Prevalence and correlates of cognitive impairment in euthymic adults with bipolar disorder: A systematic review

Relationship between theory of mind and metabolic parameters and functioning in patients with bipolar I disorder

Purpose: We aimed to investigate the relationship theory of mind abilities with functionality and metabolic alteration in patients with bipolar disorder-1 (BD-1) during the remission period. Materials and Methods: This cross-sectional study is consisted of 68 patients with bipolar disorder-1 and 45 healthy controls. Sociodemographic form, Reading the Mind in the Eyes Test (RMET), Bipolar Disorder Functioning Questionnaire (BDFQ) were administered to the participants. Body mass index (BMI), waist circumference (WC), fasting plasma glucose (FG), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), total cholesterol (TC), triglyceride (TG) levels were recorded. Results: There were significant differences between the patient group and healthy control group in terms of WC, BMI, HDL, LDL, TG. The results of independent samples t-test indicated a statistically significant difference in RMET score between the two groups with control group significantly higher than patient group. Conclusion: Patients with BD-1 during the remission period have lower performance on theory of mind abilities and more alteration in metabolic parameters than healthy controls. Metabolic alteration and theory of mind impairment should be potential treatment target for BD

Neurochemical correlates of cognitive functions in euthymic patients with bipolar disorder: 1H-MRS study

OBJECTIVES

We assessed and correlated neurochemical levels and cognitive functions in left dorsolateral prefrontal cortex (DLPFC) and left hippocampus in euthymic patients with bipolar disorder and compared these with healthy controls METHODOLOGY: Twenty-five right-handed euthymic patients (HAM-D score < 7, and YMRS score < 7) with bipolar disorder and 20 age and gender matched controls were compared for neurometabolites (n-acetylaspartate - tNAA, choline - Cho, creatinine - Cr, myoinositol - Ins, and glutamine/glutamate - Glu/Gln) measured in left DLPFC and left hippocampus using single voxel magnetic resonance spectroscopy (MRS) and cognitive functions assessed using trail making test (TMT - A and B), wisconsin card sorting test (WCST), and wechsler memory scale (WMS-III Indian adaptation).

RESULTS

The two groups were comparable on socio-demographic variables. tNAA levels in DLPFC and hippocampus, and glutamate levels in hippocampus were found to be significantly lower and Inositol and glutamine levels in hippocampus were found to be significantly higher in patients as compared to controls. Patients performed significantly poorly as compared to controls on TMT A & B, all subscales of WMS - III, 5 subscales of WCST, including perseverative responses and errors. The tNAA and glutamate levels in left DLPFC in patients correlated with scores on TMT A & B, and several subscales of WCST and WMS-III. tNAA concentration in left hippocampus in patients correlated with scores on subscales of WMS-III.

CONCLUSION

Neurochemical dysfunction in select brain areas directly correlates with impairment in cognitive functions seen in patients with bipolar disorder in euthymic phase.

Altered activity in functional brain networks involved in lexical decision making in bipolar disorder: An fMRI case-control study

BACKGROUND

Brain networks involved in language, attentional and response processes are detectable by fMRI during lexical decision (LD). Here, we investigated possible abnormalities in the functional networks involved in LD in patients with bipolar disorder (BD).

METHODS

fMRI and behavioural data were compared between BD (n = 25) and control (n = 21), with groups matched for age and sex. The functional brain networks involved in LD were extracted by manipulating the "word-likeness" of LD stimuli and using a multidimensional analysis method.

RESULTS

Attentional, response and language processes were captured in separate function-specific brain networks (default mode network, response network, linguistic processing network, respectively) in the BD and control groups, replicating the results of our previous study in an independent group of healthy adults. Behaviourally, the BD group showed higher performance than the control group in the LD task. Activity in the default mode network (DMN) and the linguistic processing network (LPN) did not differ between the groups, but the BD group had higher activation than the control group in the response network (RESP).

LIMITATIONS

Due to the small sample, the study is underpowered, capable of only detecting large effects.

CONCLUSIONS

The results suggest that BD may be associated with sustained activity in the RESP network, which might contribute to psychomotor dysfunction in BD. Future studies should investigate the possible link between altered RESP activation and psychomotor disturbances in BD, as well as the basis for altered RESP activity in BD.

The differences in serum C1q levels between first-episode patients with bipolar disorder and major depressive disorder

OBJECTIVE

This study aimed at exploring the changes of serum complement C1q levels in patients with Bipolar Disorder (BD) using a cross-sectional design, and the differences between Major Depressive Disorder (MDD) and BD. Moreover, the correlation between complement C1q and bech-rafaelsdn mania rating scales (BRMS) in patients with MDD and BD was assessed.

METHODS

Serum complement C1q levels were measured by ADVIA 2400 biochemical analyser in 104 patients with MDD, 71 patients with BD type I and 42 patients with BD type II diagnosed by Diagnostic and Statistical of Mental Disorder 5 (DSM-5). Then simple and multivariate linear regression analysis was conducted between the level of serum C1q and BRMS among patients with BD.

RESULTS

The serum complement C1q levels were higher in BD type I than BD type II (P < 0.001); Serum complement C1q levels were higher in MDD than BD type II (P < 0.001). We discovered that there was a positive correlation relationship between serum complement C1q levels and BRMS in BD type I (r = 0.756, P < 0.001).

CONCLUSION

We confirmed that serum complement C1q levels were higher in patients with BD type II than in MDD patients. These current results support the view that the complement C1q may play an important role in the pathophysiology of BD. Serum complement C1q was strongly associated with BD and is worth investigating in future studies.

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.

Peripheral insulin sensitivity predicting cognitive function in euthymic bipolar disorder patients

OBJECTIVE

High prevalence of insulin resistance (IR) has been reported in bipolar disorder (BD) patients. Importantly, impaired insulin sensitivity could modulate the course and treatment outcome in BD. Here, we hypothesized that insulin sensitivity could be potentially associated with the neurocognitive trajectory in euthymic BD. We aimed to examine differences in insulin sensitivity and executive function between BD patients and controls.

METHODS

Sixty-two patients with BD receiving mood stabilizer treatment and 62 controls, matching age, sex, and body mass index, were recruited in this study. Insulin sensitivity was estimated using the homeostasis model assessment of insulin resistance (HOMA-IR). The Wisconsin card-sorting test (WCST) was applied to test participants' ability to shift cognitive set. Group differences were measured and multivariate regression analysis was performed to examine relationships among factors.

RESULTS

The results indicated that the HOMA-IR (P = .048) value in the patients with BD were significantly higher than those in controls. With regards to executive function, the BD patients performed significantly poorer than the control subjects (P < .05). Moreover, the interaction effect between BD diagnosis and HOMA-IR value on the WCST-preservation errors was significant (P = .01), and post-hoc analyses showed that the cognitive abilities were worse in the BD patients with a higher IR than in the others groups.

CONCLUSION

Insulin sensitivity is associated with the neurocognitive performance in euthymic BD patients. Although the underlying mechanisms remain unclear, interventions to improve insulin sensitivity could potentially improve the functional outcome of BD.

Neurocognitive deficits in depression: a systematic review of cognitive impairment in the acute and remitted state

Previous research suggests a broad range of deficits in major depressive disorder. Our goal was to update the current assumptions and investigate the extent of cognitive impairment in depression in the acute and remitted state. A systematic review of the existing literature between 2009 and 2019 assessing the risk of bias within the included studies was performed. Of the 42 articles reviewed, an unclear risk of bias was shown overall. The risk of bias mainly concerned the sample selection, inadequate remedial measures, as well as the lack of blinding the assessors. In the acute phase, we found strong support for impairment in processing speed, learning, and memory. Follow-up studies and direct comparisons revealed less pronounced deficits in remission, however, deficits were still present in attention, learning and memory, and working memory. A positive correlation between the number of episodes and cognitive deficits as well as depression severity and cognitive deficits was reported. The results also demonstrate a resemblance between the cognitive profiles in bipolar disorder and depression. Comparisons of depression with schizophrenia led to unclear results, at times suggesting an overlap in cognitive performance. The main findings support the global deficit hypothesis and align with results from prior meta-analyses and reviews. Recommendations for future research are also presented.

Characterizing the polygenic overlaps of bipolar disorder subtypes with schizophrenia and major depressive disorder

BACKGROUND

Large-scale studies have shown that bipolar I disorder (BD-I) and bipolar II disorder (BD-II) have differences in genetic association with schizophrenia (SCZ) and major depressive disorder (MDD). However, the underlying shared genetic architectures between BD subtypes and both SCZ and MDD remain largely unknown.

