Abstract

In lieu of an abstract, here is a brief excerpt of the content:Philosophy, Psychiatry, & Psychology 9.1 (2002) 55-59 [Access article in PDF] One Stage Is Not Enough Andrew W. Young and Karel W. de Pauw Keywords: delusions, Cotard delusion, Capgras delusion, cognitive neuropsychiatry. WE WELCOME THE OPPORTUNITY to offer our reflections on Philip Gerrans' interesting paper. Our opinion is that on fundamental issues we agree quite a bit—but there are clear differences when it comes to details.The most basic issue concerns the nature of the enterprise. Like Gerrans, we think that it is possible to create testable accounts of the formation and maintenance of what would otherwise seem bizarre and inexplicable delusions, and that these accounts should be grounded in theoretical models of factors that underpin our everyday perception and reasoning. This general approach certainly forms part of what has been called cognitive neuropsychiatry. However, we disagree with Gerrans in that we see cognitive neuropsychiatry as an attempt to draw on the underlying logic of cognitive neuropsychology, rather than (as Gerrans implies) its current methods. The underlying logic of cognitive neuropsychological approaches has been to try to understand the effects of brain injury in terms of disruption of different components of theoretical models of normal abilities. In this approach, a model of normal performance is tested by its ability to account for the effects of brain injury. Where the model of normal performance also provides a convincing account of brain injury it is retained, and when it fails to account for effects of brain injury, it is revised or abandoned. In cognitive neuropsychiatry, the key theoretical move has been to argue that an adequate model of normal performance should be able to account for any disordered pattern (Ellis and Young 1990). The same logic of seeking to explain disordered performance by reference to models of normal function is then attempted, but for disorders that would usually fall within the province of psychiatry.In our opinion, however, cognitive neuropsychiatry will not simply involve importing the methods of cognitive neuropsychology into the new domain; they will need to be developed and adapted to fit the new agenda (Young 2000).In cognitive neuropsychology, progress has often come from the careful investigation of people with stable, selective deficits of fundamental cognitive functions involved in sensory analysis, memory, and verbal or motor output. In contrast, delusional beliefs can be relatively unstable; often they are only held for a few weeks or even days. When the delusions change, patients may modify or abandon them as suddenly as they seemed to form them, or they may give them up much more slowly and reluctantly. At the very least, this creates difficulties in the timing of investigations and in interpreting the relation of deficits and symptoms, which may be recorded on separate dates. These methodological problems [End Page 55] are exacerbated by the fact that deficits linked to complex abnormal experiences such as delusions may be multifaceted and diffuse, even when the delusions themselves have a specific content or theme. Such complications do not invalidate cognitive neuropsychiatry, but they do mean it will need to develop its own methods for dealing with them and making appropriate inferences.One of the key complexities that has surfaced already involves the idea that delusional beliefs might reflect the interaction of two or more contributory factors. Gerrans discusses a particular variant of this idea, which had been suggested by Young and Leafhead (1996) as an approach to understanding the Cotard delusion: The Cotard delusion represents a depressed person's attempt to account for abnormal perceptual experiences. It follows that the delusion is based on an unfortunate interaction between different contributory factors. One set of factors creates the abnormal perceptual experiences, which are characterised by lack of emotional responses and feelings of emptiness, depersonalisation and derealisation. The other factors result in a misinterpretation of these perceptual changes, in which the patients' depressed moods lead them correctly to attribute the changes to themselves, but to exaggerate their consequences. (Young and Leafhead, 1996, 166) Gerrans describes this as a two-stage account, but argues that a one-stage account based only on abnormal perceptual...