Meta-analyses of cognitive functioning in euthymic bipolar patients and their first-degree relatives

Social Aspect of Functioning Deteriorates More Than Individual Aspect in Patients with Remitted Bipolar Disorder

INTRODUCTION

Many studies have demonstrated that patients with bipolar disorder (BD) suffer from significant functional impairment, even during remission periods. This study aimed to assess the levels of overall functioning and specific areas of functioning in remitted patients with BD compared with those in healthy controls.

METHODS

Eighty completely remitted patients with BD and 80 healthy controls were included in the study. The Bipolar Disorder Functioning Questionnaire (BDFQ), Young Mania Rating Scale, and Beck Depression Inventory were used.

RESULTS

There were fewer married and employed cohorts in the BD group than in the control group. Compared with healthy controls, patients with BD exhibited a worse functioning in terms of intellectual and sexual functioning, feelings of stigmatization, social withdrawal, household relationships, relationships with friends, and participation in social activities. There was no difference between the groups in terms of emotional functioning, daily activities and hobbies, taking initiative and self-sufficiency, and occupation. The total BDFQ scores of patients were lower than those of healthy controls. A better functionality was observed in patients using only a mood stabilizer than in patients using three or more drugs.

CONCLUSION

Remarkably, remitted patients with BD tended to perform daily activities well when these activities were not in a social context. Stigma-oriented interpersonal approaches can be particularly beneficial for these patients.

Unraveling psychomotor slowing in bipolar disorder

BACKGROUND/AIMS

In addition to affective and cognitive symptomatology, psychomotor deficits are known to be present in bipolar disorder (BD). Psychomotor functioning includes all of the processes necessary for completing a movement, from planning to initiation and execution. While these psychomotor symptoms have been studied extensively in schizophrenia and major depressive disorder, only simple measures have been conducted in BD. The present study examines psychomotor functioning in BD.

METHODS

Twenty-two euthymic BD patients and 21 healthy controls performed three computerized copying tasks varying in cognitive load. Movement times (MT), reflecting fine motor processing, and initiation times (IT), reflecting cognitive processing of visual-spatial information, were separately measured in each group.

RESULTS

The BD patients had longer IT but not MT in the simplest task and the opposite pattern of longer MT but not IT in the complex task. However, when controlling for residual mood symptoms, the MT were no longer significantly slower in the BD group.

CONCLUSIONS

The longer MT and IT in BD reflect overall psychomotor slowing. Specifically, the results provide evidence for cognitive slowing in BD. In addition, the longer MT in the complex task reflect a slowed motor component of movement when the cognitive load is high and when depressive symptoms are present. These findings extend the current knowledge of the nature of psychomotor slowing in BD and may have important prognostic implications for patients.

The effect of self-monitoring on Wisconsin Card Sorting Test performance in euthymic patients with bipolar disorder: a pilot study

OBJECTIVES

Euthymic patients with bipolar disorder (BD) show executive impairment. Assisting cognitive function with non-pharmacological strategies has not been widely explored in BD. In schizophrenia, concomitant verbalisation (self-monitoring) during executive tests improved performance. The present pilot study assesses the effects of self-monitoring whilst completing the Wisconsin Card Sorting Test (WCST) in BD patients.

METHODS

Thirty-six euthymic BD patients and 42 healthy controls participated. Twenty patients with BD and 20 controls received standard administration and 16 patients and 22 controls used self-monitoring during the test.

RESULTS

ANCOVA revealed a significant "group by administration" interaction. Patients who received the standard administration were significantly worse than healthy controls (trials administered: p = .012, η p (2) = 0.17; trials to first category: p = .046, η p (2) = 0.11; failure to maintain set: p = .003, η p (2) = 0.23). BD patients who self-monitored performed significantly better than patients receiving the standard administration (trials to first category: p = .020, η p (2) = 0.17) and showed no significant differences in performance compared to controls.

CONCLUSION

Self-monitoring deserves further investigation as a tool that may be helpful for patients with BD. Further exploration of the utility, generalisability, and stability of the effects of self-monitoring is needed.

Neuropsychological performance and affective temperaments in Euthymic patients with bipolar disorder type II

Affective temperament has been suggested as a potential mediator of the effect between genetic predisposition and neurocognitive functioning. As such, this report seeks to assess the extent of the correlation between affective temperament and cognitive function in a group of bipolar II subjects. 46 bipolar II outpatients [mean age 41.4 years (SD 18.2); female 58.9%] and 46 healthy controls [mean age 35.1 years (SD 18); female 56.5%] were evaluated with regard to their demographic and clinical characteristics, affective temperament, and neurocognitive performance. Crude bivariate correlation analyses and multiple linear regression models were constructed between five affective temperament subscales and eight neurocognitive domains. Significant correlations were identified in bipolar patients between hyperthymic temperament and verbal memory and premorbid IQ; cyclothymic temperament and attention; and irritable temperament, attention, and verbal fluency. In adjusting for potential confounders of the relationship between temperament and cognitive function, the strongest mediating factors among the euthymic bipolar patients were found to be residual manic and depressive symptoms. It is therefore concluded that affective temperaments may partially influence the neurocognitive performance of both healthy controls and euthymic patients with bipolar disorder type II in several specific domains.

Cognitive performance and psychosocial functioning in patients with bipolar disorder, unaffected siblings, and healthy controls

Objective:

To assess cognitive performance and psychosocial functioning in patients with bipolar disorder (BD), in unaffected siblings, and in healthy controls.

Methods:

Subjects were patients with BD (n=36), unaffected siblings (n=35), and healthy controls (n=44). Psychosocial functioning was accessed using the Functioning Assessment Short Test (FAST). A sub-group of patients with BD (n=21), unaffected siblings (n=14), and healthy controls (n=22) also underwent a battery of neuropsychological tests: California Verbal Learning Test (CVLT), Stroop Color and Word Test, and Wisconsin Card Sorting Test (WCST). Clinical and sociodemographic characteristics were analyzed using one-way analysis of variance or the chi-square test; multivariate analysis of covariance was used to examine differences in neuropsychological variables.

Results:

Patients with BD showed higher FAST total scores (23.90±11.35) than healthy controls (5.86±5.47; p < 0.001) and siblings (12.60±11.83; p 0.001). Siblings and healthy controls also showed statistically significant differences in FAST total scores (p = 0.008). Patients performed worse than healthy controls on all CVLT sub-tests (p < 0.030) and in the number of correctly completed categories on WCST (p = 0.030). Siblings did not differ from healthy controls in cognitive tests.

Conclusion:

Unaffected siblings of patients with BD may show poorer functional performance compared to healthy controls. FAST scores may contribute to the development of markers of vulnerability and endophenotypic traits in at-risk populations.

Cognitive deficits in bipolar disorder: from acute episode to remission

Considerable evidence demonstrates that neuropsychological deficits are prevalent in bipolar disorder during both acute episodes and euthymia. However, it is less clear whether these cognitive disturbances are state- or trait-related. We here present the first longitudinal study employing a within-subject pre- and post-testing examining acutely admitted bipolar patients (BP) in depression or mania and during euthymia, aiming to identify cognitive performance from acute illness to remission. Cognitive performance was measured during acute episodes and repeated after at least 3 months of remission. To do so, 55 BP (35 depressed, 20 hypo-/manic) and 55 healthy controls (HC) were tested with a neuropsychological test battery (attention, working memory, verbal memory, executive functioning). The results showed global impairments in acutely ill BP compared to HC: depressed patients showed a characteristic psychomotor slowing, while manic patients had severe deficits in executive functioning. Twenty-nine remitted BP could be measured in the follow-up (dropout rate 48 %), whose cognitive functions partially recovered, whereas working memory and verbal memory were still impaired. However, we found that subthreshold depressive symptoms and persisting sleep disturbances in euthymic BP were associated with reduced speed, deficits in attention and verbal memory, while working memory was correlated with psychotic symptoms (lifetime). This result indicates working memory as trait related for a subgroup of BP with psychotic symptoms. In contrast, attention and verbal memory are negatively influenced by state factors like residual symptoms, which should be more considered as possible confounders in the search of cognitive endophenotypes in remitted BP.

