Abstract

Substance use and misuse occurs at a very high rate among people with mental health problems and the relationship between the two conditions is complex. In this paper we argue that treatment of substance use in dual diagnosis clients must begin from an understanding of the losses suffered by those with mental illness. We outline the fundamental condition of effective agency, unified agency, which is disrupted in mental illness and show how this is needed to secure access to central social and moral goods such as continuing employment and satisfying relationships. We argue that drug use will be disvaluable primarily in so far as it too prevents access to this set of agential goods and focuses the agent on synchronic well-being to the exclusion of diachronic well-being. The goals and methods of treatment for dual diagnosis patients should thus reflect the primary impairment to unified agency.