Dopaminergic modulation of probabilistic reasoning and overconfidence in errors: a double-blind study

Neural mechanisms of information seeking

We ubiquitously seek information to make better decisions. Particularly in the modern age, when more information is available at our fingertips than ever, the information we choose to collect determines the quality of our decisions. Decision neuroscience has long adopted empirical approaches where the information available to decision-makers is fully controlled by the researchers, leaving neural mechanisms of information seeking less understood. Although information seeking has long been studied in the context of the exploration-exploitation trade-off, recent studies have widened the scope to investigate more overt information seeking in a way distinct from other decision processes. Insights gained from these studies, accumulated over the last few years, raise the possibility that information seeking is driven by the reward system signaling the subjective value of information. In this piece, we review findings from the recent studies, highlighting the conceptual and empirical relationships between distinct literatures, and discuss future research directions necessary to establish a more comprehensive understanding of how individuals seek information as a part of value-based decision-making.

Associations of conservatism and jumping to conclusions biases with aberrant salience and default mode network

AIM

While conservatism bias refers to the human need for more evidence for decision-making than rational thinking expects, the jumping to conclusions (JTC) bias refers to the need for less evidence among individuals with schizophrenia/delusion compared to healthy people. Although the hippocampus-midbrain-striatal aberrant salience system and the salience, default mode (DMN), and frontoparietal networks ("triple networks") are implicated in delusion/schizophrenia pathophysiology, the associations between conservatism/JTC and these systems/networks are unclear.

METHODS

Thirty-seven patients with schizophrenia and 33 healthy controls performed the beads task, with large and small numbers of bead draws to decision (DTD) indicating conservatism and JTC, respectively. We performed independent component analysis (ICA) of resting functional magnetic resonance imaging (fMRI) data. For systems/networks above, we investigated interactions between diagnosis and DTD, and main effects of DTD. We similarly applied ICA to structural and diffusion MRI to explore the associations between DTD and gray/white matter.

RESULTS

We identified a significant main effect of DTD with functional connectivity between the striatum and DMN, which was negatively correlated with delusion severity in patients, indicating that the greater the anti-correlation between these networks, the stronger the JTC and delusion. We further observed the main effects of DTD on a gray matter network resembling the DMN, and a white matter network connecting the functional and gray matter networks (all P < 0.05, family-wise error [FWE] correction). Function and gray/white matter showed no significant interactions.

CONCLUSION

Our results support the novel association of conservatism and JTC biases with aberrant salience and default brain mode.

A systematic review of performance-based assessment studies on cognitive biases in schizophrenia spectrum psychoses and clinical high-risk states: A summary of 40 years of research

Cognitive models of psychosis have stimulated empirical studies on cognitive biases involved in schizophrenia spectrum psychoses and their symptoms. This systematic review aimed to summarize the studies on the role of cognitive biases as assessed in different performance-based tasks in schizophrenia spectrum psychoses and clinical high-risk states. We focused on five cognitive biases linked to psychosis, i.e., aberrant salience, attentional biases, source monitoring biases, jumping to conclusions, and bias against disconfirmatory evidence. We identified N = 324 studies published in N = 308 articles fulfilling inclusion criteria. Most studies have been cross-sectional and confirmed that the schizophrenia spectrum psychoses are related to exaggerated cognitive biases compared to healthy controls. On the contrary, less evidence suggests a higher tendency for cognitive biases in the UHR sample. The only exceptions were source monitoring and jumping to conclusions, which were confirmed to be exaggerated in both clinical groups. Hallucinations and delusions were the most frequent symptoms studied in the context of cognitive biases. Based on the findings, we presented a hypothetical model on the role of interactions between cognitive biases or additive effects of biases in shaping the risk of psychosis. Future research is warranted for further development of cognitive models for psychosis.

Insights into the molecular genetic basis of individual differences in metacognition

There is a striking lack of studies on the molecular genetic basis of metacognition, i.e., the higher-order ability to monitor mental processes. Here, an initial step toward resolving this issue was undertaken by investigating functional polymorphisms from three genes of the dopaminergic or serotonergic systems (DRD4, COMT, and 5-HTTLPR) in relation to behaviorally assessed metacognition in six paradigms across three cognitive domains. We report evidence for a task-dependent higher average confidence level (metacognitive bias) in carriers of at least one S or L_G-allele in the 5-HTTLPR genotype and integrate these findings within a differential susceptibility framework.

Neurocognitive bases of self-monitoring of inner speech in hallucination prone individuals

Verbal hallucinations in schizophrenia patients might be seen as internal verbal productions mistaken for perceptions as a result of over-salient inner speech and/or defective self-monitoring processes. Similar cognitive mechanisms might underpin verbal hallucination proneness in the general population. We investigated, in a non-clinical sample, the cerebral activity associated with verbal hallucinatory predisposition during false recognition of familiar words -assumed to stem from poor monitoring of inner speech-vs. uncommon words. Thirty-seven healthy participants underwent a verbal recognition task. High- and low-frequency words were presented outside the scanner. In the scanner, the participants were then required to recognize the target words among equivalent distractors. Results showed that verbal hallucination proneness was associated with higher rates of false recognition of high-frequency words. It was further associated with activation of language and decisional brain areas during false recognitions of low-, but not high-, frequency words, and with activation of a recollective brain area during correct recognitions of low-, but not high-, frequency words. The increased tendency to report familiar words as targets, along with a lack of activation of the language, recollective, and decisional brain areas necessary for their judgement, suggests failure in the self-monitoring of inner speech in verbal hallucination-prone individuals.

Can you trust this source? Advice taking in borderline personality disorder

Research suggests that patients with borderline personality disorder (BPD) share a range of cognitive biases with patients with psychosis. As the disorder often manifests in dysfunctional social interactions, we assumed associated reasoning styles would be exaggerated in a social setting. For the present study, we applied the Judge-Advisor System by asking participants to provide initial estimates of a person's age and presumed hostility based on a portrait photo. Afterwards, we presented additional cues/advice in the form of responses by anonymous previous respondents. Participants could revise their estimate, seek additional advice, or make a decision. Contrary to our preregistered hypothesis, patients with BPD (n = 38) performed similarly to healthy controls (n = 30). Patients sought the same number of pieces of advice, were equally confident, and used advice in similar ways to revise their estimates. Thus, patients with BPD did trust advice. However, patients gave higher hostility ratings to the portrayed persons. In conclusion, patients with BPD showed no cognitive biases in seeking, evaluating, and integrating socially provided information. While the study implies emotional rather than cognitive biases in the disorder, cognitive biases may still prove to be useful treatment targets in order to encourage delaying and reflecting on extreme emotional responses in social interactions.

Rethinking delusions: A selective review of delusion research through a computational lens

Delusions are rigid beliefs held with high certainty despite contradictory evidence. Notwithstanding decades of research, we still have a limited understanding of the computational and neurobiological alterations giving rise to delusions. In this review, we highlight a selection of recent work in computational psychiatry aimed at developing quantitative models of inference and its alterations, with the goal of providing an explanatory account for the form of delusional beliefs in psychosis. First, we assess and evaluate the experimental paradigms most often used to study inferential alterations in delusions. Based on our review of the literature and theoretical considerations, we contend that classic draws-to-decision paradigms are not well-suited to isolate inferential processes, further arguing that the commonly cited 'jumping-to-conclusion' bias may reflect neither delusion-specific nor inferential alterations. Second, we discuss several enhancements to standard paradigms that show promise in more effectively isolating inferential processes and delusion-related alterations therein. We further draw on our recent work to build an argument for a specific failure mode for delusions consisting of prior overweighting in high-level causal inferences about partially observable hidden states. Finally, we assess plausible neurobiological implementations for this candidate failure mode of delusional beliefs and outline promising future directions in this area.

