Information gathered through draws-to-decision, social functioning, and personal recovery among patients with schizophrenia in Japan.

INTRODUCTION: In schizophrenia, social functioning and personal recovery are pivotal outcomes potentially influenced by cognitive biases such as Jumping to Conclusions (JTC). Despite their significance, the relationship between JTC, social functioning, and personal recovery remains unclear. This study aims to investigate this relationship to inform tailored interventions for schizophrenia management. METHODS: Data were collected from 94 schizophrenia patients using standardised measures. The Beads Task assessed JTC, whereas the Brief PANSS, TMT-J, SLOF-J, and RAS-J evaluated psychiatric symptoms, neurocognitive functioning, social functioning, and personal recovery, respectively. Statistical analyses included correlation and hierarchical regression. RESULTS: Correlation analyses revealed a significant negative correlation between JTC and personal recovery (r = -0.27, p < 0.05). Hierarchical regression indicated JTC as a significant negative predictor of personal recovery (ß = -0.33, p = 0.01). No significant correlation was found between JTC and social functioning. DISCUSSION: Increased JTC was associated with lower levels of personal recovery in schizophrenia patients, independent of demographic and clinical factors. In the case of individuals with schizophrenia who demonstrate JTC, there is a potential to suggest the paradox of insight or apparent personal recovery scores.

A Bayesian predictive processing account of Othello syndrome in Parkinson's disease.

Introduction: Although delusions in Parkinson's disease (PD) are rare, when they occur they frequently take the form of "Othello syndrome": the irrational belief that a spouse or partner is being unfaithful. Hitherto dismissed as either a by-product of dopamine therapy or cognitive impairment, there are still no convincing theoretical accounts to explain why only some patients fall prey to this delusion, or why it persists despite clear disconfirmatory evidence.Methods: We discuss the limitations of existing explanations of this delusion, namely hyperdopaminergia-induced anomalous perceptual experiences and cognitive impairment, before describing how Bayesian predictive processing accounts can provide a more comprehensive explanation by foregrounding the importance of prior experience and its impact upon computation of probability. We illustrate this new conceptualisation with three case vignettes.Results: We suggest that in those with prior experience of romantic betrayal, hyperdominergic-induced aberrant prediction errors enable anomalous perceptual experiences to accrue greater prominence, which is then maintained through Bayes-optimal inferencing to confirm cognitive distortions, eliciting and shaping this dangerous delusion.Conclusions: We propose the first comprehensive mechanistic account of Othello syndrome in PD and discuss implications for clinical interventions.

A Bayesian model of the jumping-to-conclusions bias and its relationship to psychopathology.

The mechanisms by which delusion and anxiety affect the tendency to make hasty decisions (Jumping-to-Conclusions bias) remain unclear. This paper proposes a Bayesian computational model that explores the assignment of evidence weights as a potential explanation of the Jumping-to-Conclusions bias using the Beads Task. We also investigate the Beads Task as a repeated measure by varying the key aspects of the paradigm. The Bayesian model estimations from two online studies showed that higher delusional ideation promoted reduced belief updating but the impact of general and social anxiety on evidence weighting was inconsistent. The altered evidence weighting as a result of a psychopathological trait appeared insufficient in contributing to the Jumping-to-Conclusions bias. Variations in Beads Task aspects significantly affected subjective certainty at the point of decisions but not the number of draws to decisions. Repetitions of the Beads Task are feasible if one assesses the Jumping-to-Conclusions bias using number of draws to decisions.

Identifying and changing cognitive vulnerability in the classroom: preliminary evaluation of CUES-Ed, a school-based universal cognitive behavioural early intervention service for 7-10 year olds.

