Longitudinal analysis of cognitive performances in recent-onset and late-life Bipolar Disorder: A systematic review and meta-analysis

Verbal fluency in schizophrenia and bipolar disorder - A longitudinal, family study

Verbal fluency (VF) has been proposed as a putative neurocognitive endophenotype in schizophrenia (SZ) and bipolar disorder (BD). However, this hypothesis has not been examined using a longitudinal family approach. We conducted a five-group, comparative study. The sample comprised 323 adult participants, including 81 BD patients, 47 unaffected relatives of BD BD-Rel), 76 SZ patients, 40 unaffected relatives of SZ (SZ-Rel), and 79 genetically unrelated healthy controls (HC). All subjects were assessed twice with semantic VF (sem-VF) and phonological VF (ph-VF) tests over a 2-year follow-up period. ANCOVAs controlling for age and years of education were used to compare performance across groups. Patients with SZ and BD and their unaffected relatives showed sem-VF and ph-VF deficits at baseline, which persisted over time (all, p < 0.05). Moreover, BD-Rel showed an intermediate performance between SZ and HC. A repeated-measures ANOVA revealed no significant differences in the between-group trajectories comparison (p > 0.05). Our findings support that VF may represent a neurocognitive endophenotype for SZ and BD. Further longitudinal, family studies are warranted to confirm this preliminary evidence.

APOE Genotype, ApoE Plasma Levels, Lipid Metabolism, and Cognition in Monozygotic Twins with, at Risk of, and without Affective Disorders

Background: Lipids influence brain function and mental health. Understanding the role of apolipoproteins in affective disorders could provide valuable insights and potentially pave the way for novel therapeutic approaches. Methods: We examined the apolipoprotein E genotype and ApoE-levels, lipid profiles, and the correlation with cognition in 204 monozygotic (MZ) twins with unipolar or bipolar disorder in remission or partial remission (affected, AT), their unaffected co-twins (high-risk, HR), and twins with no personal or family history of affective disorder (low-risk, LR). Results: The APOE genotype was not associated with affective disorders. No significant group differences in ApoE levels were found between the three risk groups. Post hoc analysis group-wise comparisons showed higher ApoE levels in the AT than HR twins and in the concordant AT twin pairs relative to the discordant twin pairs. Within the discordant twin pairs, higher ApoE levels were observed in the affected twins (AT = 39.4 mg/L vs. HR = 36.8 mg/L, p = 0.037). Limitations: The present study could benefit from a larger sample size. We did not assess dietary habits. Conclusions: The results did not support our main hypothesis. However, exploratory post hoc analysis suggests a role for plasma ApoE and triglycerides in affective disorders. Future research is needed.

Adults with both bipolar disorder and ADHD

ADHD and bipolar disorder (BP) commonly coexist, and both share key symptoms, depending on affective state and emotional dysregulation. The overlap poses diagnostic challenges and may lead to underdiagnoses. Comorbid cases exhibit worsened symptom burden, increased psychiatric morbidity, admissions, and suicide attempts. Treating BP before ADHD is recommended. Stimulant use combined with mood stabilisers may be effective and relatively safe; however, this review finds that well-designed randomised controlled studies in the area is warranted.

Long-term course of cognitive functioning in bipolar disorder: A ten-year follow-up study

INTRODUCTION

Cognitive impairments are common in bipolar disorder (BD), but the long-term course remains understudied. Longitudinal data on cognitive functioning from the start of the first treatment could help clarify pathophysiological processes that shape the illness outcome. We here aim to investigate the 10-year cognitive course in BD compared to healthy controls (HC) and the effects of clinical symptoms on cognitive trajectories.

METHODS

Fifty-six BD participants recruited within their first year of treatment and 108 HC completed clinical and cognitive assessments at baseline and 10-year follow-up. We derived eight cognitive domain scores and a cognitive composite score, which were further investigated using linear mixed model analyses. Correlation analyses were used to assess associations between the composite score and depressive, manic and psychotic symptoms.

RESULTS

BD participants performed poorer than HCs in all domains except mental speed and verbal fluency. Verbal learning and memory, verbal fluency and the composite score improved over time in both BD participants and HC, while short-term memory, mental speed, psychomotor speed and working memory were stable. We found no significant correlations between cognition and symptom level at either time point in BD participants.

