Empirical evidence for discrete neurocognitive subgroups in bipolar disorder: clinical implications

Cognition in older age bipolar disorder: An analysis of archival data across the globe

BACKGROUND

Cognitive deficits in bipolar disorder (BD) impact functioning and are main contributors to disability in older age BD (OABD). We investigated the difference between OABD and age-comparable healthy comparison (HC) participants and, among those with BD, the associations between age, global cognitive performance, symptom severity and functioning using a large, cross-sectional, archival dataset harmonized from 7 international OABD studies.

METHODS

Data from the Global Aging and Geriatric Experiments in Bipolar Disorder (GAGE-BD) database, spanning various standardized measures of cognition, functioning and clinical characteristics, were analyzed. The sample included 662 euthymic to mildly symptomatic participants aged minimum 50years (509 BD, 153 HC), able to undergo extensive cognitive testing. Linear mixed models estimated associations between diagnosis and global cognitive performance (g-score, harmonized across studies), and within OABD between g-score and severity of mania and depressive symptoms, duration of illness and lithium use and of global functioning.

RESULTS

After adjustment for study cohort, age, gender and employment status, there was no significant difference in g-score between OABD and HC, while a significant interaction emerged between employment status and diagnostic group (better global cognition associated with working) in BD. Within OABD, better g-scores were associated with fewer manic symptoms, higher education and better functioning.

LIMITATIONS

Cross-sectional design and loss of granularity due to harmonization.

CONCLUSION

More research is needed to understand heterogenous longitudinal patterns of cognitive change in BD and understand whether particular cognitive domains might be affected in OABD in order to develop new therapeutic efforts for cognitive dysfunction OABD.

A systematic review of the biomarkers associated with cognition and mood state in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a severe psychiatric disorder characterized by changes in mood that alternate between (hypo) mania or depression and mixed states, often associated with functional impairment and cognitive dysfunction. But little is known about biomarkers that contribute to the development and sustainment of cognitive deficits. The aim of this study was to review the association between neurocognition and biomarkers across different mood states.

METHOD

Search databases were Web of Science, Scopus and PubMed. A systematic review was carried out following the PRISMA guidelines. Risk of bias was assessed with the Newcastle-Ottawa Scale. Studies were selected that focused on the correlation between neuroimaging, physiological, genetic or peripheral biomarkers and cognition in at least two phases of BD: depression, (hypo)mania, euthymia or mixed. PROSPERO Registration No.: CRD42023410782.

RESULTS

A total of 1824 references were screened, identifying 1023 published articles, of which 336 were considered eligible. Only 16 provided information on the association between biomarkers and cognition in the different affective states of BD. The included studies found: (i) Differences in levels of total cholesterol and C reactive protein depending on mood state; (ii) There is no association found between cognition and peripheral biomarkers; (iii) Neuroimaging biomarkers highlighted hypoactivation of frontal areas as distinctive of acute state of BD; (iv) A deactivation failure has been reported in the ventromedial prefrontal cortex (vmPFC), potentially serving as a trait marker of BD.

CONCLUSION

Only a few recent articles have investigated biomarker-cognition associations in BD mood phases. Our findings underline that there appear to be central regions involved in BD that are observed in all mood states. However, there appear to be underlying mechanisms of cognitive dysfunction that may vary across different mood states in BD. This review highlights the importance of standardizing the data and the assessment of cognition, as well as the need for biomarkers to help prevent acute symptomatic phases of the disease, and the associated functional and cognitive impairment.

Stable neural underpinnings of emotional cognition subgroups in patients newly diagnosed with bipolar disorder: A prospective fMRI study

OBJECTIVES

This study aimed to investigate the neural underpinnings of emotional cognition subgroups in recently diagnosed patients with bipolar disorder (BD) and change over time over a 15-month follow-up period.