METHODS

We applied univariate and bivariate causal mixture models (MiXeR) to estimate the polygenicity and polygenic overlaps on large GWASs summary statistics of BD-I (n = 25,060), BD-II (n = 6781), SCZ (n = 69,369) and MDD (n = 170,756). Then, conjunctional false discovery rate approach was used to identify specific shared genetic loci between BD subtypes and both SCZ and MDD.

RESULTS

Univariate MiXeR revealed that BD-II was substantially more polygenic (22.37 K causal variants) as compared to BD-I, SCZ and MDD (7.87-12.43 K causal variants). Bivariate MiXeR revealed substantial polygenic overlaps between BD-I and SCZ (Dice-coefficient = 0.83) and between BD-I and MDD (Dice-coefficient = 0.76), which are beyond the genetic correlation (rg = 0.71 and 0.36). Conjunctional FDR analysis identified 236 distinct shared loci between BD-I and BD-II (2 loci), BD-I and SCZ (227 loci), BD-I and MDD (19 loci), BD-II and SCZ (1 locus), and BD-II and MDD (3 loci). Most of these shared loci have concordant effect directions among BD subtypes, SCZ and MDD.

LIMITATIONS

The bivariate MiXeR model was not applied for the BD-II because of insufficient power and inadequate model fit.

CONCLUSIONS

These findings provide evidence for extensive polygenic effects across BD subtypes, SCZ and MDD, which further our understanding of the potential genetic basis for the comorbid symptoms across these disorders.

Euthymic patients with predominantly manic polarity avoid happy faces in a dot probe task

BACKGROUND

Some studies suggest a mood-congruent attentional bias in bipolar patients. However, for euthymic patients, especially in dependence on the predominant polarity, there is little and inconsistent data. A clearer understanding of emotion-related attentional biases and their relationship to dysfunctional emotion regulation could help improving the diagnostics and treatment of bipolar disorder (BD). Twenty bipolar patients in a depressive state (BP-acute-D), 32 euthymic patients with manic (BP-euth-M) or depressive (BP-euth-D) predominant polarity, and 20 healthy control participants (HC) performed a dot-probe task (DPT) with happy and sad faces presented for 250 ms or 1250 ms in two different runs. Emotion regulation strategies were assessed with two questionnaires.

RESULTS

In the short presentation condition of the DPT, BP-euth-M showed less attention for happy faces than HC (p = .03, r = - 0.48). BP-acute-D scored lower in cognitive reappraisal and putting into perspective and higher in suppression, catastrophizing, and rumination than HC. BP-euth-M scored higher in rumination and BP-euth-D lower in putting into perspective and higher in catastrophizing than HC. In BP-euth-D and HC, bias scores for sad faces in the longer presentation condition and reappraisal scores correlated positively.

CONCLUSIONS

Results of the DPT suggest an avoidance of happy faces for BP-euth-M which we interpret as a protection mechanism for triggers of mania. That individuals who apply more reappraisal show more selective attention to sad faces could on the one hand reflect a mental effort in reevaluating the sad emotional input and on the other hand a greater tolerance for it.

Gut Microbial Dysbiosis and Cognitive Impairment in Bipolar Disorder: Current Evidence

Recent studies have reported that the gut microbiota influences mood and cognitive function through the gut-brain axis, which is involved in the pathophysiology of neurocognitive and mental disorders, including Parkinson’s disease, Alzheimer’s disease, and schizophrenia. These disorders have similar pathophysiology to that of cognitive dysfunction in bipolar disorder (BD), including neuroinflammation and dysregulation of various neurotransmitters (i.e., serotonin and dopamine). There is also emerging evidence of alterations in the gut microbial composition of patients with BD, suggesting that gut microbial dysbiosis contributes to disease progression and cognitive impairment in BD. Therefore, microbiota-centered treatment might be an effective adjuvant therapy for BD-related cognitive impairment. Given that studies focusing on connections between the gut microbiota and BD-related cognitive impairment are lagging behind those on other neurocognitive disorders, this review sought to explore the potential mechanisms of how gut microbial dysbiosis affects cognitive function in BD and identify potential microbiota-centered treatment.

Serum levels of olanzapine are associated with acute cognitive effects in bipolar disorder

Bipolar (BPD) patients have deficits in cognition, but there are still controversies about the effects of some medications on their cognitive performance. Here, we investigated the relationship between cognition in terms of executive functions, memory, and attention in both first-episode medication-naive BPD patients and BPD patients taking olanzapine. Forty-one healthy controls, 40 unmedicated drug-naive BPD patients, and 34 BPD patients who took only olanzapine were recruited for the study. Cognitive performance was assessed using the Flanker test, Stroop test, and Corsi-block test. Bayesian multivariate regression analysis was run considering maximum robustness to avoid bias and to predict the outcomes. Our results revealed that unmedicated medication-naive BPD patients performed worse than healthy controls and the olanzapine group in some tasks. Additionally, BPD patients who took olanzapine had better cognitive performance than healthy controls and unmedicated BPD patients. The acute cognitive effects were predicted by olanzapine dosage and serum levels (i.e., large effects). The potential pro-cognitive effects of olanzapine in BPD patients should be carefully interpreted by considering various other clinical variables. We expect that our findings will contribute to further research in this area, with the goal of helping other researchers, patients, and the population.

Insomnia symptoms are associated with impaired resilience in bipolar disorder: Potential links with early life stressors may affect mood features and suicidal risk

AIM

The study aimed to investigate resilience and its association with early exposure to stressful events on the clinical manifestations of bipolar disorders (BDs), such as severity of mood symptoms, suicidal ideation and behaviors focusing on the possible role of insomnia symptoms.

METHOD

A sample of 188 adult participants with BD of type I or II were assessed during depressed phase using the Structural Clinical Interview for DSM-5 (SCID-5), the Beck Depression Inventory-II (BDI-II), the Young Mania Rating Scale (YMRS), the Early Trauma Inventory Self Report-Short Form (ETISR-SF), Resilience Scale for Adults (RSA), the Insomnia Severity Index (ISI) and the Scale for Suicide Ideation (SSI). Participants with or without clinically significant insomnia were compared and we carried out correlations, regression and mediation analyses.

RESULTS

Participants with insomnia showed a greater severity of depressive symptoms as well as of suicidal risk, early life stressors and lower level of resilience. Insomnia symptoms mediated the association between early life stress and low resilience, between low resilience in planning future and depressive symptoms (Z = 2.17, p = 0.029) and low resilience and suicidal risk (Z = 3.05, p = 0.0002) CONCLUSION: Insomnia may be related to the severity of BDs, to higher early life stressors and lower level of resilience. Assessing and targeting insomnia symptoms may potentially promote resilience in BDs in response to early life stressful events. These results should be interpreted in light of several limitations including the cross-sectional design affecting causal interpretations.

Therapeutic Interventions to Mitigate Mitochondrial Dysfunction and Oxidative Stress–Induced Damage in Patients with Bipolar Disorder

Bipolar disorder (BD) is characterized by mood changes, including recurrent manic, hypomanic, and depressive episodes, which may involve mixed symptoms. Despite the progress in neurobiological research, the pathophysiology of BD has not been extensively described to date. Progress in the understanding of the neurobiology driving BD could help facilitate the discovery of therapeutic targets and biomarkers for its early detection. Oxidative stress (OS), which damages biomolecules and causes mitochondrial and dopamine system dysfunctions, is a persistent finding in patients with BD. Inflammation and immune dysfunction might also play a role in BD pathophysiology. Specific nutrient supplements (nutraceuticals) may target neurobiological pathways suggested to be perturbed in BD, such as inflammation, mitochondrial dysfunction, and OS. Consequently, nutraceuticals may be used in the adjunctive treatment of BD. This paper summarizes the possible roles of OS, mitochondrial dysfunction, and immune system dysregulation in the onset of BD. It then discusses OS-mitigating strategies that may serve as therapeutic interventions for BD. It also analyzes the relationship between diet and BD as well as the use of nutritional interventions in the treatment of BD. In addition, it addresses the use of lithium therapy; novel antipsychotic agents, including clozapine, olanzapine, risperidone, cariprazine, and quetiapine; and anti-inflammatory agents to treat BD. Furthermore, it reviews the efficacy of the most used therapies for BD, such as cognitive–behavioral therapy, bright light therapy, imagery-focused cognitive therapy, and electroconvulsive therapy. A better understanding of the roles of OS, mitochondrial dysfunction, and inflammation in the pathogenesis of bipolar disorder, along with a stronger elucidation of the therapeutic functions of antioxidants, antipsychotics, anti-inflammatory agents, lithium therapy, and light therapies, may lead to improved strategies for the treatment and prevention of bipolar disorder.

