This paper discusses research findings on non-biological risk factors associated with illicit drug use. There is an established body of North American research in this field, and a growing European literature. We find that there is an interplay of individual and environmental factors associated with drug use, with the permeation of their interactions potentially limitless. Within the behavioural science literature, we identify three main analytical dimensions for understanding ‘risk factors’. These are: ‘intrapersonal’; ‘microenvironmental’; and ‘macro-environmental’. We note that it is not new to emphasize drug use as a social activity, involving social interactions within particular social environments, but that, despite this, the balance of focus in research tends towards ‘extra-environmental’ or ‘individualistic’ interpretations. We emphasize that future research is best oriented towards generating data of practical value for the development of interventions rather than attempting to delineate causative factors. The failure of most risk factors research rests in its incapacity to capture the variety of social and environmental influences on drug use, and the relevance of these for developing socially appropriate interventions. In addition to recognizing the importance of targeting interventions towards ‘high risk’ populations and ‘high risk’ forms of drug use, we emphasize throughout the importance of the ‘risk environment’ in mediating patterns of drug use.