Understanding delusions.

Delusions traditionally have been considered as fixed, false beliefs, born of morbidity. Whereas this definition serves to orient the clinician to the phenomena at hand, each element breaks down under scrutiny. It has been shown that delusions are not necessarily false, although in some sense they are discordant with reality. When delusions coincide with actual events their judgements can be shown to be independent of this evidential basis; when they refer to disorders of experience, such as first rank symptoms, the experience usually contains a distorted meaning. The supposition that delusions are a variety of belief has itself been questioned. On the one hand, they do not always refer in a meaningful way to anything, or when they do they fail to function as evaluative judgments; instead, delusions are experienced subjectively in ways that are characteristic of knowing rather than believing. On the other hand, delusions are not ascertained clinically by surveying the patient's belief system; rather their failure to achieve the status of objective knowledge leads to the post hoc relegation of delusions to the epistemologic waste basket of beliefs. To treat delusions as necessarily the product of morbidity is essentially tautologous insofar as delusions are, by definition, pathologic; that is, as defective judgments delusions are not simply erroneous, they are disordered. Finally, the fixity of delusions is an empirical matter and varies widely. Underlying this perceived intractability, however, are the subjective certainty and incorrigibility that Jaspers identified and which Spitzer has recast in the form of "epistemological asymmetry" misapplied to external reality. Although delusions typically have been recognized and categorized according to their manifest content, these formal considerations are crucial to understanding the nature of delusions.