Neurocognitive impairment across the bipolar spectrum

Transcriptome profiling as a biological marker for bipolar disorder sub-phenotypes

PURPOSE

Bipolar affective disorder (BP) causes major functional impairment and reduced quality of life not only for patients, but also for many close relatives. We aimed to investigate mRNA levels in BP patients to find differentially expressed genes linked to specific clinical course variants; assuming that several gene expression alterations might indicate vulnerability pathways for specific course and severity of the disease.

MATERIALS

We searched for up- and down-regulated genes comparing patients with diagnosis of BP type I (BPI) vs type II (BPII), history of suicide attempts, psychotic symptoms, predominance of manic/hypomanic episodes, and history of numerous episodes and comorbidity of substance use disorders or anxiety disorders. RNA was extracted from peripheral blood mononuclear cells and analyzed with use of microarray slides.

RESULTS

Differentially expressed genes (DEGs) were found in all disease characteristics compared. The lowest number of DEGs were revealed when comparing BPI and BPII patients (18 genes), and the highest number when comparing patients with and without psychotic symptoms (3223 genes). Down-regulated genes identified here with the use of the DAVID database were among others linked to cell migration, defense response, and inflammatory response.

CONCLUSIONS

The most specific transcriptome profile was revealed in BP with psychotic symptoms. Differentially expressed genes in this variant include, among others, genes involved in inflammatory and immune processes. It might suggest the overlap of biological background between BP with a history of psychotic features and schizophrenia.

Supra-second interval timing in bipolar disorder: examining the role of disorder sub-type, mood, and medication status

BACKGROUND

Widely reported by bipolar disorder (BD) patients, cognitive symptoms, including deficits in executive function, memory, attention, and timing are under-studied. Work suggests that individuals with BD show impairments in interval timing tasks, including supra-second, sub-second, and implicit motor timing compared to the neuronormative population. However, how time perception differs within individuals with BD based on disorder sub-type (BDI vs II), depressed mood, or antipsychotic medication-use has not been thoroughly investigated. The present work administered a supra-second interval timing task concurrent with electroencephalography (EEG) to patients with BD and a neuronormative comparison group. As this task is known to elicit frontal theta oscillations, signal from the frontal (Fz) lead was analyzed at rest and during the task.

RESULTS

Results suggest that individuals with BD show impairments in supra-second interval timing and reduced frontal theta power during the task compared to neuronormative controls. However, within BD sub-groups, neither time perception nor frontal theta differed in accordance with BD sub-type, depressed mood, or antipsychotic medication use.

CONCLUSIONS

This work suggests that BD sub-type, depressed mood status or antipsychotic medication use does not alter timing profile or frontal theta activity. Together with previous work, these findings point to timing impairments in BD patients across a wide range of modalities and durations indicating that an altered ability to assess the passage of time may be a fundamental cognitive abnormality in BD.

Better than expected: the gap between self-reported and objective measures of cognitive performance in remitted bipolar disorder

Background

Studies comparing objective and self-reported cognitive functioning as well as influencing factors in individuals with remitted bipolar disorder are scarce and contradictory.

Methods

The aim of this study was to compare executive functioning and other objective and self-reported cognitive impairment between 26 individuals with remitted bipolar disorder (15 BD I) and 24 healthy controls using a cross-sectional design. Executive functions were measured by the TAP Go/No-go subtest as well as the Stroop Task. Self-rated functioning was assessed using the Attention Deficit Experience Questionnaire. In addition, possible predictors of self-reported and objective cognitive functioning were examined to perform regression analyses.

Results

Individuals with remitted bipolar disorder did not differ significantly in executive functions or other objective cognitive domains from the healthy control group, but showed a significantly lower level of self-reported cognitive functioning and self-esteem. While self-esteem was the strongest predictor in healthy controls for self-reported cognitive functioning, severity of illness and subthreshold depressive mood were the most important predictors in individuals with remitted bipolar disorder.

Conclusion

The results once again demonstrate the cognitive heterogeneity in bipolar disorder. In the treatment of cognitive deficits, factors such as subthreshold depressive symptomatology and self-esteem should be focused on in addition to cognitive training in remitted patients.

Supra-second interval timing in bipolar disorder: examining the role of disorder sub-type, mood, and medication status

Background : Widely reported by bipolar disorder (BD) patients, cognitive symptoms, including deficits in executive function, memory, attention, and timing are under-studied. Work suggests that individuals with BD show impairments in interval timing tasks, including supra-second, sub-second, and implicit motor timing compared to the neuronormative population. However, how time perception differs within individuals with BD based on BD sub-type (BDI vs II), mood, or antipsychotic medication-use has not been thoroughly investigated. The present work administered a supra-second interval timing task concurrent with electroencephalography (EEG) to patients with BD and a neuronormative comparison group. As this task is known to elicit frontal theta oscillations, signal from the frontal (Fz) lead was analyzed at rest and during the task. Results : Results suggest that individuals with BD show impairments in supra-second interval timing and reduced frontal theta power compared during the task to neuronormative controls. However, within BD sub-groups, neither time perception nor frontal theta differed in accordance with BD sub-type, mood, or antipsychotic medication use. Conclusions : his work suggests that BD sub-type, mood status or antipsychotic medication use does not alter timing profile or frontal theta activity. Together with previous work, these findings point to timing impairments in BD patients across a wide range of modalities and durations indicating that an altered ability to assess the passage of time may be a fundamental cognitive abnormality in BD.

Neural Responses to a Working Memory Task in Acute Depressed and Remitted Phases in Bipolar Patients

(1) Cognitive impairments such as working memory (WM) deficits are amongst the most common dysfunctions characterizing bipolar disorder (BD) patients, severely contributing to functional impairment. We aimed to investigate WM performance and associated brain activation during the acute phase of BD and to observe changes in the same patients during remission. (2) Frontal brain activation was recorded using functional near-infrared spectroscopy (fNIRS) during n-back task conditions (one-back, two-back and three-back) in BD patients in their acute depressive (n = 32) and remitted (n = 15) phases as well as in healthy controls (n = 30). (3) Comparison of BD patients during their acute phase with controls showed a trend (p = 0.08) towards lower dorsolateral prefrontal cortex (dlPFC) activation. In the remitted phase, BD patients showed lower dlPFC and ventrolateral prefrontal cortex (vlPFC) activation (p = 0.02) compared to controls. No difference in dlPFC and vlPFC activation between BD patients' phases was found. (4) Our results showed decreased working memory performance in BD patients during the working memory task in the acute phase of disease. Working memory performance improved in the remitted phase of the disease but was still particularly attenuated for the more demanding conditions.

