Meta-analyses of cognitive functioning in euthymic bipolar patients and their first-degree relatives

Perceived cognitive loss, symptomology, and psychological well-being with bipolar disorder

BACKGROUND

Adults with bipolar disorder (BD) commonly present with cognitive deficits. Many also report subjective or perceived cognitive failures. For this study, we identified four distinct clusters of adults with BD on the basis of both BD symptoms (depression and hypo/mania) and perceived cognitive errors (i.e., forgetfulness, distractibility, false triggering). We hypothesized that participants reporting more BD symptoms and cognitive errors would report lower psychological well-being (i.e., self-efficacy, life scheme, life satisfaction). A second objective was to determine if and how clusters differed in terms of BD related factors (e.g., subtypes, sleep, medications) and sociodemographic differences such as age of participants. From the BADAS (Bipolar Affective Disorder and older Adults) Study, we identified 281adults with BD (M = 44.27 years of age, range 19-81), recruited via social media.

RESULTS

All clusters significantly differed across all grouping variables except symptoms of hypo/mania due to low frequency. Across clusters, perceived cognitive failures and BD symptoms increased in lockstep; that is, those reporting more cognitive errors also reported significantly higher symptoms of both depression and hypo/mania. As hypothesized, they also reported significantly lower psychological well-being.

CONCLUSIONS

Age did not significantly differ across clusters in contrast to existing research in which cognitive loss is objectively measured. That is, perceived cognitive errors are significantly associated with lower psychological well-being for both young and older adults with BD.

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.

Increased grey matter volumes in the temporal lobe and its relationship with cognitive functioning in euthymic patients with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is characterized by episodic mood dysregulation, although a significant portion of patients suffer persistent cognitive impairment during euthymia. Previous magnetic resonance imaging (MRI) research suggests BD patients may have accelerated brain aging, observed as lower grey matter volumes. How these neurostructural alterations are related to the cognitive profile of BD is unclear.

METHODS

We aim to explore this relationship in euthymic BD patients with multimodal structural neuroimaging. A sample of 27 euthymic BD patients and 24 healthy controls (HC) underwent structural grey matter MRI and diffusion-weighted imaging (DWI). BD patient's cognition was also assessed. FreeSurfer algorithms were used to obtain estimations of regional grey matter volumes. White matter pathways were reconstructed using TRACULA, and four diffusion metrics were extracted. ANCOVA models were performed to compare BD patients and HC values of regional grey matter volume and diffusion metrics. Global brain measures were also compared. Bivariate Pearson correlations were explored between significant brain results and five cognitive domains.

RESULTS

Euthymic BD patients showed higher ventricular volume (F(1, 46) = 6.04; p = 0.018) and regional grey matter volumes in the left fusiform (F(1, 46) = 15.03; pFDR = 0.015) and bilateral parahippocampal gyri compared to HC (L: F(1, 46) = 12.79, pFDR = 0.025/ R: F(1, 46) = 15.25, pFDR = 0.015). Higher grey matter volumes were correlated with greater executive function (r = 0.53, p = 0.008).

LIMITATIONS

We evaluated a modest sample size with concurrent pharmacological treatment.

CONCLUSIONS

Higher medial temporal volumes in euthymic BD patients may be a potential signature of brain resilience and cognitive adaptation to a putative illness neuroprogression. This knowledge should be integrated into further efforts to implement imaging into BD clinical management.

Bipolar disorder and Lewy body dementia: case report and literature review

Depressive episodes with psychotic symptoms are prevalent among the older adults, emphasizing the need to differentiate them from dementia with Lewy bodies (DLB), in which depressive and psychotic symptoms commonly coexist. In contrast, psychotic symptoms occur more frequently in depressive episodes of bipolar disorder (BD) than in major depressive disorder (MDD). Although MDD is a significant risk factor for dementia, studies exploring the relationship between BD and dementia are lacking. This report details the case of a 74-year-old female who experienced severe psychotic depression that led to suicide attempts during a long-term course of young-onset BD. Ultimately, she was diagnosed with DLB based on her neurocognitive symptoms and results of the neuroimaging examination. She had experienced multiple relapses in the past, predominantly characterized by depressive episodes in her old age. Notably, she had never undergone lithium treatment, which is known for its potential efficacy in preventing relapse and dementia. Recent systematic reviews and meta-analyses have suggested that patients with BD have a higher risk of dementia than the general population, and that lithium usage is associated with a reduced risk. Moreover, patients with BD have been suggested to have an elevated risk of developing Parkinson's disease (PD), and the pathophysiological relationship between BD and PD may be attributed to dopamine dysregulation resulting from multiple relapses. Future research is imperative to identify strategies for preventing dementia in patients with BD and to develop interventions for the comorbidities of BD and DLB.

Cognition in Euthymic Patients with Bipolar Disorder: Do Not Forget to Account for Anxiety!

Purpose

Despite the high prevalence of anxiety disorders in BD and its known impact on cognitive performance, the presence and severity of anxious symptoms is not systematically evaluated in studies on cognition in BD. Our aim was to determine if attention and/or inhibition of cognitive interference in euthymic patients with type I Bipolar Disorder (BD-I) is affected by symptoms of anxiety.

Patients and Methods

Eighty-seven euthymic BD-I patients were included. Patients with comorbidities other than Generalized Anxiety Disorder (GAD) or Panic Disorder (PD) were excluded. State anxiety was measured with the Brief Inventory of Anxious Responses and Situations (ISRA-B). Subjective cognitive performance was evaluated with the COBRA scale, attention with the Digit-Span Forward task and inhibition of cognitive interference was assessed with the StroopTest interference score. Multiple linear regression models were used to test if anxious symptoms were associated with attention or inhibition of cognitive interference, considering other known contributors for cognitive impairment.

Results

Attention was unaffected by anxiety symptoms, but the overall regression for inhibition of cognitive interference was significant: years of schooling (β=1.12, p = 0.001), cognitive complaints (β=0.44, p = 0.008), and anxiety (β=-0.21, p = 0.017) explained 15% of the interference score of the Stroop test (R2 = 0.15).

Conclusion

Beyond residual affective symptoms, anxious symptoms seem to affect inhibition of cognitive interference. We recommend routine testing of anxiety when considering cognitive evaluations, especially when screening for cognitive deficits.

Association among abnormal glycolipids, reproductive hormones, and cognitive dysfunction in female patients with bipolar disorder

BACKGROUND

Patients with bipolar disorder (BD) show abnormalities in glucolipid metabolism and reproductive hormone levels, which are of concern in women with BD. This study was dedicated to investigating the glucolipid and reproductive hormone levels of female patients, and to preliminarily investigating their relationships with cognition.

METHODS

A total of 58 unmedicated female BD patients, 61 stable-medicated female BD patients, and 63 healthy controls (HC) were recruited in this study. Serum glycolipid indexes and reproductive hormones were measured. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Stroop Color-Word Test (Stroop test).

RESULTS

Patients with BD showed significant cognitive impairment (p < 0.05), which was not affected by medication. Triglycerides (TG), luteinizing hormone (LH), and high-density lipoprotein cholesterol (HDL-c) were altered in stable-medicated BD patients. In addition, regression analysis showed that progesterone (PRGE) and prolactin (PRL) were negatively associated with cognitive performance in stable-medicated BD patients.

CONCLUSIONS

Female BD patients may have cognitive deficits and abnormal levels of glycolipids and reproductive hormones. And abnormal levels of glycolipids and reproductive hormones may be associated with cognitive dysfunction in female BD patients.

Executive Control and Associated Brain Activity in Children With Familial High-Risk of Schizophrenia or Bipolar Disorder: A Danish Register-based Study

BACKGROUND AND HYPOTHESES

Impaired executive control is a potential prognostic and endophenotypic marker of schizophrenia (SZ) and bipolar disorder (BP). Assessing children with familial high-risk (FHR) of SZ or BP enables characterization of early risk markers and we hypothesize that they express impaired executive control as well as aberrant brain activation compared to population-based control (PBC) children.

STUDY DESIGN

Using a flanker task, we examined executive control together with functional magnetic resonance imaging (fMRI) in 11- to 12-year-old children with FHR of SZ (FHR-SZ) or FHR of BP (FHR-BP) and PBC children as part of a register-based, prospective cohort-study; The Danish High Risk and Resilience study-VIA 11.

