Treatment is an art to which science can contribute: the 2nd James Rankin Oration.
Working models-beliefs-are an essential element of behaviour. Clients' models and non-scientific treatment models, need to be respected. It is contended that, practically and theoretically, scientific models have little validity or relevance for understanding and managing addictive behaviour. The WHO model of drug use, with two added elements (the self and the functions of choice and decision making; and random variation of neurophysiological activities), is used as an example. The scientific method consists of dissecting a complex phenomenon into simpler parts, testing hypotheses about these parts, collecting and summating the data, and applying the conclusions to individual cases. It is presumed that if we know enough about a person then we can predict their future behaviour, including response to therapeutic interventions. Four major arguments are produced against that presumption. The scientific method depends upon the use of meaningful numbers (representing discrete, replicable categories) and its results are presented in statistical formats (with limited individual relevance). Measurement in the behavioural sphere is neither precise nor objective. This is critical with complex interactive systems (such as the WHO model) in which an apparently insignificant change in input can result in dramatic changes in output. Progress may have been made technically, e.g. to reduce relapse, but therapy remains an art. In future, scientific endeavours should be complemented by attention to other disciplines.