Serum concentration of zinc is elevated in clinically stable bipolar disorder patients

BACKGROUND

Bipolar disorder (BD) is a chronic psychiatric disorder characterized by recurrent mood episodes interspersed with euthymic periods. A growing number of studies have indicated that zinc plays an important role in coordinating immune responses, as well as being involved in synaptic transmission. In the current study, we set out to measure serum levels of zinc in a meticulously phenotyped cohort of 121 euthymic BD subjects and 30 matched controls.

METHODS

Serum levels of zinc were measured by photometry. To assess the interplay between zinc levels and immune activation in BD, we measured serum levels of high-sensitive C-reactive protein (hsCRP) levels by immunoturbidimetric assay, and serum levels of monocyte chemoattractant protein-1 (MCP-1), chitinase 3-like protein 1 (YKL-40), and soluble cluster of differentiation 14 (sCD14) by electrochemiluminescence enzyme-linked immunosorbent assays. The baseline clinical diagnostic instrument for BD was the Affective Disorder Evaluation, and executive functioning was assessed by using the Delis-Kaplan Executive Function System.

RESULTS

Controlling for potential confounding factors, BD patients displayed increased serum levels of zinc unrelated to hsCRP, MCP-1, YKL-40, and sCD14 levels. Serum levels of zinc did not associate with executive functioning or measurements of disease severity.

DISCUSSION

This study suggests that the zinc homeostasis is disturbed in BD and that this dyshomeostasis is not related to ongoing mood symptoms or immune activation. Of note, serum levels were increased and hence do not support continuous zinc supplementation in BD.

The long-term course of cognition in bipolar disorder: a systematic review and meta-analysis of patient-control differences in test-score changes

Neuropsychological impairment represents a key aspect of bipolar disorder (BD) that is evident even in early-course patients and is a strong predictor of functional outcomes among those affected. Previous meta-analyses of longitudinal studies suggest that BD-related cognitive deficits may not progress along the course of the disorder. However, short test-retest periods were used in most primary studies and comparisons with healthy controls were limited. The aim of this review was to synthesize the findings of research reports comparing long-term neurocognitive trajectories between BD patients and healthy individuals. PubMed, PsycINFO, and Scopus databases were searched from inception through July 2021. Publications were considered for inclusion if they reported cognitive test scores of BD patients and healthy controls at two different time points, with a minimum test-retest interval of 5 years. Fifteen studies compared the long-term course of cognition in BD patients with that of healthy controls. Ten of these were included in the quantitative analysis and involved 540 BD patients and 644 healthy individuals (mean follow-up period: 8.9 years). Patient-control effect sizes (standardized mean differences) were calculated for test-score changes in 24 neuropsychological variables and combined by means of meta-analytic procedures. No significant differences were found between patients and controls regarding long-term cognitive outcomes. These findings are consistent with previous shorter-term longitudinal meta-analyses and do not provide evidence for progressive cognitive deterioration in most bipolar individuals. Future studies should address the longitudinal course of cognition in different subgroups of BD patients and its prognostic and therapeutic value.

Heterogeneity of psychosocial functioning in patients with bipolar disorder: Associations with sociodemographic, clinical, neurocognitive and biochemical variables

OBJECTIVE

This study aims to identify the functional heterogeneity in fully or partially remitted patients with bipolar disorder and explore the correlations between psychosocial functioning and sociodemographic, clinical, neurocognitive and biochemical variables.

METHODS

One hundred and forty fully or partially remitted patients with bipolar disorder (BD) and seventy healthy controls were recruited. The patients were grouped into different profiles based on the Functioning Assessment Short Test (FAST) domain scores by hierarchical cluster analysis. The characteristics of subgroups and the correlations between psychosocial functioning and sociodemographic, clinical, neurocognitive and biochemical variables in each cluster were then analyzed.

RESULTS

There were three subgroups in fully or partially remitted patients with BD: the lower functioning group (LF), performed global functioning impairments; the moderate functioning group (MF), presented selective impairments in functional domains; and the good functioning subgroup (GF), performed almost intact functioning. Among the three subgroups, there were differences in FAST domains, sociodemographic variables, clinical variables, some neurocognitive domains and several biochemical indexes.

CONCLUSIONS

The study successfully identified three functional subgroups. The characteristics of discrete subgroups and the specific clinical factors, neurocognitive domains and biochemical indexes that are correlated with functional subgroups will allow for making tailored interventions to promote functional recovery and improve the quality of life.

Affective episodes in recently diagnosed patients with bipolar disorder associated with altered working memory-related prefrontal cortex activity: A longitudinal fMRI study

INTRODUCTION

Bipolar disorder (BD) is often accompanied by trait-related cognitive impairments, but it is unclear which neurocircuitry abnormalities give rise to these impairments and whether neurocircuitry differences are exacerbated with illness progression. This longitudinal fMRI study of recently diagnosed BD patients investigates whether aberrant working memory (WM) related activity in the cognitive control network is accentuated by new affective episodes.

METHODS

Forty-seven recently diagnosed BD patients in full or partial remission and 38 healthy controls were assessed with neurocognitive tests and fMRI during the performance of a verbal n-back WM task at baseline and follow-up (15.4 months in average).

RESULTS

Patients showed WM-related hypo-activity in dorsal prefrontal cortex (dPFC) and impaired cognitive function within attention and psychomotor speed, WM and executive function, and verbal learning and memory compared to controls at baseline. During the follow-up period, 26 patients experienced at least one affective episode (BD+), while 21 remained in remission (BD-). There was no deterioration in cognitive performance in BD+ compared to BD- patients. Nevertheless, BD+ displayed increased WM-related dPFC activity at follow-up compared with BD- patients. This change in dPFC response was independent of mood symptoms and medication.

LIMITATIONS

The study did not account for type or frequency of affective episodes.

CONCLUSION

The study identifies cognitive impairment and WM-related hypo-activity in dPFC early during the course of BD. Increased high-load WM related dPFC activity over the follow-up period in BD+ versus BD- patients in the absence of changes in cognitive performance may reflect an episode-related reduction in PFC efficiency.

Sex differences in cognitive function of first-diagnosed and drug-naïve patients with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a severe mental illness that affects more than 1% the world's population with high recurrence rates and a series of comorbidities. Cognitive dysfunction is an endophenotype of BD, but sex influences in cognitive impairment remains unclear.

METHOD

We evaluated the performance of 139 patients with first-diagnosed, drug-naïve BD (44 males and 95 females) and 92 healthy controls (24 males and 68 females) using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) scale and the Stroop color-word test.

RESULT

Immediate memory, visuospatial/constructional ability, language, attention, delayed memory, total RBANS score, and Stroop color-word scores were significantly lower in patients with first-diagnosed, drug-naïve BD than healthy participants. Thus, male patients had worse attention and delayed memory scores compared with female patients with BD. Importantly, a worse performance in visuospatial/constructional ability was negatively associated with the Young Mania Rating Scale score in male patients only.

CONCLUSION

Male patients with first-diagnosed, drug-naïve bipolar disorder had worse cognitive dysfunction than female patients in attention and delayed memory. Cognitive deficits were correlated with mania severity only in male patients. These findings reveal the sexual dimorphism in the cognitive deficits of early BD patients with mild and moderated symptoms for further pathophysiological exploration.

Decision-making and cognitive control in adolescent suicidal behaviors: a qualitative systematic review of the literature

Suicide and suicidal behaviors represent a leading cause of morbidity and mortality during adolescence. While several lines of evidence suggest that suicidal behaviors are associated with risky decisions and deficient cognitive control in laboratory tasks in adults, comparatively less is known about adolescents. Here, we systematically reviewed the literature on the association between these neurocognitive variables and adolescent suicidal behaviors. The online search strategy identified 17 neurocognitive studies examining either cognitive control or decision-making processes in adolescents with past suicidal behaviors. Several studies have reported that adolescents with a history of suicidal behaviors present neuropsychological differences in the cognitive control (using Go/NoGo, suicide Stroop Test, continuous performance test, suicide/death Implicit Association Test), and decision-making (Iowa Gambling Task, Cambridge Gambling Task, cost computation, delay discounting, loss aversion tasks) domains. Due to a lack of replication or conflicting findings, our systematic review suggests that no firm conclusion can be drawn as to whether altered decision-making or poor cognitive control contribute to adolescent suicidal behaviors. However, these results collectively suggest that further research is warranted. Limitations included scarcity of longitudinal studies and a lack of homogeneity in study designs, which precluded quantitative analysis. We propose remediating ways to continue neuropsychological investigations of suicide risk in adolescence, which could lead to the identification of novel therapeutic targets and predictive markers, enabling early intervention in suicidal youth.