BACKGROUND: School-based early intervention may alleviate current emotional and behavioural problems, and, by targeting underlying vulnerability, safeguard children's future mental health. Improving on mixed outcomes to date is an international public health priority. CUES-Ed is a classroom-based, clinician-led, universal cognitive behavioural programme for primary school children, designed to promote emotional literacy and regulation. Additionally, CUES-Ed targets cognitive mechanisms implicated in the future development of mental disorder: stigmatising appraisals of emotional expression and of unusual perceptual experiences, and the tendency to jump-to-conclusions (JTC). We report here on fitness for purpose of our in-service assessment of cognitive vulnerability, and change in cognitive vulnerability following CUES-Ed and compared with a naturalistic waitlist. METHODS: From 05/2017-11/2017, 960 children participated (900 CUES-Ed; 60 naturalistic waitlist). Assessments were completed in whole classes; 732 children provided pre-post data on all measures; 227 were missing data through absence or poor completion (n = 1 declined assessment). RESULTS: Relationships between baseline cognitive vulnerability measures and their components were consistent with reliable and valid assessment. Cognitive vulnerability reduced from before to after CUES-Ed and compared with the naturalistic waitlist, for JTC (large effects) and stigmatising appraisals (small-medium effects), for all children (ESs pre-post: 0.2-1.0; between-group: 0.1-1.0) and vulnerable subgroups (ESs pre-post: 0.5-1.7; between-group: 0.2-2.0). CONCLUSIONS: Targeted cognitive vulnerability mechanisms change following CUES-Ed. As stigmatising appraisals and JTC may increase vulnerability to future mental illness, findings suggest a promise in reducing future risk. A formally controlled research study, with longer-term follow-up, is required to test this. Limitations and implications for future evaluation are discussed.

A replication study of JTC bias, genetic liability for psychosis and delusional ideation.

BACKGROUND: This study attempted to replicate whether a bias in probabilistic reasoning, or 'jumping to conclusions'(JTC) bias is associated with being a sibling of a patient with schizophrenia spectrum disorder; and if so, whether this association is contingent on subthreshold delusional ideation. METHODS: Data were derived from the EUGEI project, a 25-centre, 15-country effort to study psychosis spectrum disorder. The current analyses included 1261 patients with schizophrenia spectrum disorder, 1282 siblings of patients and 1525 healthy comparison subjects, recruited in Spain (five centres), Turkey (three centres) and Serbia (one centre). The beads task was used to assess JTC bias. Lifetime experience of delusional ideation and hallucinatory experiences was assessed using the Community Assessment of Psychic Experiences. General cognitive abilities were taken into account in the analyses. RESULTS: JTC bias was positively associated not only with patient status but also with sibling status [adjusted relative risk (aRR) ratio : 4.23 CI 95% 3.46-5.17 for siblings and aRR: 5.07 CI 95% 4.13-6.23 for patients]. The association between JTC bias and sibling status was stronger in those with higher levels of delusional ideation (aRR interaction in siblings: 3.77 CI 95% 1.67-8.51, and in patients: 2.15 CI 95% 0.94-4.92). The association between JTC bias and sibling status was not stronger in those with higher levels of hallucinatory experiences. CONCLUSIONS: These findings replicate earlier findings that JTC bias is associated with familial liability for psychosis and that this is contingent on the degree of delusional ideation but not hallucinations.

People with jumping to conclusions bias tend to make context-independent decisions rather than context-dependent decisions.

Beads task (BT) uses a probabilistic reasoning paradigm and reveals jumping to conclusions (JTC) bias, the tendency to make premature judgments based on insufficient information (i.e., making fewer draws to decision-DTD). In this study, healthy participants (N = 207) were tested on the 80:20 and 60:40 color ratio versions of BT. We investigated associations of JTC bias with a set of cognitive bias problems and Cognitive Bias Task (CBT), a non-veridical (agent-centered) decision-making task that determines context-dependent and context-independent decision-making bias.Results showed that the converted CBT scores were negatively, and cognitive bias scores were positively correlated with JTC bias (DTD ≤ 2) on both versions of the BT. The CBT demonstrated to have satisfactory convergent and predictive validity for JTC bias. The findings suggest that people with JTC bias fail to solve cognitive bias problems and are more likely to make context-independent response selections than context-dependent response selections.