METHODS

Patients and healthy controls (HC) underwent emotional and nonemotional cognitive assessments and functional magnetic resonance imaging (fMRI) at the baseline (BD n = 87; HC n = 65) and at 15-month follow-up (BD n = 44; HC n = 38). Neural activity during emotion reactivity and regulation in response to aversive pictures was assessed during fMRI. Patients were clustered into subgroups based on their emotional cognition and, with HC, were compared longitudinally on cognition and neural activity during emotion reactivity and regulation.

RESULTS

Patients were optimally clustered into two subgroups: Subgroup 1 (n = 40, 46%) was characterized by heightened emotional reactivity in negative social scenarios, which persisted over time, but were otherwise cognitively intact. This subgroup exhibited stable left amygdala hyper-activity over time during emotion reactivity compared to subgroup 2. Subgroup 2 (n = 47, 54%) was characterized by global emotional cognitive impairments, including stable difficulties with emotion regulation over time. During emotion regulation across both time points, this group exhibited hypo-activity in the left dorsolateral prefrontal cortex. Additionally, patients in subgroup 2 had poorer nonemotional cognition, had more psychiatric hospital admissions and history of psychotic episodes than those in subgroup 1.

CONCLUSIONS

Broad impairments in emotional cognition in approximately half of BD patients and associated nonemotional cognitive deficits may originate from insufficient recruitment of prefrontal resources, contributing to poorer clinical outcomes.

Efficacy and safety of established and off-label ADHD drug therapies for cognitive impairment or attention-deficit hyperactivity disorder symptoms in bipolar disorder: A systematic review by the ISBD Targeting Cognition Task Force

BACKGROUND

Abnormalities in dopamine and norepinephrine signaling are implicated in cognitive impairments in bipolar disorder (BD) and attention-deficit hyperactivity disorder (ADHD). This systematic review by the ISBD Targeting Cognition Task Force therefore aimed to investigate the possible benefits on cognition and/or ADHD symptoms and safety of established and off-label ADHD therapies in BD.

METHODS

We included studies of ADHD medications in BD patients, which involved cognitive and/or safety measures. We followed the procedures of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 statement. Searches were conducted on PubMed, Embase and PsycINFO from inception until June 2023. Two authors reviewed the studies independently using the Revised Cochrane Collaboration's Risk of Bias tool for Randomized trials.

RESULTS

Seventeen studies were identified (N = 2136), investigating armodafinil (k = 4, N = 1581), methylphenidate (k = 4, N = 84), bupropion (k = 4, n = 249), clonidine (k = 1, n = 70), lisdexamphetamine (k = 1, n = 25), mixed amphetamine salts (k = 1, n = 30), or modafinil (k = 2, n = 97). Three studies investigated cognition, four ADHD symptoms, and 10 the safety. Three studies found treatment-related ADHD symptom reduction: two involved methylphenidate and one amphetamine salts. One study found a trend towards pro-cognitive effects of modafinil on some cognitive domains. No increased risk of (hypo)mania was observed. Five studies had low risk of bias, eleven a moderate risk, and one a serious risk of bias.

CONCLUSIONS

Methylphenidate or mixed amphetamine salts may improve ADHD symptoms in BD. However, there is limited evidence regarding the effectiveness on cognition. The medications produced no increased mania risk when used alongside mood stabilizers. Further robust studies are needed to assess cognition in BD patients receiving psychostimulant treatment alongside mood stabilizers.

Implementing cognitive screenings for outpatients with bipolar disorder following optimised treatment in a specialised mood disorder clinic

