Decision making in bipolar disorder: a cognitive modeling approach

The Iowa Gambling Task: Men and Women Perform Differently. A Meta-analysis

The Iowa Gambling Task (IGT) was designed to assess decision-making under conditions of complexity and uncertainty; it is currently one of the most widely used tests to assess decision-making in both experimental and clinical settings. In the original version of the task, participants are given a loan of play money and four decks of cards and are asked to maximize profits. Although any single card unpredictably yields wins/losses, variations in frequency and size of gains/losses ultimately make two decks more advantageous in the long term. Several studies have previously suggested that there may be a sex-related difference in IGT performance. Thus, the present study aimed to explore and quantify sex differences in IGT performance by pooling the results of 110 studies. The meta-analysis revealed that males tend to perform better than females on the classic 100-trial IGT (UMD = 3.381; p < 0.001). Furthermore, the significant heterogeneity observed suggests high variability in the results obtained by individual studies. Results were not affected by publication bias or other moderators. Factors that may contribute to differences in male and female performance are discussed, such as functional sex-related asymmetries in the ventromedial prefrontal cortex and amygdala, as well as differences in sensitivity to wins/losses.

Reward and punishment learning deficits among bipolar disorder subtypes

BACKGROUND

Reward sensitivity is an essential dimension related to mood fluctuations in bipolar disorder (BD), but there is currently a debate around hypersensitivity or hyposensitivity hypotheses to reward in BD during remission, probably related to a heterogeneous population within the BD spectrum and a lack of reward bias evaluation. Here, we examine reward maximization vs. punishment avoidance learning within the BD spectrum during remission.

METHODS

Patients with BD-I (n = 45), BD-II (n = 34) and matched (n = 30) healthy controls (HC) were included. They performed an instrumental learning task designed to dissociate reward-based from punishment-based reinforcement learning. Computational modeling was used to identify the mechanisms underlying reinforcement learning performances.

RESULTS

Behavioral results showed a significant reward learning deficit across BD subtypes compared to HC, captured at the computational level by a lower sensitivity to rewards compared to punishments in both BD subtypes. Computational modeling also revealed a higher choice randomness in BD-II compared to BD-I that reflected a tendency of BD-I to perform better during punishment avoidance learning than BD-II.

LIMITATIONS

Our patients were not naive to antipsychotic treatment and were not euthymic (but in syndromic remission) according to the International Society for Bipolar Disorder definition.

CONCLUSIONS

Our results are consistent with the reward hyposensitivity theory in BD. Computational modeling suggests distinct underlying mechanisms that produce similar observable behaviors, making it a useful tool for distinguishing how symptoms interact in BD versus other disorders. In the long run, a better understanding of these processes could contribute to better prevention and management of BD.

Mathematical modeling of risk-taking in bipolar disorder: Evidence of reduced behavioral consistency, with altered loss aversion specific to those with history of substance use disorder

Bipolar disorder (BD) is associated with excessive pleasure-seeking risk-taking behaviors that often characterize its clinical presentation. However, the mechanisms of risk-taking behavior are not well-understood in BD. Recent data suggest prior substance use disorder (SUD) in BD may represent certain trait-level vulnerabilities for risky behavior. This study examined the mechanisms of risk-taking and the role of SUD in BD via mathematical modeling of behavior on the Balloon Analogue Risk Task (BART). Three groups-18 euthymic BD with prior SUD (BD+), 15 euthymic BD without prior SUD (BD-), and 33 healthy comparisons (HC)-completed the BART. We modeled behavior using 4 competing hierarchical Bayesian models, and model comparison results favored the Exponential-Weight Mean-Variance (EWMV) model, which encompasses and delineates five cognitive components of risk-taking: prior belief, learning rate, risk preference, loss aversion, and behavioral consistency. Both BD groups, regardless of SUD history, showed lower behavioral consistency than HC. BD+ exhibited more pessimistic prior beliefs (relative to BD- and HC) and reduced loss aversion (relative to HC) during risk-taking on the BART. Traditional measures of risk-taking on the BART (adjusted pumps, total points, total pops) detected no group differences. These findings suggest that reduced behavioral consistency is a crucial feature of risky decision-making in BD and that SUD history in BD may signal additional trait vulnerabilities for risky behavior even when mood symptoms and substance use are in remission. This study also underscores the value of using mathematical modeling to understand behavior in research on complex disorders like BD.

Mental health: The burden of social stigma

The burden of mental health has two facets, social and psychological. Social stigma causes individuals who suspect to be suffering from a mental condition to conceal it, importantly by seeking care from a nonspecialist provider willing to diagnose it as physical disease. In this way, social stigma adds to both the direct and indirect cost of mental health. A microeconomic model depicting an individual who searches for an accommodating provider leads to the prediction that individuals undertake more search in response to a higher degree of social stigma. However, this holds only in the absence of errors in decision-making, typically as long as mental impairment is not too serious. While government and employers have an incentive to reduce the burden of social stigma, their efforts therefore need to focus on persons with a degree of mental impairment that still allows them to avoid errors in pursuing their own interest.

Risky decision-making following prefrontal D1 receptor manipulation

The prefrontal dopamine D1 receptor (D1R) is involved in cognitive processes. Viral overexpression of this receptor in rats further increases the reward-related behaviors and even its termination induces anhedonia and helplessness. In this study, we investigated the risky decision-making during D1R overexpression and its termination. Rats conducted the rodent version of the Iowa gambling task daily. In addition, the methyl CpG–binding protein-2 (MeCP2), one regulator connecting the dopaminergic system, cognitive processes, and mood-related behavior, was investigated after completion of the behavioral tasks. D1R overexpressing subjects exhibited maladaptive risky decision-making and risky decisions returned to control levels following termination of D1R overexpression; however, after termination, animals earned less reward compared to control subjects. In this phase, MeCP2-positive cells were elevated in the right amygdala. Our results extend the previously reported behavioral changes in the D1R-manipulated animal model to increased risk-taking and revealed differential MeCP2 expression adding further evidence for a bipolar disorder-like phenotype of this model.

A qualitative exploration of how people with bipolar disorder consider risk-taking in everyday decisions

BACKGROUND

Difficulties with decision making and risk taking in individuals with bipolar disorder (BD) have been associated with mood episodes. However, there is limited information about these experiences during euthymia, the mood state where people with BD spent the majority of their time.

AIMS

To examine how individuals with BD consider risk in everyday decisions during their euthymic phase.

METHOD

We conducted a qualitative study that used semi-structured audio recorded interviews. Eight euthymic participants with confirmed BD were interviewed, and we used interpretative phenomenological analysis to analyse the data.