CONCLUSIONS

We found evidence of long-term cognitive stability or improvement in BD participants from first treatment to 10-year follow-up. Though the BD group was impaired in all domains except mental speed and verbal fluency, the change in cognitive functioning was parallel to that of HCs. These findings are not consistent with the notion of neuroprogression in BD.

Usage Patterns of Traditional Chinese Medicine for Patients with Bipolar Disorder: A Population-Based Study in Taiwan

BACKGROUND

Patients with bipolar disorder (BD) receive traditional Chinese medicine (TCM) for clinical needs unmet with psychotropic medications. However, the clinical characteristics of practices and outcomes of TCM in BD are not fully understood. This cohort study investigated the clinical characteristics, principal diagnoses, TCM interventions, and TCM prescriptions in patients with BD.

METHODS

Data for a total of 12,113 patients with BD between 1996 and 2013 were withdrawn from Taiwan's longitudinal health insurance database 2000 (LHID 2000). The chi-square test was used for categorical variables, and the independent t-test was used for continuous variables. A p-value less than 0.05 indicated significance.

RESULTS

One thousand three hundred nineteen patients who visited TCM clinics after the diagnosis of BD were in the TCM group, while those who never visited TCM were in the non-TCM group (n = 1053). Compared to the non-TCM group, patients in the TCM group had younger average age, a higher percentage of female individuals, more comorbidities of anxiety and alcohol use disorders, and higher mood stabilizer usage rates. The TCM group exhibited pain-related indications, including joint pain, myalgia, myositis, headache, and sleep disturbances. Corydalis yanhusuo and Shu-Jing-Huo-Xue-Tang were the most useful single herbs and herbal formulae.

CONCLUSIONS

Physicians need to be aware of the use of TCM in patients with BD.

Biomarkers for neurodegeneration impact cognitive function: a longitudinal 1-year case-control study of patients with bipolar disorder and healthy control individuals

BACKGROUND

Abnormalities in cerebrospinal fluid (CSF)-amyloid-beta (Aβ)42, CSF-Aβ40, CSF-Aβ38, CSF-soluble amyloid precursor proteins α and β, CSF-total-tau, CSF-phosphorylated-tau, CSF-neurofilament light protein (NF-L), CSF-neurogranin, plasma-Aβ42, plasma-Aβ40, plasma-total-tau, plasma-NF-L and, serum-S100B during affective episodes may reflect brain changes that could impact cognitive function in patients with bipolar disorder (BD). The study aimed to investigate the association between these biomarkers indicative of Alzheimer's disease and those reflecting neurodegeneration alongside their impact on cognitive function in patients with BD and healthy control individuals (HC). The primary hypothesis was that GL and VL would increase with increasing levels of CSF-Aβ42 based on data from T0 and T3 in BD and HC jointly.

METHODS

In a prospective, longitudinal case-control study euthymic patients with BD (N = 85) and HC (N = 44) were evaluated with clinical assessment and neuropsychological testing at baseline (T0) and during euthymia after a year (T3). Patients' affective states were recorded weekly as euthymic, subthreshold level, major depression, or (hypo)mania. If an episode occurred during follow-up, the patient was also assessed in post-episode euthymia. Cognitive performance was measured as a global cognitive score (GL) for four cognitive domains including verbal learning and memory (VL).

RESULTS

Estimated in a linear mixed model GL increased with 0.001 for each increase of 1 pg/ml of CSF-Aβ42 (97.5%, CI 0.00043-0.0018, adjusted-p = 0.0005) while VL increased by 0.00089 (97.5%, CI 0.00015-0.0018, adjusted-p = 0.045) in BD and HC jointly. The association was weak, however stronger in patients with BD compared to HC. Associations between other biomarkers including CSF-neurogranin, and cognitive domains were overall weak, and none remained significant after adjustment for multiple testing.

LIMITATIONS

Modest sample size. A complete data set regarding both CSF-AB-42 and cognitive test scores was obtained from merely 61 patients with BD and 38 HC individuals.

CONCLUSION

CSF-Aβ42 may be associated with cognitive dysfunction in patients with BD and HC individuals. The association appeared to be stronger in BD but with overlapping confidence intervals. Hence it remains uncertain whether the association is a general phenomenon or driven by BD.