Bipolar disorder (BD) is often accompanied by persistent cognitive impairment. However, screening for cognitive impairment in the clinic is challenged by a lack of consensus on screening procedures. This study assesses cognitive impairment prevalence and screening feasibility in alignment with the International Society for Bipolar Disorder Targeting Cognition Task Force recommendations. Between January 2022 and May 2023, 136 newly diagnosed BD outpatients were assessed with the Screen for Cognitive Impairment in Psychiatry after 15-20 months of specialised care at the Copenhagen Affective Disorder Clinic. Cognitive impairment patterns and associations with cognitive complaints, perceived stress, and functioning were examined. Most screened patients (73 %) achieved full or partial remission, with 51 % being cognitively normal, 38 % showing global impairments, and 11 % displaying selective impairments. Among remitted patients, 56 % were cognitively normal, while 31 % and 13 % exhibited global or selective impairments, respectively. Both objectively impaired patient groups reported more subjective cognitive difficulties than those who were cognitively normal. The globally impaired group also demonstrated poorer functioning, more depressive symptoms and lower quality of life than cognitively normal patients. Across all patients, lower cognitive performance correlated with more cognitive complaints, lower functioning, lower quality of life, and more depressive symptoms. Cognitive screenings were relatively easily implementable, involving only a 1.5 h session including mood ratings, feedback and cognitive strategy discussion. The study highlights the clinical relevance and feasibility of cognitive screenings in BD patients, emphasizing the need for tailored interventions given frequent cognitive impairment in clinically stable individuals.

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

OBJECTIVES

Cognitive impairment is a core feature of bipolar disorder (BD) and major depressive disorder (MDD). Deficits in processing speed (PS) and sustained attention (SA) may be particularly impaired and may underpin a broader profile of deficits, however current knowledge of the nature of these impairments is limited by heterogeneous results in the literature. Few reviews to date have attempted to disentangle sources of heterogeneity to assess the presence and magnitude of impairments in PS and SA in BD and MDD.

METHODS

One hundred and three studies were reviewed to examine performance in tests of PS and SA in BD (n = 3452) and MDD (n = 5461) compared to healthy controls (n = 8016). Neuropsychological methodology used in the literature was summarised. Data were meta-analysed to assess impairments in PS and SA for each neuropsychological test separately. Subgroup analysis was performed across mood states to investigate sources of heterogeneity.

RESULTS

Impairments were found across most neuropsychological tests, with small to large effect sizes for BD (range: d = 0.19-0.96) and MDD (range: d = 0.29-0.86). Impairments were present in symptomatic states and euthymia in most cases. Some outcome measures were not impaired in euthymia. Heterogeneity was observed for most neuropsychological tests and remained after separating by mood state. There inadequate data to meta-analyse some outcome measures, particularly for symptomatic groups.

CONCLUSION

Impairments in PS and SA in BD and MDD can be observed across most neuropsychological tests. Future research should further investigate the nature of these impairments across mood states, controlling for clinical confounds.

Psychosocial Impairment in Older Patients With Bipolar I Disorder

BACKGROUND

The goal of this study was to assess psychosocial functioning in older patients with bipolar I disorder compared with healthy subjects and to identify the psychopathological factors associated with poor functioning in patients.

METHODS

We recruited 68 euthymic patients with bipolar I disorder from the outpatient unit and 89 healthy controls who were older than 50 years of age. In addition to clinical variables, we used other standardized measures, including the Young Mania Rating Scale, the Hamilton Depression Rating Scale, the Hamilton Anxiety Rating Scale, the Functional Assessment Short Test, and the Montreal Cognitive Assessment.

RESULTS

Older patients with bipolar I disorder had poorer psychosocial functioning in general and in the domains of occupation, autonomy, and cognition than the healthy controls on the basis of previously defined Functional Assessment Short Test cutoff scores. We found that 35.3% (95% CI: 23%-47%) of the patients did not have clinically significant functional impairment, 38.2% (95% CI: 26%-50%) had mild impairment, and 26.5% (95% CI: 16%-37%) had moderate impairment. Depressive symptoms and impaired cognition were associated with poor overall functioning.

CONCLUSIONS

The level of psychosocial functioning was heterogeneous among the patients. Subsyndromal depressive symptoms, even at low levels, and impaired cognition predicted poor functioning in euthymic middle-aged and older patients with bipolar I disorder.

