Neurocognition in bipolar disorders—A closer look at comorbidities and medications

A bibliometric and visual analysis of cognitive function in bipolar disorder from 2012 to 2022

INTRODUCTION

Bipolar disorder (BD) is a chronic psychiatric disorder that combines hypomania or mania and depression. The study aims to investigate the research areas associated with cognitive function in bipolar disorder and identify current research hotspots and frontier areas in this field.

METHODOLOGY

Publications related to cognitive function in BD from 2012 to 2022 were searched on the Web of Science Core Collection (WoSCC) database. VOSviewer, CiteSpace, and Scimago Graphica were used to conduct this bibliometric analysis.

RESULTS

A total of 989 articles on cognitive function in BD were included in this review. These articles were mainly from the United States, China, Canada, Spain and the United Kingdom. Our results showed that the journal "Journal of Affective Disorders" published the most articles. Apart from "Biploar disorder" and "cognitive function", the terms "Schizophrenia", "Meta analysis", "Rating scale" were also the most frequently used keywords. The research on cognitive function in bipolar disorder primarily focused on the following aspects: subgroup, individual, validation and pathophysiology.

CONCLUSIONS

The current concerns and hotspots in the filed are: "neurocognitive impairment", "subgroup", "1st degree relative", "mania", "individual" and "validation". Future research is likely to focus on the following four themes: "Studies of the bipolar disorder and cognitive subgroups", "intra-individual variability", "Validation of cognitive function tool" and "Combined with pathology or other fields".

Alcohol Dependence Syndrome With Bipolar Affective Disorder and Hypomanic Current Episode: A Case Report

Studies have revealed that individuals with bipolar I and bipolar II have a past of substance abuse. The co-occurrence of bipolar disorder and alcoholism is frequent. Although various arguments have been put forward to explain the relationship between these disorders, it is still not fully understood. Since substance abuse is prevalent among bipolar patients, it would be beneficial to investigate the impact of substance abuse on clinical characteristics, as well as the progression of the illness. Thus, this study was carried out to investigate a case of alcohol dependence with bipolar disorder. A 49-year-old male visited the psychiatry outpatient department and then was admitted. The patient's chief complaints were alcohol consumption, cigarette smoking, daily drinking for 35 years, irritability/aggressiveness, boastful talk, overspending, and decreased need for sleep from the last 20 days. According to the literature, self-medicating with alcohol is not an effective treatment for alcoholism, unless it is being used to alleviate the psychological and neurochemical effects caused by alcohol. However, there has been limited research on how to treat individuals who have both alcoholism and another medical condition. A few studies have looked at the impact of medications like valproate, lithium, and naltrexone, as well as psychosocial interventions, in treating patients with bipolar disorder and alcoholism. However, more research is necessary to fully understand the best approach.

Comparative analysis of anticholinergic burden scales to explain iatrogenic cognitive impairment and self-reported side effects in the euthymic phase of bipolar disorders: Results from the FACE-BD cohort

Bipolar disorders (BD) are characterized by cognitive impairment during the euthymic phase, to which treatments can contribute. The anticholinergic properties of medications, i.e., the ability of a treatment to inhibit cholinergic receptors, are associated with cognitive impairment in elderly patients and people with schizophrenia but this association has not been well characterized in individuals with remitted BD. Moreover, the validity of only one anticholinergic burden scale designed to assess the anticholinergic load of medications has been tested in BD. In a literature review, we identified 31 existing scales. We first measured the associations between 27 out of the 31 scales and objective cognitive impairment in bivariable regressions. We then adjusted the bivariable models with covariates: the scales significantly associated with cognitive impairment in bivariable and multiple logistic regressions were defined as having good concurrent validity to assess cognitive impairment. In a sample of 2,031 individuals with euthymic BD evaluated with a neuropsychological battery, two scales had good concurrent validity to assess cognitive impairment, whereas chlorpromazine equivalents, lorazepam equivalents, the number of antipsychotics, or the number of treatments had not. Finally, similar analyses with subjective anticholinergic side-effects as outcome variables reported 14 scales with good concurrent validity to assess self-reported peripheral anticholinergic side-effects and 13 to assess self-reported central anticholinergic side-effects. Thus, we identified valid scales to monitor the anticholinergic burden in BD, which may be useful in estimating iatrogenic cognitive impairment in studies investigating cognition in BD.

The animated assessment of theory of mind for people with schizophrenia (AToMS): development and psychometric evaluation

Theory of mind (ToM) deficits in people with schizophrenia have been reported and associated with impaired social interactions. Thus, ToM deficits may negatively impact social functioning and warrant consideration in treatment development. However, extant ToM measures may place excessive cognitive demands on people with schizophrenia. Therefore, the study aimed to develop a comprehensible Assessment of ToM for people with Schizophrenia (AToMS) and evaluate its psychometric properties. The AToMs was developed in 5 stages, including item formation, expert review, content validity evaluation, animation production, and cognitive interviews of 25 people with schizophrenia. The psychometric properties of the 16-item AToMS (including reliability and validity) were then tested on 59 people with schizophrenia. The newly developed animated AToMS assesses 8 ToM concepts in the cognitive and affective dimensions while placing minimal neurocognitive demands on people with schizophrenia. The AToMS presented satisfactory psychometric properties, with adequate content validity (content validity index = 0.91); mostly moderate item difficulty (item difficulty index = 0.339-0.966); good discrimination (coefficients = 0.379-0.786), internal consistency (Cronbach's α = 0.850), and reliability (intraclass correlation coefficient = 0.901 for test-retest, 0.997 for inter-rater); and satisfactory convergent and divergent validity. The AToMS is reliable and valid for evaluating ToM characteristics in people with schizophrenia. Future studies are warranted to examine the AToMS in other populations (e.g., people with affective disorders) to cross-validate and extend its utility and psychometric evidence.

Neuroinflammation and neuroprogression produced by oxidative stress in euthymic bipolar patients with different onset disease times

Bipolar disorder (BD) is associated with systemic toxicity, represented by changes in biomarkers associated with mood episodes, leading to neurological damage, which may reflect cognitive functions and functionality and the progression of the disease. We aimed to analyze the effect of four biomarkers, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and thiobarbituric acid reactive substances (TBA-RS), related to oxidative stress in BD and to correlate them with cognitive functions and functionality. We studied 50 bipolar types I/II patients in the euthymic phase, which was divided into two subgroups with 25 patients each (≤ 3 years and ≥ 10 years of diagnosis, from the first episode of mania) and 25 control patients. To analyze frontal cognitive functions and functionality, we used the Frontal Assessment Battery (FAB) and Functioning Assessment Short Test (FAST) tests, respectively. The scores of the FAST and FAB tests showed an increase and decrease respectively, in both bipolar groups, when compared to the control group, demonstrating impairment in cognitive functions and functionality since the disease onset. In addition, changes occurred in all six domains of the FAST test, and in four domains of the FAB test in bipolar patients when compared to the control group. Regarding oxidative stress biomarkers, we did not find changes in SOD and GSH-Px activities; however, a significant increase in CAT activity and lipid peroxidation was observed in both groups, although the patients were euthymic and medicated. These results allow us to raise the hypothesis that since the beginning of the disease, the euthymic bipolar patient has presented a level of oxidative stress, which gets worse with the evolution of the disease, promoting impairments in the frontal cognitive functions and functionality gradually.

