Processing speed and sustained attention in bipolar disorder and major depressive disorder: A systematic review and meta-analysis

Altered resting-state brain activity in patients with major depression disorder and bipolar disorder: A regional homogeneity analysis

BACKGROUND

Major Depressive Disorder (MDD) and Bipolar Disorder (BD) exhibit overlapping depressive symptoms, complicating their differentiation in clinical practice. Traditional neuroimaging studies have focused on specific regions of interest, but few have employed whole-brain analyses like regional homogeneity (ReHo). This study aims to differentiate MDD from BD by identifying key brain regions with abnormal ReHo and using advanced machine learning techniques to improve diagnostic accuracy.

METHODS

A total of 63 BD patients, 65 MDD patients, and 70 healthy controls were recruited from the Shanghai Mental Health Center. Resting-state functional MRI (rs-fMRI) was used to analyze ReHo across the brain. We applied Support Vector Machine (SVM) and SVM-Recursive Feature Elimination (SVM-RFE), a robust machine learning model known for its high precision in feature selection and classification, to identify critical brain regions that could serve as biomarkers for distinguishing BD from MDD. SVM-RFE allows for the recursive removal of non-informative features, enhancing the model's ability to accurately classify patients. Correlations between ReHo values and clinical scores were also evaluated.

RESULTS

ReHo analysis revealed significant differences in several brain regions. The study results revealed that, compared to healthy controls, both BD and MDD patients exhibited reduced ReHo in the superior parietal gyrus. Additionally, MDD patients showed decreased ReHo values in the Right Lenticular nucleus, putamen (PUT.R), Right Angular gyrus (ANG.R), and Left Superior occipital gyrus (SOG.L). Compared to the MDD group, BD patients exhibited increased ReHo values in the Left Inferior occipital gyrus (IOG.L). In BD patients only, the reduction in ReHo values in the right superior parietal gyrus and the right angular gyrus was positively correlated with Hamilton Depression Scale (HAMD) scores. SVM-RFE identified the IOG.L, SOG.L, and PUT.R as the most critical features, achieving an area under the curve (AUC) of 0.872, with high sensitivity and specificity in distinguishing BD from MDD.

CONCLUSION

This study demonstrates that BD and MDD patients exhibit distinct patterns of regional brain activity, particularly in the occipital and parietal regions. The combination of ReHo analysis and SVM-RFE provides a powerful approach for identifying potential biomarkers, with the left inferior occipital gyrus, left superior occipital gyrus, and right putamen emerging as key differentiating regions. These findings offer valuable insights for improving the diagnostic accuracy between BD and MDD, contributing to more targeted treatment strategies.

Choroid plexus enlargement correlates with cognitive impairment and brain atrophy in patients with mood disorders

BACKGROUND

Patients with bipolar disorder (BD) and major depressive disorder (MDD) often exhibit cognitive impairments, with choroid plexus (ChP) volume linked to these deficits and cortical structures. However, the relationship between ChP volume, cognition, and brain morphology in mood disorders remains understudied. This study aimed to investigate these mechanisms.

METHOD

The study included 216 BD patients, 316 MDD patients, and 268 healthy controls who completed questionnaires, cognitive tests (e.g., the Symbol Digit Modalities Test (SDMT), the Verbal Fluency Test (VFT), the Chinese Revised Wechsler Memory Scale), and MRI scans. ChP volume, subcortical volume, and cortical thickness were measured, with group differences analyzed and correlations examined and compared.

RESULTS

BD and MDD patients had significantly larger ChP volume than healthy controls, with no difference between patient groups. In both groups, ChP volume negatively correlated with subcortical volume (r = -0.021 ∼ -0.285, q < 0.05) and cortical thickness (r = -0.149 ∼ -0.317, q < 0.05). Furthermore, ChP volume negatively correlated with logical memory (r = -0.154 ∼ -0.161, q < 0.05) and positively with visual reproduction (r = -0.159, q = 0.043) in BD, while negatively correlated with the SDMT (r = -0.122 ∼ -0.152, p < 0.05) and VFT (r = -0.118, p = 0.015) in MDD. Associations between ChP volume and right precentral gyrus thickness and memory quotient differed between the two groups.

CONCLUSION

Enlarged ChP volume in mood disorders was associated with brain atrophy and cognitive deficits, suggesting it could serve as a marker for structural and cognitive changes.