Transdiagnostic subgroups of cognitive impairment in early affective and psychotic illness

Cognitively impaired and spared patient subgroups were identified in psychosis and depression, and in clinical high-risk for psychosis (CHR). Studies suggest differences in underlying brain structural and functional characteristics. It is unclear whether cognitive subgroups are transdiagnostic phenomena in early stages of psychotic and affective disorder which can be validated on the neural level. Patients with recent-onset psychosis (ROP; N = 140; female = 54), recent-onset depression (ROD; N = 130; female = 73), CHR (N = 128; female = 61) and healthy controls (HC; N = 270; female = 165) were recruited through the multi-site study PRONIA. The transdiagnostic sample and individual study groups were clustered into subgroups based on their performance in eight cognitive domains and characterized by gray matter volume (sMRI) and resting-state functional connectivity (rsFC) using support vector machine (SVM) classification. We identified an impaired subgroup (NROP = 79, NROD = 30, NCHR = 37) showing cognitive impairment in executive functioning, working memory, processing speed and verbal learning (all p < 0.001). A spared subgroup (NROP = 61, NROD = 100, NCHR = 91) performed comparable to HC. Single-disease subgroups indicated that cognitive impairment is stronger pronounced in impaired ROP compared to impaired ROD and CHR. Subgroups in ROP and ROD showed specific symptom- and functioning-patterns. rsFC showed superior accuracy compared to sMRI in differentiating transdiagnostic subgroups from HC (BACimpaired = 58.5%; BACspared = 61.7%, both: p < 0.01). Cognitive findings were validated in the PRONIA replication sample (N = 409). Individual cognitive subgroups in ROP, ROD and CHR are more informative than transdiagnostic subgroups as they map onto individual cognitive impairment and specific functioning- and symptom-patterns which show limited overlap in sMRI and rsFC. CLINICAL TRIAL REGISTRY NAME: German Clinical Trials Register (DRKS). Clinical trial registry URL: https://www.drks.de/drks_web/ . Clinical trial registry number: DRKS00005042.

To what extent does white matter map to cognition in bipolar disorder? A systematic review of the evidence

Cognitive impairment is a prominent feature of bipolar disorder (BD), however the neural substrates underpinning it remain unclear. Several studies have explored white matter as a correlate of cognitive functioning in BD cohorts, but mixed results and varied methodologies from one to another make inferences about this relationship difficult to draw. Here we sought to systematically synthesise the findings of these studies to more clearly explicate the nature and extent of relationships between white matter and cognition in BD and determine best practice methodologies and areas for future research in this area. Using PRISMA guidelines, we identified and systematically reviewed 37 relevant studies, all of which were cross-sectional by design. There was substantial methodological heterogeneity and variability in the clinical presentations of BD cohorts encapsulated within the studies we reviewed, which complicated our synthesis of the findings. Nonetheless, there was some evidence that cognition is related to both white matter macrostructure and microstructure in people with BD. In particular, multiple microstructural studies consistently reported that higher fractional anisotropy, both globally and in the corpus callosum, associated with better complex attention skills and executive functioning. However, several reports did not identify any associations at all, and in general, associations between WM and cognition tended to only be evident in studies utilising larger samples and post-hoc selection of WM regions of interest. Further research with increased statistical power and standardised methods are required moving forward.

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

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

Associations between aberrant working memory-related neural activity and cognitive impairments in somatically healthy, remitted patients with mood disorders

BACKGROUND

Persistent cognitive deficits are prevalent in patients with bipolar disorder (BD) and unipolar disorder (UD), but treatments effectively targeting cognition in these mood disorders are lacking. This is partly due to poor insight into the neuronal underpinnings of cognitive deficits.

METHODS

The aim of this functional magnetic resonance imaging (fMRI) study was to investigate the neuronal underpinnings of working memory (WM)-related deficits in somatically healthy, remitted patients with BD or UD (n = 66) with cognitive and functional impairments compared to 38 healthy controls (HC). The participants underwent neuropsychological testing and fMRI, while performing a visuospatial and a verbal N-back WM paradigm.

