Why do delusions persist?

Abstract

Delusions are bizarre and distressing beliefs that characterize certain mental illnesses. They arise without clear reasons and are remarkably persistent. Recent models of delusions, drawing on a neuroscientific understanding of learning, focus on how delusions might emerge from abnormal experience. We believe that these models can be extended to help us understand why delusions persist. We consider prediction error, the mismatch between expectancy and experience, to be central. Surprising events demand a change in our expectancies. This involves making what we have learned labile, updating and binding the memory anew: a process of memory reconsolidation. We argue that, under the influence of excessive prediction error, delusional beliefs are repeatedly reconsolidated, strengthening them so that they persist, apparently impervious to contradiction.

The emerging biology of delusions

“…Developments in preclinical science have paved the way for plausible explanatory models to link biological disturbances to disturbed experiences in psychosis (Corlett et al 2009 ;Murray & Fletcher, 2009 ;Ziauddeen & Murray, 2010). How delusions arise, not just in schizophrenia but also in other disorders, can be accounted for by a combination of dysregulated firing in ascending midbrain dopamine neurons and reasoning bias.…”

Glutamatergic Model Psychoses: Prediction Error, Learning, and Inference

“…In the context of the model, delusional beliefs may be conceptualized as inappropriately reinforced prior expectations that are constantly updated with novel information or reconsolidated (Corlett et al, 2009b). One novel approach therefore involves engaging the prior belief and administering a drug that destabilizes it, preventing its reconsolidation (Rubin, 1976).…”

The ‘Unconscious’ in Paranoid Delusional Psychosis: Phenomenology, Neuroscience, Psychoanalysis

“…As Corlett and colleagues write, "while delusions are fi xed they are also elastic and may incorporate new information without shifting their fundamental perspective." 64 The delusional "object" (e.g., the invisible powers or devices that control one's thoughts and actions) is not fully constituted in perception or conscious judgment but remains an incomplete saliency, a partial object ( Vorgestalt , mnemic schema) that is elevated to the epistemological status of a complete object 'pregiven' with the "presumptive evidence" of world experience. 65 Following Matussek, Blankenburg proposes (paradoxically) that it is "not pathological belief but a pathological absence of belief" that is fundamental to the formation of delusions.…”