Reasoning Anomalies Associated With Delusions in Schizophrenia (original) (raw)
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Journal of Clinical and Experimental Neuropsychology, 2006
A neuropsychological paradigm is introduced that provides a measure of a bias against disconfirmatory evidence (BADE), and its correspondence with delusions in people with schizophrenia and schizoaffective disorder was investigated. Fifty-two patients diagnosed with schizophrenia or schizoaffective disorder (36 were acutely delusional) and 24 healthy control participants were presented with delusion-neutral pictures in each trial, and were asked to rate the plausibility of four written interpretations of the scenario depicted by that picture. Subsequently, new pictures that provided background information about the depicted scenario were successively presented, and participants were requested to adjust their ratings, taking into account this new information. Two of the interpretations appeared tenable initially but ultimately proved to be implausible, one appeared untenable initially but eventually proved to be plausible, and one appeared untenable at all stages. A BADE was observed for delusional compared to non-delusional patients, as well as for all patients compared to controls. In addition, regardless of symptom profile, patients were more accepting of implausible interpretations than controls. The present work suggests that deficits in reasoning may contribute to the maintenance of delusions via an impairment in the processing of disconfirmatory evidence.
Dimensions of Delusions and Attribution Biases along the Continuum of Psychosis
PLOS ONE, 2015
This study compared delusional dimensions and attribution biases along the continuum of psychosis. Participants completed questionnaires on delusion-like beliefs and attributions. Although patients with first-episode psychosis (N = 70) endorsed fewer delusion-like beliefs than non-clinical individuals with psychotic-like experiences (N = 12), they scored highest on delusional conviction, distress and preoccupation, followed by non-clinical individuals with psychotic-like experiences, and then healthy controls (N = 642). Self-serving bias was found in patients and non-clinical individuals with psychotic-like experiences, but not in healthy controls. Personalizing bias for negative events was not significantly different across the three groups. When compared with healthy controls, non-clinical individuals with psychotic-like experiences had an exaggerated self-serving bias, but were not more marked in personalizing bias. Self-serving bias and personalizing bias were both associated with delusional dimensions. However, the association between self-serving bias and number of delusion-like beliefs was stronger among patients than non-clinical participants. Future research could investigate the extent to which self-serving bias, in combination with an appraisal of delusional ideation as convincing, distress, and preoccupying, contributes to the development of clinical delusions.
Schizophrenia Research: Cognition, 2015
Patients with delusions exhibit an increased tendency to arrive at decisions based on very limited evidence (jumping-to-conclusions; JTC), making this reasoning bias relevant for the treatment of delusions. Neurocognitive deficits contribute to JTC, but it is not known whether this has any bearing on the clinical syndrome of delusions. We addressed this question by reanalyzing data from an efficacy study of nonpharmacological interventions as adjunctive treatments in schizophrenia. We investigated the longitudinal associations of cognitive functioning, JTC and delusions in patients with psychotic disorders receiving either a metacognitive intervention addressing reasoning biases (n = 59), or cognitive remediation (n = 58). Both interventions improved JTC; in the cognitive remediation group, tentative evidence suggested that better neurocognitive performance contributed to this improvement. However, JTC gains were associated with delusion improvement only in the metacognitive intervention group, suggesting a content-specific mechanism of action.
Neuropsychological functioning and jumping to conclusions in delusions
Schizophrenia Research, 2013
Background: It has been consistently demonstrated that delusions are related to jumping to conclusions (JTC), a data-gathering bias and potential candidate endophenotype of psychosis. Recent research suggests that JTC may be a marker of treatment response. However, we know little about the factors contributing to the occurrence of this reasoning bias. This study investigated the relationship between JTC and hypothesised deficits in working memory, employing standard well-validated neuropsychological tests, in people with current delusions. Method: One hundred and twenty six people with schizophrenia spectrum psychosis and current delusions were assessed for current symptoms, and tested for JTC. We compared performance on tests of working memory in those with the reasoning bias and those without. Results: As expected, 30-40% of this sample of people with current delusions showed the JTC bias. There were no differences in premorbid IQ between those with and without the JTC reasoning bias. However, the performance of the JTC group was significantly worse on tests of working memory. Conclusions: The JTC data-gathering bias is associated with impairments in working memory. New nonpharmacological interventions for people with delusions, designed to improve data gathering, may benefit from incorporating strategies to overcome deficits in working memory.
The jumping to conclusions bias in delusions: Specificity and changeability
Journal of Abnormal Psychology, 2010
There are indications that a jumping to conclusions bias (JTC) plays a role in the formation and maintenance of delusions and should be targeted in therapy. However, it is unclear whether (a) JTC is uniquely associated with delusions or simply an epiphenomenon of schizophrenia or impaired intellectual functioning and (b) it can be changed by varying task demands, motivational factors, or feedback. Seventy-one patients with schizophrenia spectrum disorders and either acute or remitted delusions and 68 healthy controls were included. Patients were assessed with self-and observer-rated symptom measures. All participants were assessed for intellectual ability and performed the classic beads task with a ratio of 80:20. They were then presented with task variations that involved increasing the difficulty of the ratio to 60:40, introducing a rule for which correct decisions were rewarded by monetary gains and false decisions led to financial losses, and providing feedback on the accuracy of the previous decisions. Participants with current delusional symptoms took fewer draws to decision (DTD) than did those in remission and healthy controls. DTD were associated with observer-rated delusions, but controlling for negative symptoms or intelligence rendered this association insignificant. DTD increased after the difficulty of the task increased and after feedback. The study demonstrated that JTC is linked to delusions but that this association is not unique. Patients with delusions are principally able to adapt their decisions to altered conditions but still decide relatively quickly even when decisions have negative consequences. These difficulties might stem in part from impaired intellectual functioning.
Journal of Abnormal Psychology, 2012
Two reasoning biases, jumping to conclusions (JTC) and belief inflexibility, have been found to be associated with delusions. We examined these biases and their relationship with delusional conviction in a longitudinal cohort of people with schizophrenia-spectrum psychosis. We hypothesized that JTC, lack of belief flexibility, and delusional conviction would form distinct factors, and that JTC and lack of belief flexibility would predict less change in delusional conviction over time. Two hundred seventy-three patients with delusions were assessed over twelve months of a treatment trial . Forty-one percent of the sample had 100% conviction in their delusions, 50% showed a JTC bias, and 50%-75% showed a lack of belief flexibility. Delusional conviction, JTC, and belief flexibility formed distinct factors although conviction was negatively correlated with belief flexibility. Conviction declined slightly over the year in this established psychosis group, whereas the reasoning biases were stable. There was little evidence that reasoning predicted the slight decline in conviction. The degree to which people believe their delusions, their ability to think that they may be mistaken and to consider alternative explanations, and their hastiness in decision making are three distinct processes although belief flexibility and conviction are related. In this established psychosis sample, reasoning biases changed little in response to medication or psychological therapy. Required now is examination of these processes in psychosis groups where there is greater change in delusion conviction, as well as tests of the effects on delusions when these reasoning biases are specifically targeted.