RESULTS

We identified four themes. The first theme, 'Who I really am', involves the relationship between individual identity and risks taken. The second theme, 'Taking back control of my life', explored the relationship between risks taken as participants strove to keep control of their lives. The third theme, 'Fear of the "what ifs"', represents how the fear of negative consequences from taking risks impacts risk decisions. Finally, the fourth theme, 'The role of family and friends', highlights the important role that a supporting network can play in their lives in the context of taking risks.

CONCLUSIONS

The study highlights aspects that can impact on an individual with BD's consideration of risk during euthymia. Identity, control, fear and support all play a role when a person considers risk in their decision-making process, and they should be taken into consideration when exploring risk with individuals with BD in clinical settings, and inform the design of future interventions.

Cognitive modelling to assess decision-making impairments in patients with current depression and with/without suicide history

It has been reported that decision making is impaired in suicide attempters. Decision making is a complex process and little is known about its different components. Yet, this information would help to understand the functioning of suicidal minds. In this study, the Prospect Valence-Learning (PVL) computational model was applied to the Iowa Gambling Task (IGT) to investigate and compare decision-making components in patients with affective disorder and with/without history of suicide attempts and in healthy controls. To this aim, 116 inpatients with current major depressive episode (among whom 62 suicide attempters) and 38 healthy controls were recruited. Decision-making performance was measured using the IGT. The Bayesian computational PVL model was applied to compare the feedback sensitivity, loss aversion, learning/memory, and choice consistency components of decision making in the different groups. Depressive symptomatology was assessed using the Beck Depression Inventory short form (BDI-SF). The total IGT net score and the loss aversion and learning/memory scores were lower in suicide attempters than in healthy controls. The choice consistency score was low in all patients (with/without suicide history) compared with healthy controls. Moreover, patients with high BDI score showed a positive relationship between the choice consistency score and suicide attempt. These findings suggest that decision-making impairment in depressed patients with and without suicidal history might be the result of underlying problems in feedback processing and task learning, which influence the building of long-term strategies. All these impairments should be targeted in therapeutic strategies for suicidal patients.

Repetitive negative thinking following exposure to a natural stressor prospectively predicts altered stress responding and decision-making in the laboratory

Repetitive negative thinking (RNT) represents a transdiagnostic risk factor for affective disorders, and stress is theorized to exacerbate this vulnerability. One mechanism by which stress may influence individual differences in psychiatric symptoms is through altered decision-making, and loss aversion in particular. The present study uses multiple methods to investigate the relationships between RNT, stress, and decision-making. We measured RNT in young adults (N = 90) recently exposed to a natural stressor, Hurricane Irma, and tested the influence of RNT on changes in affect, cortisol, and decision-making during a laboratory stress induction two months later. Post-hurricane RNT predicted greater increases in loss averse decision-making (β = 0.30 [0.14, 0.47], p < .001; rp² = 0.079) and negative affect (β = 0.59 [0.37, 0.81], p < .001; rp² = 0.319) during the early-phase response to the laboratory stressor, as well as poorer cortisol recovery (β = 0.32, [0.10, 0.54], p = .005; rp² = 0.095) in the late-phase stress response. Results highlight the role of loss aversion and stress in understanding RNT as an affective vulnerability factor.

Mental health: A Particular Challenge Confronting Policy Makers and Economists

The first objective of this paper is to expound the particular challenge posed by the occurrence of inconsistency in the expression of preferences by mental health patients to both economists and policy makers. Since this difficulty cannot be resolved, the second aim of the paper is to identify agents who may be counted upon to identify the true patient preferences. A decision rule is developed to help identify these agents who may be family members or judges in court, who have the ability and incentive to make these decisions. No single agent is found to dominate with respect to the five dimensions of preference distinguished, constituting a major challenge to policy makers.

Neurocognitive impairment and evidence-based treatment options in Bipolar disorder

BACKGROUND

The current paper briefly summarizes the literature on the neurocognitive deficit and its treatment in BD patients.

METHODS

The material was chosen on the basis of previous systematic reviews the author has taken part in.

RESULTS

The data so far suggest that the deficit is qualitatively similar but quantitatively milder in comparison to schizophrenia, it is present already since the first episode, is weakly related to mood symptoms and somewhat stronger to psychotic symptoms, it probably determines much of the disability and treatment is problematic. This deficit is also present during periods of euthymia. The possible adverse effect of psychotropic medication is rather small if any at all and is confounded by the specific clinical symptoms, for which medication is used for their treatment. This is especially true concerning antipsychotics and psychotic symptoms. The origin and the etiopathogenesis of the core neurocognitive impairment remain elusive. The presence of a neurodegenerative and of a neurodevelopmental component has both data in favor and against and they are both the focus of debate.

CONCLUSIONS

Treatment of the neurocognitive deficit and restoration of functioning is problematic. The data are limited and treatment options are few and with a weak overall effect. Pharmacological treatments, ECT and rTMS present some hard data, while the literature is inconclusive concerning psychotherapeutic interventions.

Affective cognition in bipolar disorder: A systematic review by the ISBD targeting cognition task force

BACKGROUND

Impairments in affective cognition are part of the neurocognitive profile and possible treatment targets in bipolar disorder (BD), but the findings are heterogeneous. The International Society of Bipolar Disorder (ISBD) Targeting Cognition Task Force conducted a systematic review to (i) identify the most consistent findings in affective cognition in BD, and (ii) provide suggestions for affective cognitive domains for future study and meta-analyses.

METHODS

The review included original studies reporting behavioral measures of affective cognition in BD patients vs controls following the procedures of the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) statement. Searches were conducted on PubMed/MEDLINE, EMBASE, and PsychInfo from inception until November 2018.

RESULTS

A total of 106 articles were included (of which nine included data for several affective domains); 41 studies assessed emotional face processing; 23 studies investigated reactivity to emotional words and images; 3 investigated explicit emotion regulation; 17 assessed implicit emotion regulation; 31 assessed reward processing and affective decision making. In general, findings were inconsistent. The most consistent findings were trait-related difficulties in facial emotion recognition and implicit emotion regulation, and impairments in reward processing and affective decision making during mood episodes. Studies using eye-tracking and facial emotion analysis revealed subtle trait-related abnormalities in emotional reactivity.

CONCLUSION

The ISBD Task Force recommends facial expression recognition, implicit emotion regulation, and reward processing as domains for future research and meta-analyses. An important step to aid comparability between studies in the field would be to reach consensus on an affective cognition test battery for BD.