Cognitive hierarchy in mood disorders and relations to daily functioning

Cognitive impairment affects approximately 50 % of patients with mood disorders during remission, which correlates with poorer daily-life functioning. The hierarchical organisation of cognitive processes may mean that some cognitive deficits, e.g., memory impairments, are secondary to impairments in suggested core processes, including executive functions, working memory, attention, and psychomotor speed. The exact structure of a cognitive hierarchy in mood disorders is unclear. In this study, we aimed to examine relationships between cognitive domains using network graphs. Further, we aimed to explore whether impairments in the proposed 'core cognitive domains' mediated patients' verbal memory impairment and functional disability using mediation and hierarchical regression analyses. We pooled data from patients with mood disorders and healthy controls (HC) from 10 original studies. In total, 1505 participants were included in the analyses (n = 900 patients; n = 605 HC). We found that cognitive domains were more intercorrelated in patients than in HC. Executive functions, working memory, and attention and psychomotor speed almost fully accounted for illness-associated verbal learning and memory impairments, indicating partial mediation. Of the core domains, working memory explained the largest amount of variance in memory impairments and functional disability. Our findings highlight the importance of targeting core cognitive domains in pro-cognitive interventions.

Towards Enhancing Drug Development Methodology to Treat Cognitive Impairment Associated With Schizophrenia and Other Neuropsychiatric Conditions: Insights From 2 Decades of Clinical Trials

Cognitive impairment is a core feature and leading cause of functional disability in schizophrenia and other neuropsychiatric disorders. The Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative in the early 2000s marked a pivotal moment for drug development, establishing consensus on methodology for treatment studies, including assessment strategies and trial designs, for cognitive impairment associated with schizophrenia (CIAS). Despite extensive industry-sponsored and academic drug development efforts over the last 2 decades using these strategies no pharmacological treatments have been approved for CIAS. Drawing on pharmaceutical industry experience and scientific developments since the MATRICS initiative, we review lessons learned about the practical and operational complexities of conducting large-scale CIAS clinical trials. Based on this collective experience, we identify elements of the MATRICS guidelines that may warrant reconsideration and suggest some new approaches to streamline the drug development pathway, without weakening standards for evidence. Our goal is to initiate an open exchange among all stakeholders about possible enhancements to drug development methodology that optimize our ability to develop new treatments for cognitive impairment in schizophrenia and other neuropsychiatric disorders.

Molecular genetic influences on attentional control and other executive processes and their links with psychopathology in the AFFECT study

Background

Attentional control is a critical component of executive functioning involved in numerous psychiatric and neurological disorders, yet its etiological relationships with many cognitive and behavioral phenotypes remain underexplored.

Methods

We conducted the first multivariate characterization of molecular genetic influences on attentional control and other executive processes in a cohort of more than 20,000 individuals enriched for mood disorders. We used Genomic Structural Equation Modeling to formally model patterns of genetic covariance among these task-based measures of cognition, as well as their relationships with other cognitive, clinical, and imaging-derived phenotypes.

Results

We identified two independent latent genetic factors: one broadly influencing executive function and one narrowly influencing attentional control. Both the Common Executive Function (CEF) and Attentional Control (AC) factors were genetically correlated with cognitive and clinical phenotypes, with each latent factor uniquely linked to liability for psychiatric disorders. For example, we observed myriad relationships between the factors and psychopathology, including robust and conditionally independent genetic associations with ADHD. However, despite clear links to brain-related phenotypes, genetic correlations with imaging-derived phenotypes themselves were modest and non-significant after correcting for multiple comparisons.

Conclusions

Overall, the results of our study suggest that genetic influences on attentional control are generally distinct from those that influence broader aspects of executive function. The CEF and AC factors show distinct patterns of genetic overlap with multiple cognitive and psychiatric outcomes, underscoring the need for more detailed phenotyping of cognition to generate new insights into the etiology of psychopathology.

Parsing the heterogeneity of depression: a data-driven subgroup derived from cognitive function

Background

Increasing evidences suggests that depression is a heterogeneous clinical syndrome. Cognitive deficits in depression are associated with poor psychosocial functioning and worse response to conventional antidepressants. However, a consistent profile of neurocognitive abnormalities in depression remains unclear.

Objective

We used data-driven parsing of cognitive performance to reveal subgroups present across depressed individuals and then investigate the change pattern of cognitive subgroups across the course in follow-up.