RESULTS

Relative to HC, patients exhibited hypo-activity across dorsolateral prefrontal cortex as well as frontal and parietal nodes of the cognitive control network (CCN) and hyper-activity in left orbitofrontal cortex within the default mode network (DMN) during both visuospatial and verbal WM performance. Verbal WM-related response in the left posterior superior frontal gyrus (SFG) within CCN was lower in patients and correlated positively with out-of-scanner executive function performance across all participants.

CONCLUSIONS

Our findings suggest that cognitive impairments across BD and UD are associated with insufficient recruitment of task-relevant regions in the CCN and down-regulation of task-irrelevant orbitofrontal activity within the DMN during task performance. Specifically, a lower recruitment of the left posterior SFG within CCN during verbal WM was associated with lower cognitive performance.

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.

Association between childhood trauma, cognition, and psychosocial function in a large sample of partially or fully remitted patients with bipolar disorder and healthy participants

BACKGROUND

Childhood trauma (CT) are frequently reported by patients with bipolar disorder (BD), but it is unclear whether and how CT contribute to patients' cognitive and psychosocial impairments. We aimed to examine the impact of CT on cognition and psychosocial functioning in a large sample of 345 patients with BD and 183 healthy control participants (HC) using the Childhood Trauma Questionnaire, neurocognitive tests and ratings of mood symptoms and functioning.

RESULTS

Patients showed broad cognitive impairments across memory, attention and executive function and functional disability despite being in partial or full remission and had higher levels of CT than HC. Higher levels of CT correlated with impairments across almost all cognitive domains and lower psychosocial functioning across BD patients and HC. Of these, the associations between CT and poorer working memory and lower psychosocial functioning, respectively, prevailed after adjusting for clinical and demographical variables. Diagnosis of BD and estimated verbal intelligence did not moderate these associations. Analysis of CT sub-categories showed that working memory impairments were related particularly to childhood physical and emotional abuse, while psychosocial difficulties were related to physical and emotional neglect.

CONCLUSIONS

CT may have negative implications for working memory and psychosocial functioning across both BD and healthy populations. If the findings are replicated, this would suggest that early interventions that reduce the frequency of CT in vulnerable families may aid children's cognitive and psychosocial development.

The longitudinal change pattern of cognitive subtypes in medication-free patients with major depressive disorder: a cluster analysis

This study aimed to investigate whether there are different cognitive subtypes in patients with major depressive disorder (MDD) and the change pattern of cognitive clusters across the course of MDD. A battery of comprehensive cognitive tests was used to assess the executive function, processing speed, attention, and memory of 153 medication-free patients and 142 healthy controls (HCs). After 6 months of treatment with antidepressants, 87 patients completed cognitive tests again. K-means cluster analysis was performed to determine the cognitive subtypes. A preserved cognition cluster and an impaired cognition cluster were identified in the acute episode phase and the 6-month follow-up phase. 80.5% of the patients remained in their original subgroup after 6 months of treatment. The impaired cognition cluster during the 6-month follow-up period could be predicted by impaired cognition during the episode phase, disease state (remission or non-remission), current illness duration, and education level. This study supporting the heterogeneity of cognitive performance across the course of disease in patients with MDD using cluster analysis. It was found that cognitive impairment during depressive episodes was predictive of poorer cognitive performance even after treatment with antidepressants. Therefore, interventions targeting cognitive function from the early stages of MDD is essential.

Older age bipolar disorder

PURPOSE OF REVIEW

Older age bipolar disorder (OABD) refers to patients with bipolar disorder aged 50 years and over. There is a paucity of evidence-based guidelines specific to OABD, but in recent years, several studies have been published on OABD. The current review synthesizes previous literature (up to January 1, 2021) as well as most recent literature on OABD (since January 1, 2021).