A pilot study of a combined group and individual functional remediation program for patients with bipolar I disorder

BACKGROUND

Bipolar disorder has been associated with a decrease in cognitive functioning affecting the functional outcome of patients independent of mood states. However, there have only been few attempts to investigate the effects of functional remediation for patients with bipolar disorder. The current study investigates the feasibility and effectiveness of a combined group and individual functional remediation program for bipolar disorder, including both patients and their caregivers.

METHODS

Twelve participants diagnosed with bipolar I disorder, and their caregivers, were treated with a combined group and individual functional remediation program. The feasibility of the program was evaluated by dropout rates and participants' evaluations of the program. The effectiveness of the program was explored through the assessment of functional outcome at baseline, immediately post-treatment, and follow-up three months later.

RESULTS

The results indicate a high degree of satisfaction and a low dropout rate with the current program. Assessment of outcomes suggests improved functioning in the areas of autonomy and occupational functioning, evolving from baseline to follow-up.

LIMITATIONS

Due to a small sample size and the lack of a control group the results are preliminary.

CONCLUSIONS

This relatively brief intervention offers a more tailor-made approach to functional remediation and shows good feasibility, acceptability and improvement of functioning in patients with bipolar I disorder.

Cognitive remediation versus active computer control in bipolar disorder with psychosis: study protocol for a randomized controlled trial

Background

Cognitive dysfunction is a major feature of bipolar disorder with psychosis and is strongly associated with functional outcomes. Computer-based cognitive remediation has shown promise in improving cognition in patients with schizophrenia. However, despite similar neurocognitive deficits between patients with schizophrenia and bipolar disorder, few studies have extended neuroscience-based cognitive remediation programs to this population.

Methods/Design

The Treatment to Enhance Cognition in Bipolar Disorder study is an investigator-initiated, parallel group, randomized, blinded clinical trial of an Internet-based cognitive remediation protocol for patients with bipolar disorder I with psychosis (n = 100). We also describe the development of our dose-matched active control paradigm. Both conditions involve 70 sessions of computer-based activities over 24 weeks. The control intervention was developed to mirror the treatment condition in dose and format but without the neuroplasticity-based task design and structure. All participants undergo neuropsychological and clinical assessment at baseline, after approximately 25 hours of study activities, post treatment, and after 6 months of no study contact to assess durability. Neuroimaging at baseline and post treatment are offered in an “opt-in” format. The primary outcomes are scores on the MATRICS battery; secondary and exploratory outcomes include measures of clinical symptoms, community functioning, and neuroimaging changes. Associations between change in cognitive measures and change in community functioning will be assessed. Baseline predictors of treatment response will be examined.

Discussion

The present study is the first we are aware of to implement an Internet-based cognitive remediation program in patients with bipolar disorder with psychosis and to develop a comparable web-based control paradigm. The mixed online and study-site format allows accessible treatment while providing weekly staff contact and bridging. Based on user-provided feedback, participant blinding is feasible.

Trial registration

ClinicalTrials.gov NCT01470781; 11 July 2011.

Bipolar Depression and Cognitive Impairment: Shared Mechanisms and New Treatment Avenues

Depression and cognitive impairment are pervasive and highly disabling aspects of bipolar disorder. Although cognitive impairment is partially independent from mood episodes, depressive symptoms may increase the risk of cognitive impairment in bipolar disorder through inflammatory processes as well as health risks such as obesity and sedentary behavior. Novel treatment avenues at the intersection of bipolar depression and cognitive impairment target inflammation directly or indirectly health behaviors such as diet, physical activity, and sleep hygiene.

High educational performance is a distinctive feature of bipolar disorder: a study on cognition in bipolar disorder, schizophrenia patients, relatives and controls

BACKGROUND

Schizophrenia is associated with lower intelligence and poor educational performance relative to the general population. This is, to a lesser degree, also found in first-degree relatives of schizophrenia patients. It is unclear whether bipolar disorder I (BD-I) patients and their relatives have similar lower intellectual and educational performance as that observed in schizophrenia.

METHOD

This cross-sectional study investigated intelligence and educational performance in two outpatient samples [494 BD-I patients, 952 schizophrenia spectrum (SCZ) patients], 2231 relatives of BD-I and SCZ patients, 1104 healthy controls and 100 control siblings. Mixed-effects and regression models were used to compare groups on intelligence and educational performance.

RESULTS

BD-I patients were more likely to have completed the highest level of education (odds ratio 1.88, 95% confidence interval 1.66-2.70) despite having a lower IQ compared to controls (β = -9.09, S.E. = 1.27, p < 0.001). In contrast, SCZ patients showed both a lower IQ (β = -15.31, S.E. = 0.86, p < 0.001) and lower educational levels compared to controls. Siblings of both patient groups had significantly lower IQ than control siblings, but did not differ on educational performance. IQ scores did not differ between BD-I parents and SCZ parents, but BD-I parents had completed higher educational levels.

CONCLUSIONS

Although BD-I patients had a lower IQ than controls, they were more likely to have completed the highest level of education. This contrasts with SCZ patients, who showed both intellectual and educational deficits compared to healthy controls. Since relatives of BD-I patients did not demonstrate superior educational performance, our data suggest that high educational performance may be a distinctive feature of bipolar disorder patients.

Psychological interventions for adults with bipolar disorder: systematic review and meta-analysis

BACKGROUND

Psychological interventions may be beneficial in bipolar disorder.

AIMS

To evaluate the efficacy of psychological interventions for adults with bipolar disorder.

METHOD

A systematic review of randomised controlled trials was conducted. Outcomes were meta-analysed using RevMan and confidence assessed using the GRADE method.

RESULTS

We included 55 trials with 6010 participants. Moderate-quality evidence associated individual psychological interventions with reduced relapses at post-treatment (risk ratio (RR) = 0.66, 95% CI 0.48-0.92) and follow-up (RR = 0.74, 95% CI 0.63-0.87), and collaborative care with a reduction in hospital admissions (RR = 0.68, 95% CI 0.49-0.94). Low-quality evidence associated group interventions with fewer depression relapses at post-treatment and follow-up, and family psychoeducation with reduced symptoms of depression and mania.

CONCLUSIONS

There is evidence that psychological interventions are effective for people with bipolar disorder. Much of the evidence was of low or very low quality thereby limiting our conclusions. Further research should identify the most effective (and cost-effective) interventions for each phase of this disorder.

Neuropsychological and social cognitive function in young people at genetic risk of bipolar disorder

BACKGROUND

Impairments in key neuropsychological domains (e.g. working memory, attention) and social cognitive deficits have been implicated as intermediate (endo) phenotypes for bipolar disorder (BD), and should therefore be evident in unaffected relatives.

METHOD

Neurocognitive and social cognitive ability was examined in 99 young people (age range 16-30 years) with a biological parent or sibling diagnosed with the disorder [thus deemed to be at risk (AR) of developing BD], compared with 78 healthy control (HC) subjects, and 52 people with a confirmed diagnosis of BD.

RESULTS

Only verbal intelligence and affective response inhibition were significantly impaired in AR relative to HC participants; the BD participants showed significant deficits in attention tasks compared with HCs. Neither AR nor BD patients showed impairments in general intellectual ability, working memory, visuospatial or language ability, relative to HC participants. Analysis of BD-I and BD-II cases separately revealed deficits in attention and immediate memory in BD-I patients (only), relative to HCs. Only the BD (but not AR) participants showed impaired emotion recognition, relative to HCs.

CONCLUSIONS

Selective cognitive deficits in the capacity to inhibit negative affective information, and general verbal ability may be intermediate markers of risk for BD; however, the extent and severity of impairment in this sample was less pronounced than has been reported in previous studies of older family members and BD cases. These findings highlight distinctions in the cognitive profiles of AR and BD participants, and provide limited support for progressive cognitive decline in association with illness development in BD.

Individualized identification of euthymic bipolar disorder using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and machine learning

BACKGROUND

Previous studies have reported that patients with bipolar disorder (BD) present with cognitive impairments during mood episodes as well as euthymic phase. However, it is still unknown whether reported neurocognitive abnormalities can objectively identify individual BD patients from healthy controls (HC).