Method

We assessed cognition in 163 patients with depression using The Chinese Brief Cognitive Test(C-BCT) and the scores were compared with those of 196 healthy controls (HCs). 58 patients were reassessed after 8 weeks. We used K-means cluster analysis to identify cognitive subgroups, and compared clinical variables among these subgroups. A linear mixed-effects model, incorporating time and group (with interaction term: time × group) as fixed effects, was used to assess cognitive changes over time. Stepwise logistic regression analysis was conducted to identify risk factors associated with these subgroups.

Results

Two distinct neurocognitive subgroups were identified: (1) a cognitive-impaired subgroup with global impairment across all domains assessed by the C-BCT, and (2) a cognitive-preserved subgroup, exhibited intact cognitive function, with performance well within the healthy range. The cognitive-impaired subgroup presented with more severe baseline symptoms, including depressed mood, guilt, suicidality, and poorer work performance. Significant group × time interactions were observed in the Trail Making Test Part A (TMT-A) and Continuous Performance Test (CPT), but not in Symbol Coding or Digit Span tests. Despite partial improvement in TMT-A and CPT tests, the cognitive-impaired subgroup's scores remained lower than those of the cognitive-preserved subgroup across all tests at the study endpoint. Multiple regression analysis indicated that longer illness duration, lower educational levels, and antipsychotic medication use may be risk factors for cognitive impairment.

Conclusion

This study identifies distinguishable cognitive subgroups in acute depression, thereby confirming the presence of cognitive heterogeneity. The cognitive-impaired subgroup exhibits distinct symptoms and persistent cognitive deficits even after treatment. Screening for cognitive dysfunction may facilitate more targeted interventions.

Clinical Trial Registration

https://www.chictr.org, identifier ChiCTR2400092796.

Metacognitive Training for Subjects with Bipolar Disorder: A Randomized Controlled Trial

INTRODUCTION

Impairments in social cognition in bipolar disorder (BD) have been extensively described in the last decade but few treatment strategies have been studied to address this issue. This study presents findings from a randomized controlled trial (RCT) investigating the efficacy of metacognitive training for bipolar disorder (MCT-BD) compared to Treatment as Usual (TAU) among individuals with BD in remission. The aim was to determine whether MCT-BD could improve social cognition and overall functioning in this population.

METHODS

Participants (N = 56) were recruited via social media and an internal database at the University of São Paulo Medical School. Inclusion criteria included a confirmed BD diagnosis, current state of remission, and the presence of social functioning impairments. Exclusion criteria included any impairments that could hinder neuropsychological testing. Patients were randomly assigned to either MCT-BD or TAU, with assessments conducted at baseline and follow-up. The MCT-BD program consisted of nine sessions.

RESULTS

The overall attendance rate across all MCT-BD intervention sessions was 96.6%. The MCT-BD program demonstrated added value in improving social cognition, specifically in emotion recognition reaction time. However, no significant changes were found in theory of mind, psychosocial functioning, or quality of life.

CONCLUSION

This RCT provides preliminary evidence for the efficacy of MCT-BD in improving emotion recognition latency, emphasizing the importance of targeted interventions in social cognition outcomes for individuals with BD. The study's strengths include high completion rates and comprehensive cognitive assessments. Future studies should explore long-term effects and personalized treatment approaches aiming to improve social-cognitive deficits in this population.

Effects of childhood trauma on sustained attention in major depressive disorder: the mediating role of brain activity and functional connectivity

BACKGROUND

Sustained attention deficits were reported more significant in patients with major depressive disorder (MDD) than in healthy controls (HCs), and are pivotal in both the development and aggravation of depression. Childhood trauma is also common in MDD and the exposure to childhood trauma may impede sustained attention and increase the treatment resistance in MDD. However, the underlying neuro-mechanisms link the childhood trauma to sustained attention deficits in MDD remain unclear.

METHODS

We collected resting-state functional magnetic resonance imaging data, and measured childhood trauma severity using the Childhood Trauma Questionnaire and sustained attention using the Continuous Performance Test, Identical Pairs version. After excluding subjects with significant head movement, 45 MDDs and 54 HCs were included in the analysis. We compared fractional amplitude of low-frequency fluctuation (fALFF) between the groups, conducted whole-brain correlation analysis between the fALFF and sustained attention in the MDD group, and defined significant regions as the regions of interest for the seed-to-whole brain functional connectivity (FC) analysis. We further performed mediation analyses to investigate the relationships among the childhood trauma, fALFF and FC values, and the level of sustained attention in the MDD group.