STUDY RESULTS

We included 85 (44% female) FHR-SZ, 63 (52% female) FHR-BP and 98 (50% female) PBC in the analyses. Executive control effects, caused by the spatial visuomotor conflict, showed no differences between groups. Bayesian ANOVA of reaction time (RT) variability, quantified by the coefficient of variation (CVRT), revealed a group effect with similarly higher CVRT in FHR-BP and FHR-SZ compared to PBC (BF10 = 6.82). The fMRI analyses revealed no evidence for between-group differences in task-related brain activation. Post hoc analyses excluding children with psychiatric illness yielded same results.

CONCLUSION

FHR-SZ and FHR-BP at age 11-12 show intact ability to resolve a spatial visuomotor conflict and neural efficacy. The increased variability in RT may reflect difficulties in maintaining sustained attention. Since variability in RT was independent of existing psychiatric illness, it may reflect a potential endophenotypic marker of risk.

Impulsivity and neural correlates of response inhibition in bipolar disorder and their unaffected relatives: A MEG study

BACKGROUND

Response inhibition is a core cognitive impairment in bipolar disorder (BD), leading to increased impulsivity in BD. However, the relationship between the neural mechanisms underlying impaired response inhibition and impulsivity in BD is not yet clear. Individuals who are genetically predisposed to BD give a way of identifying potential endophenotypes.

METHODS

A total of 97 participants, including 39 patients with BD, 22 unaffected relatives (UR) of patients with BD, and 36 healthy controls performed a Go/No-Go task during magnetoencephalography. We carried out time-frequency and connectivity analysis on MEG data.

RESULTS

Decreased beta power, prolonged latency and increased peak frequency in rIFG, decreased beta power in pre-SMA and reduced rIFG-to-pre-SMA connectivity were found in BD relative to healthy controls. In the UR group, we found a decrease in the beta power of pre-SMA and prolonged latency of rIFG. Furthermore, increased motor impulsiveness in BD was related to abnormal alterations in beta oscillatory activity of rIFG and functional connectivity between rIFG and pre-SMA.

CONCLUSIONS

Hypoactivity activity in rIFG and impaired dominant role of rIFG in the prefrontal control network may underlie the neuropathology of response inhibition dysfunction, resulting increased motor impulsivity in BD. Our findings point to measuring rIFG dysfunction as a potential means of identifying individuals at genetic high risk for transition to BD disease expression.

Social cognition and neurocognition in first-episode bipolar disorder and psychosis: The effect of negative and attenuated positive symptoms

BACKGROUND

Schizophrenia and bipolar disorder are associated with neurocognitive and social-cognitive impairments. To date very few studies investigated social cognition in first-episode bipolar disorder (FEBD). Our main aim was to investigate the differences in social cognition and neurocognition between FEBD and first-episode psychosis (FEP). Another aim was to investigate neurocognitive correlates of negative symptoms and attenuated psychotic symptoms in FEBD.

METHODS

This study included 55 FEBD, 64 FEP and 43 healthy controls. A comprehensive neuropsychological battery assessing social cognition, processing speed, verbal and visual memory, working memory, sustained attention, and executive functions was administered to all participants.

RESULTS

Both FEBD and FEP were associated with widespread deficits in all neurocognitive domains and social cognition. Both FEP (d = -1.19) and FEBP (d = -0.88) were also impaired in social cognition. In FEP, effect sizes (Cohen's d) of neurocognitive deficits ranged from -0.71 to -1.56. FEBD was also associated with relatively milder but similar neurocognitive deficits (d = -0.61 to-1.17). FEBD group performed significantly better than FEP group in verbal and visual memory, processing speed, and executive function domains (d = -0.40 to-0.52). Negative symptoms and social functioning were associated with neuropsychological impairment in both groups. The severity of attenuated psychotic symptoms was associated with poorer verbal memory in FEBD (r = -0.39, p < 0.01).

LIMITATIONS

The cross-sectional nature of the current study is the main limitation.

CONCLUSIONS

Neurocognitive and social-cognitive deficits are evident in both FEBD and FEP. In FEBD, more severe memory deficits might be markers of clinical overlap and shared neurobiological vulnerability with psychotic disorders.

Socio-economic status, functioning and cognition in young versus adult patients newly diagnosed with bipolar disorder and their unaffected relatives; results from a cross-sectional study

BACKGROUND

Bipolar disorders (BD) figures on top of the World Health Organization classification of disabling disorders. It is unclear if there are socioeconomic, functioning, and cognition differences in young patients newly diagnosed with BD and whether these are different for young and adult patients newly diagnosed with BD. Understanding these differences is important for tailored treatment and support.

METHODS

Participant groups included 401 patients newly diagnosed with BD, 145 of their unaffected first-degree relatives (UR) and 209 healthy control individuals (HC). First, we compared socio-economic status, functioning and cognition between young patients newly diagnosed with BD (150), UR (61) and HC (92) (15-25 years) and adult patients newly diagnosed with BD (251), UR (84) and HC (117) (>25 years), respectively. Second, within patients, we compared functioning and cognition between young and adult patients newly diagnosed with BD.

RESULTS

In both participant groups, patients newly diagnosed with BD, and to a lesser degree UR, had lower socio-economic status and impaired functioning and cognition compared with HC. Further, young patients newly diagnosed with BD were less functionally impaired, than adults newly diagnosed with BD, whereas cognition did not differ between groups.

LIMITATIONS

Applied tools for assessments of functioning and cognition are not validated below age 18.

CONCLUSIONS

Overall, lower socio-economic status and impaired functioning and cognition were found both in young and adult patients newly diagnosed with BD and their UR compared with young and adult HC, respectively. Young patients were less functionally impaired than adults, but cognition was similarly impaired.

Neurocognition and social cognition in youth and young adults at ultra-high-risk for psychosis and bipolar disorder

BACKGROUND

Schizophrenia and bipolar disorder are associated with significant deficits in neurocognition and social cognition. Unlike the studies in chronic stages of these disorders, very limited information is available regarding neurocognitive and social-cognitive impairment before the onset of bipolar disorder. Our main aim was to investigate the differences in neurocognition and social cognition between individuals at ultra-high risk for psychosis (UHR-P) and bipolar disorder (UHR-BD).

METHODS

This study included 152 help-seeking individuals identified as UHR-P (n = 78) and UHR-BD (n = 74), who were compared with a healthy control group (n = 43). A comprehensive neuropsychological battery was administered to all participants.

RESULTS

UHR-P was associated with widespread deficits in all neurocognitive and social-cognitive domains. Effect sizes (Cohen's d) of these deficits ranged from -0.57 to -1.34. UHR-BD was associated with significant deficits in processing speed, executive functions, sustained attention and social cognition (d = -0.48 to-0.70, p < 0.05). UHR-P performed significantly worse than UHR-BD in social cognition, processing speed, verbal memory and executive function domains (d = -0.39 to-0.64, p < 0.05). Negative symptoms were associated with impaired social cognition in the UHR-P group and verbal memory deficits in the UHR-BD group. Cognitive impairment was associated with functional impairment in both groups.

CONCLUSIONS

While UHR-P is associated with more widespread cognitive impairment, deficits in processing speed, executive functions, sustained attention and social cognition might be common features of both UHR groups. In early intervention services, cognition should be considered as a target for assessment and intervention not only for individuals at high risk for psychosis but also for bipolar disorder.

Impact of biological rhythms on perception of illness and cognitive flexibility in bipolar patients in remission

Our study aims to examine the possible mediating effects of biological rhythms on the relationship between illness perception, cognitive flexibility, and functionality in bipolar patients in remission. A total of 150 patients with bipolar disorder (BD) were enrolled. The sociodemographic data form, Biological Rhythm Interview of Assessment in Neuropsychiatry (BRIAN), Brief Illness Perception Questionnaire (BIPQ), Cognitive Flexibility Scale (CFS), Young Mania Rating Scale, Montgomery and Asberg Depression Scale, Beck Anxiety Inventory, and Short Functionality Assessment Scale were applied to the patients in the study. The mean age of the patients was 42.10 ± 12.92 (SD). The participants were 48.7% (n = 73) female and 66.6% (n = 100) BD-I. There was a negative correlation between the total BRIAN score and favorable BIPQ scores and a positive correlation between the total BRIAN score and unfavorable BIPQ scores (except timeline). Additionally, multiple regression analyses revealed that the total BRIAN score could predict favorable BIPQ (except treatment control) and unfavorable BIPQ (except timeline) scores (p < 0.05). The total CFS score also could predict favorable BIPQ (treatment control) and unfavorable BIPQ scores (except timeline). The second step mediation analysis showed that biological rhythm mediated the relationship between illness perception and cognitive flexibility. Our study found that biological rhythms played a full mediating role in the relationship between the perception of illness and cognitive flexibility. In addition, worsening in biological rhythms in bipolar patients could cause negative beliefs and attitudes towards their diseases with an unfavorable clinical course. Therefore, regularity in biological rhythms should be highly recommended for bipolar patients.