Cognitive impairment in euthymic patients with bipolar disorder: Prevalence estimation and model selection for predictors of cognitive performance

Objectives Although cognitive dysfunction is a prominent feature of bipolar disorder (BD), previous research presents limitations in estimating the proportion of euthymic patients experiencing clinically relevant deficits and identifying predictors of cognitive difficulties. We explored the relevance of recommended definitions of clinically significant cognitive impairment for functional outcomes, estimated its prevalence, and identified patient characteristics associated with cognition. Methods We assessed cognitive performance across four domains in 80 euthymic participants with BD. Participants were categorized based on two criteria for clinically significant cognitive impairment and we assessed the ability of these criteria to differentiate participant performance on established functional outcomes. Variable selection with elastic net regression was used to identify sociodemographic and clinical factors associated with cognitive performance. Selected variables were examined as predictors of clinically significant cognitive impairment with logistic regression. Results According to the selected criterion, 34% presented with clinically significant cognitive impairment. Poorer current cognitive performance was associated with older age, lower estimated premorbid IQ, more currently prescribed psychotropic medications, fewer previous psychological therapies, and current use of antipsychotics. A model with premorbid IQ, psychotropic medications and previous psychological therapies as predictors of cognitive impairment correctly classified 75% of the participants. Conclusions This is one of the first studies to use a model selection approach to identify factors associated with cognitive difficulties in BD. Our findings offer the initial steps towards a predictive model for cognitive impairment. This could improve treatment decisions and prioritization for euthymic patients with BD, particularly the implementation of cognitive interventions.

The effect of systemic antidepressant treatments in early stage on neurocognitive function of euthymic bipolar patients initiated with a depressive onset: An observational, cross-sectional, single-blind study protocol

OBJECTIVES

Patients with bipolar disorder (BD) have a wide range of neurocognitive dysfunction even in euthymic state, leading to impaired psychosocial function and reduced quality of life. However, the understanding on risk factors related to neurocognitive impairment in such group of people is limited. In view of significantly delayed diagnosis of BD and common use of antidepressants prior to the BD diagnosis, the study aims to clarify whether systemic antidepressant use in early stage, defined as from the initial depressive episode to the diagnosis of BD, could impact neurocognitive function of euthymic bipolar patients.

METHODS

It is an observational, cross-sectional, single-blind trial, making a comparison in neurocognitive function between euthymic bipolar patients who had a depressive episode as initial onset and being with and without systemic antidepressant treatments in early stage (n = 62 and 62, respectively); secondary outcomes include the impact of systemic antidepressant use on global function, quality of life, sleep quality, positive and negative affect, and peripheral level of neuron-specific enolase.

DISCUSSION

The study will provide a comprehensive and in-depth understanding on the effect of systemic antidepressant treatments in early stage in such group of patients. It is expected to better guide the related prevention and treatment work of BD management.

TRIAL REGISTRATION

The study was registered on Clinicaltrials.gov with protocol ID (TJAH2020-18) and clinicaltrials.gov ID (NCT04564573).

Comparison of the Neurocognitive Profile of the Children of Parents with Bipolar Disorder and Controls: a Transnational Cross-Sectional Study

INTRODUCTION

Studies that have compared the cognitive alterations of the children of parents with bipolar disorder (CPBD) versus the children of control parents (CCP), present heterogeneous results due to the studies' methodological differences, the age of the population studied, and the lack of standardisation of the measures used for the different neurocognitive domains. The objective was to compare the neurocognitive profile of CPBD versus CCP to observe if there are differences that could be proposed as possible endophenotypes of BD.

RESULTS

A total of 107 individuals (51 CPBD, and 56 CCP) with ages between 6 and 16 (mean, 12.2±2.80) years of age were evaluated. Seventy-four point five percent of the CPBD group had some disorder compared to 67.9% of the CCP group. Tests such as letter-F phonemic verbal fluency, letter-S phonemic verbal fluency, overall F-A-S phonemic verbal fluency, story recall and retrieval, and Wisconsin perseverative errors showed a difference with a small effect size, but with a high degree of uncertainty.

CONCLUSIONS

The CPBD did not have differences in their neurocognitive profile in comparison with CCP. Both groups have a high prevalence of psychopathology, which is a factor that could explain the lack of differences in neurocognitive performance.

Effect of Action-Based Cognitive Remediation on cognitive impairment in patients with remitted bipolar disorder: A randomized controlled trial

OBJECTIVES

Cognitive impairment affects many patients with bipolar disorder (BD), and treatments with replicated pro-cognitive effects are lacking. This study aimed to assess the effect of Action-Based Cognitive Remediation (ABCR) vs control treatment on cognitive impairment in patients with BD.

METHODS

Patients with remitted BD with objective cognitive impairment were randomized to 10 weeks of ABCR vs control treatment, and assessed at baseline, after 2 weeks of treatment, at treatment completion and at 6 months follow-up. The primary outcome was a cognitive composite score. Secondary outcomes were executive function and observer-rated functional capacity. Tertiary measures included additional neuropsychological tests, performance-based functional capacity and quality of life. Data were analysed with linear mixed effects models.

RESULTS

In total, 64 participants were randomized; given three dropouts before the baseline assessments, data were analysed for 61 participants (ABCR: n = 32, control: n = 29). There was no effect on ABCR vs control on the primary cognitive composite score (P-values ≥.60). At treatment completion, there was a large effect of ABCR vs control on the secondary executive function measure (treatment effect= -0.16, 95% CI [-0.27, -0.05], P ≤ .01, d = 0.65), and on subjective cognitive functioning (treatment effect = -5.38, 95% CI [-8.13, -2.67], P ≤ .001, d = 0.80), which disappeared at follow-up. There was no treatment-effect on functioning, and no association between cognitive and functional change.

CONCLUSIONS

There was no effect of ABCR on the cognitive composite score. However, there was an effect on executive function and subjective cognitive functioning suggesting that ABCR may be relevant for patients with executive dysfunction.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03295305.

Inflammatory biomarkers and cognitive functioning in individuals with euthymic bipolar disorder: exploratory study

BACKGROUND

Neurobiological research frequently implicates inflammatory and neurogenic components with core aspects of bipolar disorder. Even in periods of symptom remission (euthymia), individuals with bipolar disorder experience cognitive impairments, which are increasingly being proposed as an outcome for interventions; identifying biomarkers associated with cognitive impairment in people with bipolar disorder could advance progress in this therapeutic field through identifying biological treatment targets.

AIMS

We aimed to identify proteomic biomarker correlates of cognitive impairment in individuals with euthymic bipolar disorder.

METHOD

Forty-four adults with a bipolar disorder diagnosis in euthymia underwent a battery of cognitive assessments and provided blood for biomarkers. We examined a comprehensive panel of inflammatory and trophic proteins as putative cross-sectional predictors of cognition, conceptualised according to recommended definitions of clinically significant cognitive impairment (binary construct) and global cognitive performance (continuous measure).

RESULTS

A total of 48% of the sample met the criteria for cognitive impairment. Adjusting for potentially important covariates, regression analyses identified lower levels of three proteins as significantly and independently associated with cognitive deficits, according to both binary and continuous definitions (interleukin-7, vascular endothelial growth factor C and placental growth factor), and one positively correlated with (continuous) global cognitive performance (basic fibroblast growth factor).

CONCLUSIONS

This study identifies four candidate markers of cognitive impairment in bipolar disorder, none of which have been previously compared with cognitive function in participants with bipolar disorder. Pending replication in larger samples and support from longitudinal studies, these markers could have implications for treating cognitive dysfunction in this patient population.

Long-term trajectory of cognitive performance in people with bipolar disorder and controls: 6-year longitudinal study

BACKGROUND

Cross-sectional studies have found impaired cognitive functioning in patients with bipolar disorder, but long-term longitudinal studies are scarce.

AIMS

The aims of this study were to examine the 6-year longitudinal course of cognitive functioning in patients with bipolar disorder and healthy controls. Subsets of patients were examined to investigate possible differences in cognitive trajectories.

METHOD

Patients with bipolar I disorder (n = 44) or bipolar II disorder (n = 28) and healthy controls (n = 59) were tested with a comprehensive cognitive test battery at baseline and retested after 6 years. We conducted repeated measures ANCOVAs with group as a between-subject factor and tested the significance of group and time interaction.

RESULTS

By and large, the change in cognitive functioning between baseline and follow-up did not differ significantly between participants with bipolar disorder and healthy controls. Comparing subsets of patients, for example those with bipolar I and II disorder and those with and without manic episodes during follow-up, did not reveal subgroups more vulnerable to cognitive decline.

CONCLUSIONS

Cognitive performance remained stable in patients with bipolar disorder over a 6-year period and evolved similarly to healthy controls. These findings argue against the notion of a general progressive decline in cognitive functioning in bipolar disorder.

