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The Neuroscientist : a Review Journal... Feb 2021Delusions are irrational, tenacious, and incorrigible false beliefs that are the most common symptom of a range of brain disorders including schizophrenia, Alzheimer's,... (Review)
Review
Delusions are irrational, tenacious, and incorrigible false beliefs that are the most common symptom of a range of brain disorders including schizophrenia, Alzheimer's, and Parkinson's disease. In the case of schizophrenia and other primary delusional disorders, their appearance is often how the disorder is first detected and can be sufficient for diagnosis. At this time, not much is known about the brain dysfunctions leading to delusions, and hindering our understanding is that the complexity of the nature of delusions, and their very unique relevance to the human experience has hampered elucidation of their underlying neurobiology using either patients or animal models. Advances in neuroimaging along with improved psychiatric and cognitive modeling offers us a new opportunity to look with more investigative power into the deluded brain. In this article, based on data obtained from neuroimaging studies, we have attempted to draw a picture of the neural networks involved when delusion is present and evaluate whether different manifestations of delusions engage different regions of the brain.
Topics: Cerebral Cortex; Connectome; Delusions; Humans; Nerve Net; Schizophrenia, Paranoid; Ventral Striatum
PubMed: 32648532
DOI: 10.1177/1073858420936172 -
CMAJ : Canadian Medical Association... Aug 2019
Topics: Brain; Capgras Syndrome; Delusions; Humans; Neuropsychological Tests
PubMed: 31387959
DOI: 10.1503/cmaj.190048 -
Consciousness and Cognition May 2015Delusions are defined as irrational beliefs that compromise good functioning. However, in the empirical literature, delusions have been found to have some psychological... (Review)
Review
Delusions are defined as irrational beliefs that compromise good functioning. However, in the empirical literature, delusions have been found to have some psychological benefits. One proposal is that some delusions defuse negative emotions and protect one from low self-esteem by allowing motivational influences on belief formation. In this paper I focus on delusions that have been construed as playing a defensive function (motivated delusions) and argue that some of their psychological benefits can convert into epistemic ones. Notwithstanding their epistemic costs, motivated delusions also have potential epistemic benefits for agents who have faced adversities, undergone physical or psychological trauma, or are subject to negative emotions and low self-esteem. To account for the epistemic status of motivated delusions, costly and beneficial at the same time, I introduce the notion of epistemic innocence. A delusion is epistemically innocent when adopting it delivers a significant epistemic benefit, and the benefit could not be attained if the delusion were not adopted. The analysis leads to a novel account of the status of delusions by inviting a reflection on the relationship between psychological and epistemic benefits.
Topics: Defense Mechanisms; Delusions; Humans; Knowledge; Motivation
PubMed: 25459652
DOI: 10.1016/j.concog.2014.10.005 -
Cortex; a Journal Devoted To the Study... Dec 2014Somatoparaphrenia, a syndrome that involves at a minimum unawareness of ownership of a body part, in addition involves productive features including delusional... (Review)
Review
Somatoparaphrenia, a syndrome that involves at a minimum unawareness of ownership of a body part, in addition involves productive features including delusional misidentification and confabulation. In this review we describe some of the clinical and neuroanatomical features of somatoparaphrenia highlighting its delusional and confabulatory aspects. Possible theoretical frameworks are reviewed taking into account cognitive, psychodynamic, and philosophical views. We suggest that future studies should approach this syndrome through investigations of structural and functional connectivity and focus on the possible interplay between alterations in major functional networks of the brain, such as the default mode and salience networks, but also take into account motivational variables.
Topics: Agnosia; Brain; Brain Mapping; Delusions; Humans; Nerve Net; Neuropsychological Tests
PubMed: 25481466
DOI: 10.1016/j.cortex.2014.07.004 -
Psychiatrike = Psychiatriki 2018The Delusional Misidentification Syndromes (DMSs) are characterized by defective integration of the normally The Delusional Misidentification Syndromes (DMSs) are...