Cognitive Remediation Virtual Reality Tool a Recovery-Oriented Project for People with Bipolar Disorder: Protocol of a Feasibility Randomized Clinical Trial

Introduction

Cognitive deficits are considered a fundamental component of bipolar disorder due to the fact that they negatively impact personal/social functioning. Cognitive remediation interventions are effective in the treatment of various psychosocial disorders, including bipolar disorder. The use of Virtual reality as a rehabilitation tool has produced scientific evidence in recent years, especially in cardiovascular, neurological, and musculoskeletal rehabilitation. This study aims at evaluating the feasibility of a Cognitive Remediation Virtual Reality Program (CEREBRUM) for people with bipolar disorder in psychiatric rehabilitation.

Material and Methods

Feasibility randomized controlled cross-over clinical study; we randomized 50 people from the Consultation and Psychosomatic Psychiatry Center of the University Hospital of Cagliari (San Giovanni di Dio Civil Hospital) with a diagnosis of bipolar disorder. We propose a cognitive remediation program in virtual reality (CEREBRUM), 3 months with 2 weekly sessions, for the experimental group and a usual care program for the control group (psychiatric visit and/or psychotherapy).

Results

The results of the trial will be published in international peer-reviewed journals and will be disseminated at international meetings and congress.

Discussion

This RCT aims, with regards to its feasibility and design, to provide information about a confirmatory trial that evaluates the effectiveness of a Virtual Reality Cognitive Remediation program in psychiatric rehabilitation for the treatment of cognitive dysfunction in people with bipolar disorder.

Conclusion

The results that we analyzed at the end of the RCT will have an impact on psychiatric rehabilitation research with a focus on improving the application of technologies for mental health.Trial registration: ClinicalTrialsgov NCT05070065, registered on September 2021.

Driving performance of euthymic outpatients with bipolar disorder undergoing real-world pharmacotherapy

OBJECTIVE

Medications for the treatment of bipolar disorder (BD) could affect patients' cognitive function. Patients with BD present with neurocognitive impairment even in a remission state. Little research is available on the daily functioning, especially driving performance, of stable outpatients with BD under pharmacological treatment.

METHODS

In total, 58 euthymic outpatients with BD undergoing real-world pharmacotherapy and 80 sex- and age-matched healthy controls (HCs) were enrolled. Three driving tasks using a driving simulator-road-tracking, car-following, and harsh-braking-and three cognitive tasks-Continuous Performance Test, Wisconsin Card Sorting Test, and Trail-Making Test-were evaluated. Symptom assessment scales-Young Mania Rating Scale, Structured Interview Guide for the Hamilton Depression Rating Scale, Beck Depression Inventory-II, Social Adaptation Self-evaluation Scale, and Stanford Sleepiness Scale-were also completed.

RESULTS

Car-following and road-tracking performance were significantly impaired in patients with BD compared with HCs after adjusting for demographic variables, but these performances generally overlapped. Broad neurocognitive functions were significantly lower in the patients with BD compared to HCs, but car-following performance was significantly negatively correlated with sustained attention only. Although most patients received multiple medications rather than monotherapy, no relationship between prescriptions and driving performance was found.

CONCLUSION

Euthymic patients with BD under steady-state pharmacotherapy had impaired driving performance compared with HCs, but the overlapping distributions of driving performance suggested that driving performance is not always deteriorated in patients with BD. Therefore, attentional function may be a useful clinical feature for judging driving aptitude in patients with BD.

The impact of substance use disorder comorbidity on cognition of individuals with bipolar disorder: A systematic review

The aim of this study is to describe whether Bipolar Disorder (BD) with Substance Use Disorder (SUD) comorbidity is associated with an increased cognitive impairment as compared to BD without SUD comorbidity. This is a systematic review. The literature search was conducted in three databases: PubMed, PsycINFO and Embase. A total of 2032 studies were screened after removing duplicates. 29 articles were included for full text screening, and a total of 14 articles were included in the systematic review. Multiple cognitive domains were assessed, including verbal, spatial and visual memory, and psychomotor and executive functioning. Over half the articles (64.3%, n=9) identified cognitive impairments in individuals with BD+SUD comorbidity as compared to individuals with BD without SUD comorbidity. In addition, individuals with the comorbidity exhibited more severe impairments on tests of executive functioning, and greater impairments in verbal and visual memory. The studies included in this systematic review reinforce that individual with comorbidity of BD and SUD have increased cognitive impairment as compared to individuals with BD without SUD comorbidity. Executive functioning was the most impaired cognitive domain found across the studies included in this review. Intervention strategies focused on executive functioning would be beneficial for this specific population.

Differential association of cortisol with visual memory/learning and executive function in Bipolar Disorder

The association of cortisol with cognition has been understudied in Bipolar Disorder (BD); available evidence is inconsistent while it is unknown whether cortisol's effects vary across neurocognitive domains implicating different brain structures. This study aimed to examine the association of cortisol with two cognitive tasks targeting visual memory and executive function (planning) in BD, related to the hippocampus and prefrontal lobe, respectively. Cambridge Neuropsychological Test Automated Battery (CANTAB) tasks targeting paired associative learning (PAL) and planning (Stockings of Cambridge; SOC) were administered to 60 BD type I patients. Basal serum cortisol was also measured. Higher cortisol was associated with worse performance in PAL, but not SOC, after controlling for gender, education, illness duration and treatment with mood stabilizers. This is the first study to examine the association of cortisol with neurocognitive function in BD while controlling for clinicodemographic and treatment-related factors. We found a significant association of cortisol with hippocampal-related visual memory/learning but not with prefrontal lobe-related executive function, suggesting domain-specific underlying mechanisms of cognitive dysfunction in BD. Future studies should further explore cortisol's brain structure-specific effects on cognitive functioning in BD.

Bipolar disorder and frontotemporal dementia: A systematic review

OBJECTIVES

To detail the biological, clinical and neurocognitive characteristics differentiating bipolar disorder (BD) from frontotemporal dementia (FTD) and to investigate whether BD is a risk factor for FTD.

METHODS

A total of 16 studies were included in this systematic review. Five studies described biological and/or neurocognitive characteristics between patients with BD and FTD, and 11 studies investigated whether BD was a risk factor for FTD.

RESULTS

Individuals with FTD presented higher levels of serum neurofilament light chain, greater grey matter reduction in frontal, parietal and temporal lobes, and increased slow wave oscillations in channels F3, F4, T3, T5, T4 and T6 within an electroencephalogram (EEG), relative to individuals with BD. Patients with FTD presented greater deficits in executive function and theory of mind compared to patients with BD in a euthymic state, and more deficits in verbal fluency compared to patients with BD in a current mood episode. Patients with BD in a current mood episode showed greater impairment in attention, working memory, verbal memory and executive function relative to individuals with FTD. In addition, retrospective studies showed that 10.2%-11.6% of patients with behavioural variant FTD (bvFTD) had a preceding history of BD.

CONCLUSION

Biological and neurocognitive characteristics help to distinguish between BD and FTD, and it may help to reach a more precise diagnosis. In addition, individuals with BD are at higher risk of developing FTD. More studies are needed to identify the predictors of the conversion between BD to FTD.

The effect of concomitant benzodiazepine use on neurocognition in stable, long-term patients with bipolar disorder

OBJECTIVE

Neurocognitive dysfunction is a common feature of bipolar disorder even in euthymia, and psychopharmacological treatment could have an effect on cognition. Long-term prescription of benzodiazepines in bipolar disorder is a common practice, and their effect on neurocognition has not been well studied in this population. The aim of this study was to evaluate the impact of concomitant benzodiazepine long-term use on neurocognitive function in stable euthymic bipolar disorder patients.