Metacognitive training for psychosis (MCT): past, present, and future

This article provides an overview and retrospective on metacognitive training for psychosis (MCT), which first appeared approximately 2 decades ago. We recount how our empirical understanding of psychosis at that time led to the first preliminary version of the program. We describe setbacks and challenges that led to major changes, including revisions to existing modules (e.g., more focus on metacognitive variables, particularly on decision confidence as one of the primary targets of treatment) and the creation of new modules addressing mood, as well as attempts to improve sustainability of effects via homework exercises and a smartphone app ( www.uke.de/mct_app ). We have also enhanced dissemination efforts by creating new culturally sensitive language versions and facilitating low-threshold training through e-learning courses ( www.uke.de/e-mct ). Finally, we discuss several meta-analyses on the efficacy of MCT that have been published over the last decade. While reviews were initially inconsistent, possibly reflecting the insufficient statistical power and lower design quality of the first MCT studies, more recent meta-analyses have confirmed the efficacy of MCT on positive symptoms, insight, and cognitive biases, which has led to the inclusion of MCT in some national treatment guidelines for schizophrenia.

Confident memory errors and disrupted reality testing in early psychosis

Schizophrenia is a psychiatric disorder characterized by a disruption in reality testing most often manifest in the form of delusions and hallucinations. Because determining the reality-basis of prior experiences is dependent on episodic and associative memory, deficits in mnemonic processes could be involved in the genesis of impaired reality testing. In the present study, we used an associative memory paradigm incorporating confidence ratings to examine whether patients with a recent onset of schizophrenia (n = 48) show a greater propensity for confident, yet incorrect responses during retrieval testing than healthy controls (n = 26) and whether such confident incorrect responses, specifically, are more strongly associated with positive symptoms than with negative symptoms. Using an analysis of variance design, we found that first-episode schizophrenia patients made a significantly greater number of confident errors than controls (i.e. they expressed high confidence in having seen pairs of items that were not paired at encoding and high confidence in having not seen pairs of items that were paired at encoding). We also found that the number of confident errors was specifically and differentially associated with positive symptom severity, to a significantly greater degree than with negative symptom severity and psychosocial functioning, and this association was not found between positive symptoms and uncertain responses, nor positive symptoms and overall task performance. These findings suggest that the propensity for incorrect memory judgements with high confidence, specifically, may be uniquely associated with disrupted reality testing and that this type of cognitive impairment is distinct from general deficits in memory and cognition in this respect.

Effects of traumatic life events, cognitive biases and variation in dopaminergic genes on psychosis proneness

AIMS

Recent studies have provided evidence that interactions between variation in dopaminergic genes and stressful experiences might impact risk of psychosis. However, it remains unknown whether these interactions impact the development of subclinical symptoms, including psychotic-like experiences (PLEs). In this study, we aimed to test the effects of interactions between variation in dopaminergic genes and traumatic life events (TLEs) on a severity of PLEs.

METHODS

We assessed TLEs, cognitive biases, PLEs as well as the catechol-O-methyltransferase (COMT) rs4680 and the dopamine D2 receptor (DRD2) rs6277 gene polymorphisms in 445 university students at three urban areas.

RESULTS

There was a significant effect of the interaction between the COMT rs4680 and a history of any type of TLEs on a severity of PLEs. Among the COMT rs4680 Met allele carriers, a severity of PLEs was higher in individuals with a history of any type of TLEs. Further stratification of the sample revealed that this effect appears only in the group of participants with a high level of cognitive biases. The DRD2 rs6277 C allele was independently associated with a higher level of PLEs.

CONCLUSIONS

Our results indicate that decreased dopamine catabolism related to the COMT gene polymorphism might increase psychosis proneness in individuals with a history of TLEs and high levels of cognitive biases. Variation in the DRD2 gene might exert independent effects on psychosis proneness. These findings imply that there are various levels of complexity in the models of interactions between genetic and environmental factors explaining the mechanisms underlying psychosis proneness.

Rational inattention and tonic dopamine

Slow-timescale (tonic) changes in dopamine (DA) contribute to a wide variety of processes in reinforcement learning, interval timing, and other domains. Furthermore, changes in tonic DA exert distinct effects depending on when they occur (e.g., during learning vs. performance) and what task the subject is performing (e.g., operant vs. classical conditioning). Two influential theories of tonic DA-the average reward theory and the Bayesian theory in which DA controls precision-have each been successful at explaining a subset of empirical findings. But how the same DA signal performs two seemingly distinct functions without creating crosstalk is not well understood. Here we reconcile the two theories under the unifying framework of 'rational inattention,' which (1) conceptually links average reward and precision, (2) outlines how DA manipulations affect this relationship, and in so doing, (3) captures new empirical phenomena. In brief, rational inattention asserts that agents can increase their precision in a task (and thus improve their performance) by paying a cognitive cost. Crucially, whether this cost is worth paying depends on average reward availability, reported by DA. The monotonic relationship between average reward and precision means that the DA signal contains the information necessary to retrieve the precision. When this information is needed after the task is performed, as presumed by Bayesian inference, acute manipulations of DA will bias behavior in predictable ways. We show how this framework reconciles a remarkably large collection of experimental findings. In reinforcement learning, the rational inattention framework predicts that learning from positive and negative feedback should be enhanced in high and low DA states, respectively, and that DA should tip the exploration-exploitation balance toward exploitation. In interval timing, this framework predicts that DA should increase the speed of the internal clock and decrease the extent of interference by other temporal stimuli during temporal reproduction (the central tendency effect). Finally, rational inattention makes the new predictions that these effects should be critically dependent on the controllability of rewards, that post-reward delays in intertemporal choice tasks should be underestimated, and that average reward manipulations should affect the speed of the clock-thus capturing empirical findings that are unexplained by either theory alone. Our results suggest that a common computational repertoire may underlie the seemingly heterogeneous roles of DA.

Overestimation of volatility in schizophrenia and autism? A comparative study using a probabilistic reasoning task

BACKGROUND AND OBJECTIVES

A plethora of studies has investigated and compared social cognition in autism and schizophrenia ever since both conditions were first described in conjunction more than a century ago. Recent computational theories have proposed similar mechanistic explanations for various symptoms beyond social cognition. They are grounded in the idea of a general misestimation of uncertainty but so far, almost no studies have directly compared both conditions regarding uncertainty processing. The current study aimed to do so with a particular focus on estimation of volatility, i.e. the probability for the environment to change.

METHODS

A probabilistic decision-making task and a visual working (meta-)memory task were administered to a sample of 86 participants (19 with a diagnosis of high-functioning autism, 21 with a diagnosis of schizophrenia, and 46 neurotypically developing individuals).

