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Movement Disorders : Official Journal... Aug 2019Hallucinations, delusions, and functional neurological manifestations (conversion and somatic symptom disorders) of Parkinson's disease (PD) and dementia with Lewy... (Review)
Review
Hallucinations, delusions, and functional neurological manifestations (conversion and somatic symptom disorders) of Parkinson's disease (PD) and dementia with Lewy bodies increase in frequency with disease progression, predict the onset of cognitive decline, and eventually blend with and are concealed by dementia. These symptoms share the absence of reality constraints and can be considered comparable elements of the PD-dementia with Lewy bodies psychosis. We propose that PD-dementia with Lewy bodies psychotic disorders depend on thalamic dysfunction promoting a theta burst mode and subsequent thalamocortical dysrhythmia with focal cortical coherence to theta electroencephalogram rhythms. This theta electroencephalogram activity, also called fast-theta or pre-alpha, has been shown to predict cognitive decline and fluctuations in Parkinson's disease with dementia and dementia with Lewy bodies. These electroencephalogram alterations are now considered a predictive marker for progression to dementia. The resulting thalamocortical dysrhythmia inhibits the frontal attentional network and favors the decoupling of the default mode network. As the default mode network is involved in integration of self-referential information into conscious perception, unconstrained default mode network activity, as revealed by recent imaging studies, leads to random formation of connections that link strong autobiographical correlates to trivial stimuli, thereby producing hallucinations, delusions, and functional neurological disorders. The thalamocortical dysrhythmia default mode network decoupling hypothesis provides the rationale for the design and testing of novel therapeutic pharmacological and nonpharmacological interventions in the context of PD, PD with dementia, and dementia with Lewy bodies. © 2019 International Parkinson and Movement Disorder Society.
Topics: Attention; Cerebral Cortex; Delusions; Electroencephalography; Hallucinations; Humans; Lewy Body Disease; Neural Pathways; Parkinson Disease; Psychotic Disorders; Somatoform Disorders; Thalamus; Theta Rhythm
PubMed: 31307115
DOI: 10.1002/mds.27781 -
BMC Neurology Mar 2024Neuropsychiatric symptoms and delusions are highly prevalent among people with dementia. However, multiple roots of neurobiological bases and shared neural basis of...
BACKGROUND
Neuropsychiatric symptoms and delusions are highly prevalent among people with dementia. However, multiple roots of neurobiological bases and shared neural basis of delusion and cognitive function remain to be characterized. By utilizing a fine-grained multivariable approach, we investigated distinct neuroanatomical correlates of delusion symptoms across a large population of dementing illnesses.
METHODS
In this study, 750 older adults with mild cognitive impairment and Alzheimer's disease completed brain structural imaging and neuropsychological assessment. We utilized principal component analysis followed by varimax rotation to identify the distinct multivariate correlates of cortical thinning patterns. Five of the cognitive domains were assessed whether the general cognitive abilities mediate the association between cortical thickness and delusion.
RESULTS
The result showed that distributed thickness patterns of temporal and ventral insular cortex (component 2), inferior and lateral prefrontal cortex (component 1), and somatosensory-visual cortex (component 5) showed negative correlations with delusions. Subsequent mediation analysis showed that component 1 and 2, which comprises inferior frontal, anterior insula, and superior temporal regional thickness accounted for delusion largely through lower cognitive functions. Specifically, executive control function assessed with the Trail Making Test mediated the relationship between two cortical thickness patterns and delusions.
DISCUSSION
Our findings suggest that multiple distinct subsets of brain regions underlie the delusions among older adults with cognitive impairment. Moreover, a neural loss may affect the occurrence of delusion in dementia largely due to impaired general cognitive abilities.
Topics: Humans; Aged; Alzheimer Disease; Delusions; Cognitive Dysfunction; Cognition; Brain
PubMed: 38448803
DOI: 10.1186/s12883-024-03568-5 -
BMC Psychiatry Dec 2023Patients with Alzheimer's disease (AD) often exhibit neuropsychiatric symptoms (NPS), particularly delusions. Previous studies have shown an association between white...
BACKGROUND
Patients with Alzheimer's disease (AD) often exhibit neuropsychiatric symptoms (NPS), particularly delusions. Previous studies have shown an association between white matter hyperintensities (WMH) and specific NPS. This study aims to explore the relationship between WMH volume and delusions in AD patients by comparing the WMH volumes of delusional and non-delusional subgroups.
METHODS
80 AD patients were divided into a delusion group (n = 36) and a non-delusion group (n = 44) based on the Neuropsychiatric Inventory (NPI). The brain cortical volume and WMH volume were quantitatively calculated for all 80 patients, including total WMH volume, periventricular WMH (PVWMH) volume, deep WMH volume, as well as bilateral frontal lobe, temporal lobe, parietal lobe, and occipital lobe WMH volumes. Firstly, we compared the differences in WMH volumes between the delusion group and non-delusion group. Then, within the delusion group, we further categorized patients based on severity scores of their delusional symptoms into mild (1 point), moderate (2 points), or severe groups (3 points). We compared the WMH volumes among these three groups to investigate the role of WMH volume in delusional symptoms.
