A Genealogy of 'Dual Diagnosis' in Learning Disability.

Abstract
The dual diagnosis of learning disability and mental illness stigmatises and disenfranchises those subject to it. It silences the structural and material causes of distress, pathologises natural responses to difficult circumstances and legitimises the use of restrictive methods of governance. This study used a Foucauldian genealogical approach to explore the conditions of possibility for the emergence of dual diagnosis in Britain, its attending social practices, and the subjugated discourses that could provide alternative ways of constructing and responding to the distress that people with learning disabilities may experience. Analysis of clinical and social policy documents using Rose’s (1999) six perspectival dimensions suggested that dual diagnosis emerged within a historical context of governmental concerns regarding population control, particularly in relation to economy, productivity and social order. Distal conditions of possibility included the establishment of the state’s legal and political power over insanity; the medicalisation of idiocy and lunacy; and the emergence of disciplinary and biopolitical apparatuses of the state. The developmental (re)construction of idiocy opened up a possibility for its co-occurrence with insanity and presented a conceptual framework that would be taken up following deinstitutionalisation, when dual diagnosis offered an explanation and potential solution for the social problems caused by those who did not settle into the community as desired. Dual diagnosis is neither fixed nor inevitable; it is a ‘truth’ produced by power that has been reified and endorsed through clinical and government policy and practice. Implications for clinical practice, research and policy are discussed. It is proposed that a more helpful approach to alleviating distress, poverty and disability is to address the material and social causes and the power-networks that sustain these.