A longitudinal study of cognition, functional outcome and quality of life in bipolar disorder and major depression

OBJECTIVE

Cognitive impairments are known to be a frequent cause of disability in bipolar disorder (BD) and major depression (MDD). Yet there is no consensus regarding the particular cognitive functions whose impairments can lead to disability in each domain of functioning. The aim of this study was to perform a longitudinal evaluation of working memory, inhibition, cognitive flexibility and attention in BD and MDD, investigate the relationship of these cognitive functions to disability and quality of life, and evaluate the impact of variables related to cognitive reserve (education and daily cognitive stimulation) on cognitive performance.

METHOD

31 participants (MDD = 12; BD = 19) were evaluated at baseline and after an average time of 2 years.

RESULTS

the BD group showed improvements in attention while patients with MDD improved on measures of attention and working memory. In BD working memory performance was associated with the cognition and mobility domains of functioning, and with physical and environmental quality of life. In MDD, cognitive flexibility was related to social relationships and environmental quality of life.

CONCLUSION

working memory and cognitive flexibility may be an interesting target for interventions aiming to improve everyday functioning and quality of life in BD and MDD.

Discourse abilities in euthymic elderly patients with bipolar disorder: a preliminary study

Cognitive impairment has been well described in euthymic patients with bipolar disorder (BD), as well as in elderly patients. Language disturbances are less studied, and several inconsistencies are reported in the literature. Most language studies focus on verbal fluency and semantic alterations, with a lack of studies addressing discursive abilities in BD.

Objective

The aim of this study was to evaluate discourse abilities in euthymic elderly individuals with BD.

Methods

We studied 19 euthymic elderly patients with BD and a control group of non-BD, which performed a cognitive assessment of attention, memory, executive functions, and visual abilities. All participants produced a description from the Cookie Theft Picture in oral and written modalities that was analyzed according to micro- and macrolinguistic aspects. Generalized linear models were performed to compare intergroup linguistic performance and to determine whether any cognitive domain was associated with linguistic outcomes.

Results

The BD group produced more cohesion errors in the oral and written modalities (p=0.016 and p=0.011, respectively) and fewer thematic units in the oral modality (p=0.027) than the control group.

Conclusions

BD patients presented minimal changes in the descriptive discourse task. The BD group produced more cohesion errors than the control group in the oral (p=0.016) and written discourse (p=0.011); also, the BD group produced fewer thematic units than controls in the oral discourse (p=0.027).

Efficacy of Functional Remediation on Cognitive and Psychosocial Functioning in Patients with Bipolar Disorder: Study Protocol for a Randomized Controlled Study

BACKGROUND

Neurocognitive impairment is a prominent characteristic of bipolar disorder (BD), linked with poor psychosocial functioning. This study's purpose is to evaluate the effectiveness of functional remediation (FR) in enhancing neurocognitive dysfunctions in a sample of remitted patients with diagnosis of BD in comparison to treatment as usual-TAU. To quantify the neurocognitive damage, the Brief Assessment of Cognition in Affective Disorders (BAC-A) will be used, and the overall psychosocial functioning will be measured with the Functioning Assessment Short Test-FAST.

METHODS

The randomized, rater-blinded, controlled study will include two arms (1:1) encompassing 54 outpatients with diagnosis of BD-I and BD-II, as defined by the DSM-5 criteria. In the experimental phase, remitted patients aged 18-55 years will be involved. At the baseline, at the end of intervention and at the 6-month follow-up, patients will be evaluated using clinical scales (Young Mania Rating Scale (Y-MRS) and Hamilton Depression Rating Scale (HAM-D)). Neurocognitive measurements and psychosocial functioning will be valued, respectively, with BAC-A and FAST.

DISCUSSION

The primary expected outcome is that following FR intervention, patients will exhibit improved cognitive abilities and psychosocial outcomes compared to the participants in the TAU group. It is now recognized that neurocognitive deficits are potential predictors of functional outcome in patients with BD. In recent years, there has been a growing interest in the implementation of interventions that, in addition to symptomatic remission, are also aimed at neurocognitive dysfunctions in order to achieve a recovery of psychosocial functioning.

