Decision-making impairment in schizophrenia: Relationships with positive symptomatology

Positive symptoms of schizophrenia and their relationship with cognitive and emotional executive functions

BACKGROUND

Positive symptoms of schizophrenia are associated with significant difficulties in daily functioning, and these difficulties have been associated with impaired executive functions (EEFF). However, specific cognitive and socio-emotional executive deficits have not been fully established.

OBJECTIVE

The present study has several objectives. First, we aimed to examine the specific deficits in cognitive and socio-emotional EEFF in a group of patients with schizophrenia with a predominance of positive symptoms, as well as to determine if these patients present clinically significant scores in any of the three fronto-subcortical behavioral syndromes: Dorsolateral, Orbitofrontal, or Anterior Cingulate.

METHOD

The sample consisted of 54 patients, 27 with a predominance of positive symptoms, and 27 healthy controls matched for gender, age, and education. The two groups completed four cognitive and three socio-emotional EEFF tasks. In the group of patients, positive symptoms were evaluated using the scale for the Evaluation of Positive Symptoms (SANS), while the behavioral alterations associated with the three fronto-subcortical syndromes were evaluated using the Frontal System Behavior Scale (FrSBe).

RESULTS

The patients, in comparison with a control group, presented specific deficits in cognitive and socio-emotional EEFF. In addition, a high percentage of patients presented clinically significant scores on the three fronto-subcortical syndromes.

CONCLUSION

The affectation that these patients present, in terms of both cognitive and emotional components, highlights the importance of developing a neuropsychological EEFF intervention that promotes the recovery of the affected cognitive capacities and improves the social and emotional functioning of the affected patients.

Childhood traumatic events and the dopaminergic theory of psychosis: A mini-review of studies investigating gene – environment interactions

There is great body of evidence showing a relationship between childhood adversity and psychosis onset. Genetic factors moderate the association between childhood adversity and psychosis risk potentially by influencing biological and/or psychological reaction following exposure to adversity. In this review, we discuss studies identifying the specific genetic variants known to affect dopamine levels involved in this interaction. Our review shows that the catechol-O-methyltransferase (COMT), dopamine D2 receptor (DRD2), AKT1 gene play a key role in mediating the relationship between childhood adversity and development of psychosis. We have also found conflicting findings on the impact of dopamine genes on the relationship between childhood adversity and development of psychosis, suggesting that other genetic and environmental factors should be taken into account. We here discuss the implications of our findings and future directions.

Subjective Memory Complaints and Decision Making in Young and Older Adults: An Event-Related Potential Study

Subjective memory complaints (SMCs) may affect decision-making processes. This study aimed to investigate the neuronal correlates of feedback processing during a decision-making task in young and older adults with and without SMCs. Event-related potentials and behavioral performance during the Iowa gambling task were recorded in a total of 136 participants (65 young adults, 71 older adults). The participants were divided into two groups according to their SMCs (with SMCs: n = 60, without SMCs: n = 76). Feedback-related negativity (FRN) and P3 were analyzed in the feedback stage of the decision-making process. Older adults with SMCs scored worse in the ambiguity phase than older adults without SMCs. The FRN latency was longer for losses in older people with SMCs than in older people without SMCs in the first block. No significant differences between young and older adults with and without SMCs were observed in the other ERP measures. Compared to young adults, older adults showed delayed latency in the FRN component and reduced amplitudes and delayed latency in the P3 component. In conclusion, older people with SMCs present deficits in the decision-making process. These deficits are observed at the behavioral level, but also in neural mechanisms of early feedback processing of negative outcomes.