Divergent thinking in Italian elementary school children: the key role of probabilistic reasoning style.

Divergent thinking is widely recognised as an individual creative potential and an essential factor in fostering creativity since the early stages of life. Albeit previous research revealed that creativity could be pursued through controlled mental processes (e.g. reasoning), the debate about the impact of children's reasoning on divergent thinking and, ultimately, creativity is still open. The present study sought to deepen the relationships between probabilistic reasoning and divergent thinking in a sample of 106 Italian children (meanage = 8.64, SDage = 1.34; 58 F). The Beads Task was used to evaluate probabilistic reasoning, whereas the Alternative Uses Task was administered to assess divergent thinking. Results revealed that analytical, slow, and effortful forms of thought underpinned by high probabilistic competencies predict children's divergent production. These findings suggest that a higher score for divergence of thinking depends on a high involvement of reasoning style, which in this study relies on the ability to make probabilistic decisions in ambiguous situations. Future research directions were discussed.

The jumping to conclusions reasoning bias as a cognitive factor contributing to psychosis progression and persistence: findings from NEMESIS-2.

BACKGROUND: Contemporary models of psychosis implicate the importance of affective dysregulation and cognitive factors (e.g. biases and schemas) in the development and maintenance of psychotic symptoms, but studies testing proposed mechanisms remain limited. This study, uniquely using a prospective design, investigated whether the jumping to conclusions (JTC) reasoning bias contributes to psychosis progression and persistence. METHODS: Data were derived from the second Netherlands Mental Health Survey and Incidence Study (NEMESIS-2). The Composite International Diagnostic Interview and an add-on instrument were used to assess affective dysregulation (i.e. depression, anxiety and mania) and psychotic experiences (PEs), respectively. The beads task was used to assess JTC bias. Time series analyses were conducted using data from T1 and T2 (N = 8666), excluding individuals who reported high psychosis levels at T0. RESULTS: Although the prospective design resulted in low statistical power, the findings suggest that, compared to those without symptoms, individuals with lifetime affective dysregulation were more likely to progress from low/moderate psychosis levels (state of 'aberrant salience', one or two PEs) at T1 to high psychosis levels ('frank psychosis', three or more PEs or psychosis-related help-seeking behaviour) at T2 if the JTC bias was present [adj. relative risk ratio (RRR): 3.8, 95% confidence interval (CI) 0.8-18.6, p = 0.101]. Similarly, the JTC bias contributed to the persistence of high psychosis levels (adj. RRR: 12.7, 95% CI 0.7-239.6, p = 0.091). CONCLUSIONS: We found some evidence that the JTC bias may contribute to psychosis progression and persistence in individuals with affective dysregulation. However, well-powered prospective studies are needed to replicate these findings.

Jumping to conclusions, general intelligence, and psychosis liability: findings from the multi-centre EU-GEI case-control study.

BACKGROUND: The 'jumping to conclusions' (JTC) bias is associated with both psychosis and general cognition but their relationship is unclear. In this study, we set out to clarify the relationship between the JTC bias, IQ, psychosis and polygenic liability to schizophrenia and IQ. METHODS: A total of 817 first episode psychosis patients and 1294 population-based controls completed assessments of general intelligence (IQ), and JTC, and provided blood or saliva samples from which we extracted DNA and computed polygenic risk scores for IQ and schizophrenia. RESULTS: The estimated proportion of the total effect of case/control differences on JTC mediated by IQ was 79%. Schizophrenia polygenic risk score was non-significantly associated with a higher number of beads drawn (B = 0.47, 95% CI -0.21 to 1.16, p = 0.17); whereas IQ PRS (B = 0.51, 95% CI 0.25-0.76, p < 0.001) significantly predicted the number of beads drawn, and was thus associated with reduced JTC bias. The JTC was more strongly associated with the higher level of psychotic-like experiences (PLEs) in controls, including after controlling for IQ (B = -1.7, 95% CI -2.8 to -0.5, p = 0.006), but did not relate to delusions in patients. CONCLUSIONS: Our findings suggest that the JTC reasoning bias in psychosis might not be a specific cognitive deficit but rather a manifestation or consequence, of general cognitive impairment. Whereas, in the general population, the JTC bias is related to PLEs, independent of IQ. The work has the potential to inform interventions targeting cognitive biases in early psychosis.