RESULTS

While persons with schizophrenia showed lower visual working memory accuracy than neurotypical individuals, no significant group differences were found for metamemory or any of the probabilistic decision-making task variables. Nevertheless, exploratory analyses suggest that there may be an overestimation of volatility in subgroups of participants with autism and schizophrenia. Correlations revealed relationships between different variables reflecting (mis)estimation of uncertainty, visual working memory accuracy and metamemory.

LIMITATIONS

Limitations include the comparably small sample sizes of the autism and the schizophrenia group as well as the lack of cognitive ability and clinical symptom measures.

CONCLUSIONS

The results of the current study provide partial support for the notion of a general uncertainty misestimation account of autism and schizophrenia.

Confidence in visual motion discrimination is preserved in individuals with schizophrenia

BACKGROUND

Metacognition is the set of reflexive processes that allows humans to evaluate the accuracy of their mental operations. Metacognitive deficits have been described in people with schizophrenia using mostly narrative assessment, and they have been linked to several key symptoms.

METHODS

We assessed metacognitive performance objectively by asking people with schizophrenia or schizoaffective disorder (n = 20) and matched healthy participants (n = 21) to perform a visual discrimination task and report their confidence in their performance. Metacognitive performance was defined as the adequacy between visual discrimination performance and confidence.

RESULTS

Bayesian analyses revealed equivalent metacognitive performance in the 2 groups, despite a weaker association between confidence and trajectory tracking during task execution among people with schizophrenia. We reproduced these results using an evidence accumulation model, which showed similar decisional processes in the 2 groups.

LIMITATIONS

These results from a relatively small study sample cannot be generalized to other perceptual and nonperceptual tasks. To meet this purpose, ecological tasks are needed. As well, the role of antipsychotic medication and design deserves greater attention in the future.

CONCLUSION

We found similar decisional and metacognitive capabilities between people with schizophrenia and healthy controls in a visual discrimination task.

Using virtual reality to explore differences in memory biases and cognitive insight in people with psychosis and healthy controls

Memory biases (e.g. overconfidence in false memories) are implicated in the pathogenesis of delusions. Virtual reality (VR) may provide an opportunity to observe such biases and improve cognitive insight in patients with psychosis via corrective feedback. Thirty-nine patients with psychosis and 20 healthy controls explored VR environments designed to elicit false memories and subsequently had to recollect items and faces. We used a randomised-controlled design where half of the sample received performance feedback on the recollection task in order to correct overconfidence. Changes in cognitive insight were measured using the Beck Cognitive Insight Scale. Regarding accuracy, patients performed worse on the social task (recollection of faces) only. Patients displayed overconfidence in false memories for emotions and gave more high-confident responses compared to healthy controls on the social task. Feedback did not improve cognitive insight. Patients rated their cognitive insight higher than healthy controls. Future research should address problems with subjective measurements for cognitive insight. To conclude, patients with psychosis showed impaired social cognition and there was evidence for impaired metacognition, as patients reported higher cognitive insight despite comparable or worse performance as well as overconfidence relative to controls.

Dopamine manipulations drive changes in information sampling in healthy volunteers

BACKGROUND

Information sampling is the cognitive process of accumulating information before committing to a decision. Patients across numerous disorders show decreased information sampling relative to controls.

AIMS

Here, we used the Beads and the Best Choice Tasks to study the role of dopamine signaling in information sampling.

METHODS

Participants were given placebo, amisulpride, or ropinirole in each session, in a double-blind cross-over design.

RESULTS

We found that ropinirole (agonist) increased the number of beads drawn in the Beads Task specifically when participants faced a loss, and decreased the rank of the chosen option in the Best Choice Task.

CONCLUSIONS

These effects are likely driven by a combination of effects at presynaptic D₂ receptors, which affect dopamine release, and post-synaptic D₂ receptors. Increased D₂ relative to D₁ receptor activation in the striatum leads to increased sampling in the loss condition in the Beads Task. It also leads to choice of a poorer ranked option in the Best Choice Task. Decreased D₂ relative to D₁ receptor activation leads to decreased sampling in the Beads Task in the loss condition.

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.

Investigating the jumping to conclusion bias in bipolar disorder

INTRODUCTION

Hemsley and Garety described the "jumping to conclusions bias" in which patients with delusions may reach unreasonable results with insufficient information. In this study patients with bipolar disorder and healthy volunteers were compared in terms of jumping to conclusions bias using the beads in the jar task.

METHODS

37 patients with DSM-5 diagnosis of bipolar disorder and 30 healthy controls were tested with the Beads Task (BT), Tower of London Test (ToL) and Barrat Impulsiveness Scale (BIS).

RESULTS

In the BT, the mean score of DtD (draws to decision) and JTC (jumping to conclusions) scores were not statistically different between the two groups. In the ToL test, the duration of the total execution and the total time were significantly longer in the bipolar group than the control group. BIS scores were significantly higher in the bipolar group. YMRS (Young Mania Rating Scale) scores were not correlated with BT.

CONCLUSIONS

This study is the first clinical study to assess the jumping to conclusions bias in patients with bipolar disorder. No JTC bias was detected in bipolar disorder. Further studies may assess JTC in larger samples to determine the effects of clinical state changes, psychotic symptoms, medication and impulsivity.

Dopamine is a double-edged sword: dopaminergic modulation enhances memory retrieval performance but impairs metacognition

While memory encoding and consolidation processes have been linked with dopaminergic signaling for a long time, the role of dopamine in episodic memory retrieval remained mostly unexplored. Based on previous observations of striatal activity during memory retrieval, we used pharmacological functional magnetic resonance imaging to investigate the effects of dopamine on retrieval performance and metacognitive memory confidence in healthy humans. Dopaminergic modulation by the D2 antagonist haloperidol administered acutely during the retrieval phase improved recognition accuracy of previously learned pictures significantly and was associated with increased activity in the substantia nigra/ventral tegmental area, locus coeruleus, hippocampus, and amygdala during retrieval. In contrast, confidence for new decisions was impaired by unsystematically increased activity of the striatum across confidence levels and restricted range of responsiveness in frontostriatal networks under haloperidol. These findings offer new insights into the mechanisms underlying memory retrieval and metacognition and provide a broader perspective on the presence of memory problems in dopamine-related diseases and the treatment of memory disorders.

Cost Evaluation During Decision-Making in Patients at Early Stages of Psychosis

Jumping to conclusions during probabilistic reasoning is a cognitive bias reliably observed in psychosis and linked to delusion formation. Although the reasons for this cognitive bias are unknown, one suggestion is that psychosis patients may view sampling information as more costly. However, previous computational modeling has provided evidence that patients with chronic schizophrenia jump to conclusions because of noisy decision-making. We developed a novel version of the classical beads task, systematically manipulating the cost of information gathering in four blocks. For 31 individuals with early symptoms of psychosis and 31 healthy volunteers, we examined the numbers of "draws to decision" when information sampling had no, a fixed, or an escalating cost. Computational modeling involved estimating a cost of information sampling parameter and a cognitive noise parameter. Overall, patients sampled less information than controls. However, group differences in numbers of draws became less prominent at higher cost trials, where less information was sampled. The attenuation of group difference was not due to floor effects, as in the most costly block, participants sampled more information than an ideal Bayesian agent. Computational modeling showed that, in the condition with no objective cost to information sampling, patients attributed higher costs to information sampling than controls did, Mann-Whitney U = 289, p = 0.007, with marginal evidence of differences in noise parameter estimates, t(60) = 1.86, p = 0.07. In patients, individual differences in severity of psychotic symptoms were statistically significantly associated with higher cost of information sampling, ρ = 0.6, p = 0.001, but not with more cognitive noise, ρ = 0.27, p = 0.14; in controls, cognitive noise predicted aspects of schizotypy (preoccupation and distress associated with delusion-like ideation on the Peters Delusion Inventory). Using a psychological manipulation and computational modeling, we provide evidence that early-psychosis patients jump to conclusions because of attributing higher costs to sampling information, not because of being primarily noisy decision makers.