Internet-based cognitive assessment tool: Sensitivity and validity of a new online cognition screening tool for patients with bipolar disorder

BACKGROUND

The International Society for Bipolar Disorders Targeting Cognition Task Force recommends the Screen for Cognitive Impairment in Psychiatry (SCIP) to screen for cognitive impairment in bipolar disorder. However, SCIP must be administered by a healthcare professional, which is often impossible due to time and resource constraints. Web-based, self-administered cognition screening tools may enable assessment and monitoring of patients' cognition at a much larger scale to a reduced cost. For this purpose, we developed the Internet-Based Cognitive Assessment Tool (ICAT) as a modified web-based version of SCIP. This study aimed to investigate the sensitivity and validity of ICAT for cognition assessment in bipolar disorder.

METHOD

Thirty-five patients with bipolar disorder in full or partial remission and 35 healthy controls completed ICAT on a computer, the standard paper-and-pencil SCIP and a subjective cognition questionnaire and were rated for mood symptoms and functioning at the Copenhagen Affective Disorders Research Centre.

RESULTS

Patients displayed cognitive impairments compared to controls on the ICAT (t (61)=3.67, p<.001, d=0.93). There was a strong correlation between ICAT and SCIP Total Scores (r(61)=.72, p<.000) and moderate to strong correlations on subtest scores (r=.48-.63, ps<.001). Across all participants, lower ICAT scores correlated with more subjective cognitive complaints (r(59)=-.43, p<.001) and poorer psychosocial functioning (r(62)=-.47, p<.001).

CONCLUSION

ICAT is a sensitive and valid web-based tool for cognition assessment in patients with bipolar disorder. This highlights ICAT as a novel web-based cognition screening tool that is feasible for largescale assessment and monitoring of cognition in the clinical management of bipolar disorder.

Cognitive complaints in individuals recently diagnosed with bipolar disorder: A cross-sectional study

AIM

To assess the differences in subjective cognitive dysfunction between major depressive disorder (MDD) and recently diagnosed Bipolar Disorder (BD) across euthymia and mood episodes.

METHODS

This is a cross-sectional study corresponding to the second wave of a longitudinal study. The first wave consisted of subjects aged between 18 and 60 diagnosed with MDD. In the follow up after three years (second wave), conversion from MDD to BD diagnosis was assessed by qualified psychologists using the Mini International Neuropsychiatric Interview (MINI-Plus). Subjects were categorized in four diagnostic groups: euthymic MDD, MDD in a current mood episode, euthymic BD, and BD in a current mood episode. All subjects completed the Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA), an instrument specifically designed for detecting subjective cognitive deficits in BD.

RESULTS

The total sample (n = 468) included 410 subjects with MDD and 58 individuals recently diagnosed with BD. We subdivided the 2 groups based on their current mood state, and found a significant difference in COBRA total scores between euthymic BD individuals (median 17.00 [IQR: 8.75 - 20.75]) and euthymic MDD subjects (median 8.00 [IRQ: 5.00 - 14.00], p = 0.002), showing higher subjective cognitive dysfunction in individuals recently diagnosed with BD. The differences remained significant after adjusting for the presence of lifetime psychotic symptoms. We found no differences between MDD and BD during an acute mood episode.

LIMITATION

The small sample size of individuals with BD.

CONCLUSION

The findings suggest a higher presence of subjective cognitive complaints among individuals recently diagnosed with BD in comparison to individuals with MDD during euthymia.

Neuronal and cognitive predictors of improved executive function following action-based cognitive remediation in patients with bipolar disorder

Cognitive impairments in bipolar disorder (BD) are prevalent but effective treatments with replicated and lasting pro-cognitive effects are lacking. Treatment development is hampered by a lack of neurocircuitry biomarkers to predict treatment efficacy. Action-Based Cognitive Remediation (ABCR) improves executive function in BD and this was accompanied by increased dorsal prefrontal cortex (dPFC) response during working memory (WM) after two weeks of treatment. This study investigated whether pre-treatment WM-related dPFC response, executive dysfunction and/or subjective cognitive difficulties predicted ABCR treatment response on executive functions. Forty-five patients with fully or partially remitted BD (ABCR: n = 25, control treatment: n = 20) in our ABCR trial completed a spatial N-back WM task during functional magnetic resonance imaging (fMRI) at baseline. Patients also completed neuropsychological tests and rated their cognitive functions before and after 10 weeks of ABCR or control treatment. Multiple linear regression analyses were conducted to assess whether pre-treatment dPFC response, objective executive impairment and/or subjective cognitive difficulties predicted greater ABCR-related improvements of executive function. We found that treatment-related improvement in executive function was predicted by more WM-related dPFC hypo-activity at baseline (p = 0.03) in linear regression analyses adjusted for age, gender and education. In contrast, there was only a non-significant trend towards more executive dysfunction at baseline predicting greater ABCR-related executive improvement (p = 0.08). Subjective cognitive difficulties at baseline showed no association with treatment effects (p = 0.16). In conclusion, pre-treatment dPFC hypo-activity during WM performance predicts greater effects of ABCR treatment on executive function and may represent a neurocircuitry biomarker for treatment efficacy in this cognitive domain.

Perceived cognitive failures and quality of life for older adults with bipolar disorder

BACKGROUND

Older adults with bipolar disorder (BD) commonly present with cognitive deficits (e.g., attention, memory, verbal fluency). Concomitantly, older adults with BD commonly report subjective or perceived cognitive failures. For this study, we confirmed a 3-factor model of cognitive failures first validated with older adults free of mental illness (i.e., forgetfulness, distractibility, false triggering). We then computed a structural equation model (SEM) demonstrating the construct validity of perceived cognitive errors in relation to quality of life with BD. Use of SEM enabled us to measure quality of life broadly and germane to BD (i.e., well-being, life satisfaction, alcohol misuse, sleep quality).

METHODS

We obtained responses from an international sample of 350 older adults with BD (M = 61.26 years of age, range 50-87), recruited via micro-targeted social media advertising. Most lived in Canada, the U.S., U.K., Ireland, Australia and South Africa.

RESULTS

As hypothesized, perceived cognitive failures were predicted by BD symptoms (depression and hypo/mania). And cognitive failures directly and indirectly predicted quality of life.

LIMITATIONS

Future research is needed to replicate this QoL model over time with younger patients and those recruited using more traditional methods.

CONCLUSIONS

Perceived cognitive failures may not be strongly correlated with objective indices of cognitive deficits; nonetheless perceived cognitive failures are significantly associated with quality of life for older adults with BD. For both cognitive errors and BD symptoms, their indirect effect on quality of life (via suicide ideation) is greater than the direct effect.

Change in prefrontal activity and executive functions after action-based cognitive remediation in bipolar disorder: a randomized controlled trial

Cognitive impairment is prevalent in bipolar disorder (BD) but treatments with pro-cognitive effects are lacking. Insight concerning the neurocircuitry of cognitive improvement could provide a biomarker for pro-cognitive effects to advance treatment development. The dorsal prefrontal cortex (dPFC) is a promising region for such treatment target engagement. The aim of this functional magnetic resonance imaging (fMRI) study was to examine the effects of action-based cognitive remediation (ABCR) on early change in the dPFC blood-oxygen-level-dependent response in patients with BD in remission, and whether the observed neural change predicted improved executive functions following 10 weeks of treatment. Forty-five participants with remitted BD (ABCR: n = 26, control treatment: n = 19) completed a spatial n-back working memory task during fMRI and executive function tasks outside the scanner before and after two weeks of ABCR/control treatment, and an additional assessment of executive function at treatment completion. Thirty-four healthy controls underwent a single fMRI and executive function assessment for baseline comparisons. We found an early reversal of pretreatment hypo-activity in the dorsolateral prefrontal cortex (dlPFC) following ABCR vs. control during both high-load (2-back > 1-back) working memory (WM) (F(1,43) = 5.69, p = 0.02, η2 = 0.12) and general WM (2-back > 0-back) (F(1,43) = 5.61, p = 0.02, η2 = 0.12). This dlPFC activity increase predicted improved executive functions at treatment completion (high-load WM: B = -0.45, p = 0.01, general WM: B = -0.41, p < 0.01), independent of changes in subsyndromal symptoms. In conclusion, early dPFC increase may provide a neurocircuitry-based biomarker for pro-cognitive effects. Future cognition trials should include fMRI assessments to confirm the validity of this putative biomarker model across disorders with cognitive impairment.

