Formation Of Delusional Beliefs Research Articles

How unexpected observations lead to new beliefs: A Peircean pathway.

People acquire new beliefs in various ways. One of the most important of these is that new beliefs are acquired as a response to experiencing events that one did not expect. This involves a form of inference distinct from both deductive and inductive inference: abductive inference. The concept of abduction is due to the American pragmatist philosopher C. S. Peirce. Davies and Coltheart (in press) elucidated what Peirce meant by abduction, and identified two problems in his otherwise promising account requiring solution if that account were to become fully workable. Here we propose solutions to these problems and offer an explicit cognitive model of how people derive new beliefs from observations of unexpected events, based on Peirce's work and Sokolov's ideas about prediction error triggering new beliefs. We consider that this model casts light not only upon normal processes of belief formation but also upon the formation of delusional beliefs.

Atypical processing of uncertainty in individuals at risk for psychosis.

Current theories of psychosis highlight the role of abnormal learning signals, i.e., prediction errors (PEs) and uncertainty, in the formation of delusional beliefs. We employed computational analyses of behaviour and functional magnetic resonance imaging (fMRI) to examine whether such abnormalities are evident in clinical high risk (CHR) individuals. Non-medicated CHR individuals (n=13) and control participants (n=13) performed a probabilistic learning paradigm during fMRI data acquisition. We used a hierarchical Bayesian model to infer subject-specific computations from behaviour - with a focus on PEs and uncertainty (or its inverse, precision) at different levels, including environmental 'volatility' - and used these computational quantities for analyses of fMRI data. Computational modelling of CHR individuals' behaviour indicated volatility estimates converged to significantly higher levels than in controls. Model-based fMRI demonstrated increased activity in prefrontal and insular regions of CHR individuals in response to precision-weighted low-level outcome PEs, while activations of prefrontal, orbitofrontal and anterior insula cortex by higher-level PEs (that serve to update volatility estimates) were reduced. Additionally, prefrontal cortical activity in response to outcome PEs in CHR was negatively associated with clinical measures of global functioning. Our results suggest a multi-faceted learning abnormality in CHR individuals under conditions of environmental uncertainty, comprising higher levels of volatility estimates combined with reduced cortical activation, and abnormally high activations in prefrontal and insular areas by precision-weighted outcome PEs. This atypical representation of high- and low-level learning signals might reflect a predisposition to delusion formation.

Attentional focus moderates the relationship between attention to threat bias and delusion-like experiences in healthy adults

BackgroundThe role of cognitive biases in delusion and delusion-like experiences has been widely investigated in recent years. However, little is known about individual differences, which may influence association between cognitive biases and formation of delusional beliefs. The aim of this study was to examine the moderating effect of self-reported attentional control on the relationship between attention to threat bias (ATB) and delusion-like experiences (DLEs) in healthy adults. MethodsParticipants (n=138) completed the Davos Assessment of the Cognitive Biases Scale (DACOBS), the Attentional Control Scale (ACS) and the Peters et al. Delusions Inventory (PDI). The moderation analysis was performed to check the influence of different components of attentional control (i.e. general ability to allocate attention, focusing, shifting and divide attention) on the interplay between ATB and DLEs. ResultsThe results supported the moderation model. Specifically, we found that a higher level of ability to focus attention is associated with a stronger effect of attention to threat bias on the overall frequency of DLEs. Our results indicate that ATB contributes to the number of DLEs only in individuals with high and moderate capacity to focus attention, whereas in those who scored low on the ACS focusing attention subscale, the presence of attentional bias does not influence the frequency of DLEs. ConclusionsOur findings show that the individual difference variable, such as ability to voluntarily focus attention, may moderate the relationship between attention to threat bias and delusion-like experiences in healthy adults.

Neuropsychological aspects of delusional disorder

Delusional disorders (DDs) are clinically rare syndromes characterized by false beliefs that are held with firm conviction despite counterevidence. The neuropsychology of DDs is poorly understood. Two partially opposing models--a cognitive bias model and a cognitive deficit model--have received mixed empiric support, partly because most research has been carried out in patients with paranoid schizophrenia, with which the nosologic association of DDs is unknown. Based on these models, we review empiric findings concerning the neuropsychology of DDs (narrowly defined). We conclude that DDs can best be seen as extreme variations of cognitive mechanisms involved in rapid threat detection and defensive harm avoidance. From this viewpoint, the two models seem to be complementary in explanatory power rather than contradictory. Future research may help to clarify the question of gene-environment interaction involvement in the formation of delusional beliefs.