METHODS

Seventy-three euthymic bipolar disorder outpatients and 40 healthy individuals were assessed using a neurocognitive battery. Patients were classified in two groups according to the presence of benzodiazepines in their treatment: the benzodiazepine group (n = 34) and the non- benzodiazepine group (n = 39). Neurocognitive performance was compared between the groups using a multivariate analysis of covariance, considering age, number of depressive episodes, adjuvant antipsychotic drugs, Young Mania Rating Scale score and Hamilton Depression Rating Scale score as covariates.

RESULTS

Both bipolar disorder groups (benzodiazepine and non-benzodiazepine) showed an impairment in memory domains (Immediate Visual Memory [p = 0.013], Working Memory [p < 0.001], and Letter-Number Sequence [p < 0.001] from the Wechsler Memory Scale-Revised-III) and slower processing speed functions (Stroop Colour [p < 0.001]) relative to the control group. Nevertheless, the benzodiazepine group showed a greater impairment in executive functions (Conceptual Level Responses [p = 0.024] from the Wisconsin Card Sorting Test and Frontal Assessment Battery [p = 0.042]).

CONCLUSION

Although memory and processing speed impairments were found in bipolar disorder, regardless of their benzodiazepine treatment, benzodiazepine users presented additional neurocognitive impairments in terms of executive functioning. These findings support restricted prescription of benzodiazepines in individuals with bipolar disorder.

Is processing speed a valid neurocognitive endophenotype in bipolar disorder? Evidence from a longitudinal, family study

BACKGROUND

Substantial evidence supports the existence of neurocognitive endophenotypes in bipolar disorder (BD), but very few longitudinal studies have included unaffected relatives. In a 5-year, follow-up, family study, we have recently suggested that deficits in manual motor speed and visual memory could be endophenotype candidates for BD. We aimed to explore whether this also applies to processing speed.

METHODS

A sample of 348 individuals, including 163 BD patients, 65 unaffected first-degree relatives (BD-Rel) and 120 genetically unrelated healthy controls (HC), was assessed with the Digit Symbol Substitution Test (DSST) on two occasions over a 2-year period (T1, T2). DSST values were controlled for age, years of education, occupational status, and subsyndromic mood symptoms. Differences between groups were evaluated with ANCOVAs.

RESULTS

At T1 BD performed significantly worse than HC (p < 0.001; Cohen's d = 1.38) and BD-Rel (p < 0.001; Cohen's d = 0.82). BD-Rel showed an intermediate performance with significant differences with HC (p < 0.01; Cohen's d = 0.50). Similarly, at T2 BD performed significantly worse than HC (p < 0.001; Cohen's d = 1.44) and BD-Rel (p < 0.01; Cohen's d = 0.51). BD-Rel performance was intermediate and significantly lower than that of HC (p < 0.01; Cohen's d = 0.97). A Repeated Measures ANOVA revealed no significant between-group differences in performance over time (p > 0.05).

CONCLUSIONS

The results of this longitudinal, family study suggest that impaired processing speed may represent a suitable cognitive endophenotype for BD. Further research on the field is required to confirm these preliminary findings.

How Does Dementia Begin to Manifest in Bipolar Disorder? A Description of Prodromal Clinical and Cognitive Changes

BACKGROUND

Older adults with bipolar disorder (BD) have increased dementia risk, but signs of dementia are difficult to detect in the context of pre-existing deficits inherent to BD.

OBJECTIVE

To identify the emergence of indicators of early dementia in BD.

METHODS

One hundred and fifty-nine non-demented adults with BD from the National Alzheimer's Coordinating Center (NACC) data repository underwent annual neuropsychological assessment up to 14 years (54.0 months average follow-up). Cognitive performance was examined longitudinally with linear mixed-effects models, and yearly differences between incident dementia cases and controls were examined in the six years prior to diagnosis.

RESULTS

Forty participants (25.2%) developed dementia over the follow-up period ('incident dementia cases'). Alzheimer's disease was the most common presumed etiology, though this was likely a result of sampling biases within NACC. Incident dementia cases showed declining trajectories in memory, language, and speeded attention two years prior to dementia onset.

CONCLUSION

In a sample of BD patients enriched for Alzheimer's type dementia, prodromal dementia in BD can be detected up to two years before onset using the same cognitive tests used in psychiatrically-healthy older adults (i.e., measures of verbal recall and fluency). Cognition in the natural course of BD is generally stable, and impairment or marked decline on measures of verbal episodic memory or semantic retrieval may indicate an early neurodegenerative process.

Progression of the functional deficit in a group of patients with bipolar disorder: a cluster analysis based on longitudinal data

We aimed to examine the trajectory of psychosocial functioning in a sample of euthymic patients with bipolar disorder (BD) throughout a 5-year follow-up. Ninety-nine euthymic bipolar patients and 40 healthy controls (HC) were included. A neurocognitive assessment (17 neurocognitive measures grouped in 6 domains) was carried out at baseline. The split version of the Global Assessment of Functioning scale (GAF-F) and the Functioning Assessment Short Test (FAST) were used to examine psychosocial functioning at baseline (T1), and after a 5-year follow-up (T2). The statistical analysis was performed through repeated measures ANOVA and hierarchical cluster analysis based on the GAF-F and the FAST scores at T1 and T2. Eighty-seven patients (87.9%) were evaluated at T2. The cluster analysis identified two groups of patients. The first group included 44 patients (50.6%) who did not show a progression of the functional impairment (BD-NPI). The second cluster, which included 43 patients (49.4%), was characterized by a progression of the functional impairment (BD-PI). The BD-PI had a higher number of relapses and a higher number of hospitalizations during the follow-up period, as well as worse neurocognitive functioning than the BD-NPI. The repeated measures ANOVA confirmed that the psychosocial performance of BD-NPI is stable while there was a progression of the functional deterioration in BD-PI. The trajectory of the psychosocial functioning of patients with BD is not homogeneous. Our results suggest that in at least one subset of patients with BD, which might account for half of the patients, the disease has a progressive course.

Three-year longitudinal cognitive functioning in patients recently diagnosed with bipolar disorder

OBJECTIVE

The longitudinal course of neuropsychological functioning after the first manic episode in bipolar disorder is unknown. The present study evaluated cognitive change in bipolar disorder in the first 3 years after the initial manic episode.

METHODS

Ninety-one newly diagnosed patients with bipolar disorder and 61 demographically similar healthy participants received a neuropsychological evaluation assessing multiple cognitive domains at baseline, 1-year, and 3-year time points. Patients also received clinical assessments including mood ratings at all time points.

RESULTS

Patients showed deficits in all domains at baseline, but similar longitudinal trajectories across time relative to healthy participants in most cognitive domains. For processing speed, patients showed more gains than controls from baseline to 1 year, but these gains stabilized thereafter. Patients with alcohol/substance abuse showed an initial delay but subsequent recovery in executive functioning. Patients who discontinued antipsychotic treatment showed better cognitive outcomes in verbal memory.

CONCLUSION

Appropriately treated patients with bipolar disorder showed favorable cognitive outcome in the first 3 years after experiencing an initial manic episode, arguing against cognitive neuroprogression at this stage of the illness. Discontinuation of antipsychotic treatment may be associated with better cognitive outcomes, but clarification of the role of antipsychotics on cognitive functioning requires further investigation.

Understanding cognitive impairment in mood disorders: mediation analyses in the UK Biobank cohort

BACKGROUND

Cognitive impairment is strongly linked with persistent disability in people with mood disorders, but the factors that explain cognitive impairment in this population are unclear.

AIMS

To estimate the total effect of (a) bipolar disorder and (b) major depression on cognitive function, and the magnitude of the effect that is explained by potentially modifiable intermediate factors.