The Prominent Deck B Phenomenon in Schizophrenia: An Empirical Study on Iowa Gambling Task

Background: The Iowa Gambling Task (IGT) was established to evaluate emotion-based decision-making ability under uncertain circumstances in clinical populations, including schizophrenia (Sz). However, there remains a lack of stable behavioral measures regarding discrimination for decision-making performance in IGT between schizophrenic cases and healthy participants. None of the Sz-IGT studies has specifically verified the prominent deck B (PDB) phenomenon gradually revealed in other populations. Here, we provided a global review and empirical study to verify these Sz-IGT issues. Methods: Seeking reliable and valid behavioral measures, we reviewed 38 studies using IGT to investigate decision-making behavior in Sz groups. The IGT, the Wisconsin Card Sorting Test (WCST), and clinical symptoms evaluations were administered to 61 schizophrenia or schizoaffective cases diagnosed by psychiatrists and 62 demographically matched healthy participants. Results: There were no valid behavioral measures in IGT that could significantly identify the decision-making dysfunction of Sz. However, Sz cases, on average, made more choices from disadvantageous deck B relative to other decks, particularly in the later learning process (block 3-5). Compared to the control group, the Sz group was more impaired on the WCST. The high-gain frequency decks B and D showed significant correlations with WCST but no correlation between clinical symptoms and IGT/WCST. Conclusions: Gain-loss frequency (GLF) has a dominant and stable impact on the decision-making process in both Sz and control groups. PDB phenomenon is essentially challenging to be observed on the ground of the expected value (EV) viewpoint approach on the IGT in both populations. Consequently, caution should be exercised when launching the IGT to assess the decision-making ability of Sz under a clinical scenario.

Ineffective risk-reward learning in schizophrenia

The underpinnings of poor decision-making in schizophrenia could reflect excessively risky or inhibited behaviors. This study employed the Balloon Analogue Risk Task (BART) to compare decision-making in schizophrenia cases to that of healthy controls. Individuals with schizophrenia performed significantly differently across three trials, failing to improve their performance as shown by the control group. In the control group, cognitive ability, measured with the Wechsler Adult Intelligence Scale (WAIS-III) showed that Perceptual Organization scores predicted Average Inflations per Trial, Total Balloon Pops, and Total Earnings. Although the schizophrenia cases failed to learn, group performance on the BART was not associated with cognitive ability, but regression analyses showed 41.4% of average inflations per trial were explained by Excitement, Delusions, Emotional Withdrawal, and Poor Rapport; total balloon pops were only explained by emotional withdrawal and Total Earnings were reduced by Delusions, Excitement and Poor Rapport. Only healthy participants demonstrated a relation between cognitive ability performance improvement across trials. Schizophrenia cases showed less risk-taking, and earned significantly less money overall. Identifying the determinants of poor decision-making could inform interventions and possible treatments to improve their function and perhaps be of relevance to public safety if decisions are overly risky.

Addicted to compulsion: assessing three core dimensions of addiction across obsessive-compulsive disorder and gambling disorder

OBJECTIVE

Several studies suggested that obsessive-compulsive disorder (OCD) patients display increased impulsivity, impaired decision-making, and reward system dysfunction. In a Research Domain Criteria (RDoC) perspective, these findings are prototypical for addiction and have led some authors to view OCD as a behavioral addiction. Thus, the aim of this study was to investigate similarities and differences on impulsivity, decision-making, and reward system, as core dimensions of addiction, across OCD and gambling disorder (GD) patients.

METHODS

Forty-four OCD patients, 26 GD patients, and 40 healthy controls (HCs) were included in the study. Impulsivity was assessed through the Barratt Impulsiveness Scale, decision-making through the Iowa Gambling Task, and reward system through a self-report clinical instrument (the Shaps-Hamilton Anhedonia Scale) assessing hedonic tone and through an olfactory test assessing hedonic appraisal to odors.

RESULTS

Both OCD and GD patients showed increased impulsivity when compared to HCs. More specifically, the OCD patients showed cognitive impulsivity, and the GD patients showed both increased cognitive and motor impulsivity. Furthermore, both OCD and GD patients showed impaired decision-making performances when compared to HCs. Finally, GD patients showed increased anhedonia and blunted hedonic response to pleasant odors unrelated to gambling or depression/anxiety symptoms, while OCD patients showed only increased anhedonia levels related to OC and depression/anxiety symptoms.

