Different sides of the same coin? Intercorrelations of cognitive biases in schizophrenia

Introduction. A number of cognitive biases have been associated with delusions in schizophrenia. It is yet unresolved whether these biases are independent or represent different sides of the same coin.

Methods. A total of 56 patients with schizophrenia underwent a comprehensive cognitive battery encompassing paradigms tapping cognitive biases with special relevance to schizophrenia (e.g., jumping to conclusions, bias against disconfirmatory evidence), motivational factors (self-esteem and need for closure), and neuropsychological parameters. Psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS).

Results. Core parameters of the cognitive bias instruments were submitted to a principal component analysis which yielded four independent components: jumping to conclusions, personalising attributional style, inflexibility, and low self-esteem.

Conclusions. The study lends tentative support for the claim that candidate cognitive mechanisms for delusions only partially overlap, and thus encourage current approaches to target these biases independently via (meta)cognitive training.     

Jumping to conclusions and perceptions in early psychosis: Relationship with delusional beliefs

Introduction. Previous research has suggested that biases in cognitive processes involved in everyday reasoning may contribute to the development of delusional beliefs. The aim of this study was to explore jumping to conclusions (JTC), a data-gathering bias, and jumping to perceptions (JTP), a bias towards believing ambiguous perceptual events are real and external.

Methods. Individuals with current delusions (n=17), remitted delusions (n=17), both recruited from an early psychosis service, and nonclinical participants (n=35) were compared on a probabilistic reasoning task, an auditory perceptual bias task, and the Barely Visible Words task.

Results. The deluded participants did not demonstrate the expected JTC bias; therefore the relationship between JTC and JTP could not be examined. However, both clinical groups exhibited a JTP bias on the auditory perceptual bias task. In contrast, the lowered perceptual threshold for threat displayed by the control group was absent in the clinical groups.

Conclusions. These results suggest that the JTP bias may be a trait characteristic in those with a propensity to delusions, and that these individuals may also show a bias away from threat.     

The impact of social and sensory stress on cognitive biases and delusions in schizophrenia

Introduction: Stress aggravates delusional symptoms, but the exact underlying mechanisms are still not fully understood. One of the routes may be via exacerbation of information processing distortions frequently observed in psychosis. The aim of the present study was thus to investigate the impact of social and sensory stress on specific cognitive processes along with different dimensions of delusional thinking.

Methods: Nineteen individuals affected by schizophrenia and 15 healthy controls were assessed under 3 experimental conditions (social stress, neutral, noise stress), with counter-balanced presentation of stress conditions across participants of both groups. Under each condition participants performed parallel versions of experimental tasks and had to report their level of paranoid thinking and subjective distress.

Results: Irrespective of condition, patients showed significant impairments in metacognitive accuracy compared with controls. When social stress was applied first, mentalising accuracy decreased significantly in the subsequent condition among patients only. Following exposure to either social or sensory stress, patients reported significantly higher conviction in their paranoid ideas in the subsequent condition.

Conclusions: Only limited evidence was found for the negative impact of stress on cognitive processes in schizophrenia patients. However, this may not be true for those with more severe information processing abnormalities and/or delusions.     

Vulnerable self, poor understanding of others' minds, threat anticipation and cognitive biases as triggers for delusional experience in schizophrenia: a theoretical model

It remains unclear what processes lead to the establishment of persecutory delusions in acute phases of schizophrenia. Recently, it has been argued that persecutory delusions arise from an interaction among a range of emotional, cognitive and social factors. In this work, we explored this possibility by first discussing the relevant aspects of recent theoretical models of the causes of persecutory delusions. Then, we offered an analysis of the literature, illustrated with clinical observations suggesting that persecutory delusions are triggered during stressful intersubjective transactions by the interactions of (a) an alteration in empathetic perspective taking and in pragmatic understanding of others' minds; (b) a perception/representation of the self as vulnerable or subordinate and of the other as dominant and threatening; and (c) a hyperfunctioning of the threat/self-protection system when faced with perceived danger. Implications for future research and treatment of people suffering from this symptom are discussed.     

The role of premorbid personality and cognitive factors in awareness of illness,memory, and behavioural functioning in Alzheimer's disease

Introduction. Research has suggested an association between personality factors and awareness in patients with dementia, yet valid measurement of premorbid personality is problematic. The present study aimed to better reveal the relationship between premorbid personality and awareness by using improved methodology. Moreover, the study aims to contrast the strength of the relationship of premorbid personality and awareness with that of cognitive factors.

Methods. Awareness of illness, symptoms, mnemonic and behavioural impairments, and treatment compliance were measured in 27 patients with mild-to-moderate Alzheimer's disease (AD) diagnosed by standard criteria for probable AD. Participant premorbid personality was measured using average retrospective Neuroticism-Extroversion-Openness Inventory (NEO-FFI) scores from two informants. Correlations were performed to investigate the relationship between awareness and personality dimensions, as well as measures of cognitive style, neuropsychological function, mood, carer burden, and sociodemographic factors.

Results. There was little relationship between awareness and personality scores, but modest associations between awareness and mood, age, and age of onset of first symptoms. Awareness of memory was related to memory functioning. Increased carer burden was associated with lack of awareness of cognitive-behavioural deficits but there were only few and weak associations between awareness and measures of cognitive functioning.

Conclusions. There was little support for an association between previous personality and awareness in dementia. However, increased carer burden was associated specifically with lack of awareness of cognitive-behavioural deficits not deficits in ADL, whereas lower awareness of ADL and not cognitive-behavioural deficits was associated with age. Awareness of memory appeared to be a metamemory capacity. Mood and age rather than personality and cognition are stronger predictors of awareness in early Alzheimer's disease.