Lamotrigine as a mood stabilizer: insights from the pre-clinical evidence

INTRODUCTION

Lamotrigine (LTG) is a well-established anticonvulsant that is also approved for the prevention of mood relapses in bipolar disorder. However, the mechanisms underlying LTG mood stabilizing effects remain unclear. Areas covered: Herein, the pre-clinical evidence concerning LTG's' mode of action in depression and mania is reviewed. Bottlenecks and future perspectives for this expanding and promising field are also discussed. Pre-clinical studies have indicated that neurotransmitter systems, especially serotoninergic, noradrenergic and glutamatergic, as well as non-neurotransmitter pathways such as inflammation and oxidative processes might play a role in LTG's antidepressant effects. The mechanisms underlying LTG's anti-manic properties remain to be fully explored, but the available pre-clinical evidence points out to the role of glutamatergic neurotransmission, possibly through AMPA-receptors. Expert opinion: A major limitation of current pre-clinical investigations is that there are no experimental models that recapitulate the complexity of bipolar disorder. Significant methodological differences concerning time and dose of LTG treatment, administration route, animal strains, and behavioral paradigms also hamper the reproducibility of the findings, leading to contradictory conclusions. Moreover, the role of other mechanisms (e.g. inositol phosphate and GSK3β pathways) implicated in the mode of action of different mood-stabilizers must also be consolidated with LTG.

Bayesian techniques for analyzing group differences in the Iowa Gambling Task: A case study of intuitive and deliberate decision-makers

The Iowa Gambling Task (IGT) is one of the most popular experimental paradigms for comparing complex decision-making across groups. Most commonly, IGT behavior is analyzed using frequentist tests to compare performance across groups, and to compare inferred parameters of cognitive models developed for the IGT. Here, we present a Bayesian alternative based on Bayesian repeated-measures ANOVA for comparing performance, and a suite of three complementary model-based methods for assessing the cognitive processes underlying IGT performance. The three model-based methods involve Bayesian hierarchical parameter estimation, Bayes factor model comparison, and Bayesian latent-mixture modeling. We illustrate these Bayesian methods by applying them to test the extent to which differences in intuitive versus deliberate decision style are associated with differences in IGT performance. The results show that intuitive and deliberate decision-makers behave similarly on the IGT, and the modeling analyses consistently suggest that both groups of decision-makers rely on similar cognitive processes. Our results challenge the notion that individual differences in intuitive and deliberate decision styles have a broad impact on decision-making. They also highlight the advantages of Bayesian methods, especially their ability to quantify evidence in favor of the null hypothesis, and that they allow model-based analyses to incorporate hierarchical and latent-mixture structures.

Behavioral and Electrophysiological Alterations for Reinforcement Learning in Manic and Euthymic Patients with Bipolar Disorder

AIMS

Bipolar disorder is characterized by behavioral changes such as risk-taking and increasing goal-directed activities, which may result from altered reward processing. Patients with bipolar disorder show impaired reward learning in situations that require the integration of reinforced feedback over time. In this study, we examined the behavioral and electrophysiological characteristics of reward learning in manic and euthymic patients with bipolar disorder using a probabilistic reward task.

METHODS

Twenty-four manic and 20 euthymic patients with bipolar I disorder and 24 healthy control subjects performed the probabilistic reward task. We assessed response bias (RB) as a preference for the stimulus paired with the more frequent reward and feedback-related negativity (FRN) to correct identification of the rich stimulus.

RESULTS

Both manic and euthymic patients showed significantly lower RB scores in the early learning stage (block 1) in comparison with the late learning stage (block 2 or block 3) of the task, as well as significantly lower RB scores in the early stage compared to healthy subjects. Relatively more negative FRN amplitude is elicited by no presentation of an expected reward, compared to that elicited by presentation of expected feedback. The FRN became significantly more negative from the early (block 1) to the later stages (blocks 2 and 3) in both manic and euthymic patients, but not in healthy subjects. Changes in RB scores and FRN amplitudes between blocks 2 and 3 and block 1 correlated positively in healthy controls, but correlated negatively in manic and euthymic patients. The severity of manic symptoms correlated positively with reward learning scores and negatively with the FRN.

CONCLUSIONS

These findings suggest that patients with bipolar disorder during euthymic or manic states have behavioral and electrophysiological alterations in reward learning compared to healthy subjects. This dysfunctional reward processing may be related to the abnormal decision-making or altered goal-directed activities frequently seen in patients with bipolar disorder.

Nicotine-dopamine-transporter interactions during reward-based decision making

Our everyday-life comprises a multitude of decisions that we take whilst trying to maximize advantageous outcomes, limit risks and update current needs. The cognitive processes that guide decision making as well as the brain circuits they are based on are only poorly understood. Numerous studies point to a potential role of dopamine and nicotine in decision making but less is known about their interactions. Here, 26 healthy male subjects performed the Iowa Gambling Task (IGT) in two sessions following the administration of either nicotine or placebo. Striatal dopamine transporter (DAT) binding was measured by single-photon emission computed tomography (SPECT). Results indicate that lower DAT levels were associated with better performance in the IGT (p=0.0004). Cognitive modelling analysis using the prospect valence learning (PVL) model indicated that low DAT subjects' performance deteriorated following nicotine administration as indicated by an increased learning rate and a decreased response consistency. Our results shed light on the neurochemistry underlying reward-based decision making in humans by demonstrating a significant interaction between nicotine and the DAT. The observed interaction is consistent with the hypothesized associations between DAT expression and extracellular dopamine levels, suggestive of an inverted U-shape relationship between baseline dopamine and magnitude in response to a pro-dopaminergic compound. Our findings are of particular interest in the context of psychiatric disorders where aberrant decision making represents a part of the core symptomatology, such as addiction, schizophrenia or depression.

Beta-adrenoreceptor blockade abolishes atomoxetine-induced risk taking

RATIONALE

Clinical studies have shown that patients with exaggerated risk-taking tendencies have high baseline levels of norepinephrine. In this work, we systemically manipulated norepinephrine levels in rats and studied their behavioral changes in a probabilistic discounting task, which is a paradigm for gauging risk taking.

METHODS

This study aims to explore the effects of the selective norepinephrine reuptake inhibitor (atomoxetine at doses of 0.6, 1.0 and 1.8 mg/kg), and receptor selective antagonists (propranolol at a single dose of 1.0/kg, and prazosin at a single dose of 0.1 mg/kg), on risk taking using a probabilistic discounting task. In this task, there were two levers available to rats: pressing the 'small/certain' lever guaranteed a single food pellet, and pressing the 'large/risky' lever yielded either four pellets or none. The probability of receiving four food pellets decreased across the four experimental blocks from 100% to 12.5%.

RESULTS

Atomoxetine increased the tendency to choose the large/risky lever. It significantly reduced the lose-shift effect (i.e. pressing a different lever after losing a trial), but did not affect the win-stay effect (i.e. pressing the same lever after winning a trial). Furthermore, co-administration of beta-adrenoreceptor antagonist, propranolol, eliminated the effects of atomoxetine on risk taking and the lose-shift effect; but co-administration of alpha1-adrenoreceptor antagonist, prazosin, did not.