The Delusional Misidentification Syndromes (DMSs) are characterized by defective integration of the normally The Delusional Misidentification Syndromes (DMSs) are characterized by defective integration of the normally fused functions of perception and recognition. The classical sub-types are: the syndromes of Capgras, Fregoli,Intermetamorphosis (mentioned in 3) and Subjective doubles. These syndromes occur in a clear sensorium and shouldbe differentiated from the banal transient misidentifications occurring in confusional states and in mania and from thenon-delusional misidentifications (e.g. prosopagnosia). Joseph Capgras, who described the best-known sub-type, was indecisive on its pathogenesis. In his original report he defined the syndrome as "agnosia of identification" produced by a conflict between affective accompaniments ofsensory and mnemonic images. In his subsequent two publications, he considered the syndrome as a restitution delusionand as a psychopathological mechanism to hide incestuous desires. For more details see the chapter by J.P. Luaute in avolume on DMS. Psychodynamic approaches are, essentially, variants of the formulation that DMSs result from ambivalent feelings resolvedby directing hate feelings onto an imagined double in order to retain the original intact (and thus avoid guilt).These views have been voiced by David Enoch [relevant chapter in (3)] and with variations by many other investigatorsreviewed by Oyebode. Regression to archaic modes of thought (like thinking in terms of doubles and dualisms) due to personality disintegrationproduced by psychotic illness is a fascinating hypothesis by John Todd [mentioned in (1)]. However, if this was thecase, DMS should be much more frequent. Mayer-Gross and Ackner (mentioned in 9) had observed that when there is a delusional development, depersonalization-derealization experiences tend to be included within the delusional system. Such experiences usually precede orcoincide with the onset of DMS. In view of this, Christodoulou suggested that DMSs may represent delusional evolutions of depersonalization-derealization experiences. Similar mechanisms were proposed for false memories of familiarity,reduplicative paramnesia and autoscopy. Cerebral "dysrhythmia" has also been noted in patients with DMS. In view of clinical and prognostic similarities of DMSpatients with patients suffering from psychotic states occurring in an epileptic setting, many of these patients have beenconsidered as suffering from broadly speaking "epileptic" psychoses. Joseph [mentioned in (6)] suggested that organiccauses produce disconnection between right and left cortical areas that decode afferent sensory information. This resultsin the creation of a separate image in each hemisphere leading to an awareness of two, physically identical images. Ellis and Young [mentioned in (1) and (6)] have maintained that DMS may result from defects at different stages of aninformation processing chain. More specifically, the Capgras Syndrome appears when the route for unconscious recognitionis damaged. Similar mechanisms have been proposed for the rest of the subtypes. Margariti and Kontaxakis8 have considered that in DMS there is disruption of the ability to recognize identities ratherthan superficial appearance. Others have maintained that DMSs are multimodal neuropathologies and cannot be linkedto a single cognitive defect. Lastly, in view of the marked organic abnormalities detected in all DMS subtypes, DMSs have been linked with a greatnumber of organic conditions [reviewed in detail by Oyebode (5)]. According to Greek mythology, Procrustes was a bandit who stretched or amputated the limbs of his guests to fit hisiron bed. The DMSs do not deserve such treatment. Submitting them to the procrustean bed of uniformity should be avoided. People develop DMS for a variety of reasons. Most subjects have right hemisphere dysfunction but not exclusively.Their condition is associated not with one but with diverse phenomena (depersonalization - derealization, prosopagnosia,false memories of familiarity, autoscopy, reduplicative paramnesia etc.) similarities with psychotic phenomena associatedwith epilepsy have been suggested but this refers to some patients only. Additionally, the charged emotionalrelationship of the patient with the misidentified person(s) is neither necessary nor sufficient. Diagnostically speaking, many roads lead to DMS, ranging from the monosymptomatic and monothematic one (consideredas par excellence DMS) to that associated with disorders mainly of the schizophrenic or organic spectrum. DMScan also be reached by a more "superficial" road, the one of depression, in which the delusion is secondary and often dependenton the self-depreciation ideation. Speculating on these syndromes is a fascinating journey in psychopathologybut, although in most cases an organic contributor is present, yet the great diversity of conditions in the setting of whichDMSs occur renders the possibility of a unifying hypothesis unlikely.
Topics: Cognition Disorders; Delusions; Humans; Neuropsychological Tests; Psychotherapy, Psychodynamic; Schizophrenia, Paranoid
PubMed: 29754115
DOI: 10.22365/jpsych.2018.291.15 -
Psychiatrike = Psychiatriki Dec 2023We read with interest the recent report on the definition, diagnosis, and clinical implications of religious delusions (RD).1 In our sample of 929 delusional...
We read with interest the recent report on the definition, diagnosis, and clinical implications of religious delusions (RD).1 In our sample of 929 delusional schizophrenia patients who had been admitted to two psychiatric hospitals in Germany between 2010 and 2014, 138 patients (15%) reported RD. In 569 cases, information on religious affiliation was available. Patients with religious affiliation did not differ from patients without religious affiliation in the frequency of RD [χ2(1,569)= 0.02, p= 0.885]. Furthermore, patients with RD did not differ from patients with other types of delusion (OD) in the duration of hospitalisation [t(924)= -0.39, p= 0.695], or the number of hospitalisations [t(927)= -0.92, p= 0.358]. Additionally, in 185 cases, information on Clinical Global Impressions (CGI) and Global Assessment of Functioning (GAF) was available at the beginning and end of the hospital stay. By CGI-scores, no difference was seen in morbidity of subjects with RD relative to subjects with OD on admission [t(183)= -0.78, p= 0.437] and discharge t(183)= -1.10, p= .273 . Likewise, GAF-scores on admission did not differ in these groups [t(183)= 1.50, p= 0.135]. However, a trend was noted for lower GAF-scores on discharge in subjects with RD [t(183)= 1.91, p= .057, d= 0.39, CI 95% (-0.12-0.78)]. While RD have often been associated with a poorer prognosis in schizophrenia,2,3 we argue that this need not apply to all domains. Mohr et al4 reported that patients with RD were less likely to maintain psychiatric treatment, but did not have a more severe clinical status than patients with OD. Iyassu et al5 found higher levels of positive, but also lower levels of negative symptoms in patients with RD compared to patients with OD. Groups did not differ in terms of length of illness or level of medication. Siddle et al6 reported higher symptom scores in patients with RD at their first presentation, but a similar response to treatment when compared to patients with OD after 4 weeks of treatment. Furthermore, Ellersgaard et al7 iindicated that first-episode psychosis patients with RD at baseline were more likely to be non-delusional at follow-ups conducted after years 1, 2 and 5 when compared to patients with OD at baseline. We conclude that RD may thus interfere with short-term clinical outcome. With regard to long-term effects more favourable observations exist8 and the interplay of psychotic delusions with non-psychotic beliefs still warrants further research.
