphine (6-MAM) and morphine in the brain. Heroin produces more euphoria than other opioids upon injection. One possible explanation is the presence of 6-monoacetylmorphine, a metabolite unique to heroin. While other opioids of recreational use, such as codeine, produce only morphine, heroin also leaves 6-MAM, also a psycho-active metabolite. However, this perception is not supported by the results of clinical studies comparing the physiological and subjective effects of injected heroin and morphine in individuals formerly addicted to opioids; these subjects showed no preference for one drug over the other. Equipotent injected doses had comparable action courses, with no difference in subjects’ self-rated feelings of euphoria, ambition, nervousness, relaxation, drowsiness, or sleepiness.

Short-term addiction studies by the same researchers demonstrated that tolerance developed at a similar rate to both heroin and morphine. When compared to the opioids hydromorphone, fentanyl, oxycodone, and pethidine/meperidine, former addicts showed a strong preference for heroin and morphine, suggesting that heroin and morphine are particularly susceptible to abuse and addiction. Morphine and heroin were also much more likely to produce euphoria and other positive subjective effects when compared to these other opioids.

Some researchers have attempted to explain heroin use and the culture that surrounds it through the use of sociological theories. In Righteous Dopefiend, Philippe Bourgois and Jeff Schonberg use anomie theory to explain why people begin using heroin. By analyzing a community in San Francisco, they demonstrated that heroin use was caused in part due to internal and external factors such as violent homes and parental neglect. This lack of emotional, social, and financial support causes strain and influences individuals to engage in deviant acts, including heroin usage. They further found that heroin users practiced “retreatism”, a behavior first described by Howard Abadinsky, in which those who suffer from such strain reject society’s goals and institutionalized means of achieving them.

References: http://en.wikipedia.org/wiki/Heroin