CONCLUSIONS

Atomoxetine boosted NE levels and increased risk taking. This was because atomoxetine decreased rats' sensitivity to losses. These effects were likely mediated by beta-adrenoreceptor.

Animal models of bipolar mania: The past, present and future

Bipolar disorder (BD) is the sixth leading cause of disability in the world according to the World Health Organization and affects nearly six million (∼2.5% of the population) adults in the United State alone each year. BD is primarily characterized by mood cycling of depressive (e.g., helplessness, reduced energy and activity, and anhedonia) and manic (e.g., increased energy and hyperactivity, reduced need for sleep, impulsivity, reduced anxiety and depression), episodes. The following review describes several animal models of bipolar mania with a focus on more recent findings using genetically modified mice, including several with the potential of investigating the mechanisms underlying 'mood' cycling (or behavioral switching in rodents). We discuss whether each of these models satisfy criteria of validity (i.e., face, predictive, and construct), while highlighting their strengths and limitations. Animal models are helping to address critical questions related to pathophysiology of bipolar mania, in an effort to more clearly define necessary targets of first-line medications, lithium and valproic acid, and to discover novel mechanisms with the hope of developing more effective therapeutics. Future studies will leverage new technologies and strategies for integrating animal and human data to reveal important insights into the etiology, pathophysiology, and treatment of BD.

Lithium might be associated with better decision-making performance in euthymic bipolar patients

Bipolar disorder is associated with impaired decision-making. Little is known about how treatment, especially lithium, influences decision-making abilities in bipolar patients when euthymic. We aimed at testing for an association between lithium medication and decision-making performance in remitted bipolar patients. Decision-making was measured using the Iowa Gambling Task in 3 groups of subjects: 34 and 56 euthymic outpatients with bipolar disorder, treated with lithium (monotherapy and lithium combined with anticonvulsant or antipsychotic) and without lithium (anticonvulsant, antipsychotic and combination treatment), respectively, and 152 matched healthy controls. Performance was compared between the 3 groups. In the 90 euthymic patients, the relationship between different sociodemographic and clinical variables and decision-making was assessed by stepwise multivariate regression analysis. Euthymic patients with lithium (p=0.007) and healthy controls (p=0.001) selected significantly more cards from the safe decks than euthymic patients without lithium, with no significant difference between euthymic patients with lithium and healthy controls (p=0.9). In the 90 euthymic patients, the stepwise linear multivariate regression revealed that decision-making was significantly predicted (p<0.001) by lithium dose, level of education and no family history of bipolar disorder (all p≤0.01). Because medication was not randomized, it was not possible to discriminate the effect of different medications. Lithium medication might be associated with better decision-making in remitted bipolar patients. A randomized trial is required to test for the hypothesis that lithium, but not other mood stabilizers, may specifically improve decision-making abilities in bipolar disorder.

The neurocognitive functioning in bipolar disorder: a systematic review of data

BACKGROUND

During the last decades, there have been many different opinions concerning the neurocognitive function in Bipolar disorder (BD). The aim of the current study was to perform a systematic review of the literature and to synthesize the data in a comprehensive picture of the neurocognitive dysfunction in BD.

METHODS

Papers were located with searches in PubMed/MEDLINE, through June 1st 2015. The review followed a modified version of the recommendations of the Preferred Items for Reporting of Systematic Reviews and Meta-Analyses statement.

RESULTS

The initial search returned 110,403 papers. After the deletion of duplicates, 11,771 papers remained for further evaluation. Eventually, 250 were included in the analysis.

CONCLUSION

The current review supports the presence of a neurocognitive deficit in BD, in almost all neurocognitive domains. This deficit is qualitative similar to that observed in schizophrenia but it is less severe. There are no differences between BD subtypes. Its origin is unclear. It seems it is an enduring component and represents a core primary characteristic of the illness, rather than being secondary to the mood state or medication. This core deficit is confounded (either increased or attenuated) by the disease phase, specific personal characteristics of the patients (age, gender, education, etc.), current symptomatology and its treatment (especially psychotic features) and long-term course and long-term exposure to medication, psychiatric and somatic comorbidity and alcohol and/or substance abuse.

Reduced dopamine transporter functioning induces high-reward risk-preference consistent with bipolar disorder

Individuals with bipolar disorder (BD) exhibit deleterious decision making, negatively impacting their lives. Such aberrant decision making can be quantified using the Iowa Gambling Task (IGT), which requires choosing between advantageous and disadvantageous options based on different reward/punishment schedules. The mechanisms underlying this behavioral deficit are unknown, but may include the reduced dopamine transporter (DAT) functioning reported in BD patients. Using both human and mouse IGTs, we tested whether reduced DAT functioning would recreate patterns of deficient decision making of BD patients. We assessed the IGT performance of 16 BD subjects (7 female) and 17 healthy control (HC) subjects (12 female). We recorded standard IGT performance measures and novel post-reward and post-punishment decision-making strategies. We characterized a novel single-session mouse IGT using C57BL/6J mice (n = 44). The BD and HC IGT performances were compared with the effects of chronic (genetic knockdown (KD; n = 31) and wild-type (n = 28) mice) and acute (C57BL/6J mice (n = 89) treated with the DAT inhibitor GBR12909) reductions of DAT functioning in mice performing this novel IGT. BD patients exhibited impaired decision making compared with HC subjects. Both the good-performing DAT KD and GBR12909-treated mice exhibited poor decision making in the mouse IGT. The deficit of each population was driven by high-reward sensitivity. The single-session mouse IGT measures dynamic risk-based decision making similar to humans. Chronic and acute reductions of DAT functioning in mice impaired decision-making consistent with poor IGT performance of BD patients. Hyperdopaminergia caused by reduced DAT may impact poor decision making in BD patients, which should be confirmed in future studies.

Impulsivity: present during euthymia in bipolar disorder? - a systematic review

Because impulsivity is part of the presentation of bipolar disorder (BD) and is associated with its course, this systematic review presents the evidence whether increased impulsivity is present in a stable, euthymic mood and therefore potentially a vulnerability marker for BD. A multi-faceted model of impulsivity was adopted to explore how different facets may relate differently to BD. The evidence was explored in relation to studies employing measures of trait impulsivity (in self-report format) and studies exploring impulsivity with behavioural paradigms. Behavioural paradigms were separated into studies measuring response inhibition and those measuring the ability to delay gratification. Twenty-three papers met the inclusion criteria. Most studies using self-report measures found significant differences between euthymic BD patients and healthy controls. There was little evidence of increased impulsivity as measured by behavioural paradigms. Most studies found no significant difference in response inhibition between groups, though it is possible that much of the literature in this area was underpowered to detect an effect. Only five studies explored delay of gratification, of which the two methodologically strongest studies found no group differences. In conclusion, there is evidence that euthymic patients with BD report increased impulsivity when using self-ratings. However, there is currently limited evidence of impulsivity on behavioural measures assessing response inhibition, and this might be restricted to more severe cases. More research is needed on the ability to delay gratification before drawing any conclusions. However, to establish facets of impulsivity as vulnerability markers, future studies should include at-risk individuals to evaluate whether self-rated or behavioural impulsivity precedes the onset of BD.