CONCLUSION

OCD patients showed several similarities and some differences with GD patients when compared to HCs on impulsivity, decision-making, and reward system, three core dimensions of addiction. These results could have relevant implications for the research of new treatment targets for OCD.

Decision making of forensic psychiatric inpatients deemed incompetent to stand trial

This study examined decision making and its correlates among forensic psychiatric inpatients deemed incompetent to stand trial (IST). This study utilized archival data (n = 41; Mean Age = 44.27, SD = 15.89, 79.1% Male; 34.1% Caucasian). Decision making was measured using the Iowa Gambling Task (IGT), which is purported to simulate real-life decision making. Correlates included cognitive functioning, psychiatric symptom severity, and impulsivity. Participants selected more frequently from disadvantageous decks, which yield larger immediate monetary gains with a larger long-term monetary losses (Mean NET = -9.51, SD = 26.70), but avoided decks yielding frequent monetary losses (Mean GLF = 10.10, SD = 26.70). Consistently, participants selected most frequently from a deck yielding the most immediate monetary gains and the least frequent monetary losses compared to other decks (ps < 0.05). Based upon their selections, participants lost a significant amount of money (M = -$1,493.22, SD = $1,182.26). IGT outcomes were differentially associated with cognitive functioning (rs = -0.26 to 0.47), psychiatric symptom severity (rs = -0.41 to 0.37), and impulsivity (rs = -0.47 to 0.28; all ps = 0.003-0.98). Findings can guide future research, as well as guide competency restoration and decision-making interventions, for this population.

Structural Brain Alterations in Youth With Psychosis and Bipolar Spectrum Symptoms

OBJECTIVE

Adults with established diagnoses of serious mental illness (bipolar disorder and schizophrenia) exhibit structural brain abnormalities, yet less is known about how such abnormalities manifest earlier in development.

METHOD

Cross-sectional data publicly available from the Philadelphia Neurodevelopmental Cohort (PNC) were analyzed. Structural magnetic resonance neuroimaging data were collected on a subset of the PNC (N = 989; 9-22 years old). Cortical thickness, surface area (SA), and subcortical volumes were calculated. Study participants were assessed for psychiatric symptomatology using a structured interview and the following groups were created: typically developing (n = 376), psychosis spectrum (PS; n = 113), bipolar spectrum (BP; n = 117), and BP + PS (n = 109). Group and developmental differences in structural magnetic resonance neuroimaging measures were examined. In addition, the extent to which any structural aberration was related to neurocognition, global functioning, and clinical symptomatology was examined.

RESULTS

Compared with other groups, PS youth exhibited significantly decreased SA in the orbitofrontal, cingulate, precentral, and postcentral regions. PS youth also exhibited deceased thalamic volume compared with all other groups. The strongest effects for precentral and posterior cingulate SA decreases were seen during early adolescence (13-15 years old) in PS youth. The strongest effects for decreases in thalamic volume and orbitofrontal and postcentral SA were observed in mid-adolescence (16-18 years) in PS youth. Across groups, better overall functioning was associated with increased lateral orbitofrontal SA. Increased postcentral SA was associated with better executive cognition and less severe negative symptoms in the entire sample.

CONCLUSION

In a community-based sample, decreased cortical SA and thalamic volume were present early in adolescent development in youth with PS symptoms, but not in youth with BP symptoms or with BP and PS symptoms. These findings point to potential biological distinctions between PS and BP conditions, which could suggest additional biomarkers relevant to early identification.

Environmental dependency phenomena in schizophrenia: a pilot study

INTRODUCTION

Environmental dependency phenomena refer to the enslavement of patients' performances under the characteristics of the tasks and were first described in case of prefrontal lobe damage. Two forms of environmental dependency, executive and social, may be dissociated, which involve respectively dorsolateral and orbital prefrontal cortex (PFC) dysfunction. Schizophrenia is widely considered to be caused by PFC dysfunction, but no study to date has addressed environmental dependency in this pathology.