A one-year view on the association of metabolic syndrome and cognitive function in bipolar disorder - Preliminary data

BACKGROUND

Individuals with bipolar disorder have a high prevalence of metabolic syndrome and an increased risk for cognitive deficits. The aim of this longitudinal study was to investigate the trajectory of cognitive decline in dependence of metabolic syndrome over a one-year interval.

METHODS

52 well-diagnosed individuals with bipolar disorder, euthymic at baseline and follow-up (n = 17 with metabolic syndrome vs. n = 35 without metabolic syndrome) were investigated with a comprehensive neurocognitive test battery (Trail Making Test A/B, Digit Symbol Test, California Verbal Leaning Test, or the Verbal Learning and Memory Test respectively) twice within the interval of one year.

RESULTS

Patients with bipolar disorder and additional metabolic syndrome performed significantly worse in the domain of psychomotor and processing speed/attention than patients without metabolic syndrome at test point one. No deteriorating effects of metabolic syndrome on the cognitive domain scores and overall cognitive performance were found at the one-year follow up. However, no cognitive decline could be reported in both groups.

LIMITATIONS

Time interval, small sample size and selection of metabolic syndrome affected patients were the major limitations of this study.

CONCLUSION

There was no association of metabolic syndrome on the one-year trajectory of cognitive function in bipolar disorder. Future studies should expand the observation period and investigate larger samples.

The trajectory of emotional and non-emotional cognitive function in newly diagnosed patients with bipolar disorder and their unaffected relatives: A 16-month follow-up study

Cognitive impairments are evident in remitted patients with bipolar disorder (BD) and their unaffected relatives (UR) compared to healthy controls (HC). However, the temporal course of cognition, and whether cognition is marked by neuroprogressive changes, remain unclear. In a large prospective study of newly diagnosed patients with BD, we assessed patients with BD (n = 266), UR (n = 105) and HC (n = 190) using an extensive cognitive battery of non-emotional and emotional cognition at baseline and 16-months follow-up. Cognitive change across groups was examined with linear mixed-model analyses. Results showed no evidence of trajectory differences between patients with BD, UR, and HC in neurocognition and emotional cognition (ps≥.10). Patients with BD showed stable impairments in global neurocognitive functioning over time, as well as within the domains of 'working memory and executive function' and 'attention and psychomotor speed', compared to HC. Patients who relapsed during the follow-up time were less successful at down-regulating emotions in positive social scenarios compared to HC. Unaffected relatives also displayed stable deficits in 'working memory and executive function' over time, with performance at intermediate levels between BD probands and HC. Finally, poorer neurocognition and positive emotion regulation were associated with more subsyndromal symptoms and functional impairments. In conclusion, we found no evidence of a neuroprogressive origin of cognitive impairments in the newly diagnosed BD or in their UR. Patients' and UR's impairments in working memory and executive function may reflect a stable cognitive trait-marker of familial risk. Difficulties with positive emotion regulation may be associated with illness progression in BD.

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 subgroups and their longitudinal trajectories in bipolar disorder

INTRODUCTION

Cognitive functioning in bipolar disorder is heterogeneous with evidence for multiple subgroups. However, cognitive subgroup change patterns over time remains unknown. While prior work suggests minimal differences in cognitive functioning patterns over time between those with bipolar disorder and controls, group-based analyses may obscure unique subgroup-based changes.

MATERIAL AND METHODS

Participants diagnosed with bipolar disorder (I, II, NOS; n = 568) and unaffected controls (n = 234) completed baseline, one- and five-year neuropsychological assessments. Data reduction techniques were used to limit the number of neuropsychological variables. Bipolar disorder participant baseline neuropsychological data were entered into hierarchical cluster analyses and resultant clusters were entered in multilevel models, which tested for differences in baseline and longitudinal cognitive changes in cognition among the cluster groups and with controls.

RESULTS

Results were consistent with bipolar disorder participants forming three subgroups with high (n = 209), mid (n = 259), and low (n = 100) cognition. These groups were associated with unique clinical characteristics. Multilevel models demonstrated that over a five-year period, the low group improved, relative to the high and mid groups, and with controls, in auditory memory. Over the five-year period, the mid group, in comparison with the high group, improved in visual memory; additionally, the high group remained stable, in comparison with a slight decline in the control group, in inhibitory control.

CONCLUSION

These results demonstrate that cognition-based subgroups of bipolar disorder participants have minimal differences in their longitudinal course in relation to each other and with unaffected controls.