RESULTS

Compared with HCs, MDDs exhibited higher fALFF in the right middle frontal gyrus and left inferior frontal gyrus, and lower fALFF in the bilateral insular cortex, left medial orbital superior frontal gyrus and left angular gyrus (ANG.L). Whole-brain correlation analysis showed that impaired sustained attention was associated with increased fALFF in the left postcentral gyrus (PoCG.L), and FC of PoCG.L-left precentral gyrus (PreCG.L) and ANG.L-right superior temporal gyrus (STG.R) in the MDD group. Furthermore, mediation analyses showed that the fALFF in PoCG.L, and FC of PoCG.L-PreCG.L and ANG.L-STG.R mediated the relationship between the childhood trauma and sustained attention in the MDD group.

CONCLUSION

The fALFF in PoCG.L, and FC of PoCG.L-PreCG.L and ANG.L-STG.R might be potential neural substrate in the association between the childhood trauma and poor sustained attention in the MDDs, and might serve as potential intervention targets for the treatment of sustained attention deficits in MDDs with childhood trauma history.

The role of predominant polarity on cognitive dysfunctions in patients with bipolar disorder

BACKGROUND

Cognitive impairment is frequently observed in bipolar disorder (BD). Previous findings indicated that predominant polarity could have an effect on cognitive deficits. This study aimed to examine the association between predominant polarity and cognitive impairments in BD.

MATERIALS AND METHODS

Euthymic BD patients with manic (MPP, n = 31), depressive (DPP, n = 25), undetermined predominant polarity (UPP, n = 28), and healthy controls (HC, n = 27) participated in the study. A battery of neurocognitive and social cognitive tests was implemented. Neurocognitive domains were identified via principal component analysis.

RESULTS

The MPP group performed worse in the Controlled Oral Word Association Test (COWAT), Reading the Mind in the Eyes Test (RMET), and Hinting Test (HT) compared to the DPP group and reasoning/problem-solving skills compared to the UPP group. Both MPP and UPP groups showed impairments in processing speed compared to HC. Among patient groups, there was no significant difference in working memory, attention, processing speed, verbal, and visual domain scores. The MPP group had poorer scores compared to controls in most of the social cognitive and neurocognitive domains in the study, while the overall cognitive impairment in the DPP group was relatively milder.

CONCLUSIONS

Although our sample size was relatively small, the MPP group yielded more severe cognitive impairment in verbal fluency and social cognition tests compared to DPP. Patients with MPP are particularly vulnerable to cognitive impairment, making them a priority for cognitive enhancement interventions. Future studies should focus on the outcomes of cognitive and pharmacological interventions in these polarity subgroups.

Improvement of persistent impairments in executive functions and attention following electroconvulsive therapy in a case control longitudinal follow up study

BACKGROUND

How cognition is influenced by electroconvulsive treatment (ECT) and major depressive disorder (MDD) is still debated. The development and etiology of neurocognitive impairment in MDD were examined by investigating the cognitive profile following ECT related to the state, scar, and trait perspectives, with the former predicting improvements parallel with depressive symptoms, while the two latter expected persisting impairments. Executive functions (EF) and attention are central to cognition and alterations in these functions could influence other domains like memory. The main aims of the present study were to examine the short and long-term effects of ECT on EF and attention in patients with major depressive disorder by exploiting the rapid antidepressant effect of this treatment.

METHODS

A case-control longitudinal follow-up design was used to investigate the effects of unilateral brief-pulse ECT on EF and attention in patients with depression (n = 36) compared to untreated healthy controls (n = 16). EF and attention were measured pre-treatment, approximately two weeks, and six months post-treatment.

RESULTS

The patient group showed significantly worse performance on most tests compared to healthy controls pre-treatment, and no short- or long-term worsening of EF and attention following ECT was found. Significant improvement was identified in patients' attention, processing speed and inhibition after ECT.

CONCLUSIONS

The present study showed that there was no cognitive worsening after ECT treatment. An improvement in several of the tests measuring inhibition, attention, and processing speed was parallel to symptom reduction, with the former showing associations to symptom change, suggesting state-related effects from improved mood. Still, the patient group performed significantly worse on most measures both pre-treatment and at the short and long-term follow-ups, indicating prevailing trait or scar effects on cognitive functions and potential lack of practice effects.

CLINICAL TRIAL NUMBER

NCT04348825 (14.04.20).