RECENT FINDINGS

This review covers the following themes: diagnosis and specifiers, clinical course, psychosocial functioning, cognition, physical comorbidities, and pharmacotherapy. On the basis of the latest data, specific clinical recommendations are proposed for each theme.

SUMMARY

OABD forms a more complex subgroup of bipolar disorder, with an increased risk of cognitive deficits, physical comorbidities, impaired psychosocial functioning, and premature death. The distinctions between BD-I and BD-II and between EOBD and LOBD do not clinically represent relevant subtypes for OABD patients. Mental healthcare professionals should treat all OABD patients with an integrative care model that takes into account cognitive and physical comorbidities and that contains elements aimed at improvement of psychosocial functioning and quality of life. Older age itself should not be a reason to withhold lithium treatment. Future research should collect data on essential data domains using validated measurement scales.

Efficacy of cognitive remediation in bipolar disorder: systematic review and meta-analysis of randomized controlled trials

A significant percentage of people with bipolar disorder (BD) exhibit suboptimal functional adjustment, even when appropriately treated and after symptomatic recovery is achieved. Given that cognitive impairment is one of the strongest correlates of socio-occupational outcomes and quality of life in BD, cognitive remediation (CR) is currently acknowledged as a promising treatment that could help bridge the gap between symptomatic and full functional recovery. The aim of this review was to explore the efficacy of CR approaches in improving cognitive and functional outcomes in BD patients. PubMed, PsycINFO, and CENTRAL were searched from inception to November 2022. Randomized controlled trials exploring the effects of CR on cognition and/or functional adjustment in adult BD patients were eligible. Ten studies based on seven independent trials (n = 586) were included. Change-score effect sizes (Hedges' g) were obtained for efficacy outcome measures and combined by means of meta-analytic procedures. Small but significant overall effects were observed for working memory (g = 0.32, 95% CI 0.11-0.52), planning (g = 0.30, 95% CI 0.03-0.56), and verbal learning (g = 0.40, 95% CI 0.15-0.66). However, CR was not found to exert any significant effects on functional outcomes at treatment completion or at follow-up assessment. Although CR may modestly enhance the cognitive performance of BD patients, this effect does not translate into an improvement at the functional level. The current data do not support the inclusion of CR as a treatment recommendation in clinical practice guidelines for the management of BD.

Real-life outcomes in biotypes of psychotic disorders based on neurocognitive performance

Aiming at discerning potential biotypes within the psychotic syndrome, we have recently reported the possible existence of two clusters or biotypes across schizophrenia and bipolar disorder characterized by their cognitive performance using the Brief Assessment of Cognition in Schizophrenia (BACS) instrument and validated with independent biological and clinical indexes (Fernández-Linsenbarth et al. in Schizophr Res 229:102-111, 2021). In this previous work, the group with larger cognitive deficits (N = 93, including 69 chronic schizophrenia, 17 first episodes (FE) of schizophrenia and 7 bipolar disorder patients) showed smaller thalamus and hippocampus volume and hyper-synchronic electroencephalogram than the group with milder deficits (N = 105, including 58 chronic schizophrenia, 25 FE and 22 bipolar disorder patients). We predicted that if these biotypes indeed corresponded to different cognitive and biological substrates, their adaptation to real life would be different. To this end, in the present work we have followed up the patients' population included in that work at 1st and 3rd years after the date of inclusion in the 2021 study and we report on the statistical comparisons of each clinical and real-life outcomes between them. The first cluster, with larger cognitive deficits and more severe biological alterations, showed during that period a decreased capacity for job tenure (1st and 3rd years), more admissions to a psychiatric ward (1st year) and a higher likelihood for quitting psychiatric follow-up (3rd year). Patients in the second cluster, with moderate cognitive deficits, were less compliant with prescribed treatment at the 3rd year. The differences in real-life outcomes may give additional external validity to that yielded by biological measurements to the described biotypes based on neurocognition.