METHODS

We compared patients (N = 17) and healthy controls (N = 28) on a task dedicated to the study of environmental dependency.

RESULTS

Our results demonstrate the presence of environmental dependency in schizophrenia. Each form of environmental dependency can be highlighted independently, as previously demonstrated by studies with prefrontal patients.

CONCLUSIONS

These findings suggest specific prefrontal dysfunction for each subgroup of patients and demonstrate a dissociation between socio-cognitive and neurocognitive performance in schizophrenia. Additionally, we found relationships between symptomatology and environmental dependency. This pilot study supports the relevance of studying environmental dependency to highlight specific patterns of prefrontal disorders in schizophrenia, which may contribute to a better understanding of PFC dysfunction in schizophrenia.

Decision-Making Deficits Are Associated With Learning Impairments in Female College Students at High Risk for Anorexia Nervosa: Iowa Gambling Task and Prospect Valence Learning Model

This study investigated deficits in decision-making ability in female college students at high risk for anorexia nervosa (AN) using the Iowa Gambling Task (IGT) and the prospect valence learning (PVL) model. Based on scores on the Korean version of the Eating Attitude Test-26 (KEAT-26), participants were assigned to either the high risk for AN group (n = 42) or the control group (n = 43). The high risk for AN group exhibited significantly lower total net scores and block net scores on the third, fourth, and fifth blocks of the IGT than the control group did. The high risk for AN group selected cards significantly more often from the disadvantageous A and B decks and less often from the advantageous D deck than the control group did. In addition, the block net scores of the high risk for AN group did not differ across the five blocks, whereas those of the control group increased as the trials progressed. There was a significant negative correlation between IGT total net score and total score on the KEAT-26. The high risk for AN group had significantly lower values than the control group on the learning and response consistency parameters of the PVL model. These results indicate that female college students at high risk for AN have deficits in decision-making ability, and that these deficits are related to difficulties in remembering experience obtained from earlier trials and applying it to later trials. These difficulties further lead them to make decisions randomly.

Sex differences in animal models of decision making

The ability to weigh the costs and benefits of various options to make an adaptive decision is critical to an organism's survival and wellbeing. Many psychiatric diseases are characterized by maladaptive decision making, indicating a need for better understanding of the mechanisms underlying this process and the ways in which it is altered under pathological conditions. Great strides have been made in uncovering these mechanisms, but the majority of what is known comes from studies conducted solely in male subjects. In recent years, decision-making research has begun to include female subjects to determine whether sex differences exist and to identify the mechanisms that contribute to such differences. This Mini-Review begins by describing studies that have examined sex differences in animal (largely rodent) models of decision making. Possible explanations, both theoretical and biological, for such differences in decision making are then considered. The Mini-Review concludes with a discussion of the implications of sex differences in decision making for understanding psychiatric conditions. © 2016 Wiley Periodicals, Inc.

Risky decision-making under risk in schizophrenia: A deliberate choice?

BACKGROUND AND OBJECTIVES

Patients with schizophrenia reveal impaired decision-making strategies causing social, financial and health care problems. The extent to which deficits in decision-making reflect intentional risky choices in schizophrenia is still under debate. Based on previous studies we expected patients with schizophrenia to reveal a riskier performance on the GDT and to make more disadvantageous decisions on the IGT.

METHODS

In the present study, we investigated 38 patients with schizophrenia and 38 matched healthy control subjects with two competing paradigms regarding feedback: (1) The Game of Dice Task (GDT), in which the probabilities of winning or losing are stable and explicitly disclosed to the subject, to assess decision-making under risk and (2) the Iowa Gambling Task (IGT), which requires subjects to infer the probabilities of winning or losing from feedback, to investigate decision-making under ambiguity.