METHODS

A total of 21 euthymic BD patients and 21 demographically matched HC were included in the current study. Participants performed the computerized Cambridge Neurocognitive Test Automated Battery (CANTAB) to assess cognitive performance. The least absolute shrinkage selection operator (LASSO) machine learning algorithm was implemented to identify neurocognitive signatures to distinguish individual BD patients from HC.

RESULTS

The LASSO machine learning algorithm identified individual BD patients from HC with an accuracy of 71%, area under receiver operating characteristic curve of 0.7143 and significant at p=0.0053. The LASSO algorithm assigned individual subjects with a probability score (0-healthy, 1-patient). Patients with rapid cycling (RC) were assigned increased probability scores as compared to patients without RC. A multivariate pattern of neurocognitive abnormalities comprising of affective Go/No-go and the Cambridge gambling task was relevant in distinguishing individual patients from HC.

LIMITATIONS

Our study sample was small as we only considered euthymic BD patients and demographically matched HC.

CONCLUSION

Neurocognitive abnormalities can distinguish individual euthymic BD patients from HC with relatively high accuracy. In addition, patients with RC had more cognitive impairments compared to patients without RC. The predictive neurocognitive signature identified in the current study can potentially be used to provide individualized clinical inferences on BD patients.

Residual symptoms and specific functional impairments in euthymic patients with bipolar disorder

OBJECTIVES

The aims of the present study were to confirm the impact of residual symptoms on overall functioning in a large sample of euthymic patients with bipolar disorder in real-life conditions and to explore the relationship between residual symptoms and specific areas of functional impairment.

METHODS

This was a multicenter, cross-sectional, non-interventional study of euthymic outpatients with bipolar disorder. The Functioning Assessment Short Test was used to assess overall and specific domains of functioning (autonomy, occupational functioning, cognitive functioning, financial issues, interpersonal relationships, and leisure time). Various residual symptoms were assessed (residual mood symptoms, emotional dysregulation, sleep and sexual disorders, stigma, and perceived cognitive impairment). Logistic regression was used to determine the best model of association between functional domains and residual symptoms.

RESULTS

Almost half of the 468 patients included (42%) had poor overall functioning. Residual depressive symptoms appeared to have an impact on overall functioning and in nearly all areas of functioning. In addition, specific residual symptoms had significantly more negative effects on some domains of functioning in euthymic patients with bipolar disorder (residual manic symptoms and occupational stigma on autonomy, emotional inhibition on occupational functioning, residual manic symptoms on financial issues, family stigma on interpersonal relationships, and sexual function and occupational stigma on leisure time).

CONCLUSIONS

Our findings highlight the importance of evaluating overall functioning in clinical practice as well as functional domains. They also indicate that some residuals symptoms in patients with bipolar disorder should be targeted in personalized treatment plans, in order to improve functioning in the domains in which the patient is most impaired.

The Lithium Battery: assessing the neurocognitive profile of lithium in bipolar disorder

OBJECTIVE

The aim of the present study was to characterize the neurocognitive effects of lithium in bipolar disorder to inform clinical and research approaches for further investigation.

METHODS

Key words pertaining to neurocognition in bipolar disorder and lithium treatment were used to search recognized databases to identify relevant literature. The authors also retrieved gray literature (e.g., book chapters) known to them and examined pertinent articles from bibliographies.

RESULTS

A limited number of studies have examined the effects of lithium on neurocognition in bipolar disorder and, although in some domains a consistent picture emerges, in many domains the findings are mixed. Lithium administration appears to reshape key components of neurocognition - in particular, psychomotor speed, verbal memory, and verbal fluency. Notably, it has a sophisticated neurocognitive profile, such that while lithium impairs neurocognition across some domains, it seemingly preserves others - possibly those vulnerable to the effects of bipolar disorder. Furthermore, its effects are likely to be direct and indirect (via mood, for example) and cumulative with duration of treatment. Disentangling the components of neurocognition modulated by lithium in the context of a fluctuating and complex illness such as bipolar disorder is a significant challenge but one that therefore demands a stratified and systematic approach, such as that provided by the Lithium Battery.

CONCLUSIONS

In order to delineate the effects of lithium therapy on neurocognition in bipolar disorder within both research and clinical practice, a greater understanding and measurement of the relatively stable neurocognitive components is needed to examine those that indeed change with lithium treatment. In order to achieve this, we propose a Lithium Battery-Clinical and a Lithium Battery-Research that can be applied to these respective settings.

Neurological soft signs in euthymic bipolar I patients: A comparative study with healthy siblings and controls

Neurological Soft Signs (NSS) are endophenotypic markers widely studied in schizophrenia and remain poorly evaluated in bipolar disorder. The aims of this paper were to determine the prevalence and scores of NSS in bipolar I patients, compared to healthy siblings and controls and to explore correlations with socio-demographic and clinical features of patients. This was a case-control study comparing 92 euthymic bipolar I patients, 44 of their healthy siblings and 60 control subjects. The neurological assessment was performed through the NSS scale validated by Krebs et al. (2000). Bipolar I patients were also assessed with the Bech-Rafaelsen Mania Scale (MAS), the Hamilton Depression Rating Scale (HDRS) and the Global Assessment of Functioning (GAF). The raters were not blinded to groups. The prevalence and the total score of NSS were significantly higher in bipolar I patients compared to their healthy siblings and controls. The sibling group had significantly higher NSS prevalence and total score than controls. No correlation was found between NSS total score and socio-demographic and clinical features of patients, except a negative correlation with the school level and the GAF score. In conclusion, bipolar I patients have motor and sensory signs, which are unrelated to their clinical features.

Subcortical morphometry and psychomotor function in euthymic bipolar disorder with a history of psychosis

Psychomotor disturbances are prominent in bipolar disorder patients with a history of psychosis, but their neural correlates remain largely unexplored. We hypothesized that these psychomotor disturbances are associated with morphometric changes in functionally specific regions of the basal ganglia and thalamus. To test if psychomotor performance is associated with changes in volume and shape in these brain regions, we investigated 20 euthymic bipolar disorder patients with a history of psychosis and 20 healthy controls with structural magnetic resonance imaging and vertex-based morphometry. Within the patient group, the local shape of the basal ganglia was significantly associated with longer duration of illness, increased number of manic episodes, and treatment with antipsychotics. There were neither any statistically significant associations between psychomotor performance and morphometric measures in the patient group, nor any significant morphometric differences between patients and controls. We conclude that euthymic subjects with bipolar disorder and a previous history of psychosis show shape changes in regions of the basal ganglia associated to clinical variables that may predict psychomotor disturbances in bipolar disorder.

Cognitive impairment in late-life bipolar disorder is not associated with Alzheimer's disease pathological signature in the cerebrospinal fluid

OBJECTIVES

Cognitive impairment is a common feature of late-life bipolar disorder (BD). Yet, there is limited information on the biological mechanisms associated with this process. It is uncertain whether cognitively impaired patients with BD may present the Alzheimer's disease (AD) bio-signature in the cerebrospinal fluid (CSF), defined as a combination of low concentrations of the amyloid-beta peptide (Aβ1-42 ) and high concentrations of total tau (T-tau) and tau phosphorylated at threonine 181 (P-tau). In this study, we sought to determine whether cognitive impairment in elderly patients with BD is associated with the AD CSF bio-signature.

METHODS

Seventy-two participants were enrolled in the study. The test group comprised older adults with BD and mild cognitive impairment (BD-MCI; n = 16) and the comparison groups comprised patients with dementia due to AD (n = 17), patients with amnestic MCI (aMCI; n = 14), and cognitively healthy older adults (control group; n = 25). CSF samples were obtained by lumbar puncture and concentrations of Aβ1-42 , T-tau and P-tau were determined.

RESULTS

CSF concentrations of all biomarkers were significantly different in the AD group compared to all other groups, but did not differentiate BD-MCI subjects from aMCI subjects and controls. BD-MCI patients had a non-significant reduction in CSF Aβ1-42 compared to controls, but this was still higher than in the AD group. Concentrations of T-tau and P-tau in BD-MCI patients were similar to those in controls, and significantly lower than those in AD.

