When psychiatric diagnosis becomes an overworked tool.

A psychiatric diagnosis today is asked to serve many functions-clinical, research, medicolegal, delimiting insurance coverage, service planning, defining eligibility for state benefits (eg, for unemployment or disability), as well as providing rallying points for pressure groups and charities. These contexts require different notions of diagnosis to tackle the particular problem such a designation is meant to solve. In a number of instances, a 'status' definition (ie, a diagnostic label or category) is employed to tackle what is more appropriately seen as requiring a 'functional' approach (ie, how well the person is able to meet the demands of a test of performance requiring certain capabilities, aptitudes or skills). In these instances, a diagnosis may play only a subsidiary role. Some examples are discussed: the criteria for involuntary treatment; the determination of criminal responsibility; and, assessing entitlements to state benefits. I suggest that the distinction between 'status' versus 'function' has not been given sufficient weight in discussions of diagnosis. It is in the functional domain that some of the problematic relationships between clinical psychiatry and the social institutions with which it rubs shoulders are played out. A status, signified by a diagnosis, has often been encumbered with demands for which it is poorly equipped. It is a reductive way of solving problems of management, allocation or disposal for which a functional approach should be given greater weight. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.