Functioning in older adults with bipolar disorder: A report on recommendations by the International Society of bipolar disorder (ISBD) older adults with bipolar disorder (OABD) task force

OBJECTIVES

Despite the importance of psychosocial functioning impairment in Bipolar Disorder (BD), its role among Older Adults with BD (OABD) is not well known. The development of guidelines for the assessment of psychosocial functioning helps to facilitate a better understanding of OABD and can lead to better tailored interventions to improve the clinical outcomes of this population.

METHODS

Through a series of virtual meetings, experts from eight countries in the International Society of Bipolar Disorder (ISBD) on OABD task force developed recommendations for the assessment of psychosocial functioning.

RESULTS

We present (1) a conceptualization of functioning in OABD and differences compared with younger patients; (2) factors related to functioning in OABD; (3) current measures of functioning in OABD and their strengths and limitations; and, (4) other potential sources of information to assess functioning.

CONCLUSIONS

The task force created recommendations for assessing functioning in OABD. Current instruments are limited, so measures specifically designed for OABD, such as the validated FAST-O scale, should be more widely adopted. Following the proposed recommendations for assessment can improve research and clinical care in OABD and potentially lead to better treatment outcomes.

The effects of psychoeducation and motivational interviewing on treatment adherence and functionality in individuals with bipolar disorder

BACKGROUND

Individuals diagnosed with bipolar disorder (BD) encounter difficulties in adherence to treatment and functionality. Although it is known that psychosocial interventions such as motivational interviewing (MI) and psychoeducation are important in regard to improving adherence to treatment and functionality, the content and nature of these interventions remain uncertain.

OBJECTIVE

This study was conducted to determine the effects of psychoeducation and MI on treatment adherence and functionality in individuals diagnosed with BD.

METHOD

In this study, a quasi-experimental pretest-posttest design with three groups was adopted. The study was completed with 119 participants in the MI (n = 32), psychoeducation (n = 31), and control (n = 56) groups.

RESULTS

There was a statistically significant improvement in the psychoeducation and MI groups in terms of treatment adherence compared to the control group (F = 32.672, p = 0.001, Partial η2 = 0.364). Similarly, the psychoeducation and MI groups had significantly higher functionality levels compared to the control group, and significant differences were observed between the groups regarding the degree of improvement in functionality dimensions including the feeling of stigmatization (F = 8.433, p = 0.001, Partial η2 = 0.129) and participation in social activities (F = 7.038, p = 0.001, Partial η2 = 0.110).

CONCLUSION

It can be stated that psychoeducation and MI have positive effects in terms of improvement in treatment adherence and functionality in individuals diagnosed with BD.

Brain age and cognitive functioning in first-episode bipolar disorder

BACKGROUND

There is significant heterogeneity in cognitive function in patients with bipolar I disorder (BDI); however, there is a dearth of research into biological mechanisms that might underlie cognitive heterogeneity, especially at disease onset. To this end, this study investigated the association between accelerated or delayed age-related brain structural changes and cognition in early-stage BDI.

METHODS

First episode patients with BDI (n = 80) underwent cognitive assessment to yield demographically normed composite global and domain-specific scores in verbal memory, non-verbal memory, working memory, processing speed, attention, and executive functioning. Structural magnetic resonance imaging data were also collected from all participants and subjected to machine learning to compute the brain-predicted age difference (brainPAD), calculated by subtracting chronological age from age predicted by neuroimaging data (positive brainPAD values indicating age-related acceleration in brain structural changes and negative values indicating delay). Patients were divided into tertiles based on brainPAD values, and cognitive performance compared amongst tertiles with ANCOVA.

RESULTS

Patients in the lowest (delayed) tertile of brainPAD values (brainPAD range -17.9 to -6.5 years) had significantly lower global cognitive scores (p = 0.025) compared to patients in the age-congruent tertile (brainPAD range -5.3 to 2.4 yrs), and significantly lower verbal memory scores (p = 0.001) compared to the age-congruent and accelerated (brainPAD range 2.8 to 16.1 yrs) tertiles.