RESULTS

Patients with schizophrenia revealed an overall riskier performance on the GDT; although they adjusted their strategy over the course of the GDT, they still made significantly more disadvantageous choices than controls. More positive symptoms in patients with schizophrenia indicated by higher PANSS positive scores were associated with riskier choices and less use of negative feedback. Compared to healthy controls, they were not impaired in net score but chose more disadvantageous cards than controls on the first block of the IGT.

LIMITATIONS

Effects of medication at the time of testing cannot be ruled out.

CONCLUSIONS

Our findings suggest that patients with schizophrenia make riskier decisions and are less able to regulate their decision-making to implement advantageous strategies, even when the probabilities of winning or losing are explicitly disclosed. The dissociation between performance on the GDT and IGT suggests a pronounced impairment of executive functions related to the dorsolateral prefrontal cortex.

Striatal GPR88 Modulates Foraging Efficiency

The striatum is anatomically and behaviorally implicated in behaviors that promote efficient foraging. To investigate this function, we studied instrumental choice behavior in mice lacking GPR88, a striatum-enriched orphan G-protein-coupled receptor that modulates striatal medium spiny neuron excitability. Our results reveal that hungry mice lacking GPR88 (KO mice) were slow to acquire food-reinforced lever press but could lever press similar to controls on a progressive ratio schedule. Both WT and KO mice discriminated between reward and no-reward levers; however, KO mice failed to discriminate based on relative quantity-reward (1 vs 3 food pellets) or effort (3 vs 9 lever presses). We also demonstrate preference for the high-reward (3 pellet) lever was selectively reestablished when GPR88 expression was restored to the striatum. We propose that GPR88 expression within the striatum is integral to efficient action-selection during foraging.SIGNIFICANCE STATEMENT Evolutionary pressure driving energy homeostasis favored detection and comparison of caloric value. In wild and laboratory settings, neural systems involved in energy homeostasis bias foraging to maximize energy efficiency. This is observed when foraging behaviors are guided by superior nutritional density or minimized caloric expenditure. The striatum is anatomically and functionally well placed to perform the sensory and motor integration necessary for efficient action selection during foraging. However, few studies have examined this behavioral phenomenon or elucidated underlying molecular mechanisms. Both humans and mice with nonfunctional GPR88 have been shown to present striatal dysfunctions and impaired learning. We demonstrate that GPR88 expression is necessary to efficiently integrate effort and energy density information guiding instrumental choice.

The involvement of the striatum in decision making

Decision making has been extensively studied in the context of economics and from a group perspective, but still little is known on individual decision making. Here we discuss the different cognitive processes involved in decision making and its associated neural substrates. The putative conductors in decision making appear to be the prefrontal cortex and the striatum. Impaired decision-making skills in various clinical populations have been associated with activity in the prefrontal cortex and in the striatum. We highlight the importance of strengthening the degree of integration of both cognitive and neural substrates in order to further our understanding of decision-making skills. In terms of cognitive paradigms, there is a need to improve the ecological value of experimental tasks that assess decision making in various contexts and with rewards; this would help translate laboratory learnings into real-life benefits. In terms of neural substrates, the use of neuroimaging techniques helps characterize the neural networks associated with decision making; more recently, ways to modulate brain activity, such as in the prefrontal cortex and connected regions (eg, striatum), with noninvasive brain stimulation have also shed light on the neural and cognitive substrates of decision making. Together, these cognitive and neural approaches might be useful for patients with impaired decision-making skills. The drive behind this line of work is that decision-making abilities underlie important aspects of wellness, health, security, and financial and social choices in our daily lives.

Decision-making deficits in patients with chronic schizophrenia: Iowa Gambling Task and Prospect Valence Learning model

PURPOSE

Decision-making is the process of forming preferences for possible options, selecting and executing actions, and evaluating the outcome. This study used the Iowa Gambling Task (IGT) and the Prospect Valence Learning (PVL) model to investigate deficits in risk-reward related decision-making in patients with chronic schizophrenia, and to identify decision-making processes that contribute to poor IGT performance in these patients.