Medication adherence and cognitive performance in schizophrenia-spectrum and bipolar disorder: results from the PsyCourse Study

Existing guidelines recommend psychopharmacological treatment for the management of schizophrenia and bipolar disorder as part of holistic treatment concepts. About half of the patients do not take their medication regularly, although treatment adherence can prevent exacerbations and re-hospitalizations. To date, the relationship between medication adherence and cognitive performance is understudied. Therefore, this study investigated the relationship between medication adherence and cognitive performance by analyzing the data of 862 participants with schizophrenia-spectrum and bipolar disorders (mean [SD] age, 41.9 [12.48] years; 44.8% female) from a multicenter study (PsyCourse Study). Z-scores for three cognitive domains were calculated, global functioning was measured with the Global Assessment of Functioning Scale, and adherence was assessed by a self-rating questionnaire. We evaluated four multiple linear regression models and built three clusters with hierarchical cluster analyses. Higher adherence behavior (p < 0.001) was associated with better global functioning but showed no impact on the cognitive domains learning and memory, executive function, and psychomotor speed. The hierarchical cluster analysis resulted in three clusters with different cognitive performances, but patients in all clusters showed similar adherence behavior. The study identified cognitive subgroups independent of diagnoses, but no differences were found in the adherence behavior of the patients in these new clusters. In summary, medication adherence was associated with global but not cognitive functioning in patients with schizophrenia-spectrum and bipolar disorders. In both diagnostic groups, cognitive function might be influenced by various factors but not medication adherence.

Total healthcare cost savings through improved bipolar I disorder identification using the Rapid Mood Screener in patients diagnosed with major depressive disorder

INTRODUCTION

Misdiagnosis of bipolar I disorder (BP-I) as major depressive disorder (MDD) leads to increased healthcare resource utilization and costs. The cost-effectiveness of the Rapid Mood Screener (RMS), a tool to identify BP-I in patients with depressive symptoms, was assessed in patients diagnosed with MDD presenting with depressive episodes.

METHODS

A decision-tree model of a hypothetical cohort of 1000 patients in a US health plan was used to estimate the number of correct diagnoses and overall total, direct healthcare costs over a 3-year timeframe for RMS-screened versus unscreened patients. Model inputs included the prevalence of BP-I in patients diagnosed with MDD, RMS sensitivity/specificity, and the cost of misdiagnosing BP-I as MDD.

RESULTS

Screening with the RMS resulted in 171, 159, and 143 additional correct BP-I or MDD diagnoses at Years 1, 2, and 3, respectively. Total healthcare plan cost savings were $1279 per patient in Year 1. Cumulative cost savings per patient for RMS screening versus no RMS screening were $2307 over 2 years and $3011 over 3 years. Scenario analyses showed that the RMS would remain cost-saving assuming a lower prevalence of BP-I (20% or 10%) versus the base case (24.3%).

CONCLUSION

The RMS is a cost-effective tool to identify BP-I in patients who would otherwise be misdiagnosed with MDD. Screening with the RMS resulted in cost-savings over 3 years, with model results remaining robust even with lower prevalence of BP-I and reduced RMS sensitivity assumptions.

Cognitive profiles in bipolar I disorder and associated risk factors: Using Wechsler adult intelligence scale—IV

Background

Despite the growing evidence of cognitive impairments in bipolar disorder (BD), little work has evaluated cognitive performances utilizing the latest version of the Wechsler Intelligence Scale-IV (WAIS-IV), which is one of the most widely used neurocognitive assessments in clinical settings. Furthermore, clinical characteristics or demographic features that negatively affect the cognitive functioning of BD were not systematically compared or evaluated. Accordingly, the present study aimed to examine the cognitive profile of bipolar I disorder (BD-I) patients and associated risk factors.

Methods

Participants included 45 patients, diagnosed with BD-I, current or most recent episode manic, and matching 46 healthy controls (HC). Cognitive performance was evaluated via WAIS-IV, and clinical characteristics of the BD-I group were examined via multiple self- and clinician-report questionnaires.

Results

Multivariate analysis of covariance (MANCOVA) results indicated that the BD-I group demonstrated significantly poorer performance compared to the HC group in subtests and indexes that reflect working memory and processing speed abilities. Redundancy analysis revealed that overall symptom severity, manic symptom severity, and anxiety were significant predictors of cognitive performance in BD-I, while age of onset, past mood disorder history, depression severity, and impulsiveness showed comparatively smaller predictive values.

Conclusion

The current study suggests cognitive deterioration in the cognitive proficiency area while generalized ability, including verbal comprehension and most of the perceptual reasoning skills, remain intact in BD-I. The identified risk factors of cognitive performance provide specific clinical recommendations for intervention and clinical decision-making.

Cognitive Profile and Relationship with Quality of Life and Psychosocial Functioning in Mood Disorders

BACKGROUND

Comparisons between healthy controls (HCs) and individuals with mood disorders have shown more cognitive dysfunction among the latter group, in particular in bipolar disorder (BD). This study aimed to characterize the pattern of cognitive function of BD and major depressive disorder (MDD) and compare them to HC using the (CogState Research Battery) CSRB™.

METHOD

Participants were tested, comprising the following domains: processing speed, attention, working memory, visual memory, executive functions, and verbal memory. Quality of life and functionality were also assessed. Multiple linear regression models were performed to examine the effect of demographic characteristics and functionality on cognitive outcomes separately for BD and MDD.

RESULTS

Ninety individuals participated in the study, of which 32 had BD, 30 had MDD, and 28 were HC. Differences were found between both BD and MDD and HC for the composite cognitive score, with significant differences between BD and HC (Diff = -5.5, 95% CI = [-9.5, -1.5], p = 0.005), and MDD and HC (Diff = -4.6, 95% CI = [-8.6, -0.5], p = 0.025). There were overall significant differences in five cognitive domains: processing speed (p = 0.001 and p = 0.004), attention (p = 0.002), working memory (p = 0.02), visual memory (p = 0.021), and verbal memory (p = 0.007). BD also presented worse performance than both MDD and HC, and MDD presented better performance than BD but worse than HC in quality of life and functionality. Multiple linear regression models were significative for education (p < 0.001) and age (p = 0.004) for BD and education (p < 0.001) for MDD.

CONCLUSION

In general, cognition is more affected in BD than MDD, which could be associated with functional and quality of life impairment.

Pediatric bipolar disorder: Executive, linguistic, mnemonic, and cognitive efficiency mapping

Neuropsychological assessment can enrich our understanding of Pediatric Bipolar Disorder (PB). This study aimed to: (1) analyze the occurrence of neuropsychological frequency of deficits and difficulties in children with PB; (2) verify whether there is a performance difference between PB type I (PB-I) and PB type II (PB-II)/unspecified, and between PB with and without ADHD; and (3) verify the cognitive efficiency differences within the PB group and control groups, and among clinical subgroups. Participants in the study were 16 children diagnosed with PB and 40 children with typical development (6-12 years old). The results indicated a high frequency of deficits/difficulties in verbal fluency, cognitive efficiency in performing basic abilities, inhibitory control, cognitive flexibility, and working memory, with emphasis on verbal and executive losses. There were indications that type PB-I and comorbidity with ADHD negatively impact a child's neuropsychological development. The clinical group showed more cognitive efficiency losses compared with the control group, and greater losses were observed in PB-I and in PB with ADHD. The role of neuropsychological evaluation in multidomain and nonlinear statistical analysis is critical to gaining an understanding of the clinical and cognitive heterogeneity of PB.