Investigation of sex differences in delusion-associated cognitive biases

In the past few decades, sex differences have been identified in a number of clinical, cognitive and functional outcomes in patients with schizophrenia spectrum disorders. However, to date, sex differences in higher-order cognitive biases have not been systematically studied. The present study aimed to examine sex differences in jumping-to-conclusions and evidence integration impairment based on data collected in two previous studies in patients with schizophrenia spectrum disorders and healthy controls. For this purpose, data from n = 58 patients and n = 60 healthy controls on the Fish Task (as a measure of jumping to conclusions) and bias against disconfirmatory evidence (BADE; as a measure of evidence integration) task were analyzed. Results indicated a lack of sex differences in jumping-to-conclusions and evidence integration impairment both in patients with schizophrenia spectrum disorders and healthy controls. Although the present study was adequately powered to detect sex differences of a low medium effect size, larger studies are warranted to exclude differences of a smaller magnitude between men and women regarding delusion-associated cognitive biases.

Emotion perception and overconfidence in errors under stress in psychosis

Vulnerability stress models are well-accepted in psychosis research, but the mechanisms that link stress to psychotic symptoms remain vague. Little is known about how social cognition and overconfidence in errors, two putative mechanisms for the pathogenesis of delusions, relate to stress. Using a repeated measures design, we tested four groups (N=120) with different liability to psychosis (schizophrenia patients [n=35], first-degree relatives [n=24], participants with attenuated positive symptoms [n=19] and healthy controls [n=28]) and depression patients (n=14) as a clinical control group under three randomized experimental conditions (no stress, noise and social stress). Parallel versions of the Emotion Perception and Confidence Task, which taps both emotion perception and confidence, were used in each condition. We recorded subjective stress, heart rate, skin conductance level and salivary cortisol to assess the stress response across different dimensions. Independent of the stress condition, patients with schizophrenia showed poorer emotion perception performance and higher confidence in emotion perception errors than participants with attenuated positive symptoms and healthy controls. However, they did not differ from patients with depression or first-degree relatives. Stress did not influence emotion perception or the extent of high-confident errors, but patients with schizophrenia showed an increase in high-confident emotion perception errors conditional on higher arousal. A possible clinical implication of our findings is the necessity to provide stress management programs that aim to reduce arousal. Moreover, patients with schizophrenia might benefit from interventions that help them to reduce overconfidence in their social cognition judgements in times in which they feel being under pressure.

Attractor-like Dynamics in Belief Updating in Schizophrenia

Subjects with a diagnosis of schizophrenia (Scz) overweight unexpected evidence in probabilistic inference: such evidence becomes "aberrantly salient." A neurobiological explanation for this effect is that diminished synaptic gain (e.g., hypofunction of cortical NMDARs) in Scz destabilizes quasi-stable neuronal network states (or "attractors"). This attractor instability account predicts that (1) Scz would overweight unexpected evidence but underweight consistent evidence, (2) belief updating would be more vulnerable to stochastic fluctuations in neural activity, and (3) these effects would correlate. Hierarchical Bayesian belief updating models were tested in two independent datasets (n = 80 male and n = 167 female) comprising human subjects with Scz, and both clinical and nonclinical controls (some tested when unwell and on recovery) performing the "probability estimates" version of the beads task (a probabilistic inference task). Models with a standard learning rate, or including a parameter increasing updating to "disconfirmatory evidence," or a parameter encoding belief instability were formally compared. The "belief instability" model (based on the principles of attractor dynamics) had most evidence in all groups in both datasets. Two of four parameters differed between Scz and nonclinical controls in each dataset: belief instability and response stochasticity. These parameters correlated in both datasets. Furthermore, the clinical controls showed similar parameter distributions to Scz when unwell, but were no different from controls once recovered. These findings are consistent with the hypothesis that attractor network instability contributes to belief updating abnormalities in Scz, and suggest that similar changes may exist during acute illness in other psychiatric conditions.SIGNIFICANCE STATEMENT Subjects with a diagnosis of schizophrenia (Scz) make large adjustments to their beliefs following unexpected evidence, but also smaller adjustments than controls following consistent evidence. This has previously been construed as a bias toward "disconfirmatory" information, but a more mechanistic explanation may be that in Scz, neural firing patterns ("attractor states") are less stable and hence easily altered in response to both new evidence and stochastic neural firing. We model belief updating in Scz and controls in two independent datasets using a hierarchical Bayesian model, and show that all subjects are best fit by a model containing a belief instability parameter. Both this and a response stochasticity parameter are consistently altered in Scz, as the unstable attractor hypothesis predicts.

Beta-Blocker Propranolol Modulates Decision Urgency During Sequential Information Gathering

Arbitrating between timely choice and extended information gathering is critical for effective decision making. Aberrant information gathering behavior is thought to be a feature of psychiatric disorders such as schizophrenia and obsessive-compulsive disorder, but we know little about the underlying neurocognitive control mechanisms. In a double-blind, placebo-controlled drug study involving 60 healthy human subjects (30 female), we examined the effects of noradrenaline and dopamine antagonism on information gathering during performance of an information sampling task. We show that modulating noradrenaline function with 40 mg of the β-blocker propranolol leads to decreased information gathering behavior. Modulating dopamine function via a single dose of 400 mg of amisulpride revealed some effects that were intermediate between those of propranolol and placebo. Using a Bayesian computational model, we show that sampling behavior is best explained by inclusion of a nonlinear urgency signal that promotes commitment to an early decision. Noradrenaline blockade promotes the expression of this decision-related urgency signal during information gathering. We discuss the findings with respect to psychopathological conditions that are linked to aberrant information gathering.SIGNIFICANCE STATEMENT Knowing when to stop gathering information and commit to a choice option is nontrivial. This is an important element in arbitrating between information gain and energy conservation. In this double-blind, placebo-controlled drug study, we investigated the role of catecholamines noradrenaline and dopamine on sequential information gathering. We found that blockade of noradrenaline led to a decrease in information gathering. Dopamine blockade showed an intermediate, but nonsignificant, effect. Using a Bayesian computational model, we show that this noradrenaline effect is driven by increased decision urgency, a signal that reflects an escalating subjective cost of sampling. The observation that noradrenaline modulates decision urgency suggests new avenues for treating patients that show information gathering deficits.

fMRI correlates of jumping-to-conclusions in patients with delusions: Connectivity patterns and effects of metacognitive training

Background

Reasoning biases such as the jumping-to-conclusions bias (JTC) are thought to contribute to delusions. Interventions targeting these biases such as metacognitive training (MCT) may improve delusions. So far, it is not clear whether JTC depends on dopaminergic reward areas that constitute the main action locus of antipsychotic drugs, or on additional cortical areas. The present study aimed to investigate fMRI activation and functional connectivity patterns underlying JTC, and their changes following MCT, in patients with delusions.