The Attentional Boost Effect in Young and Adult Euthymic Bipolar Patients and Healthy Controls

In the Attentional Boost Effect (ABE), stimuli encoded with to-be-responded targets are later recognized more accurately than stimuli encoded with to-be-ignored distractors. While this effect is robust in young adults, evidence regarding healthy older adults and clinical populations is sparse. The present study investigated whether a significant ABE is present in bipolar patients (BP), who, even in the euthymic phase, suffer from attentional deficits, and whether the effect is modulated by age. Young and adult euthymic BP and healthy controls (HC) presented with a sequence of pictures paired with target or distractor squares were asked to pay attention to the pictures and press the spacebar when a target square appeared. After a 15-min interval, their memory of the pictures was tested in a recognition task. The performance in the detection task was lower in BP than in HC, in both age groups. More importantly, neither young nor adult BP exhibited a significant ABE; for HC, a robust ABE was only found in young participants. The results suggest that the increase in the attentional demands of the detection task in BP and in adult HC draws resources away from the encoding of target-associated stimuli, resulting in elimination of the ABE. Clinical implications are discussed.

The relationship between cannabis use and cognition in people with bipolar disorder: A systematic scoping review

Bipolar disorder (BD) and cannabis use are highly comorbid and are each associated with cognitive impairment.  Given the prevalence of cannabis use in people with BD, it is important to understand whether the two interact to impact cognitive function. We performed a systematic scoping review to determine what is currently known in this field. We systematically searched PubMed, Embase, CINAHL, Web of Science, and PsycINFO for studies on the relationship between cannabis use and cognition in people with BD or relevant animal models. Six observational human studies and no animal studies met inclusion criteria. Two studies found cannabis use in BD was associated with better performance in some cognitive domains, while three studies found no association. One study found cannabis use in BD was associated with worse overall cognition. Overall, most identified studies suggest cannabis use is not associated with significant cognitive impairment in BD; however, the scope of knowledge in this field is limited, and more systematic studies are clearly required. Future studies should focus on longitudinal and experimental trials, and well-controlled observational studies with rigorous quantification of the onset, frequency, quantity, duration, and type of cannabis use, as well as BD illness features.

Conceptualizing the later stage of bipolar disorder: Descriptive analyses from the ORBIT trial

OBJECTIVES

This study aimed to investigate the features of later stage bipolar disorder (BD) and specifically, factors underlying later stage BD and potential subgroups within this stage, to understand more about the later stage group and contribute to the measurement of stage.

METHODS

An exploratory factor analysis was conducted using variables relating to current phenomenological aspects of illness, followed by cluster analyses based on the identified factors. Finally, the resultant clusters were compared based on course of illness variables.

RESULTS

Fourteen extracted factors explained 57 percent of the variance. Latent structures aligned with current depressive symptoms, energy and interest, independence, occupational functioning, symptoms of anxiety, pain, elevated symptoms, interpersonal functioning, anger, perceptions of social connections, and perceptions of current medication effectiveness, cognitive issues, sleep issues, and sense of isolation. Two clusters were identified which differed significantly on each of these factors, and on a range of course of illness features including lifetime number of episodes, duration of illness and number of depressive hospitalizations.

CONCLUSIONS

Latent phenomenological features relevant to individuals in the later stage of BD were identified. Two clusters of individuals in later stage BD differ based on these features as well as course of illness, suggesting that there are distinct subgroups of individuals in the later stage of BD, distinguishable based on current phenomenology and illness history. However, findings are exploratory and therefore require confirmation before they can be applied clinically.

Neurocognitive heterogeneity in patients with bipolar disorder and their unaffected relatives: associations with emotional cognition

BACKGROUND

Recent evidence suggests that neurocognitive impairments in remitted patients with bipolar disorder (BD) are heterogeneous. Our study aims to replicate recent findings of neurocognitive subgroups, and further explore whether these are related to impairments in affective cognition, in a large sample of remitted patients recently diagnosed with BD and their unaffected relatives compared to healthy controls (HCs).

METHODS

Hierarchal cluster analysis was conducted using neurocognitive data from remitted patients with BD (n = 158). Relatives of patients with BD (n = 52) were categorised into groups consistent with their affected relative's cluster assignment. The neurocognitive clusters of patients with BD and relatives, respectively, were compared with HCs (n = 110) in neurocognition and affective cognition (i.e. emotion processing and regulation).

RESULTS

Three discrete neurocognitive clusters were identified in patients with BD: a globally impaired (23.4%), a selectively impaired (31.0%) and a cognitively intact cluster (45.6%). The neurocognitive subgroups differed in affective cognition, with patients categorised as globally impaired exhibited most impairments in facial expression recognition and emotion regulation in social scenarios. First-degree relatives of cognitively impaired patients displayed impaired facial expression recognition but no impairments in non-emotional cognition.

CONCLUSIONS

In a clinical sample of remitted patients recently diagnosed with BD 54.4% had either global or selective cognitive impairment, replicating results of previous studies in patients with longer illness duration. The results suggest that patterns of neurocognition are associated with differential impairments in affective cognition. Aberrant affective cognition in relatives of patients categorised as neurocognitively impaired indicates an inherited risk for BD.

Neuroprogression as an Illness Trajectory in Bipolar Disorder: A Selective Review of the Current Literature

Bipolar disorder (BD) is a chronic and disabling psychiatric condition that is linked to significant disability and psychosocial impairment. Although current neuropsychological, molecular, and neuroimaging evidence support the existence of neuroprogression and its effects on the course and outcome of this condition, whether and to what extent neuroprogressive changes may impact the illness trajectory is still poorly understood. Thus, this selective review was aimed toward comprehensively and critically investigating the link between BD and neurodegeneration based on the currently available evidence. According to the most relevant findings of the present review, most of the existing neuropsychological, neuroimaging, and molecular evidence demonstrates the existence of neuroprogression, at least in a subgroup of BD patients. These studies mainly focused on the most relevant effects of neuroprogression on the course and outcome of BD. The main implications of this assumption are discussed in light of specific shortcomings/limitations, such as the inability to carry out a meta-analysis, the inclusion of studies with small sample sizes, retrospective study designs, and different longitudinal investigations at various time points.

Proinflammatory Cytokine Dysregulation and Cognitive Dysfunction Among Patients with Remitted Bipolar I and II Disorders

BACKGROUND

Euthymic patients with bipolar disorder reportedly demonstrated increased levels of proinflammatory cytokines and cognitive function deficits. Because uncertain differences exist in cognitive function and proinflammatory cytokines between remitted bipolar I (BD1) and bipolar II (BD2) disorders, we performed this study to further investigate these differences.

METHOD

We enrolled 58 patients with remitted BD1 and 27 with remitted BD2, and matched them for age and sex with 51 controls. Proinflammatory cytokines, including soluble interleukin-6 receptor (sIL-6R), C-reactive protein, and soluble tumor necrosis factor receptor 1 (sTNFR1) were measured, and performance in the Word List Memory Task (WLMT) and Wisconsin Card Sorting Task (WCST) was assessed.

RESULTS

Significantly elevated levels of sTNFR1 were observed among patients with BD1 (p < .001) and BD2 (p = .038) compared with the controls; however, they did not differ between patients with BD1 and BD2 (p =.130). Working memory deficit measured by the WLMT was significantly greater in patients with BD1 (p < .001) and BD2 (p < .05) compared with controls, but did not differ between patients with BD1 and BD2 (p > 0.1). Furthermore, sTNFR1 levels were negatively correlated with cognitive function measured using the WLMT and WCST (all p < .05).

DISCUSSION

Our results showed that euthymic patients with BD1 and BD2 showed similar levels of sTNFR1 and cognitive function (especially working memory) impairments. Further investigation is required to explore whether a common pathophysiology may contribute to the shared inflammatory and cognitive alterations between BD1 and BD2.

Norms for the Screen for Cognitive Impairment in Psychiatry and cognitive trajectories in bipolar disorder

BACKGROUND

The International Society for Bipolar Disorders Targeting Cognition Task Force recommends screening for and monitoring of cognitive impairments in patients with bipolar disorder (BD) with the Screen for Cognitive Impairment in Psychiatry (SCIP). The study aimed to provide the first demographically adjusted norms and change norms for the SCIP and to compare the cognitive trajectory over one year in remitted BD patients with normative cognitive change.

METHODS

Patients with fully or partially remitted BD and healthy controls (HC) were assessed with the SCIP at baseline and at a one-year follow-up. Regression-based models were used to determine demographically adjusted norms and change norms. Using the change models, predicted follow-up scores were calculated for BD and HC, and independent t-tests were used to compare deviations of the observed from the predicted follow-up scores for BD vs. HC to assess differences in cognitive trajectories.