Changes of white matter microstructure after successful treatment of bipolar depression

BACKGROUND

Diffusion tensor imaging (DTI) measures suggest a widespread alteration of white matter (WM) microstructure in patients with bipolar disorder (BD). The chronotherapeutic combination of repeated total sleep deprivation and morning light therapy (TSD+LT) can acutely reverse depressive symptoms in approximately 60% of patients, and it has been confirmed as a model antidepressant treatment to investigate the neurobiological correlates of rapid antidepressant response.

METHODS

We tested if changes in DTI measures of WM microstructure could parallel antidepressant response in a sample of 44 patients with a major depressive episode in course of BD, treated with chronoterapeutics for one week. We used both a tract-wise and a voxel-wise approach for the whole-brain extraction of DTI measures of WM microstructure: axial (AD), radial (RD), and mean diffusivity (MD), and fractional anisotropy (FA).

RESULTS

Compared to baseline level, at one-week follow up we observed a significant increase in average FA measures paralleled by a significant decrease in MD measures of several WM tracts including cingulum, corpus callosum, corona radiata, cortico-spinal tract, internal capsule, fornix and uncinate fasciculus. The degree of change was associated to clinical response.

CONCLUSIONS

This is the first study to show changes of individual DTI measures of WM microstructure in response to antidepressant treatment in BD. Our results add new evidence to warrant a role for chronotherapeutics as a first-line treatment for bipolar depression and contribute identifying generalizable neuroimaging-based biomarkers of antidepressant response.

Neuropsychology of Bipolar Disorder

Bipolar disorder is associated with significant dysfunction in a broad range of neuropsychological domains and processes. Deficits have been reported to occur in symptomatic states (depression, [hypo]mania) as well as in remission (euthymia), having consequences for psychological well-being and social and occupational functioning. The profile and magnitude of neuropsychological deficits in bipolar disorder have been explored in a number of systematic reviews and meta-analyses. After discussing these briefly, this chapter will focus on examining the clinical and demographic factors that influence and modify the pattern and magnitude of deficits, as well as reviewing methods of assessment and analysis approaches which may improve our understanding of these problems.

Neurocognitive Impairment in Bipolar Disorder and Associated Factors: Using Population-based Norms and a Strict Criterion for Impairment Definition

BACKGROUND

Cognitive impairment is often identified in individuals with bipolar disorder and is associated with their functional impairment. However, there is controversy surrounding potential classification methods for impairment in cognitive measures.

OBJECTIVE

To examine the proportion of cognitive measures indicating impairment of attention, processing speed, memory, visuoconstructional abilities, and executive functions in individuals with bipolar disorder type I (euthymic) and healthy controls, using a strict criterion for defining impairment.

METHODS

We gave 43 individuals with bipolar disorder type I and 17 healthy controls a comprehensive clinical and neuropsychological assessment. All scores were standardized using means and standard deviations according to age. Impaired performance in all cognitive measures was determined using a distribution-based threshold of z=±1645. The effects of the sociodemographic and clinical variables on cognitive performance were examined using multiple stepwise backward regression analyses.

RESULTS

Clinically significant cognitive impairment was observed more frequently in the bipolar disorder group, compared to controls, on all measures. From participant factors, we found that level of education and number of manic episodes predicted variation in more cognitive measure scores.

DISCUSSION

The use of population-based norms to standardize cognitive measures, and a strict criterion to define cognitive impairment, in individuals with bipolar disorder type 1 and healthy controls resulted in a prevalence of impairment in cognitive domains' frequencies of deficits that fell within the ranges previously reported in meta-analyses.

CONCLUSIONS

Clinically introducing population norms and a stringent cognitive impairment criterion can facilitate more accurate measures of cognitive impairment in individuals with bipolar disorder.

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.

A systematic review on neuropsychological function in bipolar disorders type I and II and subthreshold bipolar disorders-something to think about

Neuropsychological dysfunction is a well-established finding in individuals with bipolar disorder type I (BP-I), even during euthymic periods; however, it is less clear whether this also pertains to bipolar disorder type II (BP-II) or those with subthreshold states (SBP; subthreshold bipolar disorder), such as bipolar not otherwise specified (BP-NOS). Herein, we compare the literature regarding neuropsychological performance in BP-II vs BP-I to determine the extent of relative impairment, and we present and review all related studies on cognition in SBP. After systematically searching PubMed, Medline, PsycINFO, and The Cochrane Library, we found 17 papers that comprise all the published studies relevant for this review. The areas that are consistently found to be impaired in BP are executive function, verbal memory, visual spatial working memory, and attention. More studies than not show no significant difference between BP-I and BP-II, particularly in euthymic samples. Preliminary evidence suggests that patients experiencing major depressive episodes who also meet criteria for SBP show similar profiles to BP-II; however, these results pertain only to a depressed sample. SBP were found to perform significantly better than both MDD and healthy controls in a euthymic sample. A consensus on mood state, patient selection, and neuropsychological testing needs to be agreed on for future research. Furthermore, no studies have used the most recent DSM-5 criteria for SBP; future studies should address this. Finally, the underlying bases of cognitive dysfunction in these diagnostic groups need to be further investigated. We suggest recommendations on all of the above current research challenges.

Cognitive emotional processing across mood disorders

While impairments in cognitive emotional processing are key to the experience of mood disorders, little is understood of their shared and distinct features across major depressive disorder (MDD) and bipolar disorder (BD). In this review, we discuss the similarities and differences in abnormal emotional processing associated with mood disorders across the cognitive domains of perception, attention, memory, and reward processing, with a particular focus on how these impairments relate to the clinical profile of the disorders. We consider behavioral and neuroimaging evidence, especially that of the growing consensus surrounding mood-congruent biases in cognition, in combination with state- and trait-related characteristics in an attempt to provide a more comprehensive and translational overview of mood disorders. Special consideration is given to the shared phenomenon of mood instability and its role as a potential transdiagnostic marker across the prodrome and maintenance of mood disorders.

Similar profiles of cognitive domain deficits between medication-naïve patients with bipolar II depression and those with major depressive disorder

BACKGROUND

Bipolar disorder (BD) II is more likely to be misdiagnosed as major depressive disorder (MDD) than other types of BD, leading to incorrect treatment and poor outcomes. Previous studies have shown inconsistent results regarding the differences in cognitive deficits between the two disorders. To eliminate the compounding effects of medication and aging, we sought to investigate changes in cognitive function in medication-naïve, non-late-life patients with BDII and MDD.