Differential impairments underlying decision making in anorexia nervosa and bulimia nervosa: a cognitive modeling analysis

OBJECTIVE

This study examined the underlying processes of decision-making impairments in individuals with anorexia nervosa (AN) and bulimia nervosa (BN). We deconstructed their performance on the widely used decision task, the Iowa Gambling Task (IGT) into cognitive, motivational, and response processes using cognitive modeling analysis. We hypothesized that IGT performance would be characterized by impaired memory functions and heightened punishment sensitivity in AN, and by elevated sensitivity to reward as opposed to punishment in BN.

METHOD

We analyzed trial-by-trial data of IGT obtained from 224 individuals: 94 individuals with AN, 63 with BN, and 67 healthy comparison individuals (HC). The prospect valence learning model was used to assess cognitive, motivational, and response processes underlying IGT performance.

RESULTS

Individuals with AN showed marginally impaired IGT performance compared to HC. Their performance was characterized by impairments in memory functions. Individuals with BN showed significantly impaired IGT performance compared to HC. They showed greater relative sensitivity to gains as opposed to losses than HC. Memory functions in AN were positively correlated with body mass index.

DISCUSSION

This study identified differential impairments underlying IGT performance in AN and BN. Findings suggest that impaired decision making in AN might involve impaired memory functions. Impaired decision making in BN might involve altered reward and punishment sensitivity.

Reward sensitivity and anger in euthymic bipolar disorder

According to the hypersensitive behavioral approach system (BAS) model of bipolar disorder (BP), hypersensitivity of the BAS is a trait that should be present even in the euthymic state. This would be expected to result in increased anger and reward sensitivity, both of which are related to the approach system. This study examined these predictions through the use of tasks that assess different aspects of the BAS: reward sensitivity, anger and impulsivity. These characteristics were assessed using the probabilistic classification task (PCT), ultimatum game (UG) and single key impulsivity paradigm (SKIP), respectively. Participants were euthymic adult bipolar disorder patients (BP; N=40) and healthy controls (HC; N=41). In the UG, all participants showed the standard pattern of rejecting overtly unfair offers and accepting clearly fair offers; however, BPs rejected more of the moderately unfair offers than did HCs. BP and HC participants did not differ on their ability to learn, but did show different patterns of learning from reward and punishment. Learning for reward and punishment were negatively correlated in the BP group, suggesting that individuals could learn well either from reward or punishment, but not both. No correlation was found between these forms of learning in the HC group. BP patients show signs of their disorder even in the euthymic state, as seen by the dysbalance between reward and punishment learning and their residual anger in the UG.

Dopaminergic influences on emotional decision making in euthymic bipolar patients

We recently reported that the D2/D3 agonist pramipexole may have pro-cognitive effects in euthymic patients with bipolar disorder (BPD); however, the emergence of impulse-control disorders has been documented in Parkinson's disease (PD) after pramipexole treatment. Performance on reward-based tasks is altered in healthy subjects after a single dose of pramipexole, but its potential to induce abnormalities in BPD patients is unknown. We assessed reward-dependent decision making in euthymic BPD patients pre- and post 8 weeks of treatment with pramipexole or placebo by using the Iowa Gambling Task (IGT). The IGT requires subjects to choose among four card decks (two risky and two conservative) and is designed to promote learning to make advantageous (conservative) choices over time. Thirty-four BPD patients completed both assessments (18 placebo and 16 pramipexole). Baseline performance did not differ by treatment group (F=0.63; p=0.64); however, at week 8, BPD patients on pramipexole demonstrated a significantly greater tendency to make increasingly high-risk, high-reward choices across the five blocks, whereas the placebo group's pattern was similar to that reported in healthy individuals (treatment × time × block interaction, p<0.05). Analyses of choice strategy using the expectancy valence model revealed that after 8 weeks on pramipexole, BPD patients attended more readily to feedback related to gains than to losses, which could explain the impaired learning. There were no significant changes in mood symptoms over the 8 weeks, and no increased propensity toward manic-like behaviors were reported. Our results suggest that the enhancement of dopaminergic activity influences risk-associated decision-making performance in euthymic BPD. The clinical implications remain unknown.

Allostasis as a conceptual framework linking bipolar disorder and addiction

Bipolar disorders (BDs) and addictions constitute reciprocal risk factors and are best considered under a unitary perspective. The concepts of allostasis and allostatic load (AL) may contribute to the understanding of the complex relationships between BD and addictive behaviors. Allostasis entails the safeguarding of reward function stability by recruitment of changes in the reward and stress system neurocircuitry and it may help to elucidate neurobiological underpinnings of vulnerability to addiction in BD patients. Conceptualizing BD as an illness involving the cumulative build-up of allostatic states, we hypothesize a progressive dysregulation of reward circuits clinically expressed as negative affective states (i.e., anhedonia). Such negative affective states may render BD patients more vulnerable to drug addiction, fostering a very rapid transition from occasional drug use to addiction, through mechanisms of negative reinforcement. The resulting addictive behavior-related ALs, in turn, may contribute to illness progression. This framework could have a heuristic value to enhance research on pathophysiology and treatment of BD and addiction comorbidity.

Iowa Gambling Task performance in euthymic bipolar I disorder: a meta-analysis and empirical study

BACKGROUND

The Iowa Gambling Task (IGT) has been recommended as an index of reward sensitivity, which is elevated in bipolar disorder. We conducted a meta-analysis of IGT performance in euthymic bipolar I disorder compared with control participants. Findings indicated that people with bipolar disorder make more risky choices than control participants, though the effect is small (g=0.35). It is not clear which of the many processes involved in IGT performance are involved in producing the observed group difference.

METHODS

Fifty-five euthymic people with bipolar disorder and 39 control participants completed the IGT. The Expectancy Valence Model was used to examine differences in IGT. We also examined whether variation in IGT performance within the bipolar group was related to current mood, illness course, impulsivity, or demographics.

RESULTS

Bipolar and control groups did not differ on the total number of risky choices, rate of learning, or any of the parameters of the Expectancy Valence Model. IGT performance in bipolar disorder was not related to any of the examined individual differences.