Topics: Humans; Delusions; Psychotic Disorders; Schizophrenia; Hospitalization
PubMed: 37212804
DOI: 10.22365/jpsych.2023.012 -
Schizophrenia Bulletin Mar 2017Delusion is central to the conceptualization, definition, and identification of schizophrenia. However, in current classifications, the presence of delusions is neither... (Review)
Review
Delusion is central to the conceptualization, definition, and identification of schizophrenia. However, in current classifications, the presence of delusions is neither necessary nor sufficient for the diagnosis of schizophrenia, nor is it sufficient to exclude the diagnosis of some other psychiatric conditions. Partly as a consequence of these classification rules, it is possible for delusions to exist transdiagnostically. In this article, we evaluate the extent to which this happens, and in what ways the characteristics of delusions vary according to diagnostic context. We were able to examine their presence and form in delusional disorder, affective disorder, obsessive-compulsive disorder, borderline personality disorder, and dementia, in all of which they have an appreciable presence. There is some evidence that the mechanisms of delusion formation are, at least to an extent, shared across these disorders. This transdiagnostic extension of delusions is an argument for targeting them therapeutically in their own right. However there is a dearth of research to enable the rational transdiagnostic deployment of either pharmacological or psychological treatments.
Topics: Affective Disorders, Psychotic; Borderline Personality Disorder; Comorbidity; Delusions; Dementia; Humans; Obsessive-Compulsive Disorder; Schizophrenia; Schizophrenia, Paranoid
PubMed: 28399309
DOI: 10.1093/schbul/sbw191 -
Soins. Psychiatrie 2018In their daily practice, psychiatric caregivers seek an encounter with the patient. This involves trying to understand the patient's suffering, to give meaning and to...
In their daily practice, psychiatric caregivers seek an encounter with the patient. This involves trying to understand the patient's suffering, to give meaning and to make the clinical connection. This equates to constructing together. Some care organisations are working to create spaces within units which are suited to receiving patients with an atmosphere favouring the encounter. The story of Baptiste illustrates this approach. Testimony.
Topics: Delusions; France; Humans; Male; Mental Disorders; Nurse-Patient Relations; Patient Admission; Psychiatric Department, Hospital; Psychotherapeutic Processes; Psychotherapy; Psychotic Disorders; Risk-Taking; Social Environment
PubMed: 29335128
DOI: 10.1016/j.spsy.2017.11.006 -
Consciousness and Cognition May 2018
Review
Topics: Bayes Theorem; Delusions; Humans; Models, Theoretical
PubMed: 29602712
DOI: 10.1016/j.concog.2018.03.003 -
Clinical Psychology Review Feb 2023Delusions can be conceptualized as beliefs that are both at odds with consensus reality and espoused with high conviction. While delusions represent a cardinal symptom... (Review)
Review
Delusions can be conceptualized as beliefs that are both at odds with consensus reality and espoused with high conviction. While delusions represent a cardinal symptom of schizophrenia, delusion-like beliefs can be found in the general population. Do similar cognitive mechanisms support delusionality across this spectrum? If so, what are they? Here, we examine evidence for a mechanistic role of the (associative) memory system in the formation and maintenance of delusions and delusion-like beliefs. While general neurocognitive metrics do not tend to associate with delusionality, our scoping review of the clinical and subclinical literature reveals several subdomains of memory function that do. These include a propensity to commit errors of commission (i.e., false alarms and intrusions), source memory biases, and metamemory impairment. We discuss how several of these effects may stem from aberrant associative memory function and offer recommendations for future research. Further, we propose a state/trait interaction model in which underlying traits (i.e., impaired associative and metamemory function) may become coupled with delusionality during states of acute psychosis, when memory function is particularly challenged by aberrant salience attribution and noisy perceptual input. According to this model, delusions may arise as explanations to high-salience (but low-source) mnemonic content that is endorsed with high confidence.
Topics: Humans; Delusions; Psychotic Disorders; Schizophrenia; Memory; Metacognition
PubMed: 36469975
DOI: 10.1016/j.cpr.2022.102231