Jumping to conclusions in the less-delusion-prone? Further evidence from a more reliable beads task.

BACKGROUND: A single meta-analysis has found that healthy people with higher delusion-proneness tend to gather less information (i.e., make fewer draws to decision, or DTD) on the beads task, although the findings of contributing studies were mixed, and the pooled effect size was small. However, using a new and more reliable "distractor sequences" beads task, we recently found a positive relationship between delusion-proneness and DTD in a healthy sample. In the current study, we re-tested this relationship in a new sample, and tested the possibility that the relationship is driven by participant's ability to understand and use odds or likelihood information ("odds literacy"). METHODS: Healthy participants (N = 167) completed the distractor sequences beads task, the Peters Delusions Inventory (PDI) which measures delusion-proneness, a measure of odds literacy, and the Depression, Anxiety, and Stress scale. RESULTS: PDI and DTD were positively correlated, and comparing PDI quartiles on DTD confirmed a statistically significant trend of increasing DTD with PDI quartile. Odds literacy was positively rather than negatively associated with both DTD and PDI. Anxiety was positively correlated with PDI and DTD. CONCLUSIONS: We replicated our earlier finding that DTD and delusion-proneness were positively related in a non-clinical sample, but found that increased odds-literacy did not drive lower PDI and DTD, and hence did not explain their covariance. It is possible however that anxiety and co-occurring risk aversion drive increased delusion-proneness and information-gathering, potentially accounting for the positive relationship between PDI and DTD.

Problems in measuring the JTC-bias in patients with psychotic disorders with the fish task: a secondary analysis of a baseline assessment of a randomized controlled trial.

BACKGROUND: The jumping to conclusions bias (JTC) is considered to be an important causal factor in theoretical models for the formation and maintenance of delusions. However, recent meta-analytic findings show a rather equivocal pattern of results regarding associations between JTC and delusions. Thus, the present study aims to investigate in a large sample whether the JTC-bias is more pronounced in patients with psychotic disorders in comparison to controls and whether the JTC bias is associated with a more severe delusional conviction, persecutory delusions, and positive symptoms in general. METHODS: Patients with psychotic disorders (n = 300) enrolled in a therapy trial and healthy controls (n = 51) conducted a variant of the beads task (fish task) as a measure for the JTC-bias at the start of the trial. Further, clinical interviews were used to assess patients' delusional severity and delusional conviction. RESULTS: There were no statistically significant differences between patients with psychotic disorders (with 53% displaying the JTC-bias) and controls (41%). Furthermore, there were no statistically significant correlations between JTC measures and persecutory delusions, delusional conviction, and positive symptoms. CONCLUSIONS: We found no differences in JTC between patients with psychotic disorders and healthy controls, which is in part in line with meta-analytic findings using a wide range of JTC task variants. Interestingly, patients with psychotic disorders displayed JTC rates commonly found in the literature, while healthy control subjects showed an unexpectedly high level of JTC. The task variant we used in the present study (fish task) is discussed as a potential reason for our results, as it may induce a more deliberative reasoning style in controls as compared to the traditional beads task. Furthermore, possible implications for the measurement of the JTC-bias, in general, are discussed. TRIAL REGISTRATION: ISRCTN29242879 ( isrctn.com ), date of registration: April 12th 2006, retrospectively registered.

Effort and liberal acceptance bias in patients with schizophrenia.