Differential trajectory of cognitive functions in neurocognitive subgroups of newly diagnosed patients with bipolar disorder and their unaffected first-degree relatives - A longitudinal study

BACKGROUND

Cognitive impairments exist in a large proportion of remitted patients with bipolar disorder (BD). However, no study has investigated the cognitive trajectories across neurocognitive subgroups of patients or their unaffected first-degree relatives (UR).

METHODS

Newly diagnosed BD patients, UR and healthy controls (HC) underwent comprehensive cognitive testing at baseline and at 16-months follow-up. Hierarchical cluster analysis was conducted to identify homogeneous subgroups of patients based on their neurocognitive profile at baseline. Cognitive change across subgroups of patients and UR was assessed with linear mixed-model analyses.

RESULTS

Data from baseline and follow-up were collected from 152 patients, 53 UR and 135 HC. Patients were clustered into three discrete neurocognitive subgroups: 'cognitively normal' (43%), 'mild-moderately impaired' (33%) and 'globally impaired' (24%). While 'mild-moderately impaired' patients and HC showed normative cognitive improvement over time in global cognition (p < .001), 'globally impaired' patients showed greater improvement than all groups (p < .001), whereas 'cognitively normal' patients showed a lack of normative improvement (p = .17). UR of impaired patients showed a lack of normative improvement in executive functions (p = .01). 'Globally impaired' patients also presented with stable impairments in facial expression recognition and emotion regulation.

LIMITATIONS

Follow-up data was available for 62% of participants, possibly reflecting a selection bias.

CONCLUSIONS

The greater cognitive improvement in 'globally impaired' patients partly speaks against neuroprogression. However, the lack of normative improvement in 'cognitively normal' patients could indicate negative effects of illness. Further follow-up assessments are warranted to clarify whether lack of normative improvement in executive function in UR represents an illness risk-marker.

Cognition in older adults with bipolar disorder: An ISBD task force systematic review and meta-analysis based on a comprehensive neuropsychological assessment

OBJECTIVES

We aim to characterize the cognitive performance in euthymic older adults with bipolar disorder (OABD) through a comprehensive neuropsychological assessment to obtain a detailed neuropsychological profile.

METHODS

We conducted a systematic search in MEDLINE/Pubmed, Cochrane, and PsycInfo databases. Original studies assessing cognitive function in OABD (age ≥50 years ) containing, at a minimum, the domains of attention/processing speed, memory, and executive functions were included. A random-effects meta-analysis was conducted to summarize differences between patients and matched controls in each cognitive domain. We also conducted meta-regressions to estimate the impact of clinical and socio-demographic variables on these differences.

RESULTS

Eight articles, providing data for 328 euthymic OABD patients and 302 healthy controls, were included in the meta-analysis. OABD showed worse performance in comparison with healthy controls, with large significant effect sizes (Hedge's g from -0.77 to -0.89; p < 0.001) in verbal learning and verbal and visual delayed memory. They also displayed statistically significant deficits, with moderate effect size, in processing speed, working memory, immediate memory, cognitive flexibility, verbal fluency, psychomotor function, executive functions, attention, inhibition, and recognition (Hedge's g from -0.52 to -0.76; p < 0.001), but not in language and visuoconstruction domains. None of the examined variables were associated with these deficits.

CONCLUSIONS

Cognitive dysfunction is present in OABD, with important deficits in almost all cognitive domains, especially in the memory domain. Our results highlight the importance of including a routine complete neuropsychological assessment in OABD and also considering therapeutic strategies in OABD.

Alzheimer's disease related biomarkers in bipolar disorder - A longitudinal one-year case-control study

INTRODUCTION

Bipolar disorder (BD) is a heterogeneous mental disorder characterized by recurrent relapses of affective episodes: Subgroups of patients with BD have cognitive deficits, and an increased risk of dementia.

METHODS

This prospective, longitudinal, one-year follow-up, case-control study investigated biomarkers for AD and neurodegenerative diseases, namely: cerebrospinal fluid (CSF) amyloid beta (Aβ) isoforms and ratios (Aβ42, Aβ40, Aβ38), CSF soluble amyloid precursor protein (sAPP) α and β, CSF total (t-tau) and phosphorylated tau (p-tau), CSF neurofilament-light (NF-L), CSF neurogranin (NG), plasma-isoforms Aβ42 and Aβ40, plasma-tau, plasma-NF-L, and serum S100B, in patients with BD (N = 62, aged 18-60) and gender-and-age-matched healthy control individuals (N = 40). CSF and plasma/serum samples were collected at baseline, during and after an affective episode, if it occurred, and after a year. Data were analyzed in mixed models.

