Phenomenological and neurocognitive perspectives on delusions: A critical overview.

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.