CONCLUSIONS

Cognitively impaired patients with BD do not display the so-called AD bio-signature in the CSF. We therefore hypothesize that cognitive deterioration in BD is not associated with the classical pathophysiological mechanisms observed in AD, i.e., amyloid deposition and hyperphosphorylation of microtubule-associated tau protein.

Alterations in neural systems mediating cognitive flexibility and inhibition in mood disorders

Impairment in mental flexibility may be a key component contributing to cardinal cognitive symptoms among mood disorders patients, particularly thought control disorders. Impaired ability to switch from one thought to another might reflect difficulties in either generating new mental states, inhibiting previous states, or both. However, the neural underpinnings of impaired cognitive flexibility in mood disorders remain largely unresolved. We compared a group of mood disorders patients (n = 29) and a group of matched healthy subjects (n = 32) on a novel task-switching paradigm involving happy and sad faces, that allowed us to separate generation of a new mental set (Switch Cost) and inhibition of the previous set during switching (Inhibition Cost), using fMRI. Behavioral data showed a larger Switch Cost in patients relative to controls, but the average Inhibition Cost did not differ between groups. At the neural level, a main effect of group was found with stronger activation of the subgenual cingulate cortex in patients. The larger Switch Cost in patients was reflected by a stronger recruitment of brain regions involved in attention and executive control, including the left intraparietal sulcus, precuneus, left inferior fontal gyrus, and right anterior cingulate. Critically, activity in the subgenual cingulate cortex was not downregulated by inhibition in patients relative to controls. In conclusion, mood disorder patients have exaggerated Switch Cost relative to controls, and this deficit in cognitive flexibility is associated with increased activation of the fronto-parietal attention networks, combined with impaired modulation of the subgenual cingulate cortex when inhibition of previous mental states is needed.

Comparative neurocognitive effects of lithium and anticonvulsants in long-term stable bipolar patients

BACKGROUND

The aim of choosing a mood-stabilizing drug (lithium or anticonvulsants) or a combination of them with minimal neurocognitive effects is to stimulate the development of criteria for a therapeutic adequacy, particularly in Bipolar Disorder (BD) patients who are clinically stabilized.

METHOD

Three groups of BD patients were established according to their treatment: (i) lithium monotherapy (n=29); (ii) lithium together with one or more anticonvulsants (n=28); and (iii) one or more anticonvulsants (n=16). A group of healthy controls served as the control (n=25). The following tests were applied: Wechsler Adult Intelligence Scale, Trail Making Test, Wechsler Memory Scale, Rey Complex Figure Test, Stroop color-word test, Wisconsin Card Sorting Test, Tower of Hanoi, Frontal Assessment Battery, and Reading the Mind in the Eyes Test.

RESULTS

Relative to healthy controls, BD patients showed the following: (i) those on lithium monotherapy, but not other BD groups, had preserved short-term auditory memory, long-term memory, and attention; (ii) those who took only anticonvulsants showed worse findings in short-term visual memory, working memory, and several executive functions; and (iii) all BD patients showed worse performance in processing speed, resistance to interference, and emotion recognition.

LIMITATIONS

Medication alone cannot explain why all BD patients showed common cognitive deficits despite different pharmacological treatment.

CONCLUSION

The impairment on some executive functions and emotion recognition is an inherent trait in BD patients, regardless of their pharmacological treatment. However, while memory, attention, and most of the executive functions are preserved in long-term stable BD patients, these cognitive functions are impaired in those who take anticonvulsants.

Genetics of cognitive control: Implications for Nimh's research domain criteria initiative

Cognitive control refers to a set of mental processes that modulate other cognitive and emotional systems in service of goal-directed adaptive behavior. There is growing support for the notion that cognitive control abnormalities are a central component of many of the neuropsychological deficits observed in individuals with mental illnesses, particularly those with psychotic disorders. NIMH's research domain criteria (RDoC) initiative, which is designed to develop biologically informed constructs to better understand psychopathology, designated cognitive control a construct within the cognitive systems domain. Identification of genes that influence cognitive control or its supportive brain systems will improve our understating of the RDoC construct and provide candidate genes for psychotic disorders. We examine evidence for cognitive control deficits in psychosis, determine if these measures could be useful endophenotypes, and explore work linking genetic variation to cognitive control performance. While there is a wealth of evidence to support the notion the cognitive control is a valid endophenotype for psychosis, its genetic underpinning remains ill characterized. However, existing work provides a promising foundation on which future endeavors might build. Confirming existing individual gene associations will go some way to expanding our understanding of the genetics of cognitive control, and by extension, psychotic disorders. Yet, to truly understand the molecular underpinnings of such complex traits, it may be necessary to evaluate genes in tandem, focusing not on single genes but rather on empirically derived gene sets or on functionally defined networks of genes.

The Impact of Target Frequency on Intra-Individual Variability in Euthymic Bipolar Disorder: A Comparison of Two Sustained Attention Tasks

Greater intra-individual variability (IIV) in reaction time (RT) on a sustained attention task has been reported in patients with bipolar disorder (BD) compared with healthy controls. However, it is unclear whether IIV is task specific, or whether it represents general cross-task impairment in BD. This study aimed to investigate whether IIV occurs in sustained attention tasks with different parameters. Twenty-two patients with BD (currently euthymic) and 17 controls completed two sustained attention tasks on different occasions: a low target frequency (~20%) Vigil continuous performance test (CPT) and a high target frequency (~70%) CPT version A-X (CPT-AX). Variability measures (individual standard deviation and coefficient of variation) were calculated per participant, and ex-Gaussian modeling was also applied. This was supplemented by Vincentile analysis to characterize RT distributions. Results indicated that participants (patients and controls) were generally slower and more variable when completing the Vigil CPT compared with CPT-AX. Significant group differences were also observed in the Vigil CPT, with euthymic BD patients being more variable than controls. This result suggests that IIV in BD demonstrates some degree of task specificity. Further research should incorporate analysis of additional RT distributional models (drift diffusion and fast Fourier transform) to fully characterize the pattern of IIV in BD, as well as its relationship to cognitive processes.

Effect of Pharmacological Interventions on the Fronto-Cingulo-Parietal Cognitive Control Network in Psychiatric Disorders: A Transdiagnostic Systematic Review of fMRI Studies

Executive function deficits, such as working memory, decision-making, and attention problems, are a common feature of several psychiatric disorders for which no satisfactory treatment exists. Here, we transdiagnostically investigate the effects of pharmacological interventions (other than methylphenidate) on the fronto-cingulo-parietal cognitive control network, in order to identify functional brain markers for future procognitive pharmacological interventions. Twenty-nine manuscripts investigated the effect of pharmacological treatment on executive function-related brain correlates in psychotic disorders (n = 11), depression (n = 4), bipolar disorder (n = 4), ADHD (n = 4), OCD (n = 2), smoking dependence (n = 2), alcohol dependence (n = 1), and pathological gambling (n = 1). In terms of impact on the fronto-cingulo-parietal network, the preliminary evidence for catechol-O-methyl-transferase inhibitors, nicotinic receptor agonists, and atomoxetine was relatively consistent, the data for atypical antipsychotics and anticonvulsants moderate, and interpretation of the data for antidepressants was hampered by the employed study designs. Increased activity in task-relevant areas and decreased activity in task-irrelevant areas were the most common transdiagnostic effects of pharmacological treatment. These markers showed good positive and moderate negative predictive value. It is concluded that fronto-cingulo-parietal activity changes can serve as a marker for future procognitive interventions. Future recommendations include the use of randomized double-blind designs and selective cholinergic and glutamatergic compounds.

Potential neuroprotective effect of lithium in bipolar patients evaluated by neuropsychological assessment: preliminary results

OBJECTIVE

Accumulating evidence is delineating a neuroprotective/neurotrophic role for lithium. However, its primary effects on cognition remain ambiguous. We sought to investigate the profile of cognitive impairment in patients with bipolar disorder and to determine whether continued treatment with lithium preserves cognitive functioning.

METHODS

In this cross-sectional study, we tested 15 euthymic patients with bipolar I disorder undergoing long-term clinical maintenance treatment with lithium (for at least 12 months), 15 matched patients treated with other mood-stabilizing drugs and who had never received lithium, and 15 matched healthy subjects on the Cambridge Neuropsychological Test Automated Battery. Investigated cognitive domains were visual memory, executive functions, attention, decision-making/impulsivity, and response inhibition. We controlled for age, gender, intelligence, and residual psychiatric symptomatology.