Introduction: A liberal acceptance bias is implicated in the formation and maintenance of delusions in schizophrenia. The present study tested the hypothesis that patients with schizophrenia are more quickly satisfied with their task performance than controls despite poor objective performance. Methods: Fifty patients with schizophrenia and 50 healthy controls performed the newly developed copy figure task in which participants copy a complex geometrical figure up to eight times until they are satisfied with the result. Objective performance was scored blind to group status. Subjective performance was rated on a 10-point scale. Carefulness of the drawing using anchor points served as a proxy for effort. Results: Patients made as many attempts as controls to copy the figure despite their worse subjective and objective performance. The number of attempts was negatively correlated with (persecutory) delusions and the PANSS total score. Neither effort nor possible frustration due to a plateau in performance was a reason for task termination. Conclusions: This exploratory study is in line with predictions based on the liberal acceptance model. For future studies, we recommend further cross-validating this paradigm and testing whether patients' retrospective assessment of their performance is exaggerated relative to controls. We also suggest that researchers pursue this line of research with personally meaningful material where a decreased threshold of acceptance may more easily translate into the subsequent fixation of ideas.

Jumping to conclusions in autism: integration of contextual information and confidence in decision-making processes.

Individuals with Autism spectrum condition (ASC) present cognitive biases and a difficulty to integrate emotional responses in decision-making, which is necessary for adequate social functioning. Thus, understanding the underlying mechanisms of the altered decision-making in individuals with ASC may eventually have a positive impact on their social functioning. The Picture decision task was employed to observe the effect of new information (fragments of an incomplete picture), interpretative context (verbal cues), and the level of confidence on decision-making processes. Our study administered the task to 49 children with ASC and 37 children with Typical Development (TD). Children with TD showed a higher probability of success when an interpretative context was given. Conversely, children with ASC had an equal probability of success regardless of whether an interpretative context was provided or not. In addition, unlike children with TD, the level of confidence did not allow predicting the probability of successful decisions in children with ASC. Finally, children with ASC had more probability of jumping to conclusions, a decision made quickly with only one fragment of the picture while being completely sure of it. These results are discussed in light of current cognitive and emotional theories on ASC.

Jumping to conclusions at first onset of psychosis predicts longer admissions, more compulsory admissions and police involvement over the next 4 years: the GAP study.

BACKGROUND: Jumping to conclusions (JTC), which is the proneness to require less information before forming beliefs or making a decision, has been related to formation and maintenance of delusions. Using data from the National Institute of Health Research Biomedical Research Centre Genetics and Psychosis (GAP) case-control study of first-episode psychosis (FEP), we set out to test whether the presence of JTC would predict poor clinical outcome at 4 years. METHODS: One-hundred and twenty-three FEP patients were assessed with the Positive and Negative Syndrome Scale (PANSS), Global Assessment of Functioning (GAF) and the probabilistic reasoning 'Beads' Task at the time of recruitment. The sample was split into two groups based on the presence of JTC bias. Follow-up data over an average of 4 years were obtained concerning clinical course and outcomes (remission, intervention of police, use of involuntary treatment - the Mental Health Act (MHA) - and inpatient days). RESULTS: FEP who presented JTC at baseline were more likely during the follow-up period to be detained under the MHA [adjusted OR 15.62, 95% confidence interval (CI) 2.92-83.54, p = 0.001], require intervention by the police (adjusted OR 14.95, 95% CI 2.68-83.34, p = 0.002) and have longer admissions (adjusted IRR = 5.03, 95% CI 1.91-13.24, p = 0.001). These associations were not accounted for by socio-demographic variables, IQ and symptom dimensions. CONCLUSIONS: JTC in FEP is associated with poorer outcome as indicated and defined by more compulsion police intervention and longer periods of admission. Our findings raise the question of whether the implementation of specific interventions to reduce JTC, such as Metacognition Training, may be a useful addition in early psychosis intervention programmes.

Reasoning bias, working memory performance and a transdiagnostic phenotype of affective disturbances and psychotic experiences in the general population.

