Phenomenological and neurocognitive perspectives on delusions: A critical overview

Abstract

There is considerable overlap between phenomenological and neurocognitive perspectives on delusions. In this paper, we first review major phenomenological accounts of delusions, beginning with Jaspers' ideas regarding incomprehensibility, delusional mood, and disturbed "cogito" (basic, minimal, or core self-experience) in what he termed "delusion proper" in schizophrenia. Then we discuss later studies of decontextualization and delusional mood by Matussek, changes in self and world in delusion formation according to Conrad's notions of "apophany" and "anastrophe", and the implications of ontological transformations in the felt sense of reality in some delusions. Next we consider consistencies between: a) phenomenological models stressing minimal-self (ipseity) disturbance and hyperreflexivity in schizophrenia, and b) recent neurocognitive models of delusions emphasizing salience dysregulation and prediction error. We voice reservations about homogenizing tendencies in neurocognitive explanations of delusions (the "paranoia paradigm"), given experiential variations in states of delusion. In particular we consider shortcomings of assuming that delusions necessarily or always involve "mistaken beliefs" concerning objective facts about the world. Finally, we offer some suggestions regarding possible neurocognitive factors. Current models that stress hypersalience (banal stimuli experienced as strange) might benefit from considering the potential role of hyposalience in delusion formation. Hyposalience -associated with experiencing the strange as if it were banal, and perhaps with activation of the default mode network -may underlie a kind of delusional derealization and an "anything goes" attitude. Such an attitude would be conducive to delusion formation, yet differs significantly from the hypersalience emphasized in current neurocognitive theories.

Towards integrating phenomenology and neurocognition: Possible neurocognitive correlates of basic self-disturbance in schizophrenia

“…and Byrom [40] discuss ipseity disturbance's specific relevance for understanding the distinctively "bizarre" nature of delusions in schizophrenia (and elsewhere they speculate [41] about associated neurobiological factors that may contribute to self disorder as well as to the formation and maintenance of such delusions). [45] also reported no correlation between basic self-disturbance and neurocognitive measures in a first episode schizophrenia sample and a clinical high risk for psychosis sample, respectively.…”

“…In a recent article on the phenomenology and neurobiology of delusions, Sass and Byrom [41] discuss the factors we have been considering above-sourcemonitoring abnormalities and abnormal experiences of hyper-salience-but also go on to take up a somewhat different, additional possibility: namely, experiences of hypo-salience that may be associated with an "anything goes" orientation to ongoing experience-that is, with a failure to be surprised even by what is unexpected or unusual. And this, as they note, may be correlated, on the neurobiological plane, with the failure to inhibit the "default-mode network" that has been observed in schizophrenia-a dis-inhibition that would be the neural correlate of a free-floating, ruminative, non-practical mode of experience that, if dominant in everyday life, would be conducive to accepting interpretations of the world (including "bizarre" beliefs) that most persons might quickly reject as illogical or highly implausible…”

Delusions in first-episode psychosis: Principal component analysis of twelve types of delusions and demographic and clinical correlates of resulting domains

“…It is remarkable how, at the present time, although delusions represent one of the core symptoms of schizophrenia and related psychotic disorders, it remains unclear as to whether or not these phenomena should be considered unitary or diversified (Sass and Byrom, 2015), and few studies have investigated distinct delusional themes, in particular in first-episode psychosis samples.…”

The imaginative mind

“…This manifests as "a failure to optimise uncertainty about sensory information" and leads to lower precision in prediction coding and prediction errors (Corlett, Taylor, Wang, Fletcher, and Krystal, 2010;Picard and Friston, 2014). Although there are some concerns about the extent to which this predictive error theory can comprehensively explain the exceedingly complex phenomenon of delusions (Griffiths, Langdon, Le Pelley, and Coltheart, 2014;Sass and Byrom, 2015), it is a compelling framework that accounts for how such vivid distortions of belief inference are formed and maintained.…”