METHODS

Three subject groups were enrolled: 30 depressed BDII patients, 30 depressed MDD patients and 30 healthy controls. All subjects underwent a battery of cognitive tests to assess 8 cognitive domains. The cognitive domains were compared between the three subject groups. In BDII and MDD, the effect sizes were computed as evaluation parameters, weighing the degree of the cognitive deficits and the correlations between cognitive test deficits and clinical variables were also computed.

RESULTS

Compared with the controls, the BDII and MDD patients were characterized by similar deficits in psychomotor speed, working memory, visual memory, attention switching and verbal fluency. Moderate to severe deficits in the majority of cognitive tests were observed in the BDII and MDD patients. Furthermore, correlations between the modified Wisconsin Card Sorting Test total errors and age of onset in the BDII patients and between correct digit span responses (backward and total) and depressive severity were found in the MDD patients.

CONCLUSIONS

Our findings suggest that BDII and MDD patients may suffer from similar profiles of cognitive domain deficits that may not assist in distinguishing between the two disorders. In addition, cognitive deficits may be correlated with the age of onset and depressive severity in mood disorders.

Resting-state functional connectivity in individuals with bipolar disorder during clinical remission: a systematic review

BACKGROUND

Bipolar disorder is chronic and debilitating. Studies investigating resting-state functional connectivity in individuals with bipolar disorder may help to inform neurobiological models of illness.

METHODS

We conducted a systematic review with the following goals: to summarize the literature on resting-state functional connectivity in bipolar disorder during clinical remission (euthymia) compared with healthy controls; to critically appraise the literature and research gaps; and to propose directions for future research. We searched PubMed/MEDLINE, Embase, PsycINFO, CINAHL and grey literature up to April 2017.

RESULTS

Twenty-three studies were included. The most consistent finding was the absence of differences in resting-state functional connectivity of the default mode network (DMN), frontoparietal network (FPN) and salience network (SN) between people with bipolar disorder and controls, using independent component analysis. However, 2 studies in people with bipolar disorder who were positive for psychosis history reported DMN hypoconnectivity. Studies using seed-based analysis largely reported aberrant resting-state functional connectivity with the amygdala, ventrolateral prefrontal cortex, cingulate cortex and medial prefrontal cortex in people with bipolar disorder compared with controls. Few studies used regional homogeneity or amplitude of low-frequency fluctuations.

LIMITATIONS

We found heterogeneity in the analysis methods used.

CONCLUSION

Stability of the DMN, FPN and SN may reflect a state of remission. Further, DMN hypoconnectivity may reflect a positive history of psychosis in patients with bipolar disorder compared with controls, highlighting a potentially different neural phenotype of psychosis in people with bipolar disorder. Resting-state functional connectivity changes between the amygdala, prefrontal cortex and cingulate cortex may reflect a neural correlate of subthreshold symptoms experienced in bipolar disorder euthymia, the trait-based pathophysiology of bipolar disorder and/or a compensatory mechanism to maintain a state of euthymia.

Neuropsychological Functioning in Euthymic Phase of Bipolar Affective Disorder

BACKGROUND

A substantial proportion of euthymic bipolar disorder patients have neuropsychological impairment which can have a significant impact on the overall functional recovery.

MATERIALS AND METHODS

A total of 60 bipolar disorder patients, currently in euthymic phase for the last 3 months with minimum duration of illness 2 years and current Young Mania Rating Scale <7 and Hamilton Depression Rating Scale <6, currently on medications were administrated various neuropsychological tests.

RESULTS

Approximately half of the patients have neuropsychological impairments in the areas of mental speed, sustained attention, verbal fluency, working memory, set shifting, verbal and visual memory, and visual-constructional ability.

CONCLUSION

Findings of the current study provides evidence of neuropsychological impairment in euthymic bipolar disorder patients, and type of medications also has an impact on neuropsychological functions.

Neurocognition in patients with psychotic and non-psychotic bipolar I disorder. A comparative study with individuals with schizophrenia

BACKGROUND

It has been suggested that patients with bipolar disorder with psychotic symptoms (BD-P) have larger neurocognitive impairment than patients with bipolar disorder without a history of psychotic symptoms (BD-NP). The objective of this study was to compare neurocognitive performance of BD-P and BD-NP relative to a group of patients with schizophrenia (SZ), and healthy controls (HC).

METHODS

Neurocognitive function was examined in 100 subjects with bipolar I disorder (50 BD-P, 50 BD-NP), 50 SZ, and 51 HC. All patients with BD fulfilled criteria for euthymia, while all SZ patients were stabilised for at least the previous 3 months.

RESULTS

Patients with BD-P and BD-NP performed worse than HC in all neurocognitive measures, except for sustained attention. Differences between BD-P and BD-NP were subtle and circumscribed to the working memory domain (effect size: 0.29). SZ performed worse than BD-NP in the neurocognitive composite index (NCI) and in the working memory domain. There were no differences between SZ and BD-P in any neurocognitive measure.

LIMITATIONS

The relatively small sample size, the cross-sectional design and, that patients were receiving pharmacological treatment are the main limitations of this study.

CONCLUSIONS

Our findings show that the three groups of patients have a large neurocognitive impairment. Differences are quantitative and only present in some neurocognitive domains, such as working memory. These results suggest that patients with BD and SZ can benefit from the same strategies of cognitive remediation.

Executive functioning deficits among adults with Bipolar Disorder (types I and II): A systematic review and meta-analysis

BACKGROUND

Executive functioning (EF) deficits contribute to a significant proportion of the burden of disease associated with bipolar disorder (BD). Yet, there is still debate in the literature regarding the exact profile of executive functioning in BD. The purpose of the present project was to assess whether EF deficits exist among adults suffering BD, and whether these deficits (if apparent) differ by BD subtype.

METHODS

A systematic search identified relevant literature. Randomised controlled trials that used neuropsychological assessment to investigate EF among adults 16-65 years) with a remitted DSM diagnosis of BD (type I or II) were included. Studies were published between 1994 and 2015. A systematic review and meta-analysis were undertaken. For individual studies, standardised mean differences (Cohen's d) and 95% confidence intervals were calculated and represented in forest plots to illustrate differences in executive performance between groups. Summary effects were produced and tests of heterogeneity employed to assess the dispersion and generalisability of results.

RESULTS

Thirty-six studies met criteria for inclusion. Six domains of EF were identified: Set-shifting (SS), inhibition (INH), planning (PLA), verbal fluency (VF), working memory (WM), and attention (ATT). BD1s performed worse than HCs in all domains. BD2s demonstrated impairment in VF, WM, SS, and ATT. The results were mixed for comparisons between BD1s and BD2s, but revealed that BD2s can experience similar (or sometimes greater) EF impairment.

LIMITATIONS

Only a limited number of studies that included BD2 samples were available for inclusion in the current study. Subgroup analysis to elucidate potential moderators of within-study variance was not undertaken.

CONCLUSION

This is the first systematic review and meta-analysis to have compared the EF of remitted BD1s, BD2s, and HCs. The results provided useful insight into the EF profile of patients with BD, and offered commentary as to some of the contradictory results reported in the literature. A standardised methodological protocol for assessment of EF in BD was proposed. The information in this review could enhance our understanding of EF impairment inherent in BD, and the methods and efficacy with which clinicians assess and treat this population.

Comparison of neurocognitive function in major depressive disorder, bipolar disorder, and schizophrenia in later life: A cross-sectional study of euthymic or remitted, non-demented patients using the Japanese version of the Brief Assessment of Cognition in Schizophrenia (BACS-J)

Major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SZ) are associated with cognitive dysfunction both in adulthood and in later life. In this study, we directly compared neurocognitive function between these three conditions in later life, employing stringent definitions of euthymia and symptomatic remission. Cognitive function in 60 elderly outpatients with MDD, BD, or SZ (20 patients per group) was assessed using the Japanese version of the Brief Assessment of Cognition in Schizophrenia. Patients with MDD had significantly higher z scores than both the other groups with large or moderately large effect sizes, for verbal fluency, attention and speed of information processing, and composite scores. In contrast, there were no significant differences in the degree of neurocognitive impairment between patients with BD and SZ. In later life, patients with BD and SZ showed a similar degree of neurocognitive impairment, while patients with MDD showed smaller impairments in several neurocognitive domains compared to patients with either of the other two disorders.

Resting state functional connectivity in women with bipolar disorder during clinical remission

OBJECTIVES

Periods of euthymia in bipolar disorder (BD) serve as a valuable time to study trait-based pathophysiology. The use of resting state functional connectivity (Rs-FC) can aid in the understanding of BD pathophysiology free of task or mood state biases. The present study investigated two unexplored areas of Rs-FC research in bipolar remission: (i) Rs-FC in women, controlling for the potential influence of premenstrual symptoms, and (ii) the use of both independent component analysis (ICA) and seed-based analysis (SBA) to investigate Rs-FC.

METHODS

We investigated Rs-FC of the default mode network, meso-paralimbic network and fronto-parietal network in a sample of 32 euthymic women with BD and 36 age-matched controls during the mid-follicular phase of their menstrual cycle. Rs-FC was assessed with ICA and SBA using the posterior cingulate cortex (PCC), amygdala and dorsolateral prefrontal cortex (dlPFC) as seed points for their respective resting state networks.

RESULTS

In BD, compared to controls, SBAs revealed increased coupling between the PCC and the angular gyrus (P=.002, false discovery rate [FDR]-corrected) and between the right dlPFC and the brainstem (P=.03, FDR-corrected). In BD only, PCC-angular gyrus coupling was correlated with anxiety symptoms. Group differences in Rs-FC using ICA did not survive multiple comparisons.

CONCLUSIONS

Negative findings from whole-brain ICA Rs-FC may reflect a state of clinical remission in BD. Heightened activation between the PCC and the angular gyrus and between the dlPFC and the brainstem may reflect (i) an abnormal trait integration of affective information during clinical remission and/or (ii) an adaptive compensatory mechanism required for clinical stabilization.

Predictors of the discrepancy between objective and subjective cognition in bipolar disorder: a novel methodology

OBJECTIVE

The poor relationship between subjective and objective cognitive impairment in bipolar disorder (BD) is well-established. However, beyond simple correlation, this has not been explored further using a methodology that quantifies the degree and direction of the discrepancy. This study aimed to develop such a methodology to explore clinical characteristics predictive of subjective-objective discrepancy in a large BD patient cohort.

METHODS

Data from 109 remitted BD patients and 110 healthy controls were pooled from previous studies, including neuropsychological test scores, self-reported cognitive difficulties, and ratings of mood, stress, socio-occupational capacity, and quality of life. Cognitive symptom 'sensitivity' scores were calculated using a novel methodology, with positive scores reflecting disproportionately more subjective complaints than objective impairment and negative values reflecting disproportionately more objective than subjective impairment ('stoicism').

RESULTS

More subsyndromal depressive and manic symptoms, hospitalizations, BD type II, and being male positively predicted 'sensitivity', while higher verbal IQ predicted more 'stoicism'. 'Sensitive' patients were characterized by greater socio-occupational difficulties, more perceived stress, and lower quality of life.

CONCLUSION

Objective neuropsychological assessment seems especially warranted in patients with (residual) mood symptoms, BD type II, chronic illness, and/or high IQ for correct identification of cognitive deficits before commencement of treatments targeting cognition.

The Relationship Between Neurocognitive Functioning and Occupational Functioning in Bipolar Disorder: A Literature Review

Neurocognitive impairment in Bipolar Disorder (BD) has been widely reported, even during remission. Neurocognitive impairment has been identified as a contributing factor towards unfavourable psychosocial functioning within this population. The objective of this review was to investigate the association between neurocognitive impairment and occupational functioning in BD. A literature review of English-language journal articles from January 1990 to November 2013 was undertaken utilising the PsychINFO, Scopus and Web of Knowledge databases. Studies that made specific reference to occupational outcomes were included, and those that reported on global psychosocial measures were excluded. Majority of the papers reviewed (20 out of 23) identified an association between neurocognitive impairment (particularly in executive functioning, verbal learning and memory, processing speed and attention) and occupational functioning. Several methodological issues were identified. There was a discrepancy in the measures used to assess neurocognitive function across studies and also the definition and measurement of occupational functioning. The clinical features of the samples varied across studies, and confounding variables were intermittently controlled. The review focused on English-language papers only and hence there is a bias toward the Western labour market. These limitations therefore influence the generalizability of the interpreted findings and the reliability of comparisons across studies. Neurocognitive impairment in BD appears to play a role in occupational outcomes. The findings of this review highlight the challenges for future research in this area, particularly in the measurement of neurocognitive and occupational functioning. Incorporating neurocognitive interventions in the treatment of BD, which has traditionally focussed solely on symptomatic recovery, may advance the vocational rehabilitation of these patients.

Clinical outcomes of long-acting injectable risperidone in patients with bipolar I disorder: A 1-year retrospective cohort study

OBJECTIVES

We explored the effect of risperidone long-acting injection (LAI) treatment on patients with bipolar I disorder in a real-world setting.