RESULTS

Baseline data were collected for n=273 HC and n=218 BD, and follow-up data for n=139 HC and n=74 BD. Baseline norm models included age, sex and years of education, while change models included baseline SCIP scores and age. Patients with follow-up data showed selective impairments within verbal learning and recall at baseline. They followed the normative cognitive trajectories for all cognitive domains but verbal learning.

LIMITATIONS

Cognition was assessed with a screening tool.

CONCLUSIONS

We recommend implementing demographically adjusted norms and change norms for the SCIP in clinical and research settings. Change norms seem sensitive to subtle and selective cognitive decline over one year in remitted BD.

fNIRS Evaluation of Frontal and Temporal Cortex Activation by Verbal Fluency Task and High-Level Cognition Task for Detecting Anxiety and Depression

Anxiety and depression are widespread psychosis which are believed to affect cerebral metabolism, especially in frontal and temporal cortex. The comorbidity patients of anxiety and depression (A&D) have more serious clinical symptoms. Functional near-infrared spectroscopy (fNIRS) is a noninvasive modality used to monitor human brain oxygenation, and it could be considered as a potential tool to detect psychosis which may lead to abnormal cerebral oxygen status when the brain is activated. However, how sensitive the cerebral oxygenation response to the cortex activation and whether these responses are consistent at different stages of A&D or different regions still remains unclear. In this study, a conventional physiological paradigm for cortex activation, i.e., verbal fluency task (VFT), and a relatively new paradigm, i.e., high-level cognition task (HCT), were compared to detect A&D through a longitudinal measurement of cerebral oxygen status by fNIRS. The A&D patients at the acute, consolidation and maintenance stages as well as the healthy subjects participated in the VFT and HCT paradigms, respectively. For the VTF paradigm, the subject was instructed to answer questions of phrase constructions within 60 s. For the HCT paradigm, the subject was instructed to categorize items, logical reasoning, and comprehensive judgment and write down the answers within 60 s. For most of the subjects, the oxy-Hb is found to increase remarkably, accompanied with a relatively small reduction in deoxy-Hb when subject to both paradigms. The statistical analyses show a relatively large variability within any group, leading to the significant difference that was only found between A&D at the acute stage and healthy subjects in the temporal lobe region (p < 0.001). Nevertheless, HCT would activate more oxygen increment when compared with the VFT, with a large integral value in oxy-Hb. On average, the oxy-Hb integral value of the A&D patients differs substantially at different stages when subject to HCT paradigm. Moreover, the prefrontal lobe and temporal lobe responses were more consistent to the HCT paradigm rather than the VFT paradigm. Under the VFT paradigm, however, no remarkable difference in integral value was found among the three stages, either at the prefrontal lobe or at the temporal lobe. This study indicated that HCT, which is intensively involved in brain function, would activate more oxygenation changes in the cerebral cortex. Additionally, with good performance at distinguishing different stages according to the oxy-Hb criterion, the HCT has the potential to evaluate the therapeutic effects for A&D patients.

Neurocognitive functioning in bipolar disorder: What we know and what we don’t

Introduction: This narrative review of systematic reviews and meta-analyses aims at compiling available evidence in various aspects of neurocognitive functioning in Bipolar Disorder (BD).

Methods: We conducted a MEDLINE literature search and identified 38 relevant systematic reviews and metaanalyses.

Results: Current evidence suggests that BD is associated with cognitive impairment across multiple domains and during all clinical states. However, there is a considerable cognitive heterogeneity within BD, which cannot be explained by clinical subtypes, and the pattern of neurocognitive impairment in BD overlaps with other psychiatric conditions such as major depression and schizophrenia. Residual depressive symptoms, poor clinical course and higher number of manic episodes may negatively impact cognitive performance, which is a major predictor of general functioning in BD. Evidence from available prospective studies does not support the notion of progressive cognitive decline in BD while some evidence exists to suggest patients may show some improvements in cognitive functioning following the first manic episode. Furthermore, a subset of patients may show premorbid cognitive abnormalities that could signal an early neurodevelopmental aetiology. Preliminary findings from small studies identify potential pro-cognitive effects of Cognitive Remediation, erythropoietin, intranasal insulin, lurasidone, mifepristone, repetitive Transcranial Magnetic Stimulation and transcranial Direct Current Stimulation in BD.

Discussion: Longitudinal studies in high-risk individuals can provide a better understanding of the development and progression of neurocognitive impairment in BD. Largescale randomised control trials are needed to compare the pro-cognitive efficacy of various pharmacological and non-pharmacological interventions in different cognitive subgroups of patients at different stages of BD.

Inflammation in Bipolar Disorder (BD): Identification of new therapeutic targets

Bipolar disorder (BD) is a chronic and cyclic mental disorder, characterized by unusual mood swings between mania/hypomania and depression, raising concern in both scientific and medical communities due to its deleterious social and economic impact. Polypharmacy is the rule due to the partial effectiveness of available drugs. Disease course is often unremitting, resulting in frequent cognitive deficits over time. Despite all research efforts in identifying BD-associated molecular mechanisms, current knowledge remains limited. However, the involvement of inflammation in BD pathophysiology is increasingly consensual, with the immune system and neuroinflammation playing a key role in disease course. Evidence includes altered levels of cytokines and acute-phase proteins, pathological microglial activation, deregulation of Nrf2-Keap1 system and changes in biogenic amines neurotransmitters, whose expression is regulated by TNF-α, a pro-inflammatory cytokine highly involved in BD, pointing out inflammation as a novel and attractive therapeutic target for BD. As result, new therapeutic agents including non-steroidal anti-inflammatory drugs, N-acetylcysteine and GSK3 inhibitors have been incorporated in BD treatment. Taking into consideration the latest pre-clinical and clinical trials, in this review we discuss recent data regarding inflammation in BD, unveiling potential therapeutic approaches through direct or indirect modulation of inflammatory response.

Longitudinal trajectories of mood symptoms and global functioning in youth at high risk for bipolar disorder

BACKGROUND

Little is known about the longitudinal course of mood symptoms and functioning in youth who are at high risk for bipolar disorder (BD). Identifying distinct course trajectories and predictors of those trajectories may help refine treatment approaches.

METHODS

This study examined the longitudinal course of mood symptoms and functioning ratings in 126 youth at high risk for BD based on family history and early mood symptoms. Participants were enrolled in a randomized trial of family-focused therapy and followed longitudinally (mean 2.0 years, SD = 53.6 weeks).

RESULTS

Using latent class growth analyses (LCGA), we observed three mood trajectories. All youth started the study with active mood symptoms. Following the index mood episode, participants were classified as having a "significantly improving course" (n = 41, 32.5% of sample), a "moderately symptomatic course" (n = 21, 16.7%), or a "predominantly symptomatic course" (n = 64, 50.8%) at follow-up. More severe depression, anxiety, and suicidality at the study's baseline were associated with a poorer course of illness. LCGA also revealed three trajectories of global functioning that closely corresponded to symptom trajectories; however, fewer youth exhibited functional recovery than exhibited symptomatic recovery.

LIMITATIONS

Mood trajectories were assessed within the context of a treatment trial. Ratings of mood and functioning were based on retrospective recall.

CONCLUSIONS

This study suggests considerable heterogeneity in the course trajectories of youth at high risk for BD, with a significant proportion (32.5%) showing long-term remission of symptoms. Treatments that enhance psychosocial functioning may be just as important as those that ameliorate symptoms in youth at risk for BD.

Neurocognitive Impairments (NCI) in bipolar disorder: Comparison with schizophrenia and healthy controls

BACKGROUND

Neurocognitive impairments (NCI) are common in patients with bipolar I disorder. However, reports about the affected domains, outcomes and magnitude have been inconsistent. The aim of this study was to compare the magnitude (severity) and specificity (domains), of (NCI) in euthymic Bipolar I Disorder (BD) patients with a demographically and educationally matched sample of patients with schizophrenia in remission (SC) and healthy controls (HC).

METHODS

The Screen for Cognitive Impairment in Psychiatry (SCIP) was applied in this cross-sectional study, to all consecutive and consenting euthymic outpatients with bipolar I disorder (BD) (n = 76), remitted patients with schizophrenia (n = 130) and age and gender-matched healthy controls (HC) (n = 100). The cognitive tests done included Verbal List Learning-Immediate (VLT-I), Working Memory Test (WMT), Verbal Fluency Test (VFT), Verbal Learning Test-Delayed (VLT-D) and Processing Speed Test (PST). Within the bipolar group, the association between NCI and functioning was assessed.