Impact of cognitive reserve on bipolar disorder: a systematic review

Background

Cognitive reserve (CR) is a complex concept that includes premorbid IQ, years of education, and exposure to neuropsychological stimuli through work and leisure. Previous studies have suggested that CR has a positive impact on several aspects of bipolar disorder. Synthesizing the evidence to date is an important work in providing directions for future studies. The objectives of this systematic review to summary impact of CR on onsetting, relapsing bipolar episodes, buffering cognitive dysfunctions, and maintaining quality of life (QOL) in bipolar disorder.

Methods

Two researchers independently reviewed selected paper from three database as PubMed, PsychINFO, and Web of Science. The search keywords were "bipolar disorder" and "cognitive reserve." The selected studies were classified as the levels of evidence according to the criteria of the Oxford Center for Evidence- Based Medicine. The results of the selected studies were summarized according to the objectives.

Results

Thrity six studies were included in this review. People with high CR may have fewer bipolar episodes and alleviate cognitive impairments and dysfunction. CR may keep the functional level in patients with bipolar disorder.

Conclusion

The results of this systematic review suggest that CR may be involved in preventing relapse of bipolar episodes and may alleviate cognitive dysfunction. However, effect on prevention of onset-risk and relapse of bipolar episodes need further investigation in prospective studies.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021270293, the protocol was registered with PROSERO (CRD42021270293).

The development in rating-based executive functions in children at familial high risk of schizophrenia or bipolar disorder from age 7 to age 11: the Danish high risk and resilience study

Executive functions (EF) deficits are well documented in children at familial high risk of schizophrenia (FHR-SZ), and to a lesser degree in children at familial high risk of bipolar disorder (FHR-BP). The aim of this study was to assess EF development in preadolescent children at FHR-SZ, FHR-BP and population-based controls (PBC) using a multi-informant rating scale. A total of 519 children (FHR-SZ, n = 201; FHR-BP, n = 119; PBC, n = 199) participated at age 7, at age 11 or at both time points. Caregivers and teachers completed the Behavior Rating Inventory of Executive Functions (BRIEF). The developmental pattern from age 7 to age 11, did not differ between groups. At age 11, caregivers and teachers rated children at FHR-SZ as having widespread EF deficits. A higher proportion of children at FHR-SZ had clinically significant scores on the General executive composite (GEC) and all BRIEF indices compared to PBC. According to the caregivers, children at FHR-BP had significantly more EF deficits than PBC on 9 out of 13 BRIEF scales, whereas according to teachers, they only had significantly more deficits on one subdomain (Initiate). Likewise, caregivers rated a significantly higher proportion of children at FHR-BP above the clinical cut-off on the GEC and Metacognition index, compared to PBC, whereas there were no significant differences according to teachers. This study highlights the relevance of including multi-informant rating scales in the assessment of EF in children at FHR-SZ and FHR-BP. The results imply a need to identify children at high risk who would benefit from targeted intervention.

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.

Granule cells perform frequency-dependent pattern separation in a computational model of the dentate gyrus

Mnemonic discrimination (MD) may be dependent on oscillatory perforant path input frequencies to the hippocampus in a "U"-shaped fashion, where some studies show that slow and fast input frequencies support MD, while other studies show that intermediate frequencies disrupt MD. We hypothesize that pattern separation (PS) underlies frequency-dependent MD performance. We aim to study, in a computational model of the hippocampal dentate gyrus (DG), the network and cellular mechanisms governing this putative "U"-shaped PS relationship. We implemented a biophysical model of the DG that produces the hypothesized "U"-shaped input frequency-PS relationship, and its associated oscillatory electrophysiological signatures. We subsequently evaluated the network's PS ability using an adapted spatiotemporal task. We undertook systematic lesion studies to identify the network-level mechanisms driving the "U"-shaped input frequency-PS relationship. A minimal circuit of a single granule cell (GC) stimulated with oscillatory inputs was also used to study potential cellular-level mechanisms. Lesioning synapses onto GCs did not impact the "U"-shaped input frequency-PS relationship. Furthermore, GC inhibition limits PS performance for fast frequency inputs, while enhancing PS for slow frequency inputs. GC interspike interval was found to be input frequency dependent in a "U"-shaped fashion, paralleling frequency-dependent PS observed at the network level. Additionally, GCs showed an attenuated firing response for fast frequency inputs. We conclude that independent of network-level inhibition, GCs may intrinsically be capable of producing a "U"-shaped input frequency-PS relationship. GCs may preferentially decorrelate slow and fast inputs via spike timing reorganization and high frequency filtering.

An Update on Protein Kinases as Therapeutic Targets-Part I: Protein Kinase C Activation and Its Role in Cancer and Cardiovascular Diseases

Protein kinases are one of the most significant drug targets in the human proteome, historically harnessed for the treatment of cancer, cardiovascular disease, and a growing number of other conditions, including autoimmune and inflammatory processes. Since the approval of the first kinase inhibitors in the late 1990s and early 2000s, the field has grown exponentially, comprising 98 approved therapeutics to date, 37 of which were approved between 2016 and 2021. While many of these small-molecule protein kinase inhibitors that interact orthosterically with the protein kinase ATP binding pocket have been massively successful for oncological indications, their poor selectively for protein kinase isozymes have limited them due to toxicities in their application to other disease spaces. Thus, recent attention has turned to the use of alternative allosteric binding mechanisms and improved drug platforms such as modified peptides to design protein kinase modulators with enhanced selectivity and other pharmacological properties. Herein we review the role of different protein kinase C (PKC) isoforms in cancer and cardiovascular disease, with particular attention to PKC-family inhibitors. We discuss translational examples and carefully consider the advantages and limitations of each compound (Part I). We also discuss the recent advances in the field of protein kinase modulators, leverage molecular docking to model inhibitor-kinase interactions, and propose mechanisms of action that will aid in the design of next-generation protein kinase modulators (Part II).

Linguistic characteristics in bipolar disorder versus borderline personality disorder

Scientific evidence has documented throughout the research carried out in recent years, the neuropsychological, behavioral and adaptive difficulties presented by people with Bipolar Disorder and Borderline Personality Disorder at different stages of their development. However, little importance has been given to other factors such as communication, especially in the adult population. The objective of this research was to know the language characteristics presented by people from both groups and the differences in linguistic development. The sample consisted of 60 participants between the ages of 17 and 42:31 of them with a diagnosis of Borderline Personality Disorder and the remaining 29 with a diagnosis of Bipolar Disorder. The standardized evaluation instruments were: the Social Skills Scale and the Pragmatic Competence Questionnaire completed by three different informants (families, professionals and the own person). The results obtained show that both populations manifest linguistic difficulties in adulthood and that there are differences depending on the perception of the agent involved in the language assessment. These results are highly relevant since they provide up-to-date information about language level, support the need for language intervention in adulthood, and reflect a different communicative profile in Bipolar Disorder and Borderline Personality Disorder.

Can neurological soft signs and neurocognitive deficits serve as a combined endophenotype for Han Chinese with bipolar disorder?

BACKGROUND

Bipolar disorder's (BD) potential endophenotypes include neurological soft signs (NSS) and neurocognitive disorders (ND). Few research, meanwhile, has coupled NSS and ND as combined endophenotypes of BD.

OBJECT

This study intends to investigate NSS and ND and compare their differences in euthymic patients with bipolar disorder (EBP), their unaffected first-degree relatives (FDR), and healthy controls (HC). Additionally, search for potential endophenotypic subprojects of NSS and ND and construct and verify a composite endophenotypic.

METHODS

The subjects were all Han Chinese and consisted of 86 EBP, 81 FDR, and 81HC. Cambridge Neurological Inventory and MATRICSTM Consensus Cognitive Battery tested NSS and ND independently.

RESULTS

All three groups displayed a trapezoidal distribution of NSS levels and cognitive abnormalities, with EBP having the most severe NSS levels and cognitive deficits, followed by FDR and HC. Among them, motor coordination in NSS and Information processing speed (IPS), Verbal learning (VL), and Working memory (WM) in neurocognitive function are consistent with the traits of the endophenotype of BD. The accuracy in differentiating EBP and HC or FDRs and HC was higher when these items were combined as predictor factors than in differentiating EBP and FDR.

CONCLUSION

These results provide more evidence that motor coordination, IPS, VL, and WM may be internal characteristics of bipolar disease. When these characteristics are combined into a complex endophenotype, it may be possible to distinguish BD patients and high-risk groups from normal populations.