RESULTS

Levels of CSF Aβ42 decreased in patients with BD who had an episode during follow-up (BD-E) (N = 22) compared to patients without an episode (BD-NE) (N = 25) during follow-up (P = 0.002). Stable levels were seen for all other markers in BD-E compared to BD-NE during the one-year follow-up. We found no statistically significant differences between patients with BD and HC at T0 and T3 for Aβ42, Aβ40, Aβ38, Aβ42/38, Aβ42/40, sAPPα, sAPPβ, t-tau, p-tau, p-tau /t-tau, NF-L, NG in CSF and further Aβ40, Aβ42, Aβ42/40, t-tau, NF-L in plasma, S100B in serum, and APOE-status. Furthermore, all 18 biomarkers were stable in HC during the one-year follow-up from T0 to T3.

CONCLUSION

A panel of biomarkers of Alzheimer's and neurodegeneration show no differences between patients with BD and HC. There were abnormalities of amyloid production/clearance during an acute BD episode. The abnormalities mimic the pattern seen in AD namely decreasing CSF Aβ42 and may suggest an association with brain amyloidosis.

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.

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.

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.

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.

The Heterogeneity of Longitudinal Cognitive Decline in Euthymic Bipolar I Disorder With Clinical Characteristics and Functional Outcomes

We characterized the heterogeneity and risk factors of cognitive decline in euthymic bipolar disorder (BD), and their magnitude of associations with subjective daily functions. In this retrospective cohort, BD type I patients (N = 128) were followed for an average of 6.5 years. Intelligence quotient (IQ) at index date was recorded, and premorbid IQ was estimated. We used Brief Assessment of Cognition in Affective Disorders (BAC-A) to assess cognition at follow-up. We evaluated current functions with World Health Organization Disability Assessment Schedule 2.0. Clinical and sociodemographic factors were examined for their independent effects on longitudinal cognitive decline. In addition, we employed multivariate adaptive regression spline to detect inflection points for the nature of slope changes in cognitive decline among BD patients. During follow-up years, 21 BD patients (16.4%) showed longitudinal cognitive decline. In cognitive decline group, all cognitive domains of BAC-A were significantly worsened. We found that density of episodes with psychotic features was an independent risk factor for cognitive decline after adjusted for age, gender and dose of mood stabilizer. After the age of 42 years, a steeper cognitive change was observed in the cognitive decline group. The correlation pattern between cognitive domains and functional outcomes differed between patients with and without cognitive decline. The present study characterized cognitive heterogeneity longitudinally in BD patients. As density of episodes play roles for cognitive decline, our results emphasize the importance of relapse prevention. Our findings provide hints for future personalized interventions and facilitating genetic and biological studies for dissecting the heterogeneity of bipolar illness.

Manic morbidity and executive function impairment as determinants of long-term psychosocial dysfunction in bipolar disorder

OBJECTIVE

In this study, we aimed to evaluate the role of cognitive performance and measures of clinical course-including both syndromal and subsyndromal symptomatology-as determinants of the functional outcome of patients with Bipolar Disorder (BD) during a mean follow-up period of more than 4 years.

METHODS

Seventy patients with euthymic BD completed a neurocognitive battery at study entry. Clinical course was assessed prospectively for a period longer than 48 months by two measures: time spent ill (documented using a modified life charting technique) and density of affective episodes (defined as the number of depressive and hypo/manic episodes per year of follow-up). Psychosocial functioning was assessed during euthymia using the Functioning Assessment Short Test (FAST) total score at the end of follow-up period.

RESULTS

Baseline deficits in phonological fluency, a measure of executive functions (β = -2.49; 95% CI = -3.98, -0.99), and density of hypo/manic episodes during follow-up (β = 6.54; 95% CI = 0.43, 12.65) were independently associated with FAST total score at the end of study.