RESULTS
There was a significant difference in left occipital lobe WMH volume between the delusion group and non-delusion group(P < 0.05). Within the delusion group itself, there were significant differences in overall WMH volume as well as PVWMH volume among patients with mild or severe levels of delusions(P < 0.05).
CONCLUSION
Left occipital lobe WMH volume may be associated with the occurrence of delusional AD patients, and the total volume of whole-brain WMH and PVWMH volume may affect the degree of severity of delusional symptoms.
Topics: Humans; Alzheimer Disease; White Matter; Temporal Lobe; Brain; Parietal Lobe; Magnetic Resonance Imaging
PubMed: 38057778
DOI: 10.1186/s12888-023-05420-5 -
Early Intervention in Psychiatry Dec 2022Thinking biases are posited to be involved in the genesis and maintenance of delusions. Persecutory delusions are one of the most commonly occurring delusional subtypes... (Review)
Review
AIM
Thinking biases are posited to be involved in the genesis and maintenance of delusions. Persecutory delusions are one of the most commonly occurring delusional subtypes and cause substantial distress and disability to the individuals experiencing them. Their clinical relevance confers a rationale for investigating them. Particularly, this review aims to elucidate which cognitive biases are involved in their development and persistence.
METHODS
MEDLINE, Embase, PsycINFO and Global Health were searched from the year 2000 to June 2020. A formal narrative synthesis was employed to report the findings and a quality assessment of included studies was conducted.
RESULTS
Twenty five studies were included. Overall, 18 thinking biases were identified. Hostility and trustworthiness judgement biases appeared to be specific to persecutory delusions while jumping to conclusions, self-serving attributional biases and belief inflexibility were proposed to be more closely related to other delusional subtypes. While the majority of the biases identified were suggested to be involved in delusion maintenance, hostility biases, need for closure and personalizing attributional biases were believed to also have aetiological influences.
CONCLUSIONS
These findings show that some cognitive biases are specific to paranoid psychosis and appear to be involved in the formation and/or persistence of persecutory delusions.
Topics: Humans; Delusions; Paranoid Disorders; Bias; Psychotic Disorders
PubMed: 35396904
DOI: 10.1111/eip.13292 -
BMJ Case Reports Apr 2021This is a case report of a middle-aged man with no psychiatric history who presented with severe anxiety and psychotic symptoms from COVID-19. Following his discharge...
This is a case report of a middle-aged man with no psychiatric history who presented with severe anxiety and psychotic symptoms from COVID-19. Following his discharge from intensive care unit, he was unable to sleep, was increasingly agitated and was observed hitting his head off the walls, causing haematomas. He remained highly anxious and developed paranoid delusions and auditory and tactile hallucinations, needing admission to a psychiatric ward. Treatment with antipsychotic medication gradually improved his symptoms in a few weeks. This case report highlights the new onset of psychosis due to COVID-19 infection. It demonstrates the importance of early identification and treatment of neuropsychiatric complications within an acute hospital setting. Furthermore, there is a need for research in this area to help in the prevention and treatment of such psychiatric complications due to COVID-19.
Topics: Antipsychotic Agents; COVID-19; Delusions; Humans; Male; Middle Aged; Psychotic Disorders; SARS-CoV-2; Treatment Outcome
PubMed: 33906867
DOI: 10.1136/bcr-2021-242538 -
Frontiers in Big Data 2020Psychotic symptoms, i.e., hallucinations and delusions, involve gross departures from conscious apprehension of consensual reality; respectively, perceiving and...
Psychotic symptoms, i.e., hallucinations and delusions, involve gross departures from conscious apprehension of consensual reality; respectively, perceiving and believing things that, according to same culture peers, do not obtain. In schizophrenia, those experiences are often related to abnormal sense of control over one's own actions, often expressed as a distorted sense of agency (i.e., passivity symptoms). Cognitive and computational neuroscience have furnished an account of these experiences and beliefs in terms of the brain's generative model of the world, which underwrites inferences to the best explanation of current and future states, in order to behave adaptively. Inference then involves a reliability-based trade off of predictions and prediction errors, and psychotic symptoms may arise as departures from this inference process, either an over- or under-weighting of priors relative to prediction errors. Surprisingly, there is empirical evidence in favor of both positions. Relatedly, there is evidence for both an enhanced and a diminished sense of agency in schizophrenia. How can this be? We argue that there is more than one generative model in the brain, and that ego- and allo-centric models operate in tandem. In brief, ego-centric models implement corollary discharge signals that cancel out the effects of self-generated actions while allo-centric models compare several hypothesis regarding the causes of sensory inputs (including the self among the potential causes). The two parallel hierarchies give rise to different levels of agency, with ego-centric models subserving "feelings of agency" and allo-centric predictions giving rise to "judgements of agency." Those two components are weighted according to their reliability and combined, generating a higher-level "sense of agency." We suggest that in schizophrenia a failure of corollary discharges to suppress self-generated inputs results in the absence of a "feeling of agency" and in a compensatory enhancement of allo-centric priors, which might underlie hallucinations, delusions of control but also, under certain circumstances, the enhancement of "judgments of agency." We discuss the consequences of such a model, and potential courses of action that could lead to its falsification.