Immediate post performance judgements about cognitive performance in schizophrenia and bipolar disorder: associations with test performance and subjective overall judgments regarding abilities

INTRODUCTION

The study explored associations between the accuracy of post assessment judgements of cognitive performance with global self-assessments of psychosocial functioning compared to evaluations generated by observers in schizophrenia and bipolar disorder.

METHODS

An abbreviated cognitive assessment based on the MATRICS Consensus Cognitive Battery was administered to 122 individuals with schizophrenia and 113 with bipolar disorder. They provided self-estimates of their performance after each subtest. In addition, self-reports on cognition, social cognition, and everyday functioning were collected and compared to observer ratings.

RESULTS

Both groups overestimated their cognitive function, but in bipolar disorder, there was 30% shared variance between task performance and self-rated task performance (vs. 5% in schizophrenia). Significant correlations were found between self-reported everyday outcomes and both actual and self-assessed performance. In schizophrenia, immediate judgements were only related to self-rated functioning, not to observer rated functioning. In bipolar disorder, impairments in self-assessment of performance correlated with observer ratings of cognitive ability, which was not observed in schizophrenia.

CONCLUSIONS

While both groups showed correlations between cognitive performance and introspective accuracy, individuals with bipolar disorder showed higher accuracy in assessing their cognitive performance and other outcomes. Notably, impairments in introspective accuracy were associated with observer-rated functioning exclusively in bipolar disorder.

Cognition in Bipolar Disorder: An Update for Clinicians

Bipolar disorder is associated with cognitive deficits, which persist across mood states and affect functional outcomes. This article provides an overview of recent progress in measuring cognition in bipolar disorder and its implications for both research and clinical practice. The authors summarize work conducted over the past decade that has helped guide researchers and clinicians in the appropriate measurement of cognitive functioning in bipolar disorder, the design of research studies targeting this domain for treatment, and the implementation of screening and psychoeducational tools in the clinic. Much of this work was conducted by the International Society for Bipolar Disorders Targeting Cognition Task Force. Here, the authors also highlight the need for clinicians to be informed about this aspect of illness and to be equipped with the necessary information to assess, track, and intervene on cognitive problems when appropriate. Finally, the article identifies gaps in the literature and suggests potential future directions for research in this area.

Intrinsic functional connectivity correlates of cognitive deficits involving sustained attention and executive function in bipolar disorder

BACKGROUND

The neural correlate of cognitive deficits in bipolar disorder (BD) is an issue that warrants further investigation. However, relatively few studies have examined the intrinsic functional connectivity (FC) underlying cognitive deficits involving sustained attention and executive function at both the region and network levels, as well as the different relationships between connectivity patterns and cognitive performance, in BD patients and healthy controls (HCs).

METHODS

Patients with BD (n = 59) and HCs (n = 52) underwent structural and resting-state functional magnetic resonance imaging and completed the Wisconsin Card Sorting Test (WCST), the continuous performance test and a clinical assessment. A seed-based approach was used to evaluate the intrinsic FC alterations in three core neurocognitive networks (the default mode network [DMN], the central executive network [CEN] and the salience network [SN]). Finally, we examined the relationship between FC and cognitive performance by using linear regression analyses.

RESULTS

Decreased FC was observed within the DMN, in the DMN-SN and DMN-CEN and increased FC was observed in the SN-CEN in BD. The alteration direction of regional FC was consistent with that of FC at the brain network level. Decreased FC between the left posterior cingulate cortex and right anterior cingulate cortex was associated with longer WCST completion time in BD patients (but not in HCs).

CONCLUSIONS

These findings emphasize the dominant role of the DMN in the psychopathology of BD and provide evidence that cognitive deficits in BD may be associated with aberrant FC between the anterior and posterior DMN.

The Risk for Schizophrenia-Bipolar Spectrum: Does the Apple Fall Close to the Tree? A Narrative Review

Schizophrenia (SCZ) and bipolar disorder (BD) are severe psychiatric disorders that share clinical features and several risk genes. Important information about their genetic underpinnings arises from intermediate phenotypes (IPs), quantifiable biological traits that are more prevalent in unaffected relatives (RELs) of patients compared to the general population and co-segregate with the disorders. Within IPs, neuropsychological functions and neuroimaging measures have the potential to provide useful insight into the pathophysiology of SCZ and BD. In this context, the present narrative review provides a comprehensive overview of the available evidence on deficits in neuropsychological functions and neuroimaging alterations in unaffected relatives of SCZ (SCZ-RELs) and BD (BD-RELs). Overall, deficits in cognitive functions including intelligence, memory, attention, executive functions, and social cognition could be considered IPs for SCZ. Although the picture for cognitive alterations in BD-RELs is less defined, BD-RELs seem to present worse performances compared to controls in executive functioning, including adaptable thinking, planning, self-monitoring, self-control, and working memory. Among neuroimaging markers, SCZ-RELs appear to be characterized by structural and functional alterations in the cortico-striatal-thalamic network, while BD risk seems to be associated with abnormalities in the prefrontal, temporal, thalamic, and limbic regions. In conclusion, SCZ-RELs and BD-RELs present a pattern of cognitive and neuroimaging alterations that lie between patients and healthy individuals. Similar abnormalities in SCZ-RELs and BD-RELs may be the phenotypic expression of the shared genetic mechanisms underlying both disorders, while the specificities in neuropsychological and neuroimaging profiles may be associated with the differential symptom expression in the two disorders.

Identification of a psychiatric risk gene NISCH at 3p21.1 GWAS locus mediating dendritic spine morphogenesis and cognitive function

BACKGROUND

Schizophrenia and bipolar disorder (BD) are believed to share clinical symptoms, genetic risk, etiological factors, and pathogenic mechanisms. We previously reported that single nucleotide polymorphisms spanning chromosome 3p21.1 showed significant associations with both schizophrenia and BD, and a risk SNP rs2251219 was in linkage disequilibrium with a human specific Alu polymorphism rs71052682, which showed enhancer effects on transcriptional activities using luciferase reporter assays in U251 and U87MG cells.

METHODS

CRISPR/Cas9-directed genome editing, real-time quantitative PCR, and public Hi-C data were utilized to investigate the correlation between the Alu polymorphism rs71052682 and NISCH. Primary neuronal culture, immunofluorescence staining, co-immunoprecipitation, lentiviral vector production, intracranial stereotaxic injection, behavioral assessment, and drug treatment were used to examine the physiological impacts of Nischarin (encoded by NISCH).

RESULTS

Deleting the Alu sequence in U251 and U87MG cells reduced mRNA expression of NISCH, the gene locates 180 kb from rs71052682, and Hi-C data in brain tissues confirmed the extensive chromatin contacts. These data suggested that the genetic risk of schizophrenia and BD predicted elevated NISCH expression, which was also consistent with the observed higher NISCH mRNA levels in the brain tissues from psychiatric patients compared with controls. We then found that overexpression of NISCH resulted in a significantly decreased density of mushroom dendritic spines with a simultaneously increased density of thin dendritic spines in primary cultured neurons. Intriguingly, elevated expression of this gene in mice also led to impaired spatial working memory in the Y-maze. Given that Nischarin is the target of anti-hypertensive agents clonidine and tizanidine, which have shown therapeutic effects in patients with schizophrenia and patients with BD in preliminary clinical trials, we demonstrated that treatment with those antihypertensive drugs could reduce NISCH mRNA expression and rescue the impaired working memory in mice.

CONCLUSIONS

We identify a psychiatric risk gene NISCH at 3p21.1 GWAS locus influencing dendritic spine morphogenesis and cognitive function, and Nischarin may have potentials for future therapeutic development.

The Big Five as Predictors of Cognitive Function in Individuals with Bipolar Disorder

The connection between cognitive function and the "Big Five" personality traits (openness, conscientiousness, extraversion, agreeableness, and neuroticism) in the general population is well known; however, studies researching bipolar disorder (BD) are scarce. Therefore, this study aimed to investigate the Big Five as predictors of executive function, verbal memory, attention, and processing speed in euthymic individuals with BD (cross-sectional: n = 129, including time point t1; longitudinal: n = 35, including t1 and t2). Participants completed the NEO Five-Factor Inventory, the Color and Word Interference Test, the Trail Making Test, the d2 Test of Attention Revised, and the California Verbal Learning Test. The results showed a significant negative correlation between executive function and neuroticism at t1. Changes in cognitive function between t1 and t2 did not correlate with and could not be predicted by the Big Five at t1. Additionally, worse executive function at t2 was predicted by higher neuroticism and lower conscientiousness at t1, and high neuroticism was a predictor of worse verbal memory at t2. The Big Five might not strongly impact cognitive function over short periods; however, they are significant predictors of cognitive function. Future studies should include a higher number of participants and more time in between points of measurement.