CONCLUSION

These results provide evidence linking cognitive dysfunction in the early stage of BDI to apparent delay in typical age-related brain changes. Further studies are required to assess how age-related brain changes and cognitive functioning evolve over time.

Cerebrospinal fluid erythropoietin, oxidative stress, and cognitive functions in patients with bipolar disorder and healthy control participants: A longitudinal case-control study

Persistent cognitive impairments occur in a large proportion of patients with bipolar disorder (BD) but their underlying pathological cellular processes are unclear. The aims of this longitudinal study of BD and healthy control (HC) participants were to investigate (i) the association of brain erythropoietin (EPO) and oxidative stress with cognitive functions and (ii) the changes in brain EPO during and after affective episodes. Participants underwent neurocognitive testing, lumbar punctures for cerebrospinal fluid (CSF) sampling and provided urine spot tests at baseline (all), after an affective episode (patients) and after one year (all). EPO was assayed in the CSF and oxidative stress metabolites related to RNA and DNA damage (8-dihydroguanosine [8-oxo-Guo], 8-hydroxy-2-deoxyguanosine [8-oxo-dG]) were assayed in the CSF and spot urine. Data was available for analyses for 60 BD and 37 HC participants. In unadjusted primary analyses, verbal memory decreased with increasing concentrations of CSF EPO and oxidative stress. In unadjusted explorative analyses, poorer verbal memory and psychomotor speed were associated with higher levels of oxidative stress. However, no associations between cognitive functions and CSF levels of EPO or oxidative stress were observed after adjustment for multiple testing. CSF EPO concentrations were unchanged during and after affective episodes. While CSF EPO correlated negatively with CSF DNA damage marker 8-oxo-dG, this association rendered non-significant after adjusting for multiple testing. In conclusion, EPO and oxidative stress do not seem to be robustly related to cognitive status in BD. Further insight into the cellular processes involved in cognitive impairments in BD is necessary to pave the way for novel therapeutic strategies to improve patients' cognitive outcomes.

Neurocognitive subgroups among newly diagnosed patients with schizophrenia spectrum or bipolar disorders: A hierarchical cluster analysis

Studies across schizophrenia (SZ) and bipolar disorder (BD) indicate common transdiagnostic neurocognitive subgroups. However, existing studies of patients with long-term illness precludes insight into whether impairments result from effects of chronic illness, medication or other factors. This study aimed to investigate whether neurocognitive subgroups across SZ and BD can be demonstrated during early illness stages. Data from overlapping neuropsychological tests were pooled from cohort studies of antipsychotic-naïve patients with first-episode SZ spectrum disorders (n = 150), recently diagnosed BD (n = 189) or healthy controls (HC) (n = 280). Hierarchical cluster analysis was conducted to examine if transdiagnostic subgroups could be identified based on the neurocognitive profile. Patterns of cognitive impairments and patient characteristics across subgroups were examined. Patients could be clustered into two, three and four subgroups, of which the three-cluster solution (with 83% accuracy) was selected for posthoc analyses. This solution revealed a subgroup covering 39% of patients (predominantly BD) who were cognitively relatively intact, a subgroup of 33% of patients (more equal distributions of SZ and BD) displaying selective deficits, particularly in working memory and processing speed, and a subgroup of 28% (mainly SZ) with global impairments. The globally impaired group exhibited lower estimated premorbid intelligence than the other subgroups. Globally impaired BD patients also showed more functional disability than cognitively relatively intact patients. No differences were observed across subgroups in symptoms or medications. Neurocognitive results can be understood by clustering analysis with similar clustering solutions occurring across diagnoses. The subgroups were not explained by clinical symptoms or medication, suggesting neurodevelopmental origins.

Brain atrophy and cognitive decline in bipolar disorder: Influence of medication use, symptomatology and illness duration

Bipolar disorder (BPD) is a chronic condition characterized by recurrