This is an investigation into the beliefs and experience of a group of clients in a long term methadone prescribing programme and those of staff associated with this programme. The main aims of this study were: firstly, to identify the influence of contextual factors in participants' beliefs about methadone maintenance and their experience of being in that treatment programme; secondly, to investigate the impact of these beliefs on client-staff interactions and its significance for treatment. This study was conducted at a substance misuse clinic in London. Participants were involved with what it was known as "the long term prescribers group", ie. a treatment programme characterised by the regular prescription of opiates without leading to detoxification. Interviews were carried out with nine clients and nine members of staff. The content of interviews was analyzed using a Thematic Analysis approach according to Grounded Theory. The emerging themes suggested that clients and staff do not always share the same goals of treatment and this has negative effects in their interactions. It was also found that clients and staff regarded methadone maintenance with ambivalence. Thus, participants believed that it is helpful for achieving positive lifestyle changes, but at the cost of maintaining drug dependence. It was argued that differences in beliefs about the goals of treatment were a reflection of the different discourses about addiction existing in this society. It was also argued that the dominant discourse influencing participants' ideas is one characterised by a tendency to pathologise individual's behaviour. It was postulated that this causes negative consequences for client-staff interactions and limits the effectiveness of this treatment programme.