MATERIALS AND METHODS

Thirty-nine patients with schizophrenia and 31 healthy controls participated. Decision-making was measured by total net score, block net scores, and the total number of cards selected from each deck of the IGT. PVL parameters were estimated with the Markov chain Monte Carlo sampling scheme in OpenBugs and BRugs, its interface to R, and the estimated parameters were analyzed with the Mann-Whitney U-test.

RESULTS

The schizophrenia group received significantly lower total net scores compared to the control group. In terms of block net scores, an interaction effect of group × block was observed. The block net scores of the schizophrenia group did not differ across the five blocks, whereas those of the control group increased as the blocks progressed. The schizophrenia group obtained significantly lower block net scores in the fourth and fifth blocks of the IGT and selected cards from deck D (advantageous) less frequently than the control group. Additionally, the schizophrenia group had significantly lower values on the utility-shape, loss-aversion, recency, and consistency parameters of the PVL model.

CONCLUSION

These results indicate that patients with schizophrenia experience deficits in decision-making, possibly due to failure in learning the expected value of each deck, and incorporating outcome experiences of previous trials into expectancies about options in the present trial.

Think twice: Impulsivity and decision making in obsessive-compulsive disorder

BACKGROUND AND AIMS

Recent studies have challenged the anxiety-avoidance model of obsessive-compulsive disorder (OCD), linking OCD to impulsivity, risky-decision-making and reward-system dysfunction, which can also be found in addiction and might support the conceptualization of OCD as a behavioral addiction. Here, we conducted an exploratory investigation of the behavioral addiction model of OCD by assessing whether OCD patients are more impulsive, have impaired decision-making, and biased probabilistic reasoning, three core dimensions of addiction, in a sample of OCD patients and healthy controls.

METHODS

We assessed these dimensions on 38 OCD patients and 39 healthy controls with the Barratt Impulsiveness Scale (BIS-11), the Iowa Gambling Task (IGT) and the Beads Task.

RESULTS

OCD patients had significantly higher BIS-11 scores than controls, in particular on the cognitive subscales. They performed significantly worse than controls on the IGT preferring immediate reward despite negative future consequences, and did not learn from losses. Finally, OCD patients demonstrated biased probabilistic reasoning as reflected by significantly fewer draws to decision than controls on the Beads Task.

CONCLUSIONS

OCD patients are more impulsive than controls and demonstrate risky decision-making and biased probabilistic reasoning. These results might suggest that other conceptualizations of OCD, such as the behavioral addiction model, may be more suitable than the anxiety-avoidance one. However, further studies directly comparing OCD and behavioral addiction patients are needed in order to scrutinize this model.

Cognition and Social Cognition in non-psychotic siblings of patients with schizophrenia

INTRODUCTION

Deficits in Social Cognition are common in people with schizophrenia. However, it is not clear if these deficits are a vulnerability marker and whether they are independent to cognitive difficulties. This study investigates these two issues in individuals with a genetic liability to psychosis.

METHODS

Twenty-one healthy siblings of patients with schizophrenia were compared with 21 healthy individuals on a range of cognitive and social cognitive measures. Significant differences in cognitive domains were controlled for when comparing the two groups on measures of social cognition.

RESULTS

Siblings of people with schizophrenia performed significantly worst on tests of theory of mind and social perception but not on affect recognition. Scores on tests of executive function, processing speed and general IQ were also lower in the sibling group. When controlled for differences in cognitive tests, the two groups still retained significant differences in theory of mind and social perception. However, executive function significantly contributed to theory of mind and processing speed to social perception differences.

CONCLUSIONS

These results further suggest that difficulties in some domains of social cognition are associated with a genetic vulnerability for schizophrenia. In these areas, cognitive difficulties account only partially for social cognition problems suggesting that these two domains may represent relatively independent liability factors.