Methods

Participants were 25 healthy individuals and 26 patients with current delusions who were either medication-free or on stable medication without sufficient response. We assessed (1) BOLD activity in the task-positive (TPN), task-negative (TNN), and subcortical reward network (RN); (2) Psychophysiological interactions (PPI) of peak activation areas.

Results

Presence of JTC (irrespective of group) was associated with lower RN activity during conclusion events, and with increased effective connectivity between TPN and TNN during draw events. Following MCT, changes were observed in TPN activity and in effective connectivity of inferior parietal cortex (part of the TPN) with all three target networks.

Conclusion

JTC is associated not only with reward system areas that constitute the main target of antipsychotic drugs, but also with cortical areas, particularly of the TPN.

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Faulty evidence gathering (jumping to conclusions, JTC) is associated with delusions.

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We assessed data gathering with fMRI in patients with delusions vs healthy controls.

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JTC was associated with abnormal activity and connectivity patterns.

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Changes in the task-positive network were observed following metacognitive training.

Differential relationship of jumping-to-conclusions and incorrigibility with delusion severity

Reasoning biases such as jumping-to-conclusions (JTC) and incorrigibility have been suggested to contribute to the generation and maintenance of delusions. However, it is still debated whether these biases represent stable traits of patients with delusions, or are related to state fluctuations of delusion severity. The present study aimed to elucidate this question by combining a cross-sectional with a longitudinal approach. JTC, incorrigibility and delusion severity were assessed in 79 patients with a history of delusions over a 6-month period. To allow for a differentiated look into effects of time vs. symptom changes, patients were divided into patients with (D+) and without (D-) current delusions at baseline. Significant improvement of delusions was noted in D+ at follow-up. JTC did not differ between the two patient groups either at baseline or over time. In contrast, incorrigibility was significantly higher in D+ than D- at baseline; this difference remained stable throughout the 6-month follow-up period. The two biases did not significantly co-vary over time. Our results suggest a dissociation between incorrigibility and JTC as regards their relation to current presence of delusions, and tentatively support theoretical accounts attributing different roles to the two biases in the generation (JTC) and maintenance (incorrigibility) of delusions.

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.

Neural Habituation to Painful Stimuli Is Modulated by Dopamine: Evidence from a Pharmacological fMRI Study

In constantly changing environments, it is crucial to adaptively respond to threatening events. In particular, painful stimuli are not only processed in terms of their absolute intensity, but also with respect to their context. While contextual pain processing can simply entail the repeated processing of information (i.e., habituation), it can, in a more complex form, be expressed through predictions of magnitude before the delivery of nociceptive information (i.e., adaptive coding). Here, we investigated the brain regions involved in the adaptation to nociceptive electrical stimulation as well as their link to dopaminergic neurotransmission (placebo/haloperidol). The main finding is that haloperidol changed the habituation to the absolute pain intensity over time. More precisely, in the placebo condition, activity in left postcentral gyrus and midcingulate cortex increased linearly with pain intensity only in the beginning of the experiment and subsequently habituated. In contrast, when the dopaminergic system was blocked by haloperidol, a linear increase with pain intensity was present throughout the entire experiment. Finally, there were no adaptive coding effects in any brain regions. Together, our findings provide novel insights into the nature of pain processing by suggesting that dopaminergic neurotransmission plays a specific role for the habituation to painful stimuli over time.

A two-stage cognitive theory of the positive symptoms of psychosis. Highlighting the role of lowered decision thresholds

OBJECTIVES

We outline a two-stage heuristic account for the pathogenesis of the positive symptoms of psychosis.

METHODS

A narrative review on the empirical evidence of the liberal acceptance (LA) account of positive symptoms is presented.

HYPOTHESIS

At the heart of our theory is the idea that psychosis is characterized by a lowered decision threshold, which results in the premature acceptance of hypotheses that a nonpsychotic individual would reject. Once the hypothesis is judged as valid, counterevidence is not sought anymore due to a bias against disconfirmatory evidence as well as confirmation biases, consolidating the false hypothesis. As a result of LA, confidence in errors is enhanced relative to controls. Subjective probabilities are initially low for hypotheses in individuals with delusions, and delusional ideas at stage 1 (belief formation) are often fragile. In the course of the second stage (belief maintenance), fleeting delusional ideas evolve into fixed false beliefs, particularly if the delusional idea is congruent with the emotional state and provides "meaning". LA may also contribute to hallucinations through a misattribution of (partially) normal sensory phenomena. Interventions such as metacognitive training that aim to "plant the seeds of doubt" decrease positive symptoms by encouraging individuals to seek more information and to attenuate confidence. The effect of antipsychotic medication is explained by its doubt-inducing properties.

LIMITATIONS

The model needs to be confirmed by longitudinal designs that allow an examination of causal relationships. Evidence is currently weak for hallucinations.

CONCLUSIONS

The theory may account for positive symptoms in a subgroup of patients. Future directions are outlined.

Intranasal oxytocin does not modulate jumping to conclusions in schizophrenia: Potential interactions with caudate volume and baseline social functioning

BACKGROUND

Patients with schizophrenia (SCZ) tend to sample less information when making a decision, jumping to conclusions (JTC) without sufficient evidence. This "JTC bias" may be a trait marker of the disease and may not improve with antipsychotic treatment. We conducted a double-blind, placebo-controlled trial to test whether intranasal oxytocin could reduce JTC in stable, medicated patients with SCZ and healthy controls (HCs). We also explored whether striatal volume, clinical symptoms, and baseline social functioning (SF) was related to JTC performance.

METHODS

Forty-three male, medicated SCZ patients (Mean Age: 40.81±11.44) and sixteen HCs (Mean Age: 30.38±9.85) participated in a double-blind, placebo-controlled, cross-over study. Participants completed the Beads Task on two separate visits (minimum 20days apart). Participants were randomized to receive either intranasal oxytocin (50IU in solution) or intranasal placebo (saline). Twenty of the SCZ patients and all sixteen HCs also provided T1 MRIs (3-T).

RESULTS

Patients with SCZ took fewer draws to decision (DTD) than HCs (t(57)=2.78, p=0.007). Oxytocin did not significantly change DTD in patients (t(42)=-1.11, p=0.27), nor in HCs (t(15)=-0.62, p=0.55). Exploratory analyses found ventral caudate volumes were negatively correlated with DTD (r(18)=-0.50, p=0.03) in patients. Moreover, oxytocin was more likely to improve JTC in patients with lower baseline SF. However, these exploratory findings did not survive correction for multiple comparisons.

CONCLUSIONS

We replicate increased JTC in SCZ. However, acute intranasal oxytocin did not modify JTC. Future studies with larger samples should explore how brain morphology and SF are related to JTC performance in patients with SCZ.

Dopamine, cognitive biases and assessment of certainty: A neurocognitive model of delusions

This paper examines the evidence that delusions can be explained within the framework of a neurocognitive model of how the brain assesses certainty. Here, 'certainty' refers to both low-level interpretations of one's environment and high-level (conscious) appraisals of one's beliefs and experiences. A model is proposed explaining how the brain systems responsible for assigning certainty might dysfunction, contributing to the cause and maintenance of delusional beliefs. It is suggested that delusions arise through a combination of perturbed striatal dopamine and aberrant salience as well as cognitive biases such as the tendency to jump to conclusions (JTC) and hypersalience of evidence-hypothesis matches. The role of emotion, stress, trauma and sociocultural factors in forming and modifying delusions is also considered. Understanding the mechanisms involved in forming and maintaining delusions has important clinical implications, as interventions that improve cognitive flexibility (e.g. cognitive remediation therapy and mindfulness training) could potentially attenuate neurocognitive processes.

Increased decision thresholds enhance information gathering performance in juvenile Obsessive-Compulsive Disorder (OCD)

Patients with obsessive-compulsive disorder (OCD) can be described as cautious and hesitant, manifesting an excessive indecisiveness that hinders efficient decision making. However, excess caution in decision making may also lead to better performance in specific situations where the cost of extended deliberation is small. We compared 16 juvenile OCD patients with 16 matched healthy controls whilst they performed a sequential information gathering task under different external cost conditions. We found that patients with OCD outperformed healthy controls, winning significantly more points. The groups also differed in the number of draws required prior to committing to a decision, but not in decision accuracy. A novel Bayesian computational model revealed that subjective sampling costs arose as a non-linear function of sampling, closely resembling an escalating urgency signal. Group difference in performance was best explained by a later emergence of these subjective costs in the OCD group, also evident in an increased decision threshold. Our findings present a novel computational model and suggest that enhanced information gathering in OCD can be accounted for by a higher decision threshold arising out of an altered perception of costs that, in some specific contexts, may be advantageous.

The Importance of Metamemory Functioning to the Pathogenesis of Psychosis

Many studies up to date have implied that biases in the metacognition of memory, so called metamemory, contribute to the development and maintenance of positive symptoms in schizophrenia. However, no study exists which has longitudinally followed patients experiencing positive symptoms. The present article therefore reviews cross-sectional studies on retrospective metamemory abilities in participants within different stages of a schizophrenia spectrum disorder, with heterogeneous symptom severities, creating a pseudo-longitudinal overview. Summarized, a deterioration of these abilities correlating with psychosis development can be inferred. The reviewed publications indicate that metamemory biases can already be found in patients with an at-risk mental state for psychosis (ARMS). Patients in their first episode of psychosis (FEP) seem to be more severely impaired than ARMS-patients but similarly affected compared to chronic patients. The contribution of these biases to the pathogenesis of psychosis is discussed, giving consideration to relations with other cognitive- and metacognitive functions, neurochemical processes and neural correlates. It is hypothesized that the biases represent early cognitive markers of the beginning and persisting psychotic state. An early treatment program could help patients to ameliorate the general course of illness or even to prevent the risk of a transition to psychosis.

The new frontier in health services research: a behavioural paradigm guided by genetics

The incorporation of genetics into health services research has largely floundered, despite the rapidly accelerating availability of, and access to, such data. This is expected given the ethical questions involved. However, using these new resources robustly to examine population choices when it comes to health insurer selection, coverage therein and especially the subsequent use of health services is a necessary step forward, especially given the increasing prevalence of multimorbidity. Such a novel advancement in health services research may eventually propel public and private insurers to redesign their infrastructure to more accurately reflect the behavioural inclinations of their beneficiary populations. Using this resource will likely provide equally important insight for countries with extensive mixed insurer systems (like the United States) or nations with a greater emphasis on single-payer systems (such as various European models).

Subjective versus objective cognition: Evidence for poor metacognitive monitoring in schizophrenia

BACKGROUND

Patients with schizophrenia display a number of cognitive biases, particularly a tendency to jump to conclusions, which are implicated in the pathogenesis of the disorder. The present study contrasted the degree of objective reasoning biases with subjective cognitive insight. We expected that patients with schizophrenia would display greater objective than subjective impairment suggestive of poor metacognitive awareness.

METHODS

Patients with schizophrenia (n=140) and healthy controls (n=60) underwent a test battery encompassing a cognitive bias paradigm (beads task) as well as neurocognitive tests (story recall, trail-making tests). In addition, they were administered the Beck Cognitive Insight Scale (BCIS), a subjective measure of (meta)cognitive awareness.

RESULTS

Corroborating prior research on decision making, draws to decisions were significantly delayed in controls relative to patients, whereas the core jumping to conclusion parameter (i.e., decision after one or two pieces of information) bordered significance. Patients with schizophrenia showed a lowered decision threshold and impaired neurocognition relative to nonclinical controls. Despite poor cognitive performance and prior psychotic episodes, patients with schizophrenia showed similar scores on the self-confidence subscale of the BCIS and reported even higher levels of self-reflectiveness relative to healthy controls.

DISCUSSION

The study demonstrates that patients with schizophrenia show severe cognitive biases and neurocognitive deficits but display only partial awareness herein. Raising cognitive insight in a non-insulting fashion and elevating patients' corrigibility as well as willingness to consider others' feedback and advice may help to narrow this gap and improve psychiatric symptomatology.

Overconfidence across the psychosis continuum: a calibration approach

INTRODUCTION

An 'overconfidence in errors' bias has been consistently observed in people with schizophrenia relative to healthy controls, however, the bias is seldom found to be associated with delusional ideation. Using a more precise confidence-accuracy calibration measure of overconfidence, the present study aimed to explore whether the overconfidence bias is greater in people with higher delusional ideation.

METHODS

A sample of 25 participants with schizophrenia and 50 non-clinical controls (25 high- and 25 low-delusion-prone) completed 30 difficult trivia questions (accuracy <75%); 15 'half-scale' items required participants to indicate their level of confidence for accuracy, and the remaining 'confidence-range' items asked participants to provide lower/upper bounds in which they were 80% confident the true answer lay within.

RESULTS

There was a trend towards higher overconfidence for half-scale items in the schizophrenia and high-delusion-prone groups, which reached statistical significance for confidence-range items. However, accuracy was particularly low in the two delusional groups and a significant negative correlation between clinical delusional scores and overconfidence was observed for half-scale items within the schizophrenia group. Evidence in support of an association between overconfidence and delusional ideation was therefore mixed.

CONCLUSIONS

Inflated confidence-accuracy miscalibration for the two delusional groups may be better explained by their greater unawareness of their underperformance, rather than representing genuinely inflated overconfidence in errors.

Antipsychotics decrease response confidence

Antipsychotics represent the first-choice treatment for schizophrenia. However, the cognitive and emotional pathways through which symptom reduction is achieved have remained unclear. We recently proposed that the induction of doubt is a core mechanism of action of antipsychotics. In the framework of a randomized, double-blind, placebo-controlled, crossover design, 39 nonclinical participants filled out a questionnaire tapping into cognitive and emotional changes (Effect of Antipsychotic Medication on Emotion and Cognition-revised (EAMEC-r)) each time they had received one of three substances (haloperidol, placebo, L-dopa). Participants reported more doubt under haloperidol than under L-dopa lending support to the theory that antipsychotics decrease delusional conviction via the reduction of confidence. Key points from this study are: (a) antipsychotics induce doubt, and (b) doubt may represent a core mechanism of action for the reduction of delusional ideas.