RESULTS

Taken together, bipolar patients demonstrated robust deficits in visual memory and executive functions. Once subdivided in treatment subgroups, only non-lithium bipolar patients demonstrated impairments in visual memory. Attention, decision-making, and response inhibition were preserved in both groups. No correlation emerged between neuropsychological tests performance, clinical, and psychological variables.

CONCLUSIONS

This study is the first to our knowledge to have demonstrated, by means of a highly sensitive test of visual memory, a potential hippocampus neuroprotective effect of lithium in patients with bipolar disorder. Besides, it confirms prior findings of cognitive deficits in euthymic bipolar patients.

Working memory genetics in schizophrenia and related disorders: An RDoC perspective

Improved classification of mental disorders through neurobiological measures will require a set of traits that map to transdiagnostic subgroups of patients and align with heritable, core psychopathological processes at the center of the disorders of interest. A promising candidate is working memory (WM) function, for which deficits have been reported across multiple diagnostic entities including schizophrenia, bipolar disorder, ADHD, autism, and major depressive disorder. Here we review genetic working memory associations and their brain functional correlates from the perspective of identifying patient subgroups across conventional diagnostic boundaries, explore the utility of multimodal investigations integrating functional information at the neural systems level and explore potential limitations as well as future directions for research.

Connectomic markers of disease expression, genetic risk and resilience in bipolar disorder

Bipolar disorder (BD) is characterized by emotional dysregulation and cognitive deficits associated with abnormal connectivity between subcortical-primarily emotional processing regions-and prefrontal regulatory areas. Given the significant contribution of genetic factors to BD, studies in unaffected first-degree relatives can identify neural mechanisms of genetic risk but also resilience, thus paving the way for preventive interventions. Dynamic causal modeling (DCM) and random-effects Bayesian model selection were used to define and assess connectomic phenotypes linked to facial affect processing and working memory in a demographically matched sample of first-degree relatives carefully selected for resilience (n=25), euthymic patients with BD (n=41) and unrelated healthy controls (n=46). During facial affect processing, patients and relatives showed similarly increased frontolimbic connectivity; resilient relatives, however, evidenced additional adaptive hyperconnectivity within the ventral visual stream. During working memory processing, patients displayed widespread hypoconnectivity within the corresponding network. In contrast, working memory network connectivity in resilient relatives was comparable to that of controls. Our results indicate that frontolimbic dysfunction during affect processing could represent a marker of genetic risk to BD, and diffuse hypoconnectivity within the working memory network a marker of disease expression. The association of hyperconnectivity within the affect-processing network with resilience to BD suggests adaptive plasticity that allows for compensatory changes and encourages further investigation of this phenotype in genetic and early intervention studies.

A Swedish National Prospective and Co-relative Study of School Achievement at Age 16, and Risk for Schizophrenia, Other Nonaffective Psychosis, and Bipolar Illness

While cognitive ability is inversely associated with risk for schizophrenia (SZ), the association is less clear with other nonaffective psychoses (ONAP) and bipolar illness (BPI). Using national Swedish hospital registry data, we examined the prospective relationship between school achievement (SA) and development of SZ, ONAP, and BPI in 1800643 adolescents born 1972-1990. We used Cox proportional hazard and co-relative control models to predict onset of SZ, ONAP, and BPI from standardized SA scores at age 16. The hazard ratio (HRs; and 95% CIs) for first onset of SZ as a function of SA was 0.66 (0.64-0.68) for both sexes. For ONAP, the HRs equaled 0.66 (0.64-0.68) for males and 0.72 (0.70-0.75) for females. For BPI, parallel HRs were 0.81 (0.78-0.84) and 0.71 (0.70-0.73). The association between SA and risk was stronger in the lower vs the higher ranges of SA. In most analyses, moderate increases in risk were observed at the highest levels of SA, with the strongest evidence for females and risk of ONAP. Co-relative control analyses indicated that common genetic or familial-environmental effects only marginally confounded these associations. Consistent with prior studies, these results have 3 major implications for neurodevelopmental models: (1) adolescent cognitive deficits that increase risk are not the result of prodromal changes,( 2) individual specific environmental exposures are largely responsible for the association between low SA and psychosis risk, and (3) neurodevelopmental disturbances (as indicated by low SA) are not unique to SZ but also occur in ONAP and to a lesser degree BPI.

Associations between sleep disturbance, cognitive functioning and work disability in Bipolar Disorder

Bipolar Disorder (BD) is associated with impairment in a number of areas including poor work functioning, often despite the remission of mood symptoms. The present study aimed to examine the role of sleep disturbance and cognitive functioning in occupational impairment in BD. Twenty-four euthymic BD participants and 24 healthy control participants completed a week of prospective assessment of sleep disruption via self-report and actigraphy, a battery of neuropsychological tests of executive functioning, working memory, and verbal learning, and assessments of work functioning. BD participants experienced significantly poorer cognitive functioning as well as greater months of unemployment and greater incidence of being fired than controls. Moderation analyses revealed that both poor sleep and cognitive functioning were associated with poor work performance in BD participants, but not control participants. Sleep and cognitive functioning may be impaired in euthymic BD and are associated with poor work functioning in this population. More research should be conducted to better understand how sleep and cognitive functioning may interact in BD.

The neurocognitive profile of mood disorders - a review of the evidence and methodological issues

OBJECTIVES

Cognitive abnormalities are an established part of the symptomatology of mood disorders. However, questions still exist regarding the exact profile of these deficits in terms of the domains most affected, their origins, and their relationship to clinical subtypes. This review aims to examine the current state of the evidence and to examine ways in which the field may be advanced.

METHODS

Studies examining cognitive function in bipolar disorder (BD) and unipolar major depression (MDD) were examined. Given the number and variability of such studies, particular attention was paid to meta-analyses and to meta-regression analyses which examined the possible mediators of cognitive impairment.

RESULTS

Meta-analyses are available for MDD and BD in both depression and euthymia. Several analyses examine mediators. Results do not support the presence of domain specific deficits but rather a moderate deficit across a range of domains in BD and in MDD. The data on clinical mediators is inconsistent, even with regard to the effect of mood state.

CONCLUSIONS

A two-tiered approach, with the broad-based application of standardized measures on a large-scale, and the refined application of theoretically driven experimental development would significantly further our understanding of neurocognitive processing in mood disorder.

Polymorphisms of dopamine pathway genes NRG1 and LMX1A are associated with cognitive performance in bipolar disorder

OBJECTIVES

LIM homeobox transcription factor 1, alpha (LMX1A) and neuregulin 1 (NRG1) are susceptibility genes for schizophrenia that have been implicated in the dopaminergic pathway and have been associated with altered cognitive functioning. We hypothesized that single nucleotide polymorphisms (SNPs) in LMX1A and NRG1 would be associated with cognitive functioning in bipolar disorder.

METHODS

In total, four SNPs were directly genotyped. Regression models with five aggregated cognitive domains and intelligence quotient (IQ) score were run using risk variants of LMX1A (rs11809911, rs4657412, rs6668493) and NRG1 (rs35753505) as predictors. Models were performed in a clinical sample of patients with bipolar disorder (n = 114) and healthy controls (n = 104).

RESULTS

The risk variants of the rs11809911 SNP in LMX1A were negatively associated with IQ score and memory/learning, whereas the risk variants of rs35753505 in NRG1 were positively associated with IQ score (adjusted R(2) = 0.17, Q = 0.006) and memory/learning (adjusted R(2) = 0.24, Q = 0.001). The risk variants of the rs35753505 SNP in NRG1 were positively associated with language (adjusted R(2) = 0.11, Q = 0.006), visuospatial functions (adjusted R(2) = 0.23, Q = 0.001), and attention/speed (adjusted R(2) = 0.25, Q = 0.001). Results could not be replicated in controls.

CONCLUSIONS

The risk variants of the rs35753505 SNP were associated with increased performance in several cognitive domains and IQ, whereas the risk variants of the rs11809911 SNP in LMX1A was associated with reduced IQ and memory/learning.