CONCLUSIONS

Although interrelated, manic morbidity and executive function impairments independently contribute to long-term psychosocial dysfunction in BD and could be potential targets of intervention.

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.

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.

Quality of life and psychological symptoms for women with bipolar disorder - a comparison between reproductive, menopause transition and post-menopause phases

OBJECTIVE

The menopause transition may be associated with increased symptoms for women living with bipolar disorder; however, few have explored how this compares with other reproductive phases. The aim of this study was to compare women at reproductive, menopause transition and post-menopause phases on measures of quality of life and psychological symptoms associated with bipolar disorder.

STUDY DESIGN

Women with bipolar disorder took part in a large international survey conducted online and were categorised into reproductive stages using the STRAW and Monash criteria. The 498 participants were divided into three groups: 202 (41%) in the reproductive age group, 101 (20%) in the menopause transition group and 195 (39%) in the post-menopause group.

MAIN OUTCOME MEASURES

The Menopause Rating Scale (MRS), the Depression Anxiety and Stress Scales - 21 (DASS-21), the Altman Mania Rating Scale (ASRM) and the Bipolar Disorder Quality of Life scale (BD-QoL).

RESULTS

BD-QoL scores were significantly lower in the menopause transition group than in the other groups and that group was more likely to report being constantly depressed over the past year than the other groups. Anxiety was significantly higher in the menopause transition and post-menopause groups compared with the reproductive age group.

CONCLUSIONS

Quality of life and depression are impacted by the menopause transition for women with bipolar disorder. However, anxiety may be a clinical issue for women in both the post-menopause and the menopause transition phases. Research is needed to determine how symptoms vary across the reproductive life cycle for women with bipolar disorder and if targeted treatments may assist.

The Ubiquitous Cognitive Assessment Tool for Smartwatches: Design, Implementation, and Evaluation Study

BACKGROUND

Cognitive functioning plays a significant role in individuals' mental health, since fluctuations in memory, attention, and executive functions influence their daily task performance. Existing digital cognitive assessment tools cannot be administered in the wild and their test sets are not brief enough to capture frequent fluctuations throughout the day. The ubiquitous availability of mobile and wearable devices may allow their incorporation into a suitable platform for real-world cognitive assessment.

OBJECTIVE

The aims of this study were threefold: (1) to evaluate a smartwatch-based tool for the assessment of cognitive performance, (2) to investigate the usability of this tool, and (3) to understand participants' perceptions regarding the application of a smartwatch in cognitive assessment.

METHODS

We built the Ubiquitous Cognitive Assessment Tool (UbiCAT) on a smartwatch-based platform. UbiCAT implements three cognitive tests-an Arrow test, a Letter test, and a Color test-adapted from the two-choice reaction-time, N-back, and Stroop tests, respectively. These tests were designed together with domain experts. We evaluated the UbiCAT test measures against standard computer-based tests with 21 healthy adults by applying statistical analyses significant at the 95% level. Usability testing for each UbiCAT app was performed using the Mobile App Rating Scale (MARS) questionnaire. The NASA-TLX (Task Load Index) questionnaire was used to measure cognitive workload during the N-back test. Participants rated perceived discomfort of wearing a smartwatch during the tests using a 7-point Likert scale. Upon finishing the experiment, an interview was conducted with each participant. The interviews were transcribed and semantic analysis was performed to group the findings.

RESULTS

Pearson correlation analysis between the total correct responses obtained from the UbiCAT and the computer-based tests revealed a significant strong correlation (r=.78, P<.001). One-way analysis of variance (ANOVA) showed a significant effect of the N-back difficulty level on the participants' performance measures. The study also demonstrated usability ratings above 4 out of 5 in terms of aesthetics, functionality, and information. Low discomfort (<3 out of 7) was reported by our participants after using the UbiCAT. Seven themes were extracted from the transcripts of the interviews conducted with our participants.

CONCLUSIONS

UbiCAT is a smartwatch-based tool that assesses three key cognitive domains. Usability ratings showed that participants were engaged with the UbiCAT tests and did not feel any discomfort. The majority of the participants were interested in using the UbiCAT, although some preferred computer-based tests, which might be due to the widespread use of personal computers. The UbiCAT can be administered in the wild with mentally ill patients to assess their attention, working memory, and executive function.

Neurocognitive impairment and evidence-based treatment options in Bipolar disorder

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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