Multivariate brain-cognition associations in euthymic bipolar disorder

BACKGROUND

People with bipolar disorder (BD) tend to show widespread cognitive impairment compared to healthy controls. Impairments in processing speed (PS), attention and executive function (EF) may represent 'core' impairments that have a role in wider cognitive dysfunction. Cognitive impairments appear to relate to structural brain abnormalities in BD, but whether core deficits are related to particular brain regions is unclear and much of the research on brain-cognition associations is limited by univariate analysis and small samples.

METHODS

Euthymic BD patients (n = 56) and matched healthy controls (n = 26) underwent T1-weighted MRI scans and completed neuropsychological tests of PS, attention and EF. We utilised public datasets to develop normative models of cortical thickness (n = 5977) to generate robust estimations of cortical abnormalities in patients. Canonical correlation analysis was used to assess multivariate brain-cognition associations in BD, controlling for age, sex and premorbid IQ.

RESULTS

BD showed impairments on tests of PS, attention and EF, and abnormal cortical thickness in several brain regions compared to healthy controls. Impairments in tests of PS and EF were most strongly associated with cortical thickness in the left inferior temporal, right entorhinal and right temporal pole areas.

CONCLUSION

Impairments in PS, attention and EF can be observed in euthymic BD and may be related to abnormal cortical thickness in temporal regions. Future research should continue to leverage normative modelling and multivariate methods to examine complex brain-cognition associations in BD. Future research may benefit from exploring covariance between traditional brain structural morphological metrics such as cortical thickness, cortical volume and surface area.

Evaluating psychological distress associated with life events under the traumatic experience threshold in patients with major depressive and bipolar disorder

Patients with bipolar disorder (BD) and major depressive disorder (MDD) experience psychological distress associated with daily events that do not meet the threshold for traumatic experiences, referred to as event-related psychological distress (ERPD). Recently, we developed an assessment tool for ERPD, the ERPD-24. This tool considers four factors of ERPD: feelings of revenge, rumination, self-denial, and mental paralysis. We conducted a cross-sectional study between March 2021 and October 2022 to identify the differences and clinical features of ERPD among patients with MDD and BD and healthy subjects who did not experience traumatic events. Specifically, we assessed ERPD using the ERPD-24 and anxiety-related symptoms with the State-Trait Anxiety Inventory, Liebowitz Social Anxiety Scale, and anxious-depressive attack. Regarding the ERPD-24 scores among the groups, as the data did not rigorously follow the test of normality, the Kruskal-Wallis test was used to compare the differences among the groups, followed by the Dunn-Bonferroni adjusted post-hoc test. Non-remitted MDD patients and BD patients, regardless of remission/non-remission, presented more severe ERPD than healthy subjects. This study also demonstrated the relationships between all anxiety-related symptoms, including social phobia and anxious-depressive attack and ERPD, in both BD and MDD patients and in healthy subjects. In conclusion, patients with non-remitted MDD and with BD regardless of remission/non-remission experience severe ERPD related to anxiety-related symptoms.

Changes of structural functional connectivity coupling and its correlations with cognitive function in patients with major depressive disorder

BACKGROUND

Previous neuroimaging studies have reported structural and functional brain abnormalities in major depressive disorder (MDD). This study aimed to explore whether the coherence of structural-functional networks was affected by disease and investigate its correlation with clinical manifestations.

METHODS

The severity of symptoms and cognitive function of 121 MDD patients and 139 healthy controls (HC) were assessed, and imaging data, including diffusion tensor imaging, T1 structural magnetic resonance imaging (MRI) and resting-state functional MRI, were collected. Spearman correlation coefficients of Kullback-Leibler similarity (KLS), fiber number (FN), fractional anisotropy (FA) and functional connectivity (FC) were calculated as coupling coefficients. Double-weight median correlation analysis was conducted to investigate the correlations between differences in brain networks and clinical assessments.

RESULTS

The percentage of total correct response of delayed matching to sample and the percentage of delayed correct response of pattern recognition memory was lower in MDD. Compared with the HC, KLS-FC coupling between the parietal lobe and subcortical area, FA-FC coupling between the temporal and parietal lobe, and FN-FC coupling in the frontal lobe was lower in MDD. Several correlations between structural-functional connectivity and clinical manifestations were identified.

LIMITATIONS

First, our study lacks longitudinal follow-up data. Second, the sample size was relatively small. Moreover, we only used the Anatomical Automatic Labeling template to construct the brain network. Finally, the validation of the causal relationship of neuroimaging-behavior factors was still insufficient.

CONCLUSIONS

The alternation in structural-functional coupling were related to clinical characterization and might be involved in the neuropathology of depression.