Early Childhood Neurocognition in Relation to Middle Childhood Psychotic Experiences in Children at Familial High Risk of Schizophrenia or Bipolar Disorder and Population-Based Controls: The Danish High Risk and Resilience Study

BACKGROUND AND HYPOTHESIS

Familial high-risk (FHR) studies examining longitudinal associations between neurocognition and psychotic experiences are currently lacking. We hypothesized neurocognitive impairments at age 7 to be associated with increased risk of psychotic experiences from age 7 to 11 in children at familial high risk of schizophrenia (FHR-SZ) or bipolar disorder (FHR-BP) and population-based controls (PBC), and further, impaired functioning in some neurocognitive functions to be associated with greater risk of psychotic experiences in children at FHR-SZ or FHR-BP relative to PBC.

STUDY DESIGN

Neurocognition was assessed at age 7 (early childhood) and psychotic experiences from age 7 to 11 (middle childhood) in 449 children from the Danish High Risk and Resilience Study. The neurocognitive assessment covered intelligence, processing speed, attention, visuospatial and verbal memory, working memory, and set-shifting. Psychotic experiences were assessed through face-to-face interviews with the primary caregiver and the child.

STUDY RESULTS

Set-shifting impairments at age 7 were associated with greater risk of psychotic experiences from age 7 to 11 in children at FHR-SZ. Children at FHR-BP and PBC showed no differential associations. Working memory and visuospatial memory impairments were related to increased risk of psychotic experiences across the cohort. However, adjusting for concurrent psychopathology attenuated these findings.

CONCLUSIONS

Early childhood neurocognitive impairments are risk markers of middle childhood psychotic experiences, of which impaired set-shifting appears to further increase the risk of psychotic experiences in children at FHR-SZ. More research is needed to examine longitudinal associations between neurocognitive impairments and psychotic experiences in FHR samples.

Association Between the Fronto-Limbic Network and Cognitive and Emotional Functioning in Individuals With Bipolar Disorder: A Systematic Review and Meta-analysis

Importance

Individuals with bipolar disorder (BD) experience cognitive and emotional dysfunctions. Various brain circuits are implicated in BD but have not been investigated in a meta-analysis of functional magnetic resonance imaging (fMRI) studies.

Objective

To investigate the brain functioning of individuals with BD compared with healthy control individuals in the domains of emotion processing, reward processing, and working memory.

Data Sources

All fMRI experiments on BD published before March 2020, as identified in a literature search of PubMed, Embase, Web of Science, Cochrane Library, PsycInfo, Emcare, Academic Search Premier, and ScienceDirect. The literature search was conducted on February 21, 2017, and March 2, 2020, and data were analyzed from January 2021 to January 2022.

Study Selection

fMRI experiments comparing adult individuals with BD and healthy control individuals were selected if they reported whole-brain results, including a task assessing at least 1 of the domains. In total, 2320 studies were screened, and 253 full-text articles were evaluated.

Data Extraction and Synthesis

A total of 49 studies were included after selection procedure. Coordinates reporting significant activation differences between individuals with BD and healthy control individuals were extracted. Differences in brain region activity were tested using the activation likelihood estimation method.

Main Outcomes and Measures

A whole-brain meta-analysis evaluated whether reported differences in brain activation in response to stimuli in 3 cognitive domains between individuals with BD and healthy control individuals were different.

Results

The study population included 999 individuals with BD (551 [55.2%] female) and 1027 healthy control individuals (532 [51.8%] female). Compared with healthy control individuals, individuals with BD showed amygdala and hippocampal hyperactivity and hypoactivation in the inferior frontal gyrus during emotion processing (20 studies; 324 individuals with BD and 369 healthy control individuals), hyperactivation in the orbitofrontal cortex during reward processing (9 studies; 195 individuals with BD and 213 healthy control individuals), and hyperactivation in the ventromedial prefrontal cortex and subgenual anterior cingulate cortex during working memory (20 studies; 530 individuals with BD and 417 healthy control individuals). Limbic hyperactivation was only found during euthymia in the emotion and reward processing domains; abnormalities in frontal cortex activity were also found in individuals with BD with mania and depression.

Conclusions and Relevance

This systematic review and meta-analysis revealed evidence for activity disturbances in key brain areas involved in cognitive and emotion processing in individuals with BD. Most of the regions are part of the fronto-limbic network. The results suggest that aberrations in the fronto-limbic network, present in both euthymic and symptomatic individuals, may be underlying cognitive and emotional dysfunctions in BD.

Working memory heterogeneity from age 7 to 11 in children at familial high risk of schizophrenia or bipolar disorder- The Danish High Risk and Resilience Study

BACKGROUND

Despite the genetic overlap between bipolar disorder and schizophrenia, working memory impairments are mainly found in children of parents with schizophrenia. However, working memory impairments are characterized by substantial heterogeneity, and it is unknown how this heterogeneity develops over time. We used a data-driven approach to assess working memory heterogeneity and longitudinal stability in children at familial high risk of schizophrenia (FHR-SZ) or bipolar disorder (FHR-BP).

METHODS

Based on the performances on four working memory tasks by 319 children (FHR-SZ, N = 202, FHR-BP, N = 118) measured at age 7 and 11, latent profile transition analysis was used to test for the presence of subgroups, and the stability of subgroup membership over time. Population-based controls (VIA 7, N = 200, VIA 11, N = 173) were included as a reference group. The working memory subgroups were compared based on caregiver- and teacher ratings of everyday working memory function, and dimensional psychopathology.

RESULTS

A model with three subgroups characterized by different levels of working memory function (an impaired subgroup, a mixed subgroup, and an above average subgroup) best fitted the data. The impaired subgroup had the highest ratings of everyday working memory impairments and psychopathology. Overall, 98 % (N = 314) stayed in the same subgroup from age 7 to 11.

CONCLUSION

Persistent working memory impairments are present in a subset of children at FHR-SZ and FHR-BP throughout middle childhood. Attention should be given to these children, as working memory impairments influence daily life, and may serve as a vulnerability marker of transition to severe mental illness.

The Effects of Four Compounds That Act on the Dopaminergic and Serotonergic Systems on Working Memory in Animal Studies; A Literature Review

The dopaminergic and serotonergic systems are two of the most important neuronal pathways in the human brain. Almost all psychotropic medications impact at least one neurotransmitter system. As a result, investigating how they affect memory could yield valuable insights into potential therapeutic applications or unanticipated side effects. The aim of this literature review was to collect literature data from animal studies regarding the effects on memory of four drugs known to act on the serotonergic and dopaminergic systems. The studies included in this review were identified in the PubMed database using selection criteria from the PRISMA protocol. We analyzed 29 articles investigating one of four different dopaminergic or serotonergic compounds. Studies conducted on bromocriptine have shown that stimulating D2 receptors may enhance working memory in rodents, whereas inhibiting these receptors could have the opposite effect, reducing working memory performance. The effects of serotonin on working memory are not clearly established as studies on fluoxetine and ketanserin have yielded conflicting results. Further studies with better-designed methodologies are necessary to explore the impact of compounds that affect both the dopaminergic and serotonergic systems on working memory.

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

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

Computational Modeling of the n-Back Task in the ABCD Study: Associations of Drift Diffusion Model Parameters to Polygenic Scores of Mental Disorders and Cardiometabolic Diseases

BACKGROUND

Cognitive dysfunction is common in mental disorders and represents a potential risk factor in childhood. The nature and extent of associations between childhood cognitive function and polygenic risk for mental disorders is unclear. We applied computational modeling to gain insight into mechanistic processes underlying decision making and working memory in childhood and their associations with polygenic risk scores (PRSs) for mental disorders and comorbid cardiometabolic diseases.

METHODS

We used the drift diffusion model to infer latent computational processes underlying decision making and working memory during the n-back task in 3707 children ages 9 to 10 years from the Adolescent Brain Cognitive Development (ABCD) Study. Single nucleotide polymorphism-based heritability was estimated for cognitive phenotypes, including computational parameters, aggregated n-back task performance, and neurocognitive assessments. PRSs were calculated for Alzheimer's disease, bipolar disorder, coronary artery disease (CAD), major depressive disorder, obsessive-compulsive disorder, schizophrenia, and type 2 diabetes.