METHODS

In this retrospective cohort study, 469 patients with bipolar I disorder were enrolled and treated with risperidone LAI and different oral antipsychotics and followed for 1 year. Concomitant medications, such as mood stabilizers, antidepressant, anxiolytics, hypnotics, or anticholinergics, were administered. On the basis of risperidone LAI use and treatment compliance, the patients were classified into 4 groups: the first long-acting injectable antipsychotics (LAI1) group (compliant patients receiving risperidone LAI treatment) (N=44), the second long-acting injectable antipsychotics (LAI2) group (non-compliant patients receiving risperidone LAI treatment) (N=33), the first non-LAI (NLAI1) group (compliant patients receiving oral medications) (N =337), and the second non-LAI (NLAI2) group (non-compliant patients receiving oral medications) (N=55). The rate of re-hospitalization, length of hospital stay, and rate of emergency room visit were assessed.

RESULTS

Compared with the non-LAI groups, the LAI groups had longer mean duration of illness (8.5 years, P=0.0001), higher rate of admission due to mood episodes (P<0.0001), depressive episodes (P<0.0001), or manic episodes (P=0.0002), and higher rate of emergency room visit (P=0.0003) before enrollment. After a 1-year follow-up, re-hospitalization rates were significantly lower in the LAI1 group than that before enrollment for any episodes (P=0.0001), manic episodes (P=0.005), and depressive episodes (P=0.002). The rates of emergency room visit were significantly lower in the LAI1 (P=0.0001), LAI2 (P=0.013), and NLAI1 (P=0.0001) groups compared with those before enrollment.

CONCLUSIONS

Risperidone LAI reduces the clinical severity of bipolar I disorder.

Low compliance to pharmacological treatment is linked to cognitive impairment in euthymic phase of bipolar disorder

BACKGROUND

Cognitive impairment and low compliance to pharmacological treatment are frequent complications in bipolar disorder. Moreover, low compliance in patients with bipolar disorder is one of the main reasons for relapse. This in turn, is associated with an increase in neurocognitive symptoms. The current study aimed to determine whether attention, memory, and executive function are related to the level of compliance to pharmacological treatment in individuals with bipolar disorder in euthymic phase.

METHOD

We examined 34 patients with bipolar disorder (12 with low compliance to the treatment and 22 with high compliance to the treatment) according to the DSM-IV criteria, in the range of 18-55 years. All patients were assessed through a neuropsychological battery in one single session. Analysis of covariance (ANCOVA) was used to compare neuropsychological test scores between low and high compliance patients. Clinical and sociodemographic characteristics were included as covariates in the study.

RESULTS

Patients with low level of compliance performed significantly worse than high treatment compliance on verbal memory immediate free recall (F (1)=12.14, p=.002), verbal memory immediate cued recall (F (1)=10.45, p=.003), verbal memory delayed free recall (F (1)=5.52, p=.027), and verbal memory delayed cued recall (F (1)=6.11, p=.021). Covariates such as number of manic episodes, history of psychosis and years of education were found significant for executive functions and processing speed.

CONCLUSION

We found that low compliance to pharmacological treatment is consistently linked to immediate and delayed verbal memory. In addition, executive function and processing speed were associated with clinical and demographic characteristics. Limitations of this study include the small sample size, a cross-sectional design that cannot address causality, and inability to account for pharmacologic effects.

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.

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.

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.

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.

Disruption of white matter integrity marks poor antidepressant response in bipolar disorder

BACKGROUND

Changes of white matter (WM) microstructure have been proposed as structural biomarkers of bipolar disorder (BD). The chronotherapeutic combination of repeated total sleep deprivation and morning light therapy (TSD+LT) can acutely reverse depressive symptoms in approximately 60% of patients, and it has been proposed as a model antidepressant treatment to investigate the neurobiological correlates of rapid antidepressant response.

METHODS

We tested if baseline DTI measures can predict response to treatment in 70 in-patients affected by a major depressive episode in the course of BD, treated with chronotherapeutics for one week. We performed whole-brain tract-based spatial statistics with threshold-free cluster enhancement for the DTI measures of WM microstructure integrity: fractional anisotropy, axial, radial, and mean diffusivity.

RESULTS

Increased mean and radial water diffusivity correlated with poor antidepressant response to TSD+LT in core WM tracts which are crucial for the functional integrity of the brain, including corpus callosum, corona radiata, cingulum bundle, superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and thalamic radiation.

LIMITATIONS

Limitations include issues such as generalizability, possible population stratification, medications and their effects on DTI measures, and no placebo control for chronotherapeutics. We could not consider other factors such as gene-environment interactions.

CONCLUSIONS

The association of increased radial and mean diffusivity with poor response to chronotherapeutic treatment warrants interest for the study of DTI measures of WM microstructure as markers for treatment response in bipolar depression.

Cognitive performances associate with measures of white matter integrity in bipolar disorder

BACKGROUND

Neuropsychological deficits constitute enduring trait-like features in bipolar disorder (BD), and persist in euthymia. White matter (WM) abnormalities are one of the most consistently reported findings in neuroimaging studies of BD. We hypothesized that neuropsychological performances could correlate with WM integrity in a sample of bipolar patients in core WM tracts.

METHODS

Seventy-eight patients affected by BD were evaluated for verbal memory, working memory, psychomotor coordination, executive functions, attention and information processing, and verbal fluency through the Brief Assessment of Cognition in Schizophrenia. White matter integrity was evaluated using DTI and tract-based spatial statistics with threshold free cluster enhancement (p>0.949).

RESULTS

We observed that cognitive performances in attention and information processing, working memory, executive functions and psychomotor coordination were associated with DTI measures of WM integrity in several association fibres: inferior and superior longitudinal fasciculus, inferior fronto-occipital fasciculus, cingulum bundle, corpus callosum, and corona radiata.

LIMITATION

The drug treatments administered during the course of the illness could have influenced DTI measures and neurocognitive function. Other limitations include issues such as generalizability due to the lack of a control group, possible undetected past comorbidities, population stratification, and the presence of a 28% of patients which previously experienced delusions.

CONCLUSIONS

This is the first study to use a validated cognitive battery to investigate the principal cognitive domains in BD. Our data confirm the importance of WM integrity as a neurobiological underpinning of cognitive deficits.

Left temporal activation associated with depression severity during a verbal fluency task in patients with bipolar disorder: a multichannel near-infrared spectroscopy study

BACKGROUND

Neuroimaging studies using multichannel near-infrared spectroscopy (NIRS) have provided compelling evidence about the dysfunction of the frontotemporal cortices in patients with bipolar disorder (BD). However, it remains unclear whether the dysfunction is associated with mood state or symptom severity. Using NIRS, we aimed to clarify differences in oxygenated hemoglobin (oxy-Hb) activation between depressive and euthymic states as well as regional brain dysfunction in relation to symptom severity in BD.

METHODS

Fifty-five patients with BD, including 30 with bipolar depression (BPD) and 25 with euthymic bipolar disorder (BPE), and 28 healthy controls (HCs) participated in the study. Regional hemodynamic changes during a verbal fluency task (VFT) were monitored using a 52-channel NIRS apparatus.