METHOD

Cross-sectional study using baseline data from the UK Biobank cohort. Participants were categorised as having bipolar disorder (n = 2709), major depression (n = 50 975) or no mood disorder (n = 102 931 and n = 105 284). The outcomes were computerised tests of reasoning, reaction time and memory. The potential mediators were cardiometabolic disease and psychotropic medication. Analyses were informed by graphical methods and controlled for confounding using regression, propensity score-based methods and G-computation.

RESULTS

Group differences of small magnitude were found on a visuospatial memory test. Z-score differences for the bipolar disorder group were in the range -0.23 to -0.17 (95% CI -0.39 to -0.03) across different estimation methods, and for the major depression group they were approximately -0.07 (95% CI -0.10 to -0.03). One-quarter of the effect was mediated via psychotropic medication in the bipolar disorder group (-0.05; 95% CI -0.09 to -0.01). No evidence was found for mediation via cardiometabolic disease.

CONCLUSIONS

In a large community-based sample in middle to early old age, bipolar disorder and depression were associated with lower visuospatial memory performance, in part potentially due to psychotropic medication use. Mood disorders and their treatments will have increasing importance for population cognitive health as the proportion of older adults continues to grow.

DECLARATION OF INTEREST

I.J.D. is a UK Biobank participant. J.P.P. is a member of the UK Biobank Steering Committee.

A review on shared clinical and molecular mechanisms between bipolar disorder and frontotemporal dementia

Mental disorders are highly prevalent and important causes of medical burden worldwide. Co-occurrence of neurological and psychiatric symptoms are observed among mental disorders, representing a challenge for their differential diagnosis. Psychiatrists and neurologists have faced challenges in diagnosing old adults presenting behavioral changes. This is the case for early frontotemporal dementia (FTD) and bipolar disorder. In its initial stages, FTD is characterized by behavioral or language disturbances in the absence of cognitive symptoms. Consequently, patients with the behavioral subtype of FTD (bv-FTD) can be initially misdiagnosed as having a psychiatric disorder, typically major depression disorder (MDD) or bipolar disorder (BD). Bipolar disorder is associated with a higher risk of dementia in older adults and with cognitive impairment, with a subset of patients presents a neuroprogressive pattern during the disease course. No mendelian mutations were identified in BD, whereas three major genetic causes of FTD have been identified. Clinical similarities between BD and bv-FTD raise the question whether common molecular pathways might explain shared clinical symptoms. Here, we reviewed existing data on clinical and molecular similarities between BD and FTD to propose biological pathways that can be further investigated as common or specific markers of BD and FTD.

Impact of number of episodes on neurocognitive trajectory in bipolar disorder patients: a 5-year follow-up study

BACKGROUND

The neurocognitive trajectory in bipolar disorder (BD) is variable, with controversial findings, and most evidence come from cross-sectional studies. We aimed to examine the course of neurocognitive functioning in a sample of euthymic BD patients in comparison with a control group during a 5-year follow-up.

METHODS

Ninety-nine euthymic bipolar patients and 40 healthy controls were assessed using a comprehensive neurocognitive battery (six neurocognitive domains) at baseline (T1) and then at 5-year follow-up (T2) in a longitudinal study.

RESULTS

No evidence of a progression in neurocognitive dysfunction was found either in cognitive composite index or in any of the neurocognitive domains for the whole cohort. However, there was a negative correlation between number of manic episodes and hospitalisations due to manic episodes and change in neurocognitive composite index (NCI) during the follow-up. Moreover, patients with higher number of manic and hypomanic episodes have a greater decrease in NCI, working memory and visual memory. History of psychotic symptoms was not related to the trajectory of neurocognitive impairment.

CONCLUSIONS

Our results suggest that, although the progression of cognitive decline is not a general rule in BD, BD patients who have a greater number of manic or hypomanic episodes may constitute a subgroup characterised by the progression of neurocognitive impairment. Prevention of manic and hypomanic episodes could have a positive impact on the trajectory of cognitive function.

Peripheral Oxidative Stress Markers in Patients with Bipolar Disorder during Euthymia and in Siblings

AIMS

Oxidative stress is increased during the acute phases of bipolar disorder (BD). Our aim here was to analyze oxidative stress biomarkers in patients with BD during euthymia and their siblings.

METHOD

A cross-sectional study was performed in euthymic patients with BD-I (n=48), unaffected siblings (n=23) and genetically unrelated healthy controls (n=21). Protein carbonyl content (PCC), total antioxidant capacity (TRAP), lipid peroxidation (TBARS) and uric acid were measured as biomarkers of oxidative stress in blood.

RESULTS

The antioxidant capacity (TRAP) was lower (p<0.001) in patients with BD compared to their siblings and controls, whereas no differences were observed in PCC, TBARS or uric acid. In patients, the concentrations of TRAP and TBARS were positively associated with the dose of valproic acid (p<0.05 and p<0.001, respectively). The concentrations of these biomarkers were not significantly associated with any of socio-demographic and clinical variables.

CONCLUSION

A selective reduction in antioxidant capacity is present in BD during euthymia state, whereas other markers of oxidative stress are unaltered during euthymia. Siblings did not show any alterations in oxidative stress biomarkers. Oxidative stress might represent a state-dependent marker in BD. The association between treatment with valproic acid and oxidative stress markers in euthymia deserves further studies.

Cognitive Process in Patients With Obsessive-Compulsive Disorder: A Cross-Sectional Analytic Study

Introduction:

In recent studies, deficit in cognitive process has been investigated as one of the etiological hypotheses in a wide range of Obsessive-Compulsive Disorder (OCD). This research aimed to compare cognitive process in patients with OCD and healthy groups.

Methods:

In the current cross-sectional analytic study, 43 patients with OCD and 43 healthy individuals matched with gender, age, educational and marital status were selected by convenience sampling method and assessed by Wisconsin Cart Sorting Test (WCST), Paced Auditory Serial Addition Test (PASAT) and Yale-Brown Obsessive Compulsive Scale (Y-BOCS). The obtained data were analyzed with Chi-square, Independent t test, Mann-Whitney U test and Pearson correlation in SPSS version16.

Results:

There was no difference between the patients with OCD and the healthy group in demographic characteristics (P>0.05). There was a significant differences between two group on the all subscale of WCST test and PASAT3, PASAT2 tests (P<0.01). These findings indicate that the OCD patient’s performance in cognitive process was significantly worse than the healthy controls.

Conclusion:

The findings indicate that individuals with OCD suffer from a deficiency in various aspects of cognitive processes. Therefore, paying attention to these deficiencies can make an important contribution to the treatment of these patients.

Affective versus non-affective first episode psychoses: A longitudinal study

OBJECTIVE

This study aimed to assess (1) whether there were clinical, neuropsychological and functional differences between and within affective and non-affective psychoses at baseline and two years-follow-up and (2) to explore clinical and neuropsychological predictors of psychosocial functioning in the whole sample.

METHOD

This is a subanalysis from a multicentre, naturalistic, longitudinal prospective study ('Phenotype-genotype and environmental interaction. Application of a predictive model in first psychotic episodes'). The sample consisted of 192 patients with a first psychotic episode (FEP): 142 with non-affective psychoses and 50 with affective psychoses. Student t-tests, paired t-tests, Pearson correlations, ANOVAs and regression analyses were performed.