Bias against disconfirmatory evidence in the 'at-risk mental state' and during psychosis

Prior studies have confirmed a bias against disconfirmatory evidence (BADE) in schizophrenia which has been associated with delusions. However, its role in the pathogenesis of psychosis is yet unclear. The objective was to investigate BADE for the first time in subjects with an at-risk-mental-state for psychosis (ARMS), patients with a first episode of psychosis without antipsychotic treatment (FEP) and healthy controls (HC). A standard BADE test presenting written scenarios was employed. In addition, psychometric rating scales and a neuropsychological test battery were applied. A three-staged image was revealed. FEP-patients showed a significant BADE compared to the other groups. The performance of ARMS-patients lay in between HC and FEP-patients. A trend towards significance became evident for a bias against confirmatory evidence (BACE) in FEP-patients. Results were not attributable to antipsychotic or other medication or depressive symptoms. Correlations with delusions reached medium effect sizes but failed significance after Bonferroni-corrections. These results provide evidence for aberrations in evidence integration in the pathogenesis of psychosis and contribute to our knowledge of metacognitive functioning which can be used for (meta-)cognitive intervention in psychosis.

Dopamine effects on evidence gathering and integration

BACKGROUND

Disturbances in evidence gathering and disconfirmatory evidence integration have been associated with the presence of or propensity for delusions. Previous evidence suggests that these 2 types of reasoning bias might be differentially affected by antipsychotic medication. We aimed to investigate the effects of a dopaminergic agonist (L-dopa) and a dopaminergic antagonist (haloperidol) on evidence gathering and disconfirmatory evidence integration after single-dose administration in healthy individuals.

METHODS

The study used a randomized, double-blind, placebo-controlled, 3-way crossover design. Participants were healthy individuals aged 18-40 years. We administered a new data-gathering task designed to increase sensitivity to change compared with traditional tasks. The Bias Against Disconfirmatory Evidence (BADE) task was used as a measure of disconfirmatory evidence integration.

RESULTS

We included 30 individuals in our study. In the data-gathering task, dopaminergic modulation had no significant effect on the amount of evidence gathered before reaching a decision. In contrast, the ability of participants to integrate disconfirmatory evidence showed a significant linear dopaminergic modulation pattern (highest with haloperidol, intermediate with placebo, lowest with L-dopa), with the difference between haloperidol and L-dopa marginally reaching significance.

LIMITATIONS

Although the doses used for haloperidol and L-dopa were similar to those used in previous studies, drug plasma level measurements would have added to the validity of findings.

CONCLUSION

Evidence gathering and disconfirmatory evidence integration might be differentially influenced by dopaminergic agents. Our findings are in support of a dual-disturbance account of delusions and provide a plausible neurobiological basis for the use of interventions targeted at improving reasoning biases as an adjunctive treatment in patients with psychotic disorders.

Investigation of metamemory functioning in the at-risk mental state for psychosis

BACKGROUND

Metamemory describes the monitoring and knowledge about one's memory capabilities. Patients with schizophrenia have been found to be less able in differentiating between correct and false answers (smaller confidence gap) when asked to provide retrospective confidence ratings in previous studies. Furthermore, higher proportions of very-high-confident but false responses have been found in this patient group (high knowledge corruption). Whether and how these biases contribute to the early pathogenesis of psychosis is yet unclear. This study thus aimed at investigating metamemory function in the early course of psychosis.

METHOD

Patients in an at-risk mental state for psychosis (ARMS, n = 34), patients with a first episode of psychosis (FEP, n = 21) and healthy controls (HCs, n = 38) were compared on a verbal recognition task combined with retrospective confidence-level ratings.

RESULTS

FEP patients showed the smallest confidence gap, followed by ARMS patients, followed by HCs. All groups differed significantly from each other. Regarding knowledge corruption, FEP patients differed significantly from HCs, whereas a statistical trend was revealed in comparison of ARMS and FEP groups. Correlations were revealed between metamemory, measures of positive symptoms and working memory performance.

CONCLUSIONS

These data underline the presence of a metamemory bias in ARMS patients which is even more pronounced in FEP patients. The bias might represent an early cognitive marker of the beginning psychotic state. Longitudinal studies are needed to unravel whether metacognitive deficits predict the transition to psychosis and to evaluate therapeutic interventions.

Mesocorticolimbic dopamine functioning in primary psychopathy: A source of within-group heterogeneity

Despite similar emotional deficiencies, primary psychopathic individuals can be situated on a continuum that spans from controlled to disinhibited. The constructs on which primary psychopaths are found to diverge, such as self-control, cognitive flexibility, and executive functioning, are crucially regulated by dopamine (DA). As such, the goal of this review is to examine which specific alterations in the meso-cortico-limbic DA system and corresponding genes (e.g., TH, DAT, COMT, DRD2, DRD4) might bias development towards a more controlled or disinhibited expression of primary psychopathy. Based on empirical data, it is argued that primary psychopathy is generally related to a higher tonic and population activity of striatal DA neurons and lower levels of D2-type DA receptors in meso-cortico-limbic projections, which may boost motivational drive towards incentive-laden goals, dampen punishment sensitivity, and increase future reward-expectancy. However, increasingly higher levels of DA activity in the striatum (moderate versus pathological elevations), lower levels of DA functionality in the prefrontal cortex, and higher D1-to-D2-type receptor ratios in meso-cortico-limbic projections may lead to increasingly disinhibited and impetuous phenotypes of primary psychopathy. Finally, in order to provide a more coherent view on etiological mechanisms, we discuss interactions between DA and serotonin that are relevant for primary psychopathy.

Innovative mechanisms of action for pharmaceutical cognitive enhancement: A systematic review

Pharmacological cognitive enhancement refers to improvement in cognitive functions after drug use in healthy individuals. This popular topic attracts attention both from the general public and the scientific community. The objective was to explore innovative mechanisms of psychostimulant's action, whose potential effectiveness was assessed in randomized placebo-controlled trials (RCTs). A systematic review was carried out, using the words "attention", "memory", "learning", "executive functions", and "vigilance/wakefulness" combined to "cognitive enhancer" or "smart drug". Methylphenidate, amphetamines, modafinil, nicotine, acetylcholine esterase inhibitors and antidepressants were extensively studied in previous meta-analyses and were not included in the present work. Drugs were classified according to their primary mode of action, namely catecholaminergic drugs (tolcapone, pramipexole, guanfacine), cholinergic drugs (anticholinergics), glutamatergic drugs (ampakines), histaminergic drugs, and non-specified (glucocorticoids). Overall, 50 RCTs were included in the present review. In conclusion, a number of new active drugs were found to improve some cognitive functions, in particular verbal episodic memory. However the number of RCTs was limited, and most of the studies found negative results. Future studies should assess both effectiveness and tolerance of repeated doses administration, and individual variability in dose response (including baseline characteristics and potential genetic polymorphisms). One explanation for the limited number of recent RCTs with new psychostimulants seems to be the ethical debate surrounding pharmaceutical cognitive enhancement in healthy subjects.