RESULTS

The mean oxy-Hb changes induced by VFT were significantly smaller in the BD patients than in the HCs in 18 channels in the frontotemporal regions (false-discovery rate p<0.05, p=0.000-0.011). The BPD group exhibited significantly smaller changes in mean oxy-Hb compared with the BPE group in three channels of the left temporal region (p=0.005-0.014). In the BD patients, significant negative correlations were observed between mean oxy-Hb changes in the left temporal regions and the severity of depression.

LIMITATIONS

Our sample size was small, making the results susceptible to type II errors.

CONCLUSIONS

BD patients have persistent hypofunction of the frontotemporal cortical regions. Moreover, the hemodynamic response in the left temporal regions is associated with symptom severity.

Cognitive functioning in clinically stable patients with bipolar disorder I and II

OBJECTIVES

Bipolar disorder is accompanied by cognitive impairments, which persists during euthymic phases. The purpose of the present study was to identify those neuropsychological tests that most reliably tell euthymic bipolar patients and controls apart, and to clarify the extent to which these cognitive impairments are clinically significant as judged from neuropsychological norms.

METHODS

Patients with bipolar disorder (type I: n = 64; type II: n = 44) and controls (n = 86) were examined with a comprehensive neuropsychological test battery yielding 47 measures of executive functioning, speed, memory, and verbal skills. Multivariate analysis was used to build a model of cognitive performance with the ability to expose underlying trends in data and to reveal cognitive differences between patients and controls.

RESULTS

Patients with bipolar disorder and controls were partially separated by one predictive component of cognitive performance. Additionally, the relative relevance of each cognitive measure for such separation was decided. Cognitive tests measuring set shifting, inhibition, fluency, and searching (e.g., Trail Making Test, Color-Word) had strongest discriminating ability and most reliably detected cognitive impairments in the patient group.

CONCLUSIONS

Both bipolar disorder type I and type II were associated with cognitive impairment that for a sizeable minority is significant in a clinical neuropsychological sense. We demonstrate a combination of neuropsychological tests that reliably detect cognitive impairment 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.

Restoring functioning in bipolar disorder: functional remediation

Over the past several years, many evidence-based interventions have proven to be effective as adjunctive therapies in the treatment of bipolar disorder. Only a few, however, have addressed the issue of functional recovery in bipolar euthymic patients, which is difficult to achieve after an affective episode. The functional remediation program has been designed at the Hospital Clinic of Barcelona with the main aim of treating functional impairment in bipolar disorder. The program consists of 21 weekly group sessions and is based on a neuro-cognitive-behavioral approach. Throughout the sessions, euthymic patients are trained in the use of neurocognitive skills to be applied during their daily routines. Modeling techniques, role playing, self-instructions, verbal instructions, positive reinforcement, and metacognitive cues are some of the techniques that are used in the program. The present report aims at explaining this new intervention to improve functional outcomes in euthymic bipolar patients.

Altered functional connectivity between emotional and cognitive resting state networks in euthymic bipolar I disorder patients

Bipolar disorder is characterized by a functional imbalance between hyperactive ventral/limbic areas and hypoactive dorsal/cognitive brain regions potentially contributing to affective and cognitive symptoms. Resting-state studies in bipolar disorder have identified abnormal functional connectivity between these brain regions. However, most of these studies used a seed-based approach, thus restricting the number of regions that were analyzed. Using data-driven approaches, researchers identified resting state networks whose spatial maps overlap with frontolimbic areas such as the default mode network, the frontoparietal networks, the salient network, and the meso/paralimbic network. These networks are specifically engaged during affective and cognitive tasks and preliminary evidence suggests that functional connectivity within and between some of these networks is impaired in bipolar disorder. The present study used independent component analysis and functional network connectivity approaches to investigate functional connectivity within and between these resting state networks in bipolar disorder. We compared 30 euthymic bipolar I disorder patients and 35 age- and gender-matched healthy controls. Inter-network connectivity analysis revealed increased functional connectivity between the meso/paralimbic and the right frontoparietal network in bipolar disorder. This abnormal connectivity pattern did not correlate with variables related to the clinical course of the disease. The present finding may reflect abnormal integration of affective and cognitive information in ventral-emotional and dorsal-cognitive networks in euthymic bipolar patients. Furthermore, the results provide novel insights into the role of the meso/paralimbic network in bipolar disorder.

Adverse childhood experiences influence white matter microstructure in patients with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is associated with adverse childhood experiences (ACE), which worsen the lifetime course of illness, and with signs of widespread disruption of white matter (WM) integrity in adult life. ACE are associated with changes in WM microstructure in healthy humans.

METHOD

We tested the effects of ACE on diffusion-tensor imaging (DTI) measures of WM integrity in 80 in-patients affected by a major depressive episode in the course of BD. We used whole-brain tract-based spatial statistics in the WM skeleton with threshold-free cluster enhancement of DTI measures of WM microstructure: axial, radial and mean diffusivity, and fractional anisotropy.

RESULTS

ACE hastened the onset of illness. We observed an inverse correlation between the severity of ACE and DTI measures of axial diffusivity in several WM fibre tracts contributing to the functional integrity of the brain and including the corona radiata, thalamic radiations, corpus callosum, cingulum bundle, superior longitudinal fasciculus, inferior fronto-occipital fasciculus and uncinate fasciculus.

CONCLUSIONS

Axial diffusivity reflects the integrity of axons and myelin sheaths, and correlates with functional connectivity and with higher-order abilities such as reasoning and experience of emotions. In patients with BD axial diffusivity is increased by lithium treatment. ACE might contribute to BD pathophysiology by hampering structural connectivity in critical cortico-limbic networks.

Empirical evidence for discrete neurocognitive subgroups in bipolar disorder: clinical implications

BACKGROUND

Recent data suggest trait-like neurocognitive impairments in bipolar disorder (BPD), with deficits about 1 s.d. below average, less severe than deficits noted in schizophrenia. The frequency of significant impairment in BPD is approximately 60%, with 40% of patients characterized as cognitively spared. This contrasts with a more homogeneous presentation in schizophrenia. It is not understood why some BPD patients develop deficits while others do not.

METHOD

A total of 136 patients with BPD completed the MATRICS Consensus Cognitive Battery and data were entered into hierarchical cluster analyses to: (1) determine the optimal number of clusters (subgroups) that fit the sample; and (2) assign subjects to a specific cluster based on individual profiles. We then compared subgroups on several clinical factors and real-world community functioning.

RESULTS

Three distinct neurocognitive subgroups were found: (1) an intact group with performance comparable with healthy controls on all domains but with superior social cognition; (2) a selective impairment group with moderate deficits on processing speed, attention, verbal learning and social cognition and normal functioning in other domains; and (3) a global impairment group with severe deficits across all cognitive domains comparable with deficits in schizophrenia.