LIMITATIONS

It is possible that there are group differences that are too small to detect at our sample size or that are not amenable to study via the Expectancy Valence Model.

CONCLUSIONS

We were unable to identify group differences on the IGT or correlates of IGT performance within bipolar disorder. Though the IGT may serve as a useful model for decision-making, its structure may make it unsuitable for behavioral assessment of reward sensitivity independent of punishment sensitivity.

Computational modeling reveals distinct effects of HIV and history of drug use on decision-making processes in women

Objective

Drug users and HIV-seropositive individuals often show deficits in decision-making; however the nature of these deficits is not well understood. Recent studies have employed computational modeling approaches to disentangle the psychological processes involved in decision-making. Although such approaches have been used successfully with a number of clinical groups including drug users, no study to date has used computational modeling to examine the effects of HIV on decision-making. In this study, we use this approach to investigate the effects of HIV and drug use on decision-making processes in women, who remain a relatively understudied population.

Method

Fifty-seven women enrolled in the Women's Interagency HIV Study (WIHS) were classified into one of four groups based on their HIV status and history of crack cocaine and/or heroin drug use (DU): HIV+/DU+ (n = 14); HIV+/DU− (n = 17); HIV−/DU+ (n = 14); and HIV−/DU− (n = 12). We measured decision-making with the Iowa Gambling Task (IGT) and examined behavioral performance and model parameters derived from the best-fitting computational model of the IGT.

Results

Although groups showed similar behavioral performance, HIV and DU exhibited differential relationship to model parameters. Specifically, DU was associated with compromised learning/memory and reduced loss aversion, whereas HIV was associated with reduced loss aversion, but was not related to other model parameters.

Conclusions

Results reveal that HIV and DU have differential associations with distinct decision-making processes in women. This study contributes to a growing line of literature which shows that different psychological processes may underlie similar behavioral performance in various clinical groups and may be associated with distinct functional outcomes.

Initial evidence for sex-specific effects of early emotional abuse on affective processing in bipolar disorder

PURPOSE

This study investigates the effect of sex and childhood trauma on affective processing in bipolar disorder (BPD) patients.

METHODS

In a sample of fifty-six BPD patients, we administered the Childhood Trauma Questionnaire (CTQ), and the Iowa Gambling Task (IGT) and the Affective Go/No-Go (AGNG) to measure affective processing. Analysis of Variance (ANOVA) was used to evaluate the effect of sex and childhood trauma on IGT; Repeated-Measures ANOVAs to measure accuracy and bias measures across conditions on the AGNG.

RESULTS

In the context of childhood abuse, females evidenced a more conservative cognitive style than males by selecting fewer cards from the disadvantageous decks [F(1, 49)=14.218; P<0.001] and showed an improvement throughout the task, as noted in a normal learning curve [F(1.49)=4.385; P=0.041)]. For the AGNG, an interaction specific to the negative valence stimuli on response bias measures was found. Abused females scored higher (mean=8.38; SD=6.39) than abused males (mean=0.69; SD=1.19) [F(1.46)=6.348; P=0.015].

CONCLUSION

Severity of childhood trauma was significantly different between sexes. In the context of a history of emotional abuse, male bipolar patients tended toward a more risk-taking behavior compared to female. Further investigations are needed to elucidate potential pathophysiological mechanisms underlying this interaction.

Increased salience of gains versus decreased associative learning differentiate bipolar disorder from schizophrenia during incentive decision making

BACKGROUND

Abnormalities in incentive decision making, typically assessed using the Iowa Gambling Task (IGT), have been reported in both schizophrenia (SZ) and bipolar disorder (BD). We applied the Expectancy-Valence (E-V) model to determine whether motivational, cognitive and response selection component processes of IGT performance are differentially affected in SZ and BD.

METHOD

Performance on the IGT was assessed in 280 individuals comprising 70 remitted patients with SZ, 70 remitted patients with BD and 140 age-, sex- and IQ-matched healthy individuals. Based on the E-V model, we extracted three parameters, 'attention to gains or loses', 'expectancy learning' and 'response consistency', that respectively reflect motivational, cognitive and response selection influences on IGT performance.

RESULTS

Both patient groups underperformed in the IGT compared to healthy individuals. However, the source of these deficits was diagnosis specific. Associative learning underlying the representation of expectancies was disrupted in SZ whereas BD was associated with increased incentive salience of gains. These findings were not attributable to non-specific effects of sex, IQ, psychopathology or medication.

CONCLUSIONS

Our results point to dissociable processes underlying abnormal incentive decision making in BD and SZ that could potentially be mapped to different neural circuits.

Differential effects of dopamine transporter inhibitors in the rodent Iowa gambling task: relevance to mania

RATIONALE

The Iowa Gambling Task (IGT) can be used to quantify impulsive and risky choice behaviors in psychiatric patients, e.g., bipolar disorder (BD) sufferers. Although developing treatments for these behaviors is important, few predictive animal models exist. Inhibition of the dopamine transporter (DAT) can model profiles of altered motor activity and exploration seen in patients with BD. The effect of DAT inhibition on impulsive choices related to BD has received limited study however. We used a rodent IGT to elucidate the effects of similarly acting drugs on risky choice behavior.

OBJECTIVES

We hypothesized that (1) C57BL/6 mice could adopt the "safe" choice options in the IGT and (2) DAT inhibition would alter risk preference.

METHODS

Mice were trained in the IGT to a stable risk-preference and then administered the norepinephrine/DAT inhibitor amphetamine, or the more selective DAT inhibitors modafinil or GBR12909.

RESULTS

Mice developed a preference for the "safe" option, which was potentiated by amphetamine administration. GBR12909 or modafinil administration increased motor impulsivity, motivation significantly, and risk preference subtly.

CONCLUSIONS

The rodent IGT can measure different impulse-related behaviors and differentiate similarly acting BD-related drugs. The contrasting effects of amphetamine and modafinil in mice are similar to effects in rats and humans in corresponding IGT tasks, supporting the translational validity of the task. GBR12909 and modafinil elicited similar behaviors in the IGT, likely through a shared mechanism. Future studies using a within-session IGT are warranted to confirm the suitability of DAT inhibitors to model risk-preference in BD.

Emotion and decision-making: affect-driven belief systems in anxiety and depression

Emotion processing and decision-making are integral aspects of daily life. However, our understanding of the interaction between these constructs is limited. In this review, we summarize theoretical approaches that link emotion and decision-making, and focus on research with anxious or depressed individuals to show how emotions can interfere with decision-making. We integrate the emotional framework based on valence and arousal with a Bayesian approach to decision-making in terms of probability and value processing. We discuss how studies of individuals with emotional dysfunctions provide evidence that alterations of decision-making can be viewed in terms of altered probability and value computation. We argue that the probabilistic representation of belief states in the context of partially observable Markov decision processes provides a useful approach to examine alterations in probability and value representation in individuals with anxiety and depression, and outline the broader implications of this approach.