RESULTS

At baseline, the groups differed in perseverative errors (WCST), Premorbid Adjustment Scale (PAS), family history of psychiatric disorder, negative (PANSS) and manic symptoms (YMRS). At two years follow-up, the groups differed in all the PANSS subscales and in depressive symptoms assessed by the MADRS. When the whole sample was considered, the regression model which best explained the estimated variance in functioning at follow-up (41%) was composed by PANSS total score and verbal fluency assessed by the FAS (COWAT).

CONCLUSIONS

We found clinical and neurocognitive differences at baseline which decreased in the follow-up. Reduced performances at baseline in executive functions in combination with symptom severity (PANSS) were predictors of FEP patients' poor functional outcome.

Sex-related variation of neurocognitive functioning in bipolar disorder: Focus on visual memory and associative learning

Bipolar disorder (BD) is associated with cognitive deficits in attention, verbal memory and executive functions. However, only few studies have examined sex effects on cognition despite their clinical relevance. Given that visual memory/ learning has been understudied the aim of our study was to investigate sex-related variation in cognition (executive functions and visual memory/ learning) in BD. Cognitive performance of 60 bipolar-I patients and 30 healthy controls was evaluated by using CANTAB battery tasks targeting spatial memory (SRM), paired associative learning (PAL) and executive functions. We fitted a multivariate analysis of covariance (MANCOVA), followed by task-specific ANCOVAs. A significant diagnosis by sex interaction effect was detected (MANCOVA); specifically, diagnosis-specific sex effects were found for SRM and PAL, as healthy males outperformed healthy females but this pattern was attenuated in BD patients. Patients' clinicodemographic characteristics, current psychopathology or medication status did not differ across sexes and were, therefore, unlikely to explain detected sex effects. Our study is one of few studies to assess sex-related variation in cognition in BD and the first to record a diagnosis-specific sex effect for two tasks of visuo-spatial memory/ learning, indicating that sex-related variation in healthy subjects is disrupted in BD.

Neurocognitive functioning, clinical course and functional outcome in first-treatment bipolar I disorder patients with and without clinical relapse: A 1-year follow-up study

OBJECTIVES

Due to limited research on the association between recurrence of mood episodes and the longitudinal course of neurocognitive functioning in early phase bipolar I disorder (BD I), the impact of recurrence on neurocognition remains unclear. Further, a strong correlation between neurocognitive impairment and functional impairment has been demonstrated. The longitudinal relationship between neurocognitive impairment and functional outcome in relation to recurrence is, however, not established.

METHODS

The current study investigated the longitudinal relationship between neurocognition, recurrence of mood episodes and functional outcome in a sample of first-treatment (FT) BD I patients (N = 42), with and without relapse, during a 1-year follow-up period. The longitudinal course of neurocognitive functioning in the patients was also compared to that of a group of healthy controls (N = 143).

RESULTS

Compared to both patients with relapse and healthy controls, no-relapse patients showed neurocognitive improvements. The polarity of the relapse episodes was mostly depressive, and for the no-relapse patients, reduction of symptoms was associated with neurocognitive improvement. No-relapse patients showed better global and occupational functioning.

CONCLUSIONS

The current study found different neurocognitive and functional trajectories in FT BD I patients with and without relapse, with differences at follow-up to some degree being mediated by current symptoms. The current findings highlight the importance of treatment focusing on neurocognition and symptom states with the aim of improving functional recovery.

Cognitive Impairment In Treatment-Naïve Bipolar II and Unipolar Depression

Cognition dysfunction may reflect trait characteristics of bipolarity but cognitive effects of medications have confounded previous comparisons of cognitive function between bipolar II and unipolar depression, which are distinct clinical disorders with some overlaps. Therefore, we examined the executive function (WCST), attention, cognitive speed (TMT-A) and memory (CAVLT, WMS-Visual reproduction) of 20 treatment-naïve bipolar II patients (BPII), 35 treatment-naïve unipolar depressed (UD) patients, and 35 age/sex/education matched healthy controls. The subjects were young (aged 18–35), and had no history of psychosis or substance use, currently depressed and meeting either RDC criteria for Bipolar II Disorder or DSM-IV-TR criteria for Major Depressive Disorder. The patients were moderately depressed (MADRS) and anxious(HAM-A), on average within 3.44 years of illness onset. Sociodemographic data and IQ were similar between the groups. UD patients had significantly slower cognitive speed and cognitive flexibility (WCST perseverative error). BPII depressed patients showed relatively intact cognitive function. Verbal memory (CAVLT List A total) correlated with illness chronicity only in BPII depression, but not UD. In conclusion, young and treatment-naïve BPII depressed patients differed from unipolar depression by a relatively intact cognitive profile and a chronicity-cognitive correlation that suggested a stronger resemblance to Bipolar I Disorder than Unipolar Depression.

Cognitive effects of creatine monohydrate adjunctive therapy in patients with bipolar depression: Results from a randomized, double-blind, placebo-controlled trial

BACKGROUND

Depressive episodes and cognitive impairment are major causes of morbidity and dysfunction in individuals suffering from bipolar disorder (BD). Novel treatment approaches that target clinical and cognitive aspects of bipolar depression are needed, and research on pathophysiology suggests that mitochondrial modulators such as the nutraceutical creatine monohydrate might have a therapeutic role for this condition.

METHODS

Eighteen (N=18) patients with bipolar depression according to DSM-IV criteria who were enrollled in a 6-week, randomized, double-blind, placebo-controlled trial of creatine monohydrate 6g daily as adjunctive therapy were submitted to neuropsychological assessments (Wisconsin Card Sorting Test, Digit Span subtest of the Wechsler Adult Intelligence Scale-Third Edition, Stroop Color-Word Test, Rey-Osterrieth complex figure test, FAS Verbal Fluency Test) at baseline and week 6.

RESULTS

There was a statistically significant difference between the treatment groups of the change on the total scores after 6 weeks in the verbal fluency test, with improvement in the group receiving adjunctive treatment with creatine. We did not find significant differences between the groups of the changes on other neuropsychological tests.

LIMITATIONS

Small sample and lack of a control group of healthy subjects.

CONCLUSIONS

Our trial, which was the first to investigate the cognitive effects of creatine monohydrate on bipolar depression, indicates that supplementation with this nutraceutical for 6 weeks is associated with improvement in verbal fluency tests in patients with this condition.

Meta-analysis of longitudinal studies of cognition in bipolar disorder: comparison with healthy controls and schizophrenia

BACKGROUND

Bipolar disorder (BP) is associated with significant cognitive impairment. Recent evidence suggests that cognitive deficits are already evident after first-episode mania. However, it is not clear whether BP is associated with further decline in cognitive functions in individuals with established illness. Aim of this meta-analytic review was to examine longitudinal neurocognitive changes in BP and to compare trajectory of cognitive deficits in BP with schizophrenia and healthy controls.

METHODS

Electronic databases were searched for the studies published between January 1987 and November 2016. In total 22 reports were included in the current meta-analysis. The main analysis assessed the longitudinal change in cognition in 643 patients with BP. Further analyses were conducted in studies investigating cognitive changes in BP along with healthy controls (459 BP and 367 healthy controls) and schizophrenia (172 BP and 168 schizophrenia).

RESULTS

There was no cognitive decline overtime neither in short-term (mean duration = 1.5 years) nor in long-term (mean duration = 5.5 years) follow-up studies in BP. In contrast, there was evidence for modest improvements in task performance in memory and working memory at follow-up. The trajectory of cognitive functioning in BP was not significantly different from changes in schizophrenia and healthy controls.

CONCLUSIONS

Together with the findings in early BP and individuals at genetic risk for BP, current findings suggest that neurodevelopmental factors might play a significant role in cognitive deficits in BP and do not support the notion of progressive cognitive decline in most patients with BP.