Facial recognition deficits as a potential endophenotype in bipolar disorder

Bipolar disorder (BD) is considered a highly heritable and genetically complex disorder. Several cognitive functions, such as executive functions and verbal memory have been suggested as promising candidates for endophenotypes. Although there is evidence for deficits in facial emotion recognition in individuals with BD, studies investigating these functions as endophenotypes are rare. The current study investigates emotion recognition as a potential endophenotype in BD by comparing 36 BD participants, 24 of their 1st degree relatives and 40 healthy control participants in a computerised facial emotion recognition task. Group differences were evaluated using repeated measurement analysis of co-variance with age as a covariate. Results revealed slowed emotion recognition for both BD and their relatives. Furthermore, BD participants were less accurate than healthy controls in their recognition of emotion expressions. We found no evidence of emotion specific differences between groups. Our results provide evidence for facial recognition as a potential endophenotype in BD.

Optimising screening for cognitive dysfunction in bipolar disorder: Validation and evaluation of objective and subjective tools

INTRODUCTION

Cognitive impairment is common in bipolar disorder and contributes to socio-occupational difficulties. The objective was to validate and evaluate instruments to screen for and monitor cognitive impairments, and improve the understanding of the association between cognitive measures and socio-occupational capacity.

METHODS

Patients with bipolar disorder in partial or full remission (n=84) and healthy controls (n=68) were assessed with the Screen for Cognitive Impairment in Psychiatry (SCIP), Cognitive Complaints in Bipolar Disorder Rating Scale (COBRA), and established neuropsychological tests and subjective rating scales. Socio-occupational function and affective symptoms were evaluated with the Functional Assessment Short Test, and the Hamilton Depression Rating Scale 17-items and Young Mania Rating Scale, respectively. Concurrent validity of the SCIP and COBRA were assessed by correlation with established objective and subjective cognitive measures, and decision validity was determined with Receiver-Operating-Characteristic analyses. Correlations and linear regression analyses were conducted to determine the associations between objective and subjective cognitive impairment, and socio-occupational difficulties.

RESULTS

The SCIP and COBRA correlated strongly with established objective and subjective cognitive measures, respectively. The SCIP yielded higher sensitivity and specificity for detection of cognitive dysfunction than the COBRA or a combined SCIP-COBRA measure. Correlations between objective and subjective cognitive impairment were weak but both were associated with socio-occupational difficulties.

LIMITATIONS

Influence of ageing was not investigated.

CONCLUSIONS

The SCIP and COBRA are valid for detection of objective and subjective cognitive impairment in bipolar disorder. Screening for cognitive dysfunction should be conducted with an objective measure like the SCIP.

The relationship between sleep quality and neurocognition in bipolar disorder

BACKGROUNDS

Sleep and circadian rhythm disruptions are prominent, trait-like features of bipolar disorder (BD) which precede the onset of mood episodes. Neurocognitive impairments also characterize BD not only during acute phases of the illness but also during remission. Although the relationship between these two debilitating aspects of the illness might seem intuitive, very little is known about their relationship. We examined the association between sleep dysfunction and neurocognition in BD.

METHODS

In a sample of 117 BD patients (mean age=45.0±10.7; 59.0% (n=69) male), neurocognitive functioning was assessed using the MATRICS Consensus Cognitive Battery (MCCB). Sleep quality data were collected using the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). Partial Pearson correlations tested for a relationship between sleep and neurocognition. Path analyses were conducted to examine the hypothesized direct influence of sleep disruption on neurocognition.

RESULTS

Higher levels of sleep disruptions were associated with a more severe clinical presentation and poorer performance in social cognition, visual learning and working memory. Social cognition and working memory were directly (negatively) predicted by sleep disruptions.

LIMITATIONS

The study was limited by a relatively small sample size and the lack of behavioral and biological objectives measure of activity/rest cycles.

CONCLUSIONS

Our study suggests that in patients with BD, sleep disruptions have a detrimental effect on general level of psychopathology and contribute directly to impaired cognitive functioning in the domains of social cognition and working memory. More research using objective measurement of sleep should be pursued to support these data and to further investigate the causal relationship between these disabling aspects of the illness.

Identification of circadian gene variants in bipolar disorder in Latino populations

BACKGROUND

Variations in circadian genes can impact biological rhythms. Given the rhythm disturbances that characterize bipolar disorder (BD), genes encoding components of molecular clocks are good candidate genes for the illness.

METHODS

A family based association analysis of circadian gene single nucleotide polymorphisms (SNPs) and BD was conducted in Latino pedigrees. 884 individuals from 207 pedigrees (473BP phenotype and 411 unaffected family members) were genotyped. Family based single marker association testing was performed. Ancestral haplotypes (SNPs found to be in strong LD defined using confidence intervals) were also tested for association with BD.

RESULTS

Multiple suggestive associations between circadian gene SNPs and BD were noted. These included CSNK1E (rs1534891, p=0.00689), ARNTL (rs3789327, p=0.021172), CSNK1D (rs4510078, p=0.022801), CLOCK (rs17777927, p=0.031664). Individually, none of the SNPs were significantly associated with BD after correction for multiple testing. However, a 4-locus CSNK1E haplotype encompassing the rs1534891 SNP (Z-score=2.685, permuted p=0.0076) and a 3-locus haplotype in ARNTL (Z-score=3.269, permuted p=0.0011) showed a significant association with BD.

LIMITATIONS

Larger samples are required to confirm these findings and assess the relationship between circadian gene SNPs and BD in Latinos.

CONCLUSIONS

The results suggest that ARNTL and CSKN1E variants may be associated with BD. Further studies are warranted to assess the relationships between these genes and BD in Latino populations.

Neurocognition in individuals at high familial risk of mood disorders with or without subsequent onset of depression

BACKGROUND

Neurocognitive performance deficits have been observed in mood disorder patients and their unaffected relatives and may therefore qualify as endophenotypes. However, the precise time course of neurocognitive deficits has not been studied so that it is unknown whether neurocognitive abnormalities reflect the early effects of familial vulnerability to mood disorders or if they emerge at illness onset.

METHOD

A neuropsychological test battery was administered at baseline and after a 2-year follow-up interval in 111 initially unaffected young adults at high familial risk of mood disorders and 93 healthy controls (HC). During the follow-up period, 20 high-risk subjects developed major depressive disorder (HR-MDD), with the remainder remaining well (HR-well). Linear mixed-effects models were used to investigate differences and longitudinal changes in the domains of attentional processing, working memory, verbal learning and memory, and cognitive flexibility.

RESULTS

Reduced long delay verbal memory and extradimensional set-shifting performance across both time points were found in the HR-well group relative to controls. The HR-MDD group displayed decreased extradimensional set-shifting abilities across both time points as compared with the HC group only. There were no significant performance differences between the two high-risk groups.

CONCLUSIONS

Reduced verbal memory and cognitive flexibility are familial trait markers for vulnerability to mood disorders in individuals with a close family history of bipolar disorder. Both neurocognitive performance deficits appear to be relatively stable over a 2-year time period and do not appear to be linked to the onset of MDD. These findings support their use as stable quantitative endophenotypes for mood disorders.

The role of negative mood induction on working memory capacity in individuals putatively at risk for bipolar disorder: A pilot study

OBJECTIVE

Bipolar disorder (BD) is characterized by cognitive deficits. Usually individuals at risk for BD do not exhibit such deficits but they might be evident under cognitive or emotionally stressful conditions. To our knowledge this is the first study examining working memory capacity under mood induction in individuals at risk for BD.

METHODS

Using the Hypomanic Personality Scale (HPS) 68 participants out of an initial pool of 148 students were divided into groups at high and low risk for BD. They completed twice a Dual Task Paradigm (DTP) task assessed under high and low cognitive load prior to and following a negative mood induction.

RESULTS

As expected stimuli incongruency, high cognitive load and mood induction increased response times. Contrary to our hypothesis the mood induction did not differentially affect at-risk individuals. However, they generally reacted faster to neutral stimuli compared to those at low risk.