The neural basis of decision-making and reward processing in adults with euthymic bipolar disorder or attention-deficit/hyperactivity disorder (ADHD)

Background

Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) share DSM-IV criteria in adults and cause problems in decision-making. Nevertheless, no previous report has assessed a decision-making task that includes the examination of the neural correlates of reward and gambling in adults with ADHD and those with BD.

Methodology/Principal Findings

We used the Iowa gambling task (IGT), a task of rational decision-making under risk (RDMUR) and a rapid-decision gambling task (RDGT) which elicits behavioral measures as well as event-related potentials (ERPs: fERN and P3) in connection to the motivational impact of events. We did not observe between-group differences for decision-making under risk or ambiguity (RDMUR and IGT); however, there were significant differences for the ERP-assessed RDGT. Compared to controls, the ADHD group showed a pattern of impaired learning by feedback (fERN) and insensitivity to reward magnitude (P3). This ERP pattern (fERN and P3) was associated with impulsivity, hyperactivity, executive function and working memory. Compared to controls, the BD group showed fERN- and P3-enhanced responses to reward magnitude regardless of valence. This ERP pattern (fERN and P3) was associated with mood and inhibitory control. Consistent with the ERP findings, an analysis of source location revealed reduced responses of the cingulate cortex to the valence and magnitude of rewards in patients with ADHD and BD.

Conclusions/Significance

Our data suggest that neurophysiological (ERPs) paradigms such as the RDGT are well suited to assess subclinical decision-making processes in patients with ADHD and BD as well as for linking the cingulate cortex with action monitoring systems.

Social cognition in euthymic bipolar disorder: systematic review and meta-analytic approach

OBJECTIVE

Deficits in social cognition have been reported in euthymic subjects with bipolar disorder (BD). However, some studies have failed to find differences favoring controls. As most investigations have been conducted with small samples, they have not had sufficient power to detect statistically significant differences. Furthermore, studies communicating positive results have scarcely attempted to estimate effect sizes for patient-control differences. The aim of this study was to summarize the findings of reports on social cognition in patients with euthymic BD and to combine their data to identify possible deficits and quantify their magnitude.

METHOD

Systematic literature review and meta-analysis.

RESULTS

Impairments of moderate magnitude (0.5 < d < 0.8) were noted across mentalizing skills, whereas small but significant effect sizes (d < 0.5) were observed for facial emotion recognition. No patient-control differences were found for decision-making.

CONCLUSION

Meta-analytic findings provide evidence for emotion processing and theory of mind deficits in remitted bipolar patients. However, it is not yet clear whether these areas of impairment are related to neurocognitive dysfunctions or to medication effects. The results are discussed with regard to targets for future neuropsychological research on BDs.

Neurocognitive impairment across the bipolar spectrum

Bipolar disorder is a severe mental illness that affects nearly 4.4% of the general population when bipolar spectrum disorders are taken into account. Neurocognitive impairment is thought to be a core deficit of this illness since it is present during euthymia. In fact, 40-60% of euthymic patients present with neurocognitive disturbances. Not only the clinical factors but also disturbances in neurocognition can influence the functional outcome of BD patients. Hence, further research is needed in order to clarify the relationship between these variables. Despite the growing body of evidence that has emerged during the last decade, no unique neurocognitive profile has been proposed yet for either BD subtype. The majority of the studies recluted heterogeneous samples (including both bipolar I and II) or focused on BD-I patients only. The aim of this review is to give an overall picture of the main neurocognitive disturbances found in the bipolar spectrum and particularly in BD-II, where the findings are more ambiguous. An extensive review of all the literature has been done regarding this subtype (from 1980 until July 2009). Data available until now suggest that deficits are present across the bipolar spectrum (BD-I and BD-II), but they seem slightly more severe in BD-I. The extent to which either subtype share-or not-some similarities is still unknown. More studies are required but it would also be interesting to reach a consensus in the neuropsychological assessment of BD to facilitate comparisons between the different studies.

The behavioral activation system and mania

For over two decades, theorists have suggested that mania relates to heightened sensitivity of the behavioral activation system (BAS). In this article, we review a burgeoning empirical literature on this model, drawing on both cross-sectional and prospective studies. As evidence has emerged for this model, we argue that it is time to consider more specific aspects of BAS sensitivity in this disorder. We review evidence that bipolar disorder relates to an increased willingness to expend effort toward reward and to increases in energy and goal pursuit after an initial reward. We conclude by considering the strengths and weaknesses of this literature, with an eye toward future directions and implications for treatment.

The behavioral activation system and mania

For over two decades, theorists have suggested that mania relates to heightened sensitivity of the behavioral activation system (BAS). In this article, we review a burgeoning empirical literature on this model, drawing on both cross-sectional and prospective studies. As evidence has emerged for this model, we argue that it is time to consider more specific aspects of BAS sensitivity in this disorder. We review evidence that bipolar disorder relates to an increased willingness to expend effort toward reward and to increases in energy and goal pursuit after an initial reward. We conclude by considering the strengths and weaknesses of this literature, with an eye toward future directions and implications for treatment.

Temporal discounting of rewards in patients with bipolar disorder and schizophrenia

Patients with bipolar disorder (BD) and schizophrenia (SZ) often show decision-making deficits in everyday circumstances. A failure to appropriately weigh immediate versus future consequences of choices may contribute to these deficits. We used the delay discounting task in individuals with BD or SZ to investigate their temporal decision making. Twenty-two individuals with BD, 21 individuals with SZ, and 30 healthy individuals completed the delay discounting task along with neuropsychological measures of working memory and cognitive function. Both BD and SZ groups discounted delayed rewards more steeply than did the healthy group even after controlling for current substance use, age, gender, and employment. Hierarchical multiple regression analyses showed that discounting rate was associated with both diagnostic group and working memory or intelligence scores. In each group, working memory or intelligence scores negatively correlated with discounting rate. The results suggest that (a) both BD and SZ groups value smaller, immediate rewards more than larger, delayed rewards compared with the healthy group and (b) working memory or intelligence is related to temporal decision making in individuals with BD or SZ as well as in healthy individuals.

Trait-related decision-making impairment in the three phases of bipolar disorder

BACKGROUND

In bipolar disorder (BD), little is known about how deficits in neurocognitive functions such as decision-making are related to phase of illness. We predicted that manic, depressed, and euthymic bipolar patients (BPs) would display impaired decision-making, and we tested whether clinical characteristics could predict patients' decision-making performance.