Effects of disrupting medial prefrontal cortex GABA transmission on decision-making in a rodent gambling task

RATIONALE

Decision-making is a complex cognitive process that is mediated, in part, by subregions of the medial prefrontal cortex (PFC). Decision-making is impaired in a number of psychiatric conditions including schizophrenia. Notably, people with schizophrenia exhibit reductions in GABA function in the same PFC areas that are implicated in decision-making. For example, expression of the GABA-synthesizing enzyme GAD67 is reduced in the dorsolateral PFC of people with schizophrenia.

OBJECTIVES

The goal of this experiment was to determine whether disrupting cortical GABA transmission impairs decision-making using a rodent gambling task (rGT).

METHODS

Rats were trained on the rGT until they reached stable performance and then were implanted with guide cannulae aimed at the medial PFC. Following recovery, the effects of intra-PFC infusions of the GABAA receptor antagonist bicuculline methiodide (BMI) or the GABA synthesis inhibitor L-allylglycine (LAG) on performance on the rGT were assessed.

RESULTS

Intracortical infusions of BMI (25 ng/μl/side), but not LAG (10 μg/μl/side), altered decision-making. Following BMI infusions, rats made fewer advantageous choices. Follow-up experiments suggested that the change in decision-making was due to a change in the sensitivity to the punishments, rather than a change in the sensitivity to reward magnitudes, associated with each outcome. LAG infusions increased premature responding, a measure of response inhibition, but did not affect decision-making.

CONCLUSIONS

Blocking GABAA receptors, but not inhibiting cortical GABA synthesis, within the medial PFC affects decision-making in the rGT. These data provide proof-of-concept evidence that disruptions in GABA transmission can contribute to the decision-making deficits in schizophrenia.

Relationships between brain-derived neurotrophic factor, clinical symptoms, and decision-making in chronic schizophrenia: data from the Iowa Gambling Task

The levels of brain-derived neurotrophic factor (BDNF) are significantly decreased in patients with schizophrenia and correlate with impairments in cognitive function. However, no study has investigated the relationship between the serum BDNF levels and decision-making. We compared patients with schizophrenia to healthy controls with respect to their decision-making ability and serum BDNF levels. Eighty-six chronic schizophrenia patients and 51 healthy controls participated in this study. We controlled for gender, age, and estimated intelligence quotient (IQ), and we investigated the differences in decision-making performance on the Iowa Gambling Task (IGT) between the schizophrenia patient and control groups. We also compared the IGT scores, the serum BDNF levels, and the clinical symptoms between the groups. The IGT scores of the schizophrenia patients were lower than those of the controls. A negative correlation was detected between the mean net scores on the trials in the final two blocks and the serum BDNF levels (p < 0.05). Multiple regression analysis revealed that depressive symptoms and the serum BDNF levels were significantly associated with the mean net scores on the trials in the final two blocks. Based on these results, impaired sensitivity to both reward and punishment is associated with depressive symptoms and reduced serum BDNF levels in chronic schizophrenia patients and may be related to their poor performance on the IGT.

Positive symptoms in first-episode psychosis patients experiencing low maternal care and stressful life events: a pilot study to explore the role of the COMT gene

COMT Val(158)Met moderates the effect of stress on psychotic symptoms. Exposure to stress is also associated with mesolimbic dopamine release in individuals experiencing low maternal care. We therefore test the hypothesis that recent stressful life events are associated with more severe positive symptoms (associated with mesolimbic dopamine release) in first-episode psychosis (FEP) patients who experienced low maternal care during childhood. We hypothesized that COMT Val(158)Met moderates this association. A total of 149 FEP patients recruited within the Psychosis Incident Cohort Outcome Study (PICOS) participated in the present study. Maternal care was assessed by the Parental Bonding Instrument (PBI), stressful life events were collected by the List of Events Scale and positive symptoms were assessed by the Positive and Negative Syndrome Scale (PANSS). We found that low maternal care and recent stressful life events were associated with higher level of positive symptoms at the onset (analysis of variance [ANOVA], p = 0.012), and that patients who were also homozygotes for the COMT Val(158) allele had the highest level of positive symptoms (ANOVA, p = 0.024). Low maternal care and severe stressful life events may contribute to a symptomatology characterized by more severe positive symptoms at the onset, possibly due to an increased mesolimbic dopamine release. Homozygosity for the COMT Val(158) allele seems to confer a biological predisposition to the stress-related hyperactivity of the mesolimbic dopaminergic system. The data imply that the mesolimbic dopaminergic system is involved in the mediation/modulation of the effect of stressful events on the vulnerability for psychosis.

