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Schizophrenia Bulletin Nov 2023The neurocomputational framework of predictive processing (PP) provides a promising approach to explaining delusions, a key symptom of psychotic disorders. According to... (Review)
Review
BACKGROUND AND HYPOTHESIS
The neurocomputational framework of predictive processing (PP) provides a promising approach to explaining delusions, a key symptom of psychotic disorders. According to PP, the brain makes inferences about the world by weighing prior beliefs against the available sensory data. Mismatches between prior beliefs and sensory data result in prediction errors that may update the brain's model of the world. Psychosis has been associated with reduced weighting of priors relative to the sensory data. However, delusional beliefs are highly resistant to change, suggesting increased rather than decreased weighting of priors. We propose that this "delusion paradox" can be resolved within a hierarchical PP model: Reduced weighting of prior beliefs at low hierarchical levels may be compensated by an increased influence of higher-order beliefs represented at high hierarchical levels, including delusional beliefs. This may sculpt perceptual processing into conformity with delusions and foster their resistance to contradictory evidence.
STUDY DESIGN
We review several lines of experimental evidence on low- and high-level processes, and their neurocognitive underpinnings in delusion-related phenotypes and link them to predicted processing.
STUDY RESULTS
The reviewed evidence supports the notion of decreased weighting of low-level priors and increased weighting of high-level priors, in both delusional and delusion-prone individuals. Moreover, we highlight the role of prefrontal cortex as a neural basis for the increased weighting of high-level prior beliefs and discuss possible clinical implications of the proposed hierarchical predictive-processing model.
CONCLUSIONS
Our review suggests the delusion paradox can be resolved within a hierarchical PP model.
Topics: Humans; Delusions; Psychotic Disorders; Brain; Prefrontal Cortex
PubMed: 37478890
DOI: 10.1093/schbul/sbad084 -
Emergency Medicine Clinics of North... Feb 2024Schizophrenia is a chronic condition characterized by positive symptoms (auditory hallucinations, delusion), negative symptoms (avolition, social withdrawal), and... (Review)
Review
Schizophrenia is a chronic condition characterized by positive symptoms (auditory hallucinations, delusion), negative symptoms (avolition, social withdrawal), and disorganized thoughts/behaviors. Although the pathophysiology is incompletely understood, several neurobiological mechanisms have been proposed. Treatment usually involves antipsychotic medication as well as psychotherapy and supportive services. When evaluating patients in the emergency department, acute safety considerations are paramount. Patients should be assessed for suicide risk, violence risk, inability to care for self, and the risk of being the victim of a crime. Persons with schizophrenia are at an increased risk of substance use and a variety of medical problems.
Topics: Humans; Schizophrenia; Hallucinations; Violence; Antipsychotic Agents; Emergency Medicine
PubMed: 37977755
DOI: 10.1016/j.emc.2023.06.012 -
Psychopharmacology Bulletin Jul 2023Introduction The purpose of this guide is to provide convenient and useful information on about Alzheimer's disease and dementias of late life. The information includes...
Introduction The purpose of this guide is to provide convenient and useful information on about Alzheimer's disease and dementias of late life. The information includes selected facts, diagnostic criteria tables, descriptions of selected tests and screens, guidelines, clinical pharmacological data and references. This guide is divided into several sections: Background factsDiagnostic aids and criteria for dementia diagnosesMedications used for Alzheimer's disease and dementia Basic information on marketed treatments is provided although the treatment may not be FDA approved for this use. Approved cholinesterase inhibitors, memantine, and monoclonal antibodies are listed. No treatment is recommended or endorsed, however. This guide does not address the evidence base for the efficacy of the treatments listed. : Except for treatments above, discussions of medications for people with dementia nearly always involve off label use. For example, antidepressants and antipsychotics are indicated in the FDA-approved prescribing information for major depression and schizophrenia, and not for depressive symptoms or the delusions or hallucinations occurring within the context of dementia with two exceptions. In these instances, the doses listed are for reference only and should not be considered as recommendations or appropriate use. Physicians should consult the product package labeling for any drug mentioned.
Topics: Humans; Alzheimer Disease; Antipsychotic Agents; Depressive Disorder, Major; Hallucinations; Memantine
PubMed: 37489152
DOI: No ID Found -
Psychiatry Research Sep 2023A number of prescribed medicines have been reported in cases of drug-induced delusion, such as dopaminergic agents or psychostimulants. But to this day, most studies are... (Review)
Review
INTRODUCTION
A number of prescribed medicines have been reported in cases of drug-induced delusion, such as dopaminergic agents or psychostimulants. But to this day, most studies are based on a limited number of cases and focus on a few drug classes, so a clear overview of this topic remains difficult. To address this issue, we provide in this article a comprehensive analysis of drug-induced delusion, based on the World Health Organization (WHO) pharmacovigilance database.
METHODS
We performed a disproportionality analysis of this database using the information component (IC). The IC compares observed and expected values to find associations between drugs and delusion, using disproportionate Bayesian reporting. An IC0.25 (lower end of the IC 95% credibility interval) > 0 is considered statistically significant.
RESULTS
Here we present an analysis of 4559 suspected drug-induced delusion reports in the WHO pharmacovigilance database. These results identified 66 molecules statistically associated with delusion and an extensive analysis of confounding factors and coprescriptions was performed, using full database as background with an IC0.25 > 0. The main drug classes involved were antidepressants, antiepileptics, dopaminergic agents, opioids, antiinfective agents, benzodiazepines, anti-dementia drugs and psychostimulants.
CONCLUSION
These results will help clinicians identify potential suspected drugs associated with delusion and decide which drug to discontinue and eventually lead to a re-evaluation of drug labels for some molecules.
Topics: Humans; Pharmacovigilance; Bayes Theorem; Delusions; Antidepressive Agents; Databases, Factual; World Health Organization; Adverse Drug Reaction Reporting Systems; Central Nervous System Stimulants
PubMed: 37517106
DOI: 10.1016/j.psychres.2023.115365