METHODS

Subjects (N = 317; age range: 18-65 years) including 167 BPs (45 manic and 32 depressed inpatients, and 90 euthymic outpatients) and 150 age-, IQ-, and gender-matched healthy control (HC) participants, were included within three university psychiatric hospitals using a cross-sectional design. The relationship between predictor variables and decision-making was assessed by one-step multivariate analysis. The main outcome measures were overall decision-making ability on the Iowa Gambling Task (IGT) and an index of sensitivity to punishment frequency.

RESULTS

Manic, depressed, and euthymic BPs selected significantly more cards from the risky decks than HCs (p < .001, p < .01, and p < .05, respectively), with no significant differences between the three BD groups. However, like HCs, BPs preferred decks that yielded infrequent penalties over those yielding frequent penalties. In multivariate analysis, decision-making impairment was significantly (p < .001) predicted by low level of education, high depressive scores, family history of BD, use of benzodiazepines, and nonuse of serotonin and norepinephrine reuptake inhibitor (SNRI) antidepressants.

CONCLUSIONS

BPs have a trait-related impairment in decision-making that does not vary across illness phase. However, some subtle differences between the BD groups in the individual deck analyses may point to subtle state influences on reinforcement mechanisms, in addition to a more fundamental trait impairment in risk-sensitive decision making.

Increased risk-taking behavior in dopamine transporter knockdown mice: further support for a mouse model of mania

Reduced functioning of the dopamine transporter (DAT) has been linked to bipolar disorder (BD). Mice with reduced DAT functioning (knockdown, KD) exhibit a behavioral profile in the mouse Behavioral Pattern Monitor (BPM) consistent with patients with BD mania in the human BPM. Patients with BD also exhibit increased risk taking, which can be quantified using the Iowa Gambling Task (IGT). We hypothesized that DAT KD mice would exhibit increased risk-taking behavior in a novel mouse version of the IGT. DAT KD and wildtype (WT) littermates were trained in the mouse IGT. In session 1, KD mice initially made riskier choices, but later performed comparably to WT mice. Once trained to stable choice performance, DAT KD mice continued to exhibit a trend to choose the riskier options more than WT mice. Finally, we confirmed that these DAT KD mice also exhibited an exploratory profile in the BPM consistent with patients with BD mania, where risky choice behavior modestly correlated with specific exploration. These data demonstrate that DAT KD mice chose the riskier options more than WT mice, providing further support for the use of DAT KD mice as a model of BD mania.

Serotonin transporter gene-linked polymorphic region (5-HTTLPR) influences decision making under ambiguity and risk in a large Chinese sample

Risky decision making is a complex process that involves weighing the probabilities of alternative options that can be desirable, undesirable, or neutral. Individuals vary greatly in how they make decisions either under ambiguity and/or under risk. Such individual differences may have genetic bases. Based on previous studies on the genetic basis of decision making, two decision making tasks [i.e., the Iowa Gambling Task (IGT) and Loss Aversion Task (LAT)] were used to test the effect of 5-HTTLPR polymorphism on decision making under ambiguity and under risk in a large Han Chinese sample (572 college students, 312 females). Basic intelligence and memory tests were also included to control for the influence of basic cognitive abilities on decision making. We found that 5-HTTLPR polymorphism significantly influenced performance in both IGT and LAT. After controlling for intelligence and memory abilities, subjects homozygous for s allele had lower IGT scores than l carriers in the first 40 trials of the IGT task. They also exhibited higher loss aversion than l carriers in the LAT task. Moreover, the effects of 5-HTTLPR were stronger for males than for females. These results extend the literature on the important role of emotion in decision making under ambiguity and risk, and shed additional lights on how decision making is influenced by culture as well as sex differences. Combining our results with existing literature, we propose that these effects might be mediated by a neural circuitry that comprises the amygdala, ventromedial prefrontal cortex, and insular cortex. Understanding the genetic factors affecting decision making in healthy subjects may allow us to better identify at-risk individuals, and better target the development of new potential treatments for specific disorders such as schizophrenia, addiction, and depression.

The International Society for Bipolar Disorders-Battery for Assessment of Neurocognition (ISBD-BANC)

OBJECTIVES

Although cognitive impairment is recognized as an important clinical feature of bipolar disorder, there is no standard cognitive battery that has been developed for use in bipolar disorder research. The aims of this paper were to identify the cognitive measures from the literature that show the greatest magnitude of impairment in bipolar disorder, to use this information to determine whether the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB), developed for use in schizophrenia, might be suitable for bipolar disorder research, and to propose a preliminary battery of cognitive tests for use in bipolar disorder research.

METHODS

The project was conducted under the auspices of the International Society for Bipolar Disorders and involved a committee that comprised researchers with international expertise in the cognitive aspects of bipolar disorder. In order to identify cognitive tasks that show the largest magnitude of impairment in bipolar disorder, we reviewed the literature on studies assessing cognitive functioning (including social cognition) in bipolar disorder. We further provided a brief review of the cognitive overlap between schizophrenia and bipolar disorder and evaluated the degree to which tasks included in the MCCB (or other identified tasks) might be suitable for use in bipolar disorder.

RESULTS

Based on evidence that cognitive deficits in bipolar disorder are similar in pattern but less severe than in schizophrenia, it was judged that most subtests comprising the MCCB appear appropriate for use in bipolar disorder. In addition to MCCB tests, other specific measures of more complex verbal learning (e.g., the California Verbal Learning Test) or executive function (Stroop Test, Trail Making Test-part B, Wisconsin Card Sorting Test) also show substantial impairment in bipolar disorder.

CONCLUSIONS

Our analysis reveals that the MCCB represents a good starting point for assessing cognitive deficits in research studies of bipolar disorder, but that other tasks including more complex verbal learning measures and tests of executive function should also be considered in assessing cognitive compromise in bipolar disorder. Several promising cognitive tasks that require further study in bipolar disorder are also presented.

Impulsivity in mania

Impulsivity, a breakdown in the balance between initiation and screening of action that leads to reactions to stimuli without adequate reflection or regard for consequences, is a core feature of bipolar disorder and is prominent in manic episodes. Catecholaminergic function is related to impulsivity and mania. Manic individuals have abnormal dopaminergic reactions to reward and abnormal responses in the ventral prefrontal cortex that are consistent with impulsive behavior. Impulsivity in mania is pervasive, encompassing deficits in attention and behavioral inhibition. Impulsivity is increased with severe course of illness (eg, frequent episodes, substance use disorders, and suicide attempts). In mixed states, mania-associated impulsivity combines with depressive symptoms to increase the risk of suicide. Clinical management of impulsivity in mania involves addressing interpersonal distortions inherent in mania; reducing overstimulation; alertness to medical-, trauma-, or substance-related problems; and prompt pharmacologic treatment. Manic episodes must be viewed in the context of the life course of bipolar disorder.