PubMed: 33693400
DOI: 10.3389/fdata.2020.00027 -
Schizophrenia Research Jul 2020Sleep disturbance is a common clinical issue for patients with psychosis. It has been identified as a putative causal factor in the onset and persistence of psychotic... (Review)
Review
BACKGROUND
Sleep disturbance is a common clinical issue for patients with psychosis. It has been identified as a putative causal factor in the onset and persistence of psychotic experiences (paranoia and hallucinations). Hence sleep disruption may be a potential treatment target to prevent the onset of psychosis and reduce persistent psychotic experiences. The aim of this review is to describe developments in understanding the nature, causal role, and treatment of sleep disruption in psychosis.
METHOD
A systematic literature search was conducted to identify studies, published in the last five years, investigating subjective sleep disruption and psychotic experiences.
RESULTS
Fifty-eight papers were identified: 37 clinical and 21 non-clinical studies. The studies were correlational (n = 38; 20 clinical, 18 non-clinical), treatment (n = 7; 1 non-clinical), qualitative accounts (n = 6 clinical), prevalence estimates (n = 5 clinical), and experimental tests (n = 2 non-clinical). Insomnia (50%) and nightmare disorder (48%) are the most prevalent sleep problems found in patients. Sleep disruption predicts the onset and persistence of psychotic experiences such as paranoia and hallucinations, with negative affect identified as a partial mediator of this relationship. Patients recognise the detrimental effects of disrupted sleep and are keen for treatment. All psychological intervention studies reported large effect size improvements in sleep and there may be modest resultant improvements in psychotic experiences.
CONCLUSIONS
Sleep disruption is a treatable clinical problem in patients with psychosis. It is important to treat in its own right but may also lessen psychotic experiences. Research is required on how this knowledge can be implemented in clinical services.
Topics: Delusions; Hallucinations; Humans; Paranoid Disorders; Psychotic Disorders; Schizophrenia; Sleep
PubMed: 31831262
DOI: 10.1016/j.schres.2019.11.014 -
BJPsych Bulletin Feb 2022This is an article about exclusion. We might not like to admit it - even fail to realise it - but National Health Service (NHS) mental health service structures have... (Review)
Review
This is an article about exclusion. We might not like to admit it - even fail to realise it - but National Health Service (NHS) mental health service structures have become increasingly focused on how to deny people care instead of help them to access it. Clinicians learn the art of self-delusion, convincing ourselves we are not letting patients down but, instead, doing the clinically appropriate thing. Well-meant initiatives become misappropriated to justify neglect. Are we trying to protect ourselves against the knowledge that we're failing our patients, or is collusion simply the easiest option? Problematic language endemic in psychiatry reveals a deeper issue: a culture of fear and falsehood, leading to iatrogenic harm. An excessively risk-averse and under-resourced system may drain its clinicians of compassion, losing sight of the human being behind each 'protected' bed and rejected referral.
PubMed: 34517935
DOI: 10.1192/bjb.2021.86 -
Cognitive Science Jul 2022The mistiming and fusion of predictive thought and actual perception result in postdiction in awareness, a critical factor in the emergence of nonrational beliefs....
The mistiming and fusion of predictive thought and actual perception result in postdiction in awareness, a critical factor in the emergence of nonrational beliefs. Individuals with delusive thinking tend to experience a temporal reversal of prediction ("I guess the rain will fall.") and real perception ("I feel the rain falling."), incorrectly showing conviction that their predictions are correct. It is unknown how postdiction is related to religious cognition with a particular reference to intrinsic religiosity when religious beliefs and values are master motives and fundamental frameworks of life. Using a temporal decision-making task, we investigated a group of religiously committed individuals, atheists, and people from the general community. Results revealed higher postdiction at short thought-precept time intervals in the intrinsic religious group relative to the atheists. Intrinsic religiosity, but not delusive thinking, was predicted by postdiction in both religious individuals and the general population. These results indicate that people who display pronounced thought-percept reversal and fusion feel that they are close to a higher power and the sacred.
Topics: Cognition; Humans; Motivation; Religion
PubMed: 35738491
DOI: 10.1111/cogs.13171