BACKGROUND: The jumping to conclusions (JTC) reasoning bias and decreased working memory performance (WMP) are associated with psychosis, but associations with affective disturbances (i.e. depression, anxiety, mania) remain inconclusive. Recent findings also suggest a transdiagnostic phenotype of co-occurring affective disturbances and psychotic experiences (PEs). This study investigated whether JTC bias and decreased WMP are associated with co-occurring affective disturbances and PEs. METHODS: Data were derived from the second Netherlands Mental Health Survey and Incidence Study (NEMESIS-2). Trained interviewers administered the Composite International Diagnostic Interview (CIDI) at three time points in a general population sample (N = 4618). The beads and digit-span task were completed to assess JTC bias and WMP, respectively. CIDI was used to measure affective disturbances and an add-on instrument to measure PEs. RESULTS: Compared to individuals with neither affective disturbances nor PEs, the JTC bias was more likely to occur in individuals with co-occurring affective disturbances and PEs [moderate psychosis (1-2 PEs): adjusted relative risk ratio (RRR) 1.17, 95% CI 0.98-1.41; and high psychosis (3 or more PEs or psychosis-related help-seeking behaviour): adjusted RRR 1.57, 95% CI 1.19-2.08], but not with affective disturbances and PEs alone, whereas decreased WMP was more likely in all groups. There was some evidence of a dose-response relationship, as JTC bias and decreased WMP were more likely in individuals with affective disturbances as the level of PEs increased or help-seeking behaviour was reported. CONCLUSION: The findings suggest that JTC bias and decreased WMP may contribute to a transdiagnostic phenotype of co-occurring affective disturbances and PEs.

Does uncertainty breed conviction? On the possible role of compensatory conviction in jumping to conclusions and overconfidence in psychosis.

Background: Jumping to conclusions (JTC) and overconfidence in errors are well established in individuals with a liability to psychosis. Experimental research suggests that subjecting individuals to dilemmas and doubt prompts a subsequent hardening of attitudes and may foster delusion-like convictions. For the present study, we examined whether this compensatory conviction process is exaggerated in individuals with a liability to psychosis and might in part explain JTC and overconfidence. Methods: A large sample of participants from the general population were screened for psychotic experiences with the Community Assessment of Psychic Experiences scale (CAPE) and then randomly allocated to either a condition in which they should experience doubt or a control condition. Participants (final sample, n = 650) were then tested on JTC and overconfidence. Results: Participants who scored high on the positive subscale of the CAPE made fewer draws to decision, showed greater confidence, and made more errors relative to low scorers. Yet, none of the parameters was modulated by experimental condition. Conclusions: Our results at present do not support the idea that JTC is elevated by a prior experience of a dilemma or doubt. Yet, this possibility should not be entirely dismissed as the presumed process may take time to evolve and perhaps needs to be more pervasive.

The role of effective connectivity between the task-positive and task-negative network for evidence gathering [Evidence gathering and connectivity].

Reports linking a 'jumping-to-conclusions' bias to delusions have led to growing interest in the neurobiological correlates of probabilistic reasoning. Several brain areas have been implicated in probabilistic reasoning; however, findings are difficult to integrate into a coherent account. The present study aimed to provide additional evidence by investigating, for the first time, effective connectivity among brain areas involved in different stages of evidence gathering. We investigated evidence gathering in 25 healthy individuals using fMRI and a new paradigm (Box Task) designed such as to minimize the effects of cognitive effort and reward processing. Decisions to collect more evidence ('draws') were contrasted to decisions to reach a final choice ('conclusions') with respect to BOLD activity. Psychophysiological interaction analysis was used to investigate effective connectivity. Conclusion events were associated with extensive brain activations in widely distributed brain areas associated with the task-positive network. In contrast, draw events were characterized by higher activation in areas assumed to be part of the task-negative network. Effective connectivity between the two networks decreased during draws and increased during conclusion events. Our findings indicate that probabilistic reasoning may depend on the balance between the task-positive and task-negative network, and that shifts in connectivity between the two may be crucial for evidence gathering. Thus, abnormal connectivity between the two systems may significantly contribute to the jumping-to-conclusions bias.