CONCLUSIONS

These results suggest the presence of multiple cognitive subgroups in BPD with unique profiles and begin to address the relationships between these subgroups, several clinical factors and functional outcome. Next steps will include using these data to help guide future efforts to target these disabling symptoms with treatment.

Fronto-limbic disconnection in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a severe, disabling and life-threatening illness. Disturbances in emotion and affective processing are core features of the disorder with affective instability being paralleled by mood-congruent biases in information processing that influence evaluative processes and social judgment. Several lines of evidence, coming from neuropsychological and imaging studies, suggest that disrupted neural connectivity could play a role in the mechanistic explanation of these cognitive and emotional symptoms. The aim of the present study is to investigate the effective connectivity in a sample of bipolar patients.

METHODS

Dynamic causal modeling (DCM) technique was used to study 52 inpatients affected by bipolar disorders consecutively admitted to San Raffaele hospital in Milano and forty healthy subjects. A face-matching task was used as activation paradigm.

RESULTS

Patients with BD showed a significantly reduced endogenous connectivity in the DLPFC to Amy connection. There was no significant group effect upon the endogenous connection from Amy to ACC, from ACC to Amy and from DLPFC to ACC.

CONCLUSIONS

Both DLPFC and ACC are part of a network implicated in emotion regulation and share strong reciprocal connections with the amygdale. The pattern of abnormal or reduced connectivity between DLPFC and amygdala may reflect abnormal modulation of mood and emotion typical of bipolar patients.

Autobiographical memory and its association with neuropsychological function in bipolar disorder

OBJECTIVE

The aim of this study was to investigate the overgeneralization of autobiographical memory (AM) in bipolar disorder (BD) and assess its association with multiple cognitive domains.

METHOD

Twenty-eight clinically stable bipolar I patients and an equal number of age- and gender-matched healthy controls (HC) were included. All participants were examined using the autobiographical memory test (AMT) and the neuropsychological battery including the general intelligence, attention, verbal memory, verbal fluency, visual memory, and executive functions domain. Demographic, clinical, and test variables were compared between BD and HC groups. Correlation analyses of AMT scores with cognitive functions were performed within each group, controlling for demographic and clinical variables.

RESULTS

Total and negative scores of AMT were significantly lower in BD patients compared to HC individuals. AMT scores were significantly correlated with WAIS similarities, WCST perseverative errors, and WCST categories completed in BD, whereas AMT scores were correlated with verbal memory and verbal fluency in HC.

CONCLUSION

Our findings suggest that overgeneral AM is a characteristic of BD and is related to executive function. Future studies should investigate the benefit of additional treatment focusing on overgeneral AM in BD.

Psychotherapy for Bipolar Disorder in Adults: A Review of the Evidence

Although pharmacotherapy is the mainstay of treatment for bipolar disorder, medication offers only partial relief for patients. Treatment with pharmacologic interventions alone is associated with disappointingly low rates of remission, high rates of recurrence, residual symptoms, and psychosocial impairment. Bipolar-specific therapy is increasingly recommended as an essential component of illness management. This review summarizes the available data on psychotherapy for adults with bipolar disorder. We conducted a search of the literature for outcome studies published between 1995 and 2013 and identified 35 reports of 28 randomized controlled trials testing individual or group psychosocial interventions for adults with bipolar disorder. These reports include systematic trials investigating the efficacy and effectiveness of individual psychoeducation, group psychoeducation, individual cognitive-behavioral therapy, group cognitive-behavioral therapy, family therapy, interpersonal and social rhythm therapy, and integrated care management. The evidence demonstrates that bipolar disorder-specific psychotherapies, when added to medication for the treatment of bipolar disorder, consistently show advantages over medication alone on measures of symptom burden and risk of relapse. Whether delivered in a group or individual format, those who receive bipolar disorder-specific psychotherapy fare better than those who do not. Psychotherapeutic strategies common to most bipolar disorder-specific interventions are identified.

Are adults with bipolar disorder active? Objectively measured physical activity and sedentary behavior using accelerometry

BACKGROUND

Little is known about physical activity and sedentary behavior of adults with bipolar disorder (BP). Physical activity and sedentary behaviors may be modifiable factors associated with elevated rates of obesity, diabetes, cardiovascular disease, metabolic syndrome, and mortality in adults with BP.

METHODS

Sixty adult outpatients treated for BP (> 18 yr) wore accelerometers for seven consecutive days. Each minute epoch was assigned an activity level based on the number of counts per minute; sedentary(<100 counts), light(101-1951 counts), or moderate/vigorous(>1952 counts). Adults with BP were matched 1:1 to users and non-users of mental health services (MHS) (NHANES 2003-2004) by gender, closest BMI, and age.

RESULTS

On average, adults with BP wore actigraphs over 17 h/day. The majority of monitoring time (78%) was classified as sedentary (approximately 13.5h/day). Light physical activity accounted for 21% of the monitoring time/day (215 min/day). None achieved 150 min/wk of moderate/vigorous activity as recommended by national guidelines. Adults with BP were significantly less active and more sedentary than MHS users and non-users in NHANES 2003-2004 (p<0.01).

LIMITATIONS

Majority of the participants were relatively asymptomatic with most (87%) having no more than mild depressive symptoms and none experiencing severe manic symptoms. The sedating effects of medications on physical activity were not investigated.

CONCLUSION

From clinical perspectives, these findings justify physical activity interventions targeting adults with BP as a possible means to improve their physical and mental health and to reduce the elevated risk of commonly observed medical comorbidities in this high-risk population.

Affect recognition across manic and euthymic phases of bipolar disorder in Han-Chinese patients

Patients with bipolar disorder (BD) have affect recognition deficits. Whether affect recognition deficits constitute a state or trait marker of BD has great etiopathological significance. The current study aims to explore the interrelationships between affect recognition and basic neurocognitive functions for patients with BD across different mood states, using the Diagnostic Analysis of Non-Verbal Accuracy-2, Taiwanese version (DANVA-2-TW) as the index measure for affect recognition. To our knowledge, this is the first study examining affect recognition deficits of BPD across mood states in the Han Chinese population. Twenty-nine manic patients, 16 remitted patients with BD, and 40 control subjects are included in the study. Distinct association patterns between affect recognition and neurocognitive functions are demonstrated for patients with BD and control subjects, implicating alternations in emotion associated neurocognitive processing. Compared to control subjects, manic patients but not remitted subjects perform significantly worse in the recognition of negative emotions as a whole and specifically anger, after adjusting for differences in general intellectual ability and basic neurocognitive functions. Affect recognition deficit may be a relatively independent impairment in BD rather than consequences arising from deficits in other basic neurocognition. The impairments of manic patients in the recognition of negative emotions, specifically anger, may further our understanding of core clinical psychopathology of BD and have implications in treating bipolar patients across distinct mood phases.