Subjective competence breeds overconfidence in errors in psychosis. A hubris account of paranoia

BACKGROUND AND OBJECTIVES

Overconfidence in errors is a well-replicated cognitive bias in psychosis. However, prior studies have sometimes failed to find differences between patients and controls for more difficult tasks. We pursued the hypothesis that overconfidence in errors is exaggerated in participants with a liability to psychosis relative to controls only when they feel competent in the respective topic and/or deem the question easy. Whereas subjective competence likely enhances confidence in those with low psychosis liability as well, we still expected to find more 'residual' caution in the latter group.

METHODS

We adopted a psychometric high-risk approach to circumvent the confounding influence of treatment. A total of 2321 individuals from the general population were administered a task modeled after the "Who wants to be a millionaire" quiz. Participants were requested to endorse one out of four response options, graded for confidence, and were asked to provide ratings regarding subjective competence for the knowledge domain as well as the subjective difficulty of each item.

RESULTS

In line with our assumption, overconfidence in errors was increased overall in participants scoring high on the Paranoia Checklist core paranoia subscale (2 SD above the mean). This pattern of results was particularly prominent for items for which participants considered themselves competent and which they rated as easy.

LIMITATIONS

Results need to be replicated in a clinical sample.

DISCUSSION

In support of our hypothesis, subjective competence and task difficulty moderate overconfidence in errors in psychosis. Trainings that teach patients the fallibility of human cognition may help reduce delusional ideation.

Jumping to conclusions and the persistence of delusional beliefs in first episode psychosis

BACKGROUND

Cognitive biases may contribute to delusion persistence. We tested this in a longitudinal study of first episode psychosis (FEP).

METHODS

34 FEP patients completed assessments of delusions and Jumping to Conclusions (JTC) at baseline and 12-month follow-up.

RESULTS

JTC was associated with baseline delusion severity (t(32)=2.7, p=0.01). Baseline delusions persisted at follow-up for 8/20 participants (40%), who all jumped to conclusions (8/8, 100%), compared to half of those with no or changeable delusions (14/26, 54%; χ(2) (df=1)=5.7, p=0.03; Phi=0.4).

CONCLUSION

Findings implicate cognitive biases in delusion persistence, and support the potential to reduce delusions through reasoning-focused interventions.

Associations between visual perception accuracy and confidence in a dopaminergic manipulation study

Delusions are defined as fixed erroneous beliefs that are based on misinterpretation of events or perception, and cannot be corrected by argumentation to the opposite. Cognitive theories of delusions regard this symptom as resulting from specific distorted thinking styles that lead to biased integration and interpretation of perceived stimuli (i.e., reasoning biases). In previous studies, we were able to show that one of these reasoning biases, overconfidence in errors, can be modulated by drugs that act on the dopamine system, a major neurotransmitter system implicated in the pathogenesis of delusions and other psychotic symptoms. Another processing domain suggested to involve the dopamine system and to be abnormal in psychotic disorders is sensory perception. The present study aimed to investigate whether (lower-order) sensory perception and (higher-order) overconfidence in errors are similarly affected by dopaminergic modulation in healthy subjects. Thirty-four healthy individuals were assessed upon administration of l-dopa, placebo, or haloperidol within a randomized, double-blind, cross-over design. Variables of interest were hits and false alarms in an illusory perception paradigm requiring speeded detection of pictures over a noisy background, and subjective confidence ratings for correct and incorrect responses. There was a significant linear increase of false alarm rates from haloperidol to placebo to l-dopa, whereas hit rates were not affected by dopaminergic manipulation. As hypothesized, confidence in error responses was significantly higher with l-dopa compared to placebo. Moreover, confidence in erroneous responses significantly correlated with false alarm rates. These findings suggest that overconfidence in errors and aberrant sensory processing might be both interdependent and related to dopaminergic transmission abnormalities in patients with psychosis.

Neurocognitive deficits are relevant for the jumping-to-conclusions bias, but not for delusions: A longitudinal study

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 non-pharmacological 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.

Metamemory in schizophrenia: retrospective confidence ratings interact with neurocognitive deficits

Prior studies with schizophrenia patients described a reduced ability to discriminate between correct and false memories in terms of confidence compared to control groups. This metamemory bias has been associated with the emergence and maintenance of delusions. The relation to neuropsychological performance and other clinical dimensions is incompletely understood. In a cross-sectional study, metamemory functioning was explored in 32 schizophrenia patients and 25 healthy controls. Metamemory was assessed using a verbal recognition task combined with retrospective confidence level ratings. Associations of metamemory performance with six neuropsychological domains (executive functioning/problem solving, speed of processing, working memory, verbal and visual learning, and attention/vigilance) and psychopathological measures were analyzed. Results revealed a significantly smaller discrepancy between confidence ratings for correct and incorrect recognitions in the patient group. Furthermore, patients showed significantly lower recognition accuracy in the metamemory task and marked deficits in all neuropsychological domains. Across all participants, metamemory performance significantly correlated with executive functioning and working memory. No associations with delusions were found. This data confirms prior findings of metamemory biases in schizophrenia. Selective neuropsychological abilities seem to be modulating factors of metamemory functioning. Longitudinal studies in at risk mental state and first-episode patients are needed to reveal causal interrelations.

Jumping to conclusions in schizophrenia

Schizophrenia is a mental disorder associated with a variety of symptoms, including hallucinations, delusions, social withdrawal, and cognitive dysfunction. Impairments on decision-making tasks are routinely reported: evidence points to a particular deficit in learning from and revising behavior following feedback. In addition, patients tend to make hasty decisions when probabilistic judgments are required. This is known as "jumping to conclusions" (JTC) and has typically been demonstrated by presenting participants with colored beads drawn from one of two "urns" until they claim to be sure which urn the beads are being drawn from (the proportions of colors vary in each urn). Patients tend to make early decisions on this task, and there is evidence to suggest that a hasty decision-making style might be linked to delusion formation and thus be of clinical relevance. Various accounts have been proposed regarding what underlies this behavior. In this review, we briefly introduce the disorder and the decision-making deficits associated with it. We then explore the evidence for each account of JTC in the context of a wider decision-making deficit and then go on to summarize work exploring JTC in healthy controls using pharmacological manipulations and functional imaging. Finally, we assess whether JTC might have a role in therapy.

Overconfidence in incorrect perceptual judgments in patients with schizophrenia

Background

Patients with schizophrenia show overconfidence in memory and social cognition errors. The present investigation examined whether this cognitive distortion also manifests in perceptual tasks.

Methods

A total of 55 individuals with schizophrenia, 58 with obsessive–compulsive disorder (OCD) as well as 45 non-clinical controls were presented 24 blurry black and white pictures, half of which contained a hidden object; the other half contained (“snowy”) visual noise. Participants had to judge whether the pictures depicted an object or not and how confident they were in this judgment.

Results

Participants with schizophrenia showed overconfidence in errors and an enhanced knowledge corruption index (i.e. rate of high-confident errors on all high-confident responses) relative to both control groups. In contrast, accuracy scores did not differ between clinical groups. Metacognitive parameters were correlated with self-rated levels of current paranoia.

Discussion

To the best of our knowledge, this is the first study to demonstrate overconfidence in errors among individuals with psychosis using a visual perception task. Speaking to the specificity of this abnormality for schizophrenia and its pathogenetic relevance, overconfidence in errors and knowledge corruption were elevated in patients with schizophrenia relative to both control groups and were correlated with paranoia.