Cognitive deficits in bipolar disorders: Implications for emotion

Prominent cognitive deficits have been documented in bipolar disorder, and multiple studies suggest that these deficits can be observed among non-affected first-degree relatives of those with bipolar disorder. Although there is variability in the degree of cognitive deficits, these deficits are robustly relevant for functional outcomes. A separate literature documents clear difficulties in emotionality, emotion regulation, and emotion-relevant impulsivity within bipolar disorder, and demonstrates that these emotion-relevant variables are also central to outcome. Although cognitive and emotion domains are typically studied independently, basic research and emergent findings in bipolar disorder suggest that there are important ties between cognitive deficits and the emotion disturbances observed in bipolar disorder. Understanding these relationships has relevance for fostering more integrative research, for clarifying relevant aspects related to functionality and vulnerability within bipolar disorder, and for the development of novel treatment interventions. Bipolar disorder (BD) is a severe psychiatric illness that has been ranked as one of the 20 leading medical causes of disability (WHO, 2011). BD has been shown to be the psychiatric disorder with the highest rates of completed suicide across two major cohort studies (Ilgen et al., 2010; Nordentoft, Mortensen, & Pedersen, 2011). In a cross-national representative sample, one in four persons diagnosed with bipolar I disorder reported a suicide attempt (Merikangas et al., 2011). Rates of relapse remain high despite available treatments (Gitlin, Swendsen, Heller, & Hammen, 1995), and in the year after hospitalization for manic episode, two-thirds of patients do not return to work (Strakowski et al., 1998). Poverty, homelessness, and incarceration are all too common (Copeland et al., 2009). Despite the often poor outcomes, there is also evidence for outstanding accomplishments and creativity among those with milder forms of the disorder and their family members (Coryell et al., 1989; Jamison, 1993; Murray & Johnson, 2010). Some individuals appear to achieve more than the general population, suggesting the importance of understanding the variables that predict differential outcome within bipolar disorder. Within this paper, we focus on two key predictors of outcomes within bipolar disorder: cognition and emotionality. We review evidence that problems in cognition and emotionality are prominent among those diagnosed with the disorder, are not artifacts of symptom state, and relate substantively to poorer outcomes. Although traditionally studied separately, new work points toward the idea that cognition and emotionality are intricately linked within bipolar disorder. Drawing from research within bipolar disorder as well as outside of bipolar disorder, we build a model of how cognition and emotionality might be tied within bipolar disorder. We then provide suggestions for future research. Before considering findings, it is worth noting that there are several forms of the disorder, defined by varying degrees and duration of manic symptoms (APA, 2013; WHO, 1993). Manic episodes are defined by abnormally elevated or irritable mood, accompanied by increased activity and at least three symptoms (four if mood is only irritable) such as decreased need for sleep, increased self-confidence, racing thoughts or flight of ideas, rapid speech, distractibility, goal-directed activity, and engagement in pleasurable activities without regard to potential negative consequences. To meet criteria for mania, these symptoms must persist for at least one week or require hospitalization, and must lead to difficulties with functioning. If functional impairment is not more than mild and duration is between 4 and 6 days, the episode is considered a hypomanic episode. Bipolar I disorder (BD I) is diagnosed on the basis of at least one lifetime manic episode within the DSM-5 and by at least two episodes within the ICD, whereas bipolar II disorder is diagnosed on the basis of at least one hypomanic episode (and no manic episodes) as well as major depressive episodes. Cyclothymic disorder is defined by chronic but milder fluctuations between manic and depressive symptoms. Most research focuses on BD I. In addition to diagnosed samples, research has focused on those at high risk for bipolar disorder, including first-degree relatives of those with BD. This work draws on the evidence for extremely high heritability of BD I, with estimates from community-based twin studies of 0.85 (Kieseppä, Partonen, Haukka, Kaprio, & Lönnqvist, 2014). Other research has considered high risk for BD by virtue of lifetime subsyndromal symptoms, as measured by scales such as the Hypomanic Personality Scale (Eckblad & Chapman, 1986) or the General Behavior Inventory (Depue, Krauss, Spoont, & Arbisi, 1989). The study of high-risk individuals provides a way to decipher whether deficits are present before the onset of the disorder, of importance given models suggesting that episodes of the disorder may change brain function (Chang, Steiner, & Ketter, 2000; Strakowski, 2012) as well as individuals' perceptions of their emotion regulation. Beyond defining BD, it is worth defining some of the many different neuropsychological tasks that have been widely studied in BD. Perhaps no area has received more attention than executive function. Executive function is related to three core functions: 1) inhibition, the ability to suppress irrelevant information in working memory in order to accomplish an established goal; 2) working memory, the ability to hold and manipulate information in mind; and 3) cognitive flexibility, the ability to shift strategies in response to feedback (Diamond, 2013; Miyake et al., 2000). Attention (defined as the process of selecting information reception from internal or external cues) is implicated in all three of these aspects of executive function. Much of the literature we will discuss focuses on response inhibition, or the ability to suppress a prepotent response, which is considered a subtype of inhibition. Some tests measure multiple facets of executive function; for example the Trails B test likely requires working memory and cognitive flexibility (Sánchez-Cubillo et al., 2009). Aside from executive function, multiple other facets of cognition have been widely studied in bipolar disorder. Verbal and non-verbal memory are related to the ability to register, store and retrieve verbal or visual information (Lezak, 1995). Verbal fluency is measured as the number of verbal responses a person can generate to a given target, such as a specific semantic category (e.g., animals, furniture) or phonetic category (e.g., words that begin with letter F) (Diamond, 2013). Although cognitive tasks have been designed to evaluate these specific functions, it is important to note that most measures are highly inter-correlated and may assess multiple overlapping functions to some extent (for example, the Trails B test is often described as an "executive function" task, although this task likely involves both working memory and cognitive flexibility. Not surprisingly, then, some authors label the function of certain tests differently, and this is particularly evident in meta-analyses of cognition. As we describe findings in this paper, we will use the terms proposed by the authors but will also identify key tests used to define a cognitive construct. With this background in mind, we turn to a discussion of cognitive deficits, then of emotion-related traits. Our hope is that those concise summaries provide evidence for the importance of both domains, but also specificity regarding the facets of emotion and cognition that are most impaired in BD. This specificity then guides our consideration of models that integrate cognition and emotion.

The relationship between executive functions and fluid intelligence in euthymic Bipolar Disorder patients

Distinct cognitive deficits have been described in Bipolar disorder (BD), including executive impairments, commonly attributed to frontal dysfunction. However, recent attention has been paid to the heterogeneity of cognitive functioning in this population, suggesting that the executive deficits observed in BD might be due to a loss in fluid intelligence (g). Following our previous line of investigation in multiple neurological and psychiatric conditions we aimed at determining the role of g in frontal deficits in BD. Euthymic BD patients (n = 51) and healthy controls (n = 37) were assessed with Wisconsin Card Sorting Test (WCST), Verbal Fluency, Trail Making Test B (TMTB), a multitasking test, and a theory of mind test. A general cognitive battery was used to derive a measure of g. As in other neuropsychiatric conditions, significant patient-control differences in WCST, Verbal Fluency and TMTB were removed when g was introduced as a covariate. Deficits remained significant in the multitasking test. We suggest that neuropsychological assessment in BD should include tests of general intelligence, together with one or more specific tasks that allow for the assessment of residual frontal deficits, putatively associated with anterior frontal functioning.

