Exploring the Rationality of Patients with Delusions through Semi-Structure Discourse

What patients reveal in their first person verbal accounts forms the basis of the clinical assessment (e.g. PANSS) and Diagnosis (DSM) upon which all subsequent research hinges. Much of the rich experience (phenomenology) of someone with psychosis does not lend itself to objective methods, yet these experiences are those we need to understand if psychological and neuroscientific theories are to advance. In this paper I propose a method, knowledge elicitation, to systematically explore patient's verbal reports of their delusions and other beliefs. The method has been well used in psychology to reveal the processes used by experts when making decisions in naturalistic situations. The assumption is that patients are also experts in how they proceed in evaluating the truth of their own and other peoples' beliefs. Utilizing two case studies it is shown that this method can turn up rich information concerning a patient's skills in deliberating about truth and falsity of beliefs and the likelihood that the use of such skills may be context specific. When asked to evaluate the beliefs of others, even if these include a delusional belief identical to their own, then there is considerably more deliberation and greater use of established procedures that expert decision maker's use, resulting in the presentation of greater rationality than would otherwise be assumed.