An investigation into the jumping-to-conclusions bias in social anxiety.

'Jumping-to-Conclusions' (JTC) is a data-gathering bias characterised by hasty decision-making, and is typically seen in individuals with high levels of delusions or paranoia. JTC has also been found in people with high trait and state anxiety. The present study aimed to explore the relationship between JTC and trait social anxiety and state anxiety, given paranoia is common in both social anxiety and psychotic disorders. One-hundred-and-eighty-six undergraduate students were allocated to a manipulation or control condition, and classified as high or low socially anxious. All participants completed the 'beads task' to assess JTC, and the State-Trait Anxiety Inventory (state subscale) to assess state anxiety. Participants in the manipulation condition were given an anxiety-inducing situation. Although the manipulation was effective in inducing state anxiety, there was no significant correlation between JTC and trait or state social anxiety. High socially anxious individuals showed more conservative decision-making than controls over time, which was posited to be caused by inhibited working memory resulting from increased state anxiety.

Reasoning in psychosis: risky but not necessarily hasty.

INTRODUCTION: A liberal acceptance (LA) threshold for hypotheses has been put forward to explain the well-replicated "jumping to conclusions" (JTC) bias in psychosis, particularly in patients with paranoid symptoms. According to this account, schizophrenia patients rest their decisions on lower subjective probability estimates. The initial formulation of the LA account also predicts an absence of the JTC bias under high task ambiguity (i.e., if more than one response option surpasses the subjective acceptance threshold). METHODS: Schizophrenia patients (n = 62) with current or former delusions and healthy controls (n = 30) were compared on six scenarios of a variant of the beads task paradigm. Decision-making was assessed under low and high task ambiguity. Along with decision judgments (optional), participants were required to provide probability estimates for each option in order to determine decision thresholds (i.e., the probability the individual deems sufficient for a decision). RESULTS: In line with the LA account, schizophrenia patients showed a lowered decision threshold compared to controls (82% vs. 93%) which predicted both more errors and less draws to decisions. Group differences on thresholds were comparable across conditions. At the same time, patients did not show hasty decision-making, reflecting overall lowered probability estimates in patients. CONCLUSIONS: Results confirm core predictions derived from the LA account. Our results may (partly) explain why hasty decision-making is sometimes aggravated and sometimes abolished in psychosis. The proneness to make risky decisions may contribute to the pathogenesis of psychosis. A revised LA account is put forward.

Who "jumps to conclusions"? A comprehensive assessment of probabilistic reasoning in psychosis following traumatic brain injury (PFTBI), and comparison with TBI, schizophrenia, and nonclinical controls.

INTRODUCTION: The "jumping to conclusions" (JTC) bias has received significant attention in the schizophrenia and delusion literature as an important aspect of cognition characterising psychosis. The JTC bias has not been explored in psychosis following traumatic brain injury (PFTBI). METHODS: JTC was investigated in 10 patients with PFTBI using the beads task (ratios 85:15 and 60:40). Probabilistic predictions, draws-to-decision, self-rated decision confidence, and JTC bias were recorded. Responses from 10 patients with traumatic brain injury (TBI), 23 patients with schizophrenia, and 23 nonclinical controls were compared. Relationships were explored between draws-to-decision and current intelligence quotient, affective state, executive function, delusions (severity and type), and illness chronicity (duration). RESULTS: Groups were comparable on JTC measures. Delusion severity and type were not related to draws-to-decision for either trial. In the entire sample, executive function (reduced mental flexibility) was significantly related to more draws-to-decision on the 60:40 ratio trial. CONCLUSIONS: We found no evidence for an elevated JTC bias in patients with PFTBI or TBI alone. The influence of executive dysfunction should be considered by future studies using the beads tasks in patient populations. These findings need to be replicated in larger PFTBI and TBI samples.