Construct representation and definitions in psychopathology: the case of delusion

In this paper, we attempt to show the major limitations of the definition of delusion from a non-essentialist point of view.The problem is analyzed within the framework of constructs and their translation into definitions. Different linguistic and epistemological perspectives that do concur when one deals with psychopathological phenomena are also considered.The 'construct of delusion', rather than its clinical instances, is the reference in which its definition appears inept. Here we claim that the broad contextual and pragmatic bases that underpin the construct of delusion tend to be either overlooked or downplayed in the quest for a satisfactory definition of this phenomenon."Whatever is made explicit, something is always left implicit." Tim Thornton [1]Since the 16th century, delusions have been conceptualized as judgments, beliefs, or ideas that are pathologically false, erroneous, or impossible [2,3]. Currently, the most widespread definitions of delusion still rest upon this basis, with the addition of the external features put forward by Karl Jaspers in the early 20th century, which would supposedly help us to recognize such phenomenon: its incorrigibility and the certainty with which it is held. Along these lines, in the DSM-IV [4], and very similarly in the ICD-10 [5], delusion is defined as:"...a false personal belief [falsity] based on incorrect inference about external reality and firmly sustained [conviction] despite of what almost everyone else believes and despite of what constitutes incontrovertible and obvious proof or evidence to the contrary [incorrigibility]. The belief is not one ordinarily accepted by other members of the person's culture or sub-culture". Authors' brackets.However, each of these features could be seen as a defeasible element in the definition of delusion. Accordingly, some authors emphasize that delusional statements are occasionally found to be true [6-8]. For example, someone who firmly believes they are secretly watched by