RESULTS

Heritability estimates of cognitive phenotypes ranged from 12% to 38%. Bayesian mixed models revealed that slower accumulation of evidence was associated with higher PRSs for CAD and schizophrenia. Longer nondecision time was associated with higher PRSs for Alzheimer's disease and lower PRSs for CAD. Narrower decision threshold was associated with higher PRSs for CAD. Load-dependent effects on nondecision time and decision threshold were associated with PRSs for Alzheimer's disease and CAD, respectively. Aggregated neurocognitive test scores were not associated with PRSs for any of the mental or cardiometabolic phenotypes.

CONCLUSIONS

We identified distinct associations between computational cognitive processes and genetic risk for mental illness and cardiometabolic disease, which could represent childhood cognitive risk factors.

Socio-economic functioning in patients with bipolar disorder and their unaffected siblings - results from a nation-wide population-based longitudinal study

BACKGROUND

Few studies have reported real-life data on socio-economic functioning in patients with bipolar disorder and their unaffected first-degree relatives.

METHODS

We used Danish nation-wide population-based longitudinal register linkage to investigate socio-economic functioning in 19 955 patients with bipolar disorder, their 13 923 siblings and 20 sex, age and calendar-matched control individuals from the general population. Follow-up was from 1995 to 2017.

RESULTS

Patients with a diagnosis of bipolar disorder had lower odds of having achieved the highest educational level [OR 0.75 (95% confidence interval (CI) 0.73-0.77)], being employed [OR 0.16 (95% CI 0.159-0.168)], having achieved the 80% highest quartile of income [OR 0.33 (95% CI 0.32-0.35)], cohabitating [OR 0.44 (95% CI 0.43-0.46)] and being married [OR 0.54 (95% CI 0.52-0.55)] at first contact to hospital psychiatry as inpatient or outpatient compared with control individuals from the general population. Similarly, siblings to patients with bipolar disorder had a lower functioning within all five socio-economic areas than control individuals. Furthermore, patients and partly siblings showed substantially decreased ability to enhance their socio-economic functioning during the 23 years follow-up compared to controls.

CONCLUSIONS

Socio-economic functioning is substantially decreased in patients with bipolar disorder and their siblings and does not improve during long-term follow-up after the initial hospital contact, highlighting a severe and overlooked treatment gap.

Correlates of neurological soft signs in bipolar disorder

Recent research has focused on neurological soft signs (NSS) in bipolar disorder (BD), but there is still scarce evidence on their correlates with other relevant variables. The aim of this study was to explore the association between NSS and clinical demographic, neurocognitive, and functional variables. Eighty-eight euthymic BD patients were included in whom NSS were assessed using the Neurological Evaluation Scale. All subjects performed an extensive neurocognitive battery selected to assess premorbid IQ, attention, language, verbal memory, and executive functions. Psychosocial outcomes were assessed by means of the Functioning Assessment Short Test. Among the demographical variables, NSS tended to be negatively associated with years of education and increased with age. Likewise, NSS were higher in BD type I than in BD type II, but independent of age at illness onset and number of previous affective episodes. There was a negative correlation between NSS and premorbid IQ, as well as with performance in attention, language, and executive functions. Results tended to be unchanged when controlled for potential confounders. Although NSS were associated with poor psychosocial functioning in the bivariate analysis, when added to a multiple regression model including neurocognition, these neurological features did not significantly contribute to the variance of the functional outcome. Our findings contribute to a better characterization of NSS in BD; their potential clinical and theoretical implications are discussed in the manuscript.

Characterisation of Deficits and Sex Differences in Verbal and Visual Memory/Learning in Bipolar Disorder

OBJECTIVE

Cognitive impairment is consistently reported in bipolar disorder (BD), but few studies have characterised which memory component processes are affected. Further, it is unknown whether the component processes underlying memory impairment are moderated by sex. The present study examined diagnosis and sex differences in both verbal and visual memory/learning domains in patients with BD and psychiatrically healthy controls.

METHOD

Verbal and visual memory/learning were measured using the Hopkins Verbal Learning Test-Revised (HVLT-R) and Brief Visuospatial Memory Test-Revised (BVMT-R). 114 patients with BD (n = 50 males, n = 64 females), were compared to 105 psychiatrically healthy controls (n = 42 males, n = 63 females).

RESULTS

Patients with BD had worse performance in verbal and visual immediate and total recall, verbal and visual delayed free recall, and verbal recognition discrimination scores, but there were no group differences in learning slopes and cumulative learning index scores. There were trends for BD females to outperform BD males in visual memory/learning free recall and cumulative learning, but these results did not survive multiple testing correction. These findings did not change in a secondary sensitivity analysis comparing only strictly euthymic BD patients to controls (n = 64).

CONCLUSION

The present study found trait-like verbal and visual memory/learning impairment in BD that was attributable to deficient encoding and/or consolidation processes rather than deficits in learning. We did not find marked sex differences in either visual or verbal memory/learning measures, although some trend level effects were apparent and deserve exploration in future studies.

Disrupted network switching in euthymic bipolar disorder: Working memory and self-referential paradigms

BACKGROUND

Patients with bipolar disorder (BD) frequently suffer from neurocognitive deficits that can persist during periods of clinical stability. Specifically, impairments in executive functioning such as working memory and in self-processing have been identified as the main components of the neurocognitive profile observed in euthymic BD patients. The study of the neurobiological correlates of these state-independent alterations may be a prerequisite to develop reliable biomarkers in BD.

METHODS

A sample of 27 euthymic BD patients and 25 healthy participants (HC) completed working memory and self-referential functional Magnetic Resonance Imaging (fMRI) tasks. Activation maps obtained for each group and contrast images (i.e., 2-back > 1-back/self > control) were used for comparisons between patients and HC.

RESULTS

Euthymic BD patients, in comparison to HC, showed a higher ventromedial prefrontal cortex activation during working memory, a result driven by the lack of deactivation in BD patients. In addition, euthymic BD patients displayed a greater dorsomedial and dorsolateral prefrontal cortex activation during self-reference processing.

LIMITATIONS

Pharmacotherapy was described but not included as a confounder in our models. Sample size was modest.

CONCLUSION

Our findings revealed a lack of deactivation in the anterior default mode network (aDMN) during a working memory task, a finding consistent with prior research in BD patients, but also a higher activation in frontal regions within the central executive network (CEN) during self-processing. These results suggest that an imbalance of neural network dynamics underlying external/internal oriented cognition (the CEN and the aDMN, respectively) may be one of the first reliable biomarkers in euthymic bipolar patients.

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.

Accuracy of immediate self-assessment of neurocognitive test performance: Associations with psychiatric diagnosis and longitudinal psychotic symptoms

Participants with schizophrenia (SCZ) and bipolar disorder (BD) have challenges in self-evaluation of their cognitive and functional abilities, referred to as introspective accuracy (IA). Although psychotic symptoms are commonly found to be uncorrelated with cognitive performance, many models of the development of delusions focus on failures in self-assessment and responses biases during momentary monitoring. We performed a single 4-test cognitive assessment on 240 participants (schizophrenia n = 126; bipolar disorder n = 114) and asked them to make a judgment about their performance immediately after completion of each task. We related performance and these judgments to results of Ecological Momentary Assessments (EMA) of the momentary occurrence of psychotic symptoms (Voices, paranoid ideas, other delusions) collected over up to 90 surveys over a 30 days prior to the single cognitive assessment. We examined test performance and the accuracy of self-assessment at that assessment, looking at diagnostic differences in performance and mis-estimation of performance. Participants with bipolar disorder had better cognitive performance, but there were no differences in mis-estimation. Analyses of the correlation between cognitive performance and self-assessment were all significant and better cognitive performance predicted reduced errors in self-assessment. Examination of the 30-day course of psychotic symptoms and IA could only be performed in participants with schizophrenia, revealing correlations between more common occurrences of all three psychotic symptoms and increased absolute values for IA errors. These data are consistent with theories of cognitive response biases and the formation of delusions.

Association of PPP1R1B polymorphisms with working memory in healthy Han Chinese adults

Aims

The dopamine- and cAMP-regulated phosphoprotein (DARPP-32), which is encoded by the PPP1R1B gene, plays a converging regulatory role in the central nervous system by mediating the actions of dopamine, serotonin, and glutamate. Previous studies have demonstrated that variations in genes related to the dopamine system influence working memory. The present study thus investigated whether polymorphisms in PPP1R1B gene were associated with working memory.