CONCLUSIONS

While we replicated former results related to the DTP, we did not find evidence for the hypothesis that individuals putatively at risk for BD will be more affected by negative mood when doing such a cognitive task. Replication using a larger sample is needed which should also examine whether changes in positive mood might more relevant in the context of risk for mania.

Neurocognitive intra-individual variability in mood disorders: effects on attentional response time distributions

BACKGROUND

Attentional impairment is a core cognitive feature of major depressive disorder (MDD) and bipolar disorder (BD). However, little is known of the characteristics of response time (RT) distributions from attentional tasks. This is crucial to furthering our understanding of the profile and extent of cognitive intra-individual variability (IIV) in mood disorders.

METHOD

A computerized sustained attention task was administered to 138 healthy controls and 158 patients with a mood disorder: 86 euthymic BD, 33 depressed BD and 39 medication-free MDD patients. Measures of IIV, including individual standard deviation (iSD) and coefficient of variation (CoV), were derived for each participant. Ex-Gaussian (and Vincentile) analyses were used to characterize the RT distributions into three components: mu and sigma (mean and standard deviation of the Gaussian portion of the distribution) and tau (the 'slow tail' of the distribution).

RESULTS

Compared with healthy controls, iSD was increased significantly in all patient samples. Due to minimal changes in average RT, CoV was only increased significantly in BD depressed patients. Ex-Gaussian modelling indicated a significant increase in tau in euthymic BD [Cohen's d = 0.39, 95% confidence interval (CI) 0.09-0.69, p = 0.011], and both sigma (d = 0.57, 95% CI 0.07-1.05, p = 0.025) and tau (d = 1.14, 95% CI 0.60-1.64, p < 0.0001) in depressed BD. The mu parameter did not differ from controls.

CONCLUSIONS

Increased cognitive variability may be a core feature of mood disorders. This is the first demonstration of differences in attentional RT distribution parameters between MDD and BD, and BD depression and euthymia. These data highlight the utility of applying measures of IIV to characterize neurocognitive variability and the great potential for future application.

Impaired conflict resolution and vigilance in euthymic bipolar disorder

Difficulty attending is a common deficit of euthymic bipolar patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network. According to the attention network approach, attention is best understood in terms of three functionally and neuroanatomically distinct networks-alerting, orienting, and executive control. In this study, we explored whether and which of the three attentional networks are altered in euthymic Bipolar Disorder (BD). A sample of euthymic BD patients and age-matched healthy controls completed the Attention Network Test for Interactions and Vigilance (ANTI-V) that provided not only a measure of orienting, executive, and alerting networks, but also an independent measure of vigilance (tonic alerting). Compared to healthy controls, BD patients have impaired executive control (greater interference), reduced vigilance (as indexed by a decrease in the d' sensitivity) as well as slower overall reaction times and poorer accuracy. Our results show that deficits in executive attention and sustained attention often persist in BD patients even after complete remission of affective symptoms, thus suggesting that cognitive enhancing treatments programmed to improve these deficits could contribute to improve their functional recovery.

Altered prefrontal cortex activity during working memory task in Bipolar Disorder: A functional Magnetic Resonance Imaging study in euthymic bipolar I and II patients

BACKGROUND

Working memory (WM) deficits are among the most frequently impaired cognitive domains in patients with Bipolar Disorder (BD), being considered promising cognitive endophenotype of the disorder. However, the related neurobiological correlates still deserve further investigation. The present study was aimed to explore whether dorsolateral prefrontal cortex (DLPFC) activity during WM processing was abnormal in euthymic bipolar patients and may represent a potential trait-related phenotype associated with the disorder.

METHODS

Using 3 Tesla functional Magnetic Resonance Imaging (3T fMRI), we studied 28 euthymic bipolar patients (15 BDI and 13 BDII), and 27 healthy controls (HCs), matched for a series of socio-demographic variables, while performing the N-back task for WM assessment.

RESULTS

We found that euthymic bipolar patients showed increased right middle frontal gyrus engagement compared with HCs (FWE-corrected p = 1 × 10(-3)), regardless of WM load, and in spite of similar WM behavioral performance between groups. In particular, BDI patients had greater BOLD signal change compared to HCs (post-hoc Tukey HSD, p = 1 × 10(-3)), while BDII patients expressed an intermediate pattern of activation between BDI patients and HCs. No other significant effects were detected in the corrected whole-brain analysis.

LIMITATIONS

Sample size, cross-sectional assessment and potential influence of some clinical variables.

CONCLUSIONS

Results provide direct evidence of a primary physiological abnormality in DLPFC function in BDI and II, even in the absence of behavioral differences with HCs. Such exaggerated fMRI response suggests inefficient WM processing in prefrontal circuitry, and further studies are warranted to investigate whether the dysfunction is related to the genetic risk for the disorder.

Functional dysconnection in the prefrontal-amygdala circuitry in unaffected siblings of patients with bipolar I disorder

OBJECTIVES

Bipolar I disorder (BD) is a highly heritable disorder characterized by mood swings between high-energy and low-energy states. Amygdala hyperactivity and cortical inhibitory hypoactivity [e.g., of the dorsolateral prefrontal cortex (dlPFC)] have been found in patients with BD, as evidenced by their abnormal resting-state functional connectivity (FC) and glucose utilization (GU). However, it has not been determined whether functional abnormalities of the dlPFC-amygdala circuit exist in unaffected, healthy siblings of the patients with BD (BDsib).

METHODS

Twenty euthymic patients with BD, 20 unaffected matching BDsib of the patient group, and 20 well-matched healthy control subjects were recruited. We investigated seed-based FC (seeds: dlPFC) with resting-state functional magnetic resonance imaging and GU in the regions of interest (e.g., dlPFC and amygdala) using (18) F-fluorodeoxyglucose positron emission tomography.

RESULTS

The FC in the dlPFC (right)-amygdala circuit was statistically abnormal in patients with BD and BDsib, but only the patients with BD demonstrated hypoactive GU bilaterally in the dlPFC and hyperactive GU bilaterally in the amygdala. Facilitating differentiation between the BD groups, the altered FC between dlPFC (right) and amygdala (left) was even more prominent in the patients with BD (p < 0.05).

CONCLUSIONS

There was a dysfunctional connection with intact GU in the dlPFC-amygdala circuit of the BDsib, which highlights the vulnerability in families with BD. Diminished top-down control from the bilateral dlPFC, which prevents adequate inhibition of limbic hyperactivity, might mediate the development of BD.

Executive function in parents of patients with familial versus sporadic bipolar disorder

OBJECTIVE

Studies investigating the cognitive function of healthy relatives of patients with bipolar disorder are conflicting, and the neurocognitive profile of relatives of bipolar disorder probands is still unclear. We aimed to evaluate executive function in unaffected parents of familial and sporadic patients with bipolar disorder.

METHODS

The study included 24 unaffected familial parents (FP) of patients with bipolar disorder, 26 unaffected sporadic parents (SP) of patients with bipolar disorder and 26 controls matched with the parents for gender, age and duration of education (76 subjects in total). All of the subjects were interviewed with the Structured Clinical Interview for DSM-IV-Axis I. Executive function was assessed using the California Verbal Learning Test (CVLT), the Trail Making Test (TMT), the Wisconsin Card Sorting Test (WCST) and the Stroop test.

RESULTS

In comparison to their respective matched controls, FP performed significantly worse on the CVLT, TMT, WCST and Stroop test, whereas SP performed significantly worse only on WCST perseverative errors and Stroop color test. FP performed significantly worse than SP on the CVLT, TMT, and WCST.

CONCLUSION

The present study investigated relatives with and without a family history of bipolar disorder separately and found that executive function was impaired in parents with a positive family history of bipolar disorder. These findings bring more evidence suggesting that deficits in prefrontal executive function and verbal memory are associated with familial vulnerability to bipolar disorder and that executive function and verbal memory impairments may represent a potential endophenotype of bipolar disorder.