Medial prefrontal cortex lesions impair decision-making on a rodent gambling task: reversal by D1 receptor antagonist administration

Decision-making is a complex cognitive process that is impaired in a number of psychiatric disorders. In the laboratory, decision-making is frequently assessed using "gambling" tasks that are designed to simulate real-life decisions in terms of uncertainty, reward and punishment. Here, we investigate whether lesions of the medial prefrontal cortex (PFC) cause impairments in decision-making using a rodent gambling task (rGT). In this task, rats have to decide between 1 of 4 possible options: 2 options are considered "advantageous" and lead to greater net rewards (food pellets) than the other 2 "disadvantageous" options. Once rats attained stable levels of performance on the rGT they underwent sham or excitoxic lesions of the medial PFC and were allowed to recover for 1 week. Following recovery, rats were retrained for 5 days and then the effects of a dopamine D1-like receptor antagonist (SCH23390) or a D2-like receptor antagonist (haloperidol) on performance were assessed. Lesioned rats exhibited impaired decision-making: they made fewer advantageous choices and chose the most optimal choice less frequently than did sham-operated rats. Administration of SCH23390 (0.03 mg/kg), but not haloperidol (0.015-0.03 mg/kg) attenuated the lesion-induced decision-making deficit. These results indicate that the medial PFC is important for decision-making and that excessive signaling at D1 receptors may contribute to decision-making impairments.

A further evaluation of decision-making under risk and under ambiguity in schizophrenia

Abnormal decision-making has been described as a key-concept to understand some behavioral disturbances in schizophrenia. However, whether schizophrenia patients display impairments in profitable decision-making on experimental designs is still controversial (1) to assess performance on decision-making paradigms under ambiguity and under risk conditions in a large sample of schizophrenia patients and (2) to study the impact of clinical variables on decision-making performance in schizophrenia. The Iowa gambling task (IGT) and the game of dice task (GDT) were administered to assess, respectively, decision-making under ambiguity and under risk in 63 schizophrenia patients and 67 healthy controls. In addition, clinical variables (e.g., schizophrenic symptoms, self-reported depression, and impulsivity) were evaluated using appropriate questionnaires the same day. Pharmacological treatments were reported. Schizophrenia patients had impaired performances on both IGT and GDT tasks. No correlation between the decision-making tasks performance and clinical variables was found. Lower gains on the GDT were associated with executive dysfunctioning in schizophrenia. These findings give evidence that schizophrenia patients display impairments in both decision-making under ambiguity and under risk.

Translational application of neuromodulation of decision-making

Recent cognitive neuroscience studies indicate that noninvasive brain stimulation can modulate a wide spectrum of behaviors in healthy individuals. Such modulation of behaviors provides novel insights into the fundamentals and neurobiology of cognitive functions in the healthy brain, but also suggests promising prospects for translational applications into clinical populations. One type of behavior that can be modulated with noninvasive brain stimulation is decision-making. For instance, brain stimulation can induce more cautious or riskier behaviors. The capacity of influencing processes involved in decision-making is of particular interest because such processes are at the core of human social and emotional functioning (or dysfunctioning). We review cognitive neuroscience studies that have successfully modulated processes involved in decision-making with transcranial direct current stimulation (tDCS) or transcranial magnetic stimulation (TMS), including risk taking, reward seeking, impulsivity, and fairness consideration. We also discuss potential clinical relevance of these findings for patients who have still unmet therapeutic need and whose alterations in decision-making represent hallmarks of their clinical symptomatology, such as individuals with addictive disorders.