Disrupted prediction-error signal in psychosis: evidence for an associative account of delusions

Delusions are maladaptive beliefs about the world. Based upon experimental evidence that prediction error-a mismatch between expectancy and outcome--drives belief formation, this study examined the possibility that delusions form because of disrupted prediction--error processing. We used fMRI to determine prediction-error-related brain responses in 12 healthy subjects and 12 individuals (7 males) with delusional beliefs. Frontal cortex responses in the patient group were suggestive of disrupted prediction-error processing. Furthermore, across subjects, the extent of disruption was significantly related to an individual's propensity to delusion formation. Our results support a neurobiological theory of delusion formation that implicates aberrant prediction-error signalling, disrupted attentional allocation and associative learning in the formation of delusional beliefs.

Cognitive Therapy for Delusions in Schizophrenia: Models, Benefits, and New Approaches

The main purpose of the review is to demonstrate how cognitive models of psychosis translate into cognitive-behavioral approaches for intervening with psychotic symptoms in schizophrenia. Several cognitive-behavioral factors which play a role in the maintenance and possibly formation of delusional beliefs are discussed, including attentional bias to threat, “data gathering” deficits, dysfunctional metacognition, and safety behaviors. Strategies for engagement, problem formulation, and psychoeducation with deluded patients are described. Cognitive-behavioral interventions are presented, specifically, cognitive restructuring, behavioral experiments, and coping skills training. Challenges to conducting cognitive-behavioral therapy (CBT) with delusions in schizophrenia are reviewed. Novel cognitive therapies, which address these challenges, are presented.

Cognitive biases involved in the formation of delusional beliefs

The clinical overlaps between schizophrenia and obsessive–compulsive disorder (OCD) seem to be related to thought disorders involving obsessions, overvalued ideas, and delusions. Overvalued ideas are beliefs falling in between obsessions and delusions and are stronger than obsessions but weaker than delusions. The goal of the present study was to compare patients with OCD to those with schizophrenia in terms of cognitive functions and to relate cognition and overvalued ideas in OCD.Twenty three patients with OCD (free of depression), 24 patients with schizophrenia, and 22 healthy subjects matched to patients in age, gender, education, and hand dominance were included in the study. All subjects were administered neurocognitive tests assessing verbal learning-memory, executive functions, verbal fluency, attention and verbal working memory.Patients with schizophrenia showed worse performance on cognitive tests than the OCD and control groups. The severity of overvalued ideas was significantly correlated to cognitive functions in the OCD group. There were no significant differences in cognitive functions between schizophrenia group and the OCD patients who had higher scores on the Overvalued Ideas Scale (OVIS).Overvalued ideas in OCD may be related to cognitive dysfunctions in OCD and this subtype of OCD may have similar characteristics to schizophrenia in terms of cognition.

Processing of threat-related affect is delayed in delusion-prone individuals.

On the basis of previous reports of an attentional bias for threat-related emotional material in deluded schizophrenics (e.g. Bentall & Kaney, 1989), the present study examined the proposal that a similar bias would be demonstrated by delusion-prone individuals, reflected by longer response latencies for the task of processing threat-related facially displayed affects (e.g. anger, fear). A non-randomized matched group design was employed to examine the performance of delusion-prone individuals in comparison with a control group. 50 psychiatrically healthy participants completed the Peters et al. Delusions Inventory (PDI) as an index of delusional ideation (Peters, Day, & Garety, 1996; Peters, Joseph, & Garety, 1999). Subjects were presented with a standard set of facial stimuli depicting happy, sad, neutral, fearful and angry emotion expressions (Mazurski & Bond, 1993). Reaction times for the task of identifying each type of affect were compared between groups of high and low scorers on the PDI. Highly delusion-prone individuals displayed a significant delay in processing angry facial expressions in comparison with low scorers on the PDI. The increased response latency for processing angry expressions was interpreted as evidence of attentional bias for material posing a threat to the self, supporting previous cognitive data in relation to deluded patients. Threatening facial expressions may be regarded with increased significance by delusion-prone individuals, and it is possible that this bias is involved in the formation of delusional beliefs.

How to understand the formation of delusional beliefs: a proposal.

The formation of delusional beliefs is elucidated by the expressed experiences of 75 delusional patients. It is found that such beliefs may develop regardless of the presence (64%) or absence (20%) of anomalous experiences. Patients within the same diagnostic category remember it very differently. Many patients (71%) find a simple and reassuring way of understanding and relating to the external world by the formation of delusional beliefs. To many patients (47%) the delusional theme remains unchanged from the start and from one psychotic episode to another, while to other patients (24%) the theme changes in a hierarchical way. It is suggested that the formation of delusional beliefs is caused by impaired two-way communication or metathinking and that the delusional theme indicates the severity of cognitive dysfunction or mental disorder.