Regressing to Prior Response Preference After Set Switching Implicates Striatal Dysfunction Across Psychotic Disorders: Findings From the B-SNIP Study

Difficulty switching behavioral response sets is established in psychotic disorders. In rodent models, prefrontal lesions cause difficulty initially switching to new response sets (perseverative errors) while striatal lesions cause difficulty suppressing responses to previous choice preferences (regressive errors). Studies of psychotic disorders have not previously assessed these 2 error types. Bipolar and Schizophrenia Network on Intermediate Phenotypes (B-SNIP) participants included probands with schizophrenia (N = 212), psychotic bipolar (N = 192), and schizoaffective disorder (N = 131), their first-degree relatives (N = 267,226,165 respectively), and healthy controls (N = 258). Participants completed the Penn Conditional Exclusion Test (PCET) to assess cognitive set switching and the Brief Assessment of Cognition in Schizophrenia (BACS) to assess generalized neuropsychological dysfunction. All proband groups displayed elevated rates of perseverative and regressive errors compared to controls. After correcting for generalized cognitive deficits to identify specific deficits in set shifting and maintenance, there were no significant group differences for perseverative errors, while the increased rate of regressive errors remained significant. Level of regressive errors was similar across proband groups with minimal correlations with antipsychotic medication dose, clinical ratings, and demographic characteristics. Relatives of schizophrenia patients showed increased rates of regressive errors, but familiality of this trait was significant only in bipolar pedigrees. Regressive errors were partially independent of generalized cognitive deficits, suggesting a potentially informative and specific cognitive deficit across psychotic disorders. Preclinical data indicate that this deficit could be related to altered function in a neural system that may include the dorsal striatum or other elements of frontostriatal systems.

Cognitive performance and cerebrospinal fluid biomarkers of neurodegeneration: a study of patients with bipolar disorder and healthy controls

The purpose of the present study was to investigate if cerebrospinal fluid (CSF) biomarkers of neurodegeneration are associated with cognition in bipolar disorder and healthy controls, respectively. CSF concentrations of total and phosphorylated tau, amyloid beta (Aβ)1-42, ratios of Aβ42/40 and Aβ42/38, soluble amyloid precursor protein α and β, and neurofilament light chain protein were analyzed in relation to neuropsychological performance in 82 euthymic bipolar disorder patients and 71 healthy controls. Linear regression models were applied to account for performance in five cognitive domains using the CSF biomarkers. In patients, the CSF biomarkers explained a significant proportion of the variance (15–36%, p=.002 - <.0005) in all cognitive domains independently of age, medication, disease status, and bipolar subtype I or II. However, the CSF biomarkers specifically mirroring Alzheimer-type brain changes, i.e., P-tau and Aβ1-42, did not contribute significantly. In healthy controls, CSF biomarkers did not explain the variance in cognitive performance. Selected CSF biomarkers of neurodegenerative processes accounted for cognitive performance in persons with bipolar disorder, but not for healthy controls. Specifically, the ratios of Aβ42/40 and Aβ42/38 were consistently associated with altered cognitive performance.

Brain structure-function associations in multi-generational families genetically enriched for bipolar disorder

Recent theories regarding the pathophysiology of bipolar disorder suggest contributions of both neurodevelopmental and neurodegenerative processes. While structural neuroimaging studies indicate disease-associated neuroanatomical alterations, the behavioural correlates of these alterations have not been well characterized. Here, we investigated multi-generational families genetically enriched for bipolar disorder to: (i) characterize neurobehavioural correlates of neuroanatomical measures implicated in the pathophysiology of bipolar disorder; (ii) identify brain-behaviour associations that differ between diagnostic groups; (iii) identify neurocognitive traits that show evidence of accelerated ageing specifically in subjects with bipolar disorder; and (iv) identify brain-behaviour correlations that differ across the age span. Structural neuroimages and multi-dimensional assessments of temperament and neurocognition were acquired from 527 (153 bipolar disorder and 374 non-bipolar disorder) adults aged 18-87 years in 26 families with heavy genetic loading for bipolar disorder. We used linear regression models to identify significant brain-behaviour associations and test whether brain-behaviour relationships differed: (i) between diagnostic groups; and (ii) as a function of age. We found that total cortical and ventricular volume had the greatest number of significant behavioural associations, and included correlations with measures from multiple cognitive domains, particularly declarative and working memory and executive function. Cortical thickness measures, in contrast, showed more specific associations with declarative memory, letter fluency and processing speed tasks. While the majority of brain-behaviour relationships were similar across diagnostic groups, increased cortical thickness in ventrolateral prefrontal and parietal cortical regions was associated with better declarative memory only in bipolar disorder subjects, and not in non-bipolar disorder family members. Additionally, while age had a relatively strong impact on all neurocognitive traits, the effects of age on cognition did not differ between diagnostic groups. Most brain-behaviour associations were also similar across the age range, with the exception of cortical and ventricular volume and lingual gyrus thickness, which showed weak correlations with verbal fluency and inhibitory control at younger ages that increased in magnitude in older subjects, regardless of diagnosis. Findings indicate that neuroanatomical traits potentially impacted by bipolar disorder are significantly associated with multiple neurobehavioural domains. Structure-function relationships are generally preserved across diagnostic groups, with the notable exception of ventrolateral prefrontal and parietal association cortex, volumetric increases in which may be associated with cognitive resilience specifically in individuals with bipolar disorder. Although age impacted all neurobehavioural traits, we did not find any evidence of accelerated cognitive decline specific to bipolar disorder subjects. Regardless of diagnosis, greater global brain volume may represent a protective factor for the effects of ageing on executive functioning.

Peripheral and central glucose utilizations modulated by mitochondrial DNA 10398A in bipolar disorder

Bipolar disorder (BD) is highly heritable and associated with dysregulation of brain glucose utilizations (GU). The mitochondrial DNA (mtDNA) 10398A polymorphism, as a reported BD risk factor, leads to deficient glycolytic energy production by affecting mitochondrial matrix pH and intracellular calcium levels. However, whether mtDNA-10398A has functional effects on the brain and how our body responds remain elusive. We compared peripheral and central glucose-utilizing patterns between mtDNA A10398G polymorphisms in BD and their unaffected siblings (BDsib). Since siblings carry identical mtDNA, we hypothesized that certain characteristics co-segregate in BD families. We recruited twenty-seven pairs of non-diabetic BD patients and their BDsib and 30 well-matched healthy control subjects (HC). The following were investigated: mtDNA, fasting plasma glucose/insulin, cognitive functions including Montreal Cognitive Assessment (MoCA), and brain GU at rest. Insulin resistance was rechecked in sixty-one subjects (19-BD, 18-BDsibib, and 24-HC) six months later. We found that BD-pairs (BD+BDsib) carried more mtDNA-10398A and had higher fasting glucose, even after controlling for many covariates. BD-pairs had abnormally lower dorso-prefrontal-GU and higher cerebellar-GU, but only BD demonstrated lower medio-prefrontal-GU and MoCA. Subjects carrying mtDNA-10398A had significantly lower prefrontal-GU (FWE-corrected p<0.05). An abnormal inverse pattern of insulin-GU and insulin-MoCA correlation was found in BD-pairs. The insulin-MoCA correlation was particularly prominent in those carrying mtDNA-10398A. mtDNA-10398A predicted insulin resistance 6 months later. In conclusion, mtDNA-10398A was associated with impaired prefrontal-GU. An up-regulation of glucose utilizations was found in BD-pairs, probably compensating for mtDNA-10398A-related energy loss.

Pathological brain plasticity and cognition in the offspring of males subjected to postnatal traumatic stress

Traumatic stress in early-life increases the risk for cognitive and neuropsychiatric disorders later in life. Such early stress can also impact the progeny even if not directly exposed, likely through epigenetic mechanisms. Here, we report in mice that the offspring of males subjected to postnatal traumatic stress have decreased gene expression in molecular pathways necessary for neuronal signaling, and altered synaptic plasticity when adult. Long-term potentiation is abolished and long-term depression is enhanced in the hippocampus, and these defects are associated with impaired long-term memory in both the exposed fathers and their offspring. The brain-specific gamma isoform of protein kinase C (Prkcc) is one of the affected signaling components in the hippocampus. Its expression is reduced in the offspring, and DNA methylation at its promoter is altered both in the hippocampus of the offspring and the sperm of fathers. These results suggest that postnatal traumatic stress in males can affect brain plasticity and cognitive functions in the adult progeny, possibly through epigenetic alterations in the male germline.