Materials and methods

A sample of 124 healthy Han Chinese were genotyped for three single nucleotide polymorphisms of PPP1R1B gene, namely rs12601930C/T, rs879606A/G, and rs3764352A/G, using polymerase chain reaction and restriction fragment length polymorphism analysis. Working memory performance was assessed using the Wisconsin Card Sorting Test (WCST).

Results

Significant differences were observed in the Total Correct (TC), Total Errors (TE), and Conceptual Level Responses (CLR) scores of the WCST among the three rs12601930C/T genotypes (p = 0.044, 0.044, and 0.047, respectively); in TC, TE, Non-Perseverative Errors (NPE), and CLR scores between participants with the CC and (CT + TT) rs12601930C/T polymorphism genotypes (p = 0.032, 0.032, 0.019, and 0.029, respectively); in TC, TE, Perseverative Errors (PE), NPE, and CLR scores between participants with the (CT + CC) and TT rs12601930C/T polymorphism genotypes (p = 0.001, 0.001, 0.011, 0.004, and 0.001, respectively); and in NPE and CLR scores between participants with the GG and (AG + AA) genotypes of the rs3764352A/G polymorphism (p = 0.011 and 0.010). Furthermore, for males only, there were significant differences in TC, TE, PE, NPE, and CLR scores among the rs12601930C/T genotypes (p = 0.020, 0.020, 0.037, 0.029, and 0.014, respectively) and NPE and CLR scores among the rs3764352 genotypes (p = 0.045 and 0.042).

Conclusion

PPP1R1B gene polymorphisms rs12601930C/T and rs3764352A/G might be associated with working memory assessed by the WCST in healthy Chinese adults, especially among males.

The effect of continuation and maintenance electroconvulsive therapy on cognition: A systematic review of the literature and meta-analysis

BACKGROUND

Electroconvulsive therapy (ECT) is an effective treatment for depression, mania, and refractory schizophrenia. Its tolerability profile is established for acute treatment, but less is known regarding the effects of longer treatment courses, particularly on cognitive performance.

OBJECTIVES

To assess the effect of the long-term ECT on cognition.

METHODS

We searched CINAHL, EMBASE, PsychInfo and Pubmed, for the period between January 1, 2010, and June 30, 2022, in English or French, for randomized controlled trials, prospective or retrospective studies of ECT continued for at least 2 months for the treatment of mood or schizophrenic disorders and which measured cognition before and at the end of treatment. Non-peer reviewed records were excluded. The Cochrane Risk of Bias tool was used to assess study quality. Classical meta-analyses, with heterogeneity statistics (tau², I²) were complemented with three level-meta-analysis and Bayesian Meta-analyses.

RESULTS

Nine studies were included in the narrative and quantitative review. Controlled comparison at 6 months (k = 6, n = 334) and at 12 months (k = 3, n = 56), within-subject comparisons at 6 (k = 6, n = 218) and 12 months (k = 4, n = 147) showed no detrimental effect of maintenance or continuation ECT on cognition, with little to no heterogeneity. Bayesian analysis further confirmed that data better supported the no effects hypothesis.

LIMITATIONS

Insufficient data resulted in imprecision in estimates.

CONCLUSIONS

Continuation and maintenance ECT do not appear detrimental for cognitive performance. However, the low number of studies limit the interpretation of the results.

Current Evidence and Theories in Understanding the Relationship between Cognition and Depression in Childhood and Adolescence: A Narrative Review

The present narrative review has covered the current evidence regarding the role of cognitive impairments during the early phase of major depressive disorder (MDD), attempting to describe the cognitive features in childhood, adolescence and in at-risk individuals. These issues were analyzed considering the trait, scar and state hypotheses of MDD by examining the cold and hot dimensions, the latter explained in relation to the current psychological theoretical models of MDD. This search was performed on several electronic databases up to August 2022. Although the present review is the first to have analyzed both cold and hot cognitive impairments considering the trait, scar and state hypotheses, we found that current evidence did not allow to exclusively confirm the validity of one specific hypothesis since several equivocal and discordant results have been proposed in childhood and adolescence samples. Further studies are needed to better characterize possible cognitive dysfunctions assessing more systematically the impairments of cold, hot and social cognition domains and their possible interaction in a developmental perspective. An increased knowledge on these topics will improve the definition of clinical endophenotypes of enhanced risk to progression to MDD and, to hypothesize preventive and therapeutic strategies to reduce negative influences on psychosocial functioning and well-being.

A critical overview of tools for assessing cognition in bipolar disorder

Cognitive deficits are prevalent in bipolar disorder even during the euthymic phase, having a negative impact on global functioning and quality of life. As such, more and more mental health professionals agree that neuropsychological assessment should be considered an essential component of the clinical management of bipolar patients. However, no gold standard tool has been established so far. According to bipolar disorder experts targeting cognition, appropriate cognitive tools should be brief, easy to administer, cost-effective and validated in the target population. In this commentary, we critically appraised the strengths and limitations of the tools most commonly used to assess cognitive functioning in bipolar patients, both for screening and diagnostic purposes.

A distinct neurocognitive profile: unipolar mania

OBJECTIVE

Despite a growing number of studies reporting patients with a history of mania without depression have several socio-demographic and clinical differences than bipolar disorder patients, unipolar mania is recognized as bipolar I disorder in the most commonly used classification systems. Studies showing that unipolar mania is a separate clinical entity are insufficient in number, and to the best of our knowledge, there has been no study investigating the neuropsychological differences in this area. The aim of this study is to evaluate the neurocognitive differences between unipolar mania, bipolar I disorder and healthy controls, and to reveal the underlying neurocognitive differences.

MATERIALS AND METHODS

Cambridge Neuropsychological Test Automated Battery was applied to 18 unipolar mania, 19 bipolar I disorder patients and 21 healthy controls matched for age, sex and education levels.

RESULTS

Unipolar mania group had worse performance regarding visual memory and executive functions, and had specific social cognition deficits compared to both bipolar I disorder and healthy control groups.

CONCLUSION

The results of our study indicate that unipolar mania might have unique neurocognitive differences compared to bipolar I disorder, which might support the hypothesis that unipolar mania is a distinct neurocognitive disorder within bipolar spectrum disorders.

Clinical Value of Inflammatory and Neurotrophic Biomarkers in Bipolar Disorder: A Systematic Review and Meta-Analysis

Bipolar disorder (BD) is a multifactorial chronic psychiatric disease highly defined by genetic, clinical, environmental and social risk factors. The present systematic review and meta-analysis aimed to examine the relationship between inflammatory and neurotrophic factors and clinical, social and environmental factors involved in the development and the characterization of BD. Web of Science, PubMed, PsycINFO, Scopus and Science Direct were searched by two independent reviewers. The systematic review was registered in PROSPERO (CRD42020180626). A total of 51 studies with 4547 patients with a diagnosis of BD were selected for systematic review. Among them, 18 articles were included for meta-analysis. The study found some evidence of associations between BDNF and/or inflammatory factors and different stressors and functional and cognitive impairment, but limitations prevented firm conclusions. The main finding of the meta-analysis was a negative correlation between circulating levels of BDNF and depression severity score (standardized mean difference = −0.22, Confidence Interval 95% = −0.38, −0.05, p = 0.01). Evidence indicates that BDNF has a role in the depressive component of BD. However, the poor consistency found for other inflammatory mediators clearly indicates that highly controlled studies are needed to identity precise biomarkers of this disorder.

The Role of Kynurenines in Cognitive Dysfunction in Bipolar Disorder

INTRODUCTION

Chronic low-grade inflammation is suggested to play a pathophysiological role in bipolar disorder (BD) and its related cognitive dysfunctions. Although kynurenine (KYN) pathway metabolites are key inflammatory mediators, studies investigating the association between KYN metabolism and cognition in BD are scarce. We aimed to explore the relationship between KYN metabolism and cognitive functioning across different mood states in BD.

METHODS

Sixty-seven patients with BD (35 depressed and 32 [hypo] manic) and 29 healthy controls were included. Cognitive functioning was assessed at 3 time intervals (baseline, 4, and 8 months) assessing processing speed, sustained attention, verbal memory, working memory, and response inhibition. Plasma samples for quantification of 3-hydroxykynurenine, quinolinic acid, and kynurenic acid (KYNA) were concurrently provided. Linear mixed models were used for statistical analysis.

RESULTS

The manic group showed deficits in all assessed cognitive domains with the exception of verbal memory at all test moments. The bipolar depression group showed deficits in the processing speed at all test moments. Throughout the whole follow-up period, KYNA was significantly lower in both patient groups than in controls. Only in the bipolar depression group, low KYNA was associated with worse global cognitive functioning (B = 0.114, p = 0.02) and slower processing speed in particular (B = 0.139, p = 0.03).