RESULTS

There was a significant difference in the proportions of participants that had cognitive impairment from the 3 groups (37% (HC) vs. 71.1% (BD) vs. 91.5%(SC) (p=<0.001). The BD group in comparison to the HCs did worse on all domains of the SCIP except WMT and PST. The BD group was not significantly different from the SC group in all neuropsychological domains of the SCIP except WMT. BD group significantly functions better than the SC group. The severity of depressive symptomatology and VLT-I were independent predictors of functioning in the BD group.

CONCLUSION

Cognitive impairment affects almost all the neurocognitive domains of the BD group. The difference in NCI between euthymic BD patients and SC in remission are quantitative rather than qualitative.

Neurocognitive predictors of long-term clinical course in bipolar disorder

OBJECTIVE

The aim of this study was to estimate whether neurocognitive deficits are predictors of the long-term clinical course of patients with bipolar disorder.

METHODS

A total of 76 outpatients with bipolar disorder performed a neurocognitive assessment at baseline and were followed for a period of at least 48 months. The clinical course during the follow-up period was documented by two measures: (1) number of affective episodes and (2) time spent ill.

RESULTS

Patients had lower performance than controls in the domains of verbal memory and executive functions, and they were followed-up for a mean period of 70.73 months. Global cognitive deficits (performance 1.5 standard deviations below the mean in two or more cognitive domain) were independent predictors of both hypo/manic episode density and time spent with hypo/manic symptoms during follow-up. On the contrary, no neurocognitive measure showed a relationship with depressive morbidity during follow-up.

CONCLUSION

Our findings suggest that cognitive deficits could be useful for predicting hypo/manic morbidity in the long-term clinical course. Theoretical and clinical implications of these findings are discussed.

S100B and brain derived neurotrophic factor in monozygotic twins with, at risk of and without affective disorders

BACKGROUND

The calcium binding protein S100B and brain derived neurotrophic factor (BDNF) are both biomarkers implicated in neuronal processes in the central nervous system and seem to be associated with affective disorders. Here we investigated both markers in a sample of monozygotic (MZ) twins with, at risk of and without affective disorders, aiming to evaluate whether these markers have a role as causal factors- or trait markers for affective disorders.

METHOD

We measured serum S100B and plasma BDNF levels in 204 monozygotic twins (MZ) with unipolar or bipolar disorder in remission or partial remission (affected), their unaffected co-twins (high-risk) and twins with no personal or family history of affective disorder (low-risk).

RESULTS

No significant group differences in S100B and BDNF levels were found between the three groups. Exploratory analysis revealed that higher S100B levels were correlated with lower cognitive performance.

LIMITATIONS

The cross-sectional design cannot elucidate the two neuronal biomarkers role as causal factors. We would have preferred a higher sample size in the high- and low-risk groups.

CONCLUSION

The present result did not support a role for S100B and BDNF as neither causal factors nor trait markers for affective disorders. Elevated S100B levels may associate with impaired cognition, but further studies are warranted.

The effects of cognitive reserve and depressive symptoms on cognitive performance in major depression and bipolar disorder

BACKGROUND

Significant heterogeneity is observed in the cognitive profiles of bipolar disorder (BD) and major depression (MDD), characterized in part by differences in individual and clinical variables such as cognitive reserve (CR) and depression severity. However, no other study evaluated how this variables may interact regarding neurocognitive functioning. The aim of the present exploratory study was to evaluate the interaction between different depressive symptoms severity, CR and diagnosis with neurocognitive functioning.

METHOD

202 participants (MDD=91; BD=111) classified either as euthymic, with mild depression or moderate to severe depression, and low or high CR completed a neuropsychological evaluation of verbal fluency, working memory (WM), inhibitory control (IC), cognitive flexibility (CF) and attention (Att).

RESULTS

Neuroprotective effects of CR were observed in patients with BD within a major depressive episode in WM, IC, FC and Att. In MDD, CR acted as a neuroprotective factor during euthymia and moderate to severe depression in the same cognitive functions. CR and depression severity differentiated the cognitive profiles of individuals with BD and MDD.

LIMITATIONS

Some variables related to neurocognitive performance like medication use, number of mood episodes, illness duration or previous hospitalizations were not controlled.

CONCLUSION

CR may be protective against cognitive impairment in both BD and MDD, and these effects were observed in euthymia and during depressive episodes of varying severity. These findings highlight the importance of investigating such variables in the neuropsychological evaluation of mood disorders, which may help to understand the cognitive heterogeneity within these populations.

Functioning in euthymic patients with bipolar disorder: A systematic review and meta-analysis using the Functioning Assessment Short Test

OBJECTIVES

Systematically review the prevalence of functional impairment (FI) in euthymic patients with bipolar disorder (BD), as assessed only with the Functioning Assessment Short Test (FAST), explore the prevalence of this impairment among all the domains, identify the most compromised of them and the clinical variables associated with low functioning in this population.

METHODS

Meta-analyses were performed, searching for relevant papers published from 2007 to 2019 in Medline, Embase, Cochrane, PsycINFO databases and via hand-searching, without language restrictions. 1128 studies were initially identified, 13 of which were ultimately chosen based on the eligibility criteria. A two-step meta-analysis was performed using the mean difference with a 95% confidence interval for continuous variables and proportion estimation with a fixed-effects model for categorical variables.

RESULTS

In the first step, all FAST domains showed worse FI in patients than in healthy controls, with significant differences between groups. In the second step, the prevalence of FI domains were as follows: global, 58.6%; occupational, 65.6%; cognitive, 49.2%; autonomy, 42.6%; interpersonal relationships, 42.1%; leisure, 29.2%; and financial issues, 28.8%. Residual depressive symptoms were the most frequently cited variable associated with FI.

CONCLUSIONS

This study reinforces the relevant functional impact of BD in this population and suggests that the occupational domain may be the most impaired. Greater efforts should be directed toward targeting functioning in patient care, as it constitutes the most meaningful endpoint of response to treatment, especially with occupational and cognitive rehabilitation, thus allowing patients to overcome the course of illness and carry fulfilling lives.

Disrupted Rich Club Organization of Hemispheric White Matter Networks in Bipolar Disorder

Neuroimaging studies suggest disrupted connections of the brain white matter (WM) network in bipolar disorder (BD). A group of highly interconnected high-density structures, termed the 'rich club,' represents an important network for brain functioning. Recent works have revealed abnormal rich club organization in brain networks in BD. However, little is known regarding changes in the rich club organization of the hemispheric WM network in BD. Forty-nine BD patients and fifty-five age- and sex-matched normal controls (NCs) underwent diffusion tensor imaging (DTI). Graph theory approaches were applied to quantify group-specific rich club organization and nodal degree of hemispheric WM networks. We demonstrated that rich club organization of hemispheric WM networks in BD was disrupted, with disrupted feeder and local connections among hub and peripheral regions located in the default mode network (DMN) and the control execution network (CEN). In addition, BD patients showed abnormal asymmetry in the feeder and local connections, involving the hub and peripheral regions associated with emotion regulation and visuospatial functions. Moreover, the clinical symptoms of BD showed a significant correlation with the aberrant asymmetry in the regional degree of peripheral regions. These findings reveal that BD is closely associated with disrupted feeder and local connections but no alteration in rich-club connections in the rich club organization of hemispheric WM networks and provide novel insight into the changes of brain functions in BD.

Aberrant cognition in newly diagnosed patients with bipolar disorder and their unaffected relatives

BACKGROUND

Patients with bipolar disorder (BD) experience persistent impairments in both affective and non-affective cognitive function, which is associated with a worse course of illness and poor functional outcomes. Nevertheless, the temporal progression of cognitive dysfunction in BD remains unclear and the identification of objective endophenotypes can inform the aetiology of BD.

METHODS

The present study is a cross-sectional investigation of cognitive baseline data from the longitudinal Bipolar Illness Onset-study. One hundred seventy-two remitted patients newly diagnosed with BD, 52 of their unaffected relatives (UR), and 110 healthy controls (HC) were compared on a large battery of behavioural cognitive tasks tapping into non-affective (i.e. neurocognitive) and affective (i.e. emotion processing and regulation) cognition.

RESULTS

Relative to HCs, patients with BD exhibited global neurocognitive deficits (ps < 0.001), as well as aberrant emotion processing and regulation (ps ⩽ 0.011); including decreased emotional reactivity to positive social scenarios, impaired ability to down-regulate positive emotion, as well as a specific deficit in the ability to recognise surprised facial expressions. Their URs also showed a trend towards difficulties identifying surprised faces (p = 0.075). No other differences in cognitive function were found for URs compared to HCs.

CONCLUSIONS

Neurocognitive deficits and impairments within emotion processing and regulation may be illness-related deficits of BD that present after illness-onset, whereas processing of emotional faces may represent an early risk marker of BD. However, longitudinal studies are needed to examine the association between cognitive impairments and illness progression in BD.