Clinical and treatment-related predictors of cognition in bipolar disorder: focus on visual paired associative learning

Bipolar disorder (BD) is associated with impairment in cognitive domains such as verbal memory and executive functions. However, visual paired associative learning (PAL) has been far less researched. Neurocognitive dysfunction in BD patients has been related to several clinical factors, but data on the effect of medication are relatively scarce and inconsistent. The aim of our study was to explore the effect of clinical and treatment-related parameters on executive functions and visual memory/learning, including PAL, in BD. Cognitive performance of 60 bipolar I patients and 30 healthy subjects was evaluated by using CANTAB battery tasks targeting spatial recognition memory, PAL and executive functions (set shifting, planning, inhibitory control). Bipolar patients showed poorer performance in PAL, set shifting, planning and inhibitory control than healthy subjects; however, only differences in PAL and planning survived correction for multiple comparisons. Number of previous manic episodes and illness duration predicted worse performance in set shifting and PAL, respectively, whereas current treatment with valproate predicted better performance in PAL. This is one of the first studies to assess clinical and treatment-related predictors of PAL in BD. We report a possibly beneficial effect of valproate on PAL, which warrants further investigation.

Bipolar Disorder and Cognitive Dysfunction: A Complex Link

The aim of this article was to describe the current evidence regarding phenomenon of cognitive functioning and dementia in bipolar disorder (BD). Cochrane Library and PubMed searches were conducted for relevant articles, chapters, and books published before 2016. Search terms used included "bipolar disorder," "cognitive dysfunction," and "dementia." At the end of the selection process, 159 studies were included in our qualitative synthesis. As result, cognitive impairments in BD have been previously considered as infrequent and limited to the affective episodes. Nowadays, there is evidence of stable and lasting cognitive dysfunctions in all phases of BD, including remission phase, particularly in the following domains: attention, memory, and executive functions. The cause of cognitive impairment in BD raises the question if it subtends a neurodevelopmental or a neurodegenerative process. Impaired cognitive functioning associated with BD may contribute significantly to functional disability, in addition to the distorted affective component usually emphasized.

The impact of chronic psychiatric disorders on cognitive decline

OBJECTIVES

Based on seemingly contradictory results in the existing literature, the objective of our study was to investigate whether older individuals suffering from chronic psychiatric disorders show a more rapid decline in cognitive performances than their non-psychiatric counterparts, or if the pattern of decline through older age is similar in both groups.

METHOD

A total of 820 older adults were selected from the Ageing Multidisciplinary Investigation (AMI) cohort study, which studies health-related issues of people over 65 years old living in rural areas. Among them, 30 suffer from chronic psychiatric disorders. Cognition was assessed with four neuropsychological tests: the Mini-Mental State Examination, the Digit Symbol Substitution Test, the Free and Cued Selective Reminding test and the Isaacs Set Test. Linear mixed models were used to compare the evolution of cognitive performances in the two groups between baseline and the four-year follow-up.

RESULTS

Despite lower performances at baseline, the pattern of cognitive decline of the psychiatric group is similar to that of the control group.

CONCLUSION

As suggested by this study conducted in rural communities, community-dwelling people suffering from chronic psychiatric disorders should not be considered at greater risk of age-related accelerated cognitive decline than the non-psychiatric older population.

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.

Manual motor speed dysfunction as a neurocognitive endophenotype in euthymic bipolar disorder patients and their healthy relatives. Evidence from a 5-year follow-up study

BACKGROUND

Few studies have examined Manual Motor Speed (MMS) in bipolar disorder (BD). The aim of this longitudinal, family study was to explore whether dysfunctional MMS represents a neurocognitive endophenotype of BD.

METHODS

A sample of 291 subjects, including 131 BD patients, 77 healthy first-degree relatives (BD-Rel), and 83 genetically-unrelated healthy controls (HC), was assessed with the Finger-Tapping Test (FTT) on three occasions over a 5-year period. Dependence of FTT on participants´ age was removed by means of a lineal model of HC samples, while correcting simultaneously the time and learning effect. Differences between groups were evaluated with an ANOVA test.

RESULTS

The patients' performance was significantly worse than that of HC over time (p≤0.006), and these deficits remained when non-euthymic BD patients (n=9) were excluded from analysis. Some significant differences between BD patients and BD-Rel (p≤0.037) and between BD-Rel and HC (p≤0.033) were found, but they tended to disappear as time progressed (p≥0.057). Performance of the BD-Rel group was intermediate to that of BD and HC. Most sociodemographic and clinical variables did not affect these results in patients. (p≥0.1). However, treatment with carbamazepine and benzodiazepines may exert a iatrogenic effect on MMS performance (p≤0.006).

LIMITATIONS

Only right-handed subjects were included in this study. Substantial attrition over time was detected.

CONCLUSIONS

There were significant differences between the patients´ MMS performance and that of healthy relatives and controls, regardless of most clinical and sociodemographic variables. Dysfunctional MMS could be considered an endophenotype of BD. Further studies are needed to rule out possible iatrogenic effects of some psychopharmacological treatments.

Cognitive Impairment in Bipolar Disorder: Treatment and Prevention Strategies

Over the last decade, there has been a growing appreciation of the importance of identifying and treating cognitive impairment associated with bipolar disorder, since it persists in remission periods. Evidence indicates that neurocognitive dysfunction may significantly influence patients' psychosocial outcomes. An ever-increasing body of research seeks to achieve a better understanding of potential moderators contributing to cognitive impairment in bipolar disorder in order to develop prevention strategies and effective treatments. This review provides an overview of the available data from studies examining treatments for cognitive dysfunction in bipolar disorder as well as potential novel treatments, from both pharmacological and psychological perspectives. All these data encourage the development of further studies to find effective strategies to prevent and treat cognitive impairment associated with bipolar disorder. These efforts may ultimately lead to an improvement of psychosocial functioning in these patients.

Social cognition in first-degree relatives of patients with bipolar disorder: A meta-analysis

Cognitive impairment is evident euthymic patients with bipolar disorder (BP) and in their first-degree relatives (BP-Rel). Increasing evidence suggests that BP is also associated with social cognitive impairment. It is important to establish whether social cognitive impairment is also evident in BP-Rel. A novel meta-analysis of theory of mind (ToM) and facial emotion recognition in BP-Rel including 16 studies (728 first-degree relatives of patients with BP and 865 healthy controls) was conducted. ToM (d=0.34, CI=0.16-0.52) was significantly impaired in BP-Rel. The effect size for the difference between BP-Rel and healthy controls was smaller for facial emotion recognition (d=0.17, CI=0.16-0.29) and could be nonsignificant after the effect of publication bias was taken into account. First-degree relatives of patients with BP underperform healthy subjects in social cognitive abilities, particularly in ToM. However, the effect size for between-group difference is small. ToM impairment might be a vulnerability marker of BP.

High cognitive reserve in bipolar disorders as a moderator of neurocognitive impairment

BACKGROUND

Cognitive reserve (CR) reflects the capacity of the brain to endure neuropathology, minimize clinical manifestations and successfully complete cognitive tasks. The present study aims to determine whether high CR may constitute a moderator of cognitive functioning in bipolar disorder (BD).

METHODS

102 patients with BD and 32 healthy controls were enrolled. All patients met DSM-IV criteria for I or II BD and were euthymic (YMRS≤6 and HDRS≤8) during a 6-month period. All participants were tested with a comprehensive neuropsychological battery, and a Cerebral Reserve Score (CRS) was estimated. Subjects with a CRS below the group median were classified as having low CR, whereas participants with a CRS above the median value were considered to have high CR.

RESULTS

Participants with BD with high CR displayed a better performance in measures of attention (digits forward: F=4.554, p=0.039); phonemic and semantic verbal fluency (FAS: F=9.328, p=0.004; and Animal Naming: F=8.532, p=0.006); and verbal memory (short cued recall of California Verbal Learning Test: F=4.236, p=0.046), after multivariable adjustment for potential confounders, including number of admissions and prior psychotic symptoms.

LIMITATIONS

The cross-sectional design of the study does not allow the establishment of causal inferences. Additionally, the small size of the sample may have limited some results.

CONCLUSIONS

High cognitive reserve may therefore be a valuable construct to explore for predicting neurocognitive performance in patients with BD regarding premorbid status.

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.

Mitochondrial dysfunction in bipolar disorder: Evidence, pathophysiology and translational implications

Bipolar disorder (BD) is a chronic psychiatric illness characterized by severe and biphasic changes in mood. Several pathophysiological mechanisms have been hypothesized to underpin the neurobiology of BD, including the presence of mitochondrial dysfunction. A confluence of evidence points to an underlying dysfunction of mitochondria, including decreases in mitochondrial respiration, high-energy phosphates and pH; changes in mitochondrial morphology; increases in mitochondrial DNA polymorphisms; and downregulation of nuclear mRNA molecules and proteins involved in mitochondrial respiration. Mitochondria play a pivotal role in neuronal cell survival or death as regulators of both energy metabolism and cell survival and death pathways. Thus, in this review, we discuss the genetic and physiological components of mitochondria and the evidence for mitochondrial abnormalities in BD. The final part of this review discusses mitochondria as a potential target of therapeutic interventions in BD.

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.

Increased Beta Frequency (15-30 Hz) Oscillatory Responses in Euthymic Bipolar Patients Under Lithium Monotherapy

The effect of lithium on neurocognition is not still fully explored. Brain oscillatory activity is altered in bipolar disorder. We aimed to assess the oscillatory responses of euthymic bipolar patients and how they are affected by lithium monotherapy. Event-related oscillations in response to visual target stimulus during an oddball paradigm in 16 euthymic drug-free and 13 euthymic lithium-treated bipolar patients were compared with 16 healthy controls. The maximum peak-to-peak amplitudes were measured for each subject's averaged beta (15-30 Hz) responses in the 0- to 300-ms time window over frontal (F3, Fz, F4), central (C3, Cz, C4), temporal (T7, T8), temporo-parietal (TP7, TP8), parietal (P3, Pz, P4), and occipital (O1, Oz, O2) areas. Patients under lithium monotherapy had significantly higher beta responses to visual target stimuli than healthy controls (P=.017) and drug-free patients (P=.015). The increase in beta response was observed at all electrode locations, however, the difference was statistically significant for the left (T7; P=.016) and right (T8; P=.031) temporal beta responses. Increased beta responses in drug-free patients and further significant increase in lithium-treated patients may be indicative of a core pathophysiological process of bipolar disorder and how it is affected by lithium. Whether the finding corresponds to lithium's corrective effect on the underlying pathology or to its neurocognitive side effect remains to be further explored. In either case, the finding is a sign that the oscillatory activity may be useful in tracking medication effect in bipolar disorder.

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.

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.

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.

Amphetamine sensitization in mice is sufficient to produce both manic- and depressive-related behaviors as well as changes in the functional connectivity of corticolimbic structures

It has been suggested that amphetamine abuse and withdrawal mimics the diverse nature of bipolar disorder symptomatology in humans. Here, we determined if a single paradigm of amphetamine sensitization would be sufficient to produce both manic- and depressive-related behaviors in mice. CD-1 mice were subcutaneously dosed for 5 days with 1.8 mg/kg d-amphetamine or vehicle. On days 6-31 of withdrawal, amphetamine-sensitized (AS) mice were compared to vehicle-treated (VT) mice on a range of behavioral and biochemical endpoints. AS mice demonstrated reliable mania- and depression-related behaviors from day 7 to day 28 of withdrawal. Relative to VT mice, AS mice exhibited long-lasting mania-like hyperactivity following either an acute 30-min restraint stress or a low-dose 1 mg/kg d-amphetamine challenge, which was attenuated by the mood-stabilizers lithium and quetiapine. In absence of any challenge, AS mice showed anhedonia-like decreases in sucrose preference and depression-like impairments in the off-line consolidation of motor memory, as reflected by the lack of spontaneous improvement across days of training on the rotarod. AS mice also demonstrated a functional impairment in nest building, an ethologically-relevant activity of daily living. Western blot analyses revealed a significant increase in methylation of histone 3 at lysine 9 (H3K9), but not lysine 4 (H3K4), in hippocampus of AS mice relative to VT mice. In situ hybridization for the immediate-early gene activity-regulated cytoskeleton-associated protein (Arc) further revealed heightened activation of corticolimbic structures, decreased functional connectivity between frontal cortex and striatum, and increased functional connectivity between the amygdala and hippocampus of AS mice. The effects of amphetamine sensitization were blunted in C57BL/6J mice relative to CD-1 mice. These results show that a single amphetamine sensitization protocol is sufficient to produce behavioral, functional, and biochemical phenotypes in mice that are relevant to bipolar disorder.

Bipolar disorder comorbid with alcohol use disorder: focus on neurocognitive correlates

Bipolar disorder (BD) and alcohol use disorders (AUDs) are usually comorbid, and both have been associated with significant neurocognitive impairment. Patients with the BD-AUD comorbidity (dual diagnosis) may have more severe neurocognitive deficits than those with a single diagnosis, but there is paucity of research in this area. To explore this hypothesis more thoroughly, we carried out a systematic literature review through January 2015. Eight studies have examined the effect of AUDs on the neurocognitive functioning of BD patients. Most studies found that BD patients with current or past history of comorbid AUDs show more severe impairments, especially in verbal memory and executive cognition, than their non-dual counterparts. Greater neurocognitive dysfunction is another facet of this severe comorbid presentation. Implications for clinical practice and research are discussed. Specifically, the application of holistic approaches, such as clinical staging and systems biology, may open new avenues of discoveries related to the BD-AUD comorbidity.

Lithium excessively enhances event related beta oscillations in patients with bipolar disorder

BACKGROUND

Previous resting-state electroencephalography studies have consistently shown that lithium enhances delta and theta oscillations in default mode networks. Cognitive task based networks differ from resting-state networks and this is the first study to investigate effects of lithium on evoked and event-related beta oscillatory responses of patients with bipolar disorder.

METHODS

The study included 16 euthymic patients with bipolar disorder on lithium monotherapy, 22 euthymic medication-free patients with bipolar disorder and 21 healthy participants. The maximum peak-to-peak amplitudes were measured for each subject's averaged beta responses (14-28 Hz) in the 0-300 ms time window. Auditory simple and oddball paradigm were presented to obtain evoked and event-related beta oscillatory responses.

RESULTS

There were significant differences in beta oscillatory responses between groups (p=0.010). Repeated measures ANOVA revealed location (p=0.007), laterality X group (p=0.043) and stimulus X location (p=0.013) type effects. Serum lithium levels were correlated with beta responses.

LIMITATIONS

The lithium group had higher number of previous episodes, suggesting that patients of the lithium were more severe cases than patients of the medication-free group.

DISCUSSION

Lithium stimulates neuroplastic cascades and beta oscillations become prominent during neuroplastic changes. Excessively enhanced beta oscillatory responses in the lithium-treated patients may be indicative of excessive activation of the neuron groups of the certain cognitive networks and dysfunctional GABAergic modulation during cognitive activity.