CONCLUSION

Only in the bipolar depression group, lower KYNA was associated with worse cognitive functioning. Future large-scale longitudinal studies are warranted to confirm the role of KYN metabolites in cognitive impairment in patients with BD and the possible therapeutic implications of this relationship.

Looking for factors affecting functioning in euthymic patients with bipolar I disorder: the importance of cognitive complaints and BDNF's Val66Met polymorphism

INTRODUCTION

Functioning in Bipolar Disorder (BD) is affected in a substantial proportion of patients. The impact of demographic, clinical, cognitive, and genetic factors on functioning has been shown individually; however, as a complex phenomenon, a global approach to identify the most relevant as well as possible interactions is needed.

METHODS

102 patients with type I BD in euthymia were invited for evaluation of demographic, clinical, and cognitive characteristics as well as genotype for Val66Met polymorphism of BDNF gene to determine those associated with poor functioning according to the FAST scale cut-off score. Clinical evaluation included assessment of residual affective symptoms and anxiety. Cognitive evaluation included the COBRA scale, verbal memory, and executive functions testing.

RESULTS

Residual depressive symptoms, anxiety, cognitive complaints and being a Met carrier were more frequent in the poor functioning group and were entered in a logistic regression model. Being a Met carrier (OR=4.46, CI=1.19-16.67) and cognitive complaints (OR=1.29, CI= 1.13-1.46) were the most important predictors of poor functioning in type I BD.

LIMITATIONS

Cross-sectional study, with select population limiting generalizability of findings.

CONCLUSIONS

A better understanding of underlying factors affecting cognition, including the possible involvement of BDNF Val66Met polymorphism, its systematic evaluation and a continued search for targeted treatment, along with recognition and attention of residual affective and anxious symptoms might improve psychosocial outcomes such as functioning in this population.

Nutrition, Overweight, and Cognition in Euthymic Bipolar Individuals Compared to Healthy Controls

Bipolar disorder (BD) is associated with impairments in cognitive functions, in which metabolic factors, e.g., overweight, seem to play a significant role. The aim of this study was to investigate the association between nutritional factors and cognitive performance in euthymic individuals with BD. A study cohort of 56 euthymic individuals with BD was compared to a sample of 53 mentally healthy controls. To assess cognitive function, the following tests were applied: California Verbal Learning Test, Trail Making Test A/B, d2 Test of Attention-Revised, and Stroop’s Color-Word Interference Test. Furthermore, a 4-day food record was processed to evaluate dietary intake of macronutrients, specific micronutrients, and food diversity. Body mass index and waist to height ratio were calculated to assess overweight and central obesity. Results showed no nutritional differences between individuals with BD and controls. Individuals with BD performed worse in the d2 test than controls. Hierarchical regression analyses yielded no association between cognitive and nutritional parameters. However, waist to height ratio was negatively correlated with almost all cognitive tests. Central obesity seems to affect cognitive functioning in BD, while the lack of finding differences in nutritional data might be due to problems when collecting data and the small sample size. Consequently, further studies focusing on objectively measuring food intake with adequate sample size are needed.

BIPOLAR DISORDER, MOOD STABILIZERS AND COGNITIVE FLEXIBILITY: TRANSLATIONALLY DISSECTING ILLNESS FROM DRUG EFFECTS

Bipolar disorder (BD) effects on cognition are confounded by the putative cognitive impact of its major pharmacological treatments, given the neurotrophic potential of mood stabilizers, particularly lithium. We examined the area of cognitive flexibility (CF), aiming to disentangle BD from medication effects, using translational methodology. CF was assessed by CANTAB-IED (intra- extra-dimensional shift; Study 1, euthymic BD participants) and its animal analogue (Study 2, rats). Both studies included groups (1) control, (2) lithium, chronic, current treatment (LI-CHRON-C, A: >2 years, N=32; B: 2 months, N=11); (3) valproate, chronic, current treatment (VPA-CHRON-C, A: >2 years, N=30; B: 2 months, N=12). Study 2 included 2 additional groups; Group 4: LI-CHRON-PAST (2 months, stopped 1 month pretest, N=13); Group 5: LI-ACUTE (LI on test days only, N=13). In Study 1, neither total nor stage (discrimination: D; reversal R; intra- extra-dimensional shifts: IED) IED errors differed between groups [(Kruskal-Wallis: H(2, N= 94) 0.95 > p > 0.65]. Similarly in Study 2, errors did not differentiate the 5 pharmacological groups. Differences emerged only between LI-ACUTE and Controls in response latencies (D, R, IED ANOVAS: 0.002 > p > 0.0003; contrasts D, R: p = 0.002, 0.0001). In conclusion, LI and VPA BD patients were indistinguishable from Controls in IED errors, as were animals treated with LI-CHRON, current or past, or VPA-CHRON-C vs Controls. LI-ACUTE treatment produced significant latency deficits vs. Controls. Within the limitations of translational comparisons, our results suggest that the normal CF noted in euthymic BDs is not attributable to mood stabilizer effects.

Relationship between cognitive flexibility and subsequent course of mood symptoms and suicidal ideation in young adults with childhood-onset bipolar disorder

Neurocognitive deficits, such as cognitive flexibility impairments, are common in bipolar disorder (BD) and predict poor academic, occupational, and functional outcomes. However, the association between neurocognition and illness trajectory is not well understood, especially across developmental transitions. This study examined cognitive flexibility and subsequent mood symptom and suicidal ideation (SI) course in young adults with childhood-onset BD-I (with distinct mood episodes) vs. BD-not otherwise specified (BD-NOS) vs. typically-developing controls (TDCs). Sample included 93 young adults (ages 18-30) with prospectively verified childhood-onset DSM-IV BD-I (n = 34) or BD-NOS (n = 15) and TDCs (n = 44). Participants completed cross-sectional neuropsychological tasks and clinical measures. Then participants with BD completed longitudinal assessments of mood symptoms and SI at 6-month intervals (M = 39.18 ± 16.57 months of follow-up data). Analyses included ANOVAs, independent-samples t tests, chi-square analyses, and multiple linear regressions. Participants with BD-I had significant deficits in cognitive flexibility and executive functioning vs. BD-NOS and TDCs, and impaired spatial working memory vs. TDCs only. Two significant BD subtype-by-cognitive flexibility interactions revealed that cognitive flexibility deficits were associated with subsequent percentage of time depressed and with SI in BD-I but not BD-NOS, regardless of other neurocognitive factors (full-scale IQ, executive functioning, spatial working memory) and clinical factors (current and prior mood and SI symptoms, age of BD onset, global functioning, psychiatric medications, comorbidity). Thus, cognitive flexibility may be an important etiological brain/behavior mechanism, prognostic indicator, and intervention target for childhood-onset BD-I, as this deficit appears to endure into young adulthood and is associated with worse prognosis for subsequent depression and SI.

A scoping review of near infrared spectroscopy studies employing a verbal fluency task in bipolar disorder

BACKGROUND

Deficits in cognitive functioning, including attention, memory, and executive functions, along with impairments in language production, are present in patients with bipolar disorder (BD) patients during mood phases, but also during euthymia.Verbal fluency tasks (VFTs), being able to evaluate integrity of a wide range of cognitive domains and represent, can be used to screen for these disturbances. Neuroimaging studies, including Near-InfraRed Spectroscopy (NIRS), have repeatedly showed widespread alterations in the prefrontal and temporal cortex during the performance of VFTs in BD patients. This review aims to summarize the results of NIRS studies that evaluated hemodynamic responses associated with the VFTs in prefrontal and temporal regions in BD patients.

METHODS

We performed a scoping review of studies evaluating VFT-induced activation in prefrontal and temporal regions in BD patients, and the relationship between NIRS data and various clinical variables.

RESULTS

15 studies met the inclusion criteria. In BD patients, compared to healthy controls, NIRS studies showed hypoactivation of the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex and anterior temporal regions. Moreover, clinical variables, such as depressive and social adaptation scores, were negatively correlated with hemodynamic responses in prefrontal and temporal regions, while a positive correlation were reported for measures of manic symptoms and impulsivity.

LIMITATIONS

The heterogeneity of the studies in terms of methodology, study design and clinical characteristics of the samples limited the comparability of the findings.

CONCLUSIONS

Given its non-invasiveness, good time-resolution and no need of posturalconstraint, NIRS technique could represent a useful tool for the evaluation of prefrontal and temporal haemodynamic correlates of cognitive performances in BD patients.