Heroin exerts its main effects through psychological mechanisms of action, the user feels a sense of great warmth and well-being and views the world with greatly reduced anxiety and emotional distress. These feelings last for a relatively short period of time of around 4-6 hours. With repeated use the user develops tolerance and the user will need greater quantities of the substance to achieve the same effect. In time, as addiction develops the user lifestyle alters to accommodate spending an increasing amount of time obtaining and consuming drugs. This is likely to lead to difficulties in employment and relationships, with less attention being given to their responsibilities and the needs of others. As a result they may turn to criminal activity to fund their habit, likely entailing physical and emotional hazards and bring them into contact with a dubious assortment of people. This essay will examine how the social, psychological and biological factors interact in heroin addiction and look at what therapeutic approaches exist to deal with this form of dependency.
Substance addiction, in general, is defined as the continued use of a substance despite it being clear that it is harming the individual (DSM IV, 1994). The most common form of treatment in heroin addiction is that of methadone maintenance treatment (MMT). Methadone is a synthetic opioid which acts on the opioid receptors in the brain, producing many of the same effects as heroin, thus acting as replacement therapy and reducing craving. Craving represents a feeling of desire to approach a pleasant stimulus (Oldham and Wright, 2001). At higher dosages methadone can block the euphoric effects of heroin and other similar opioid drugs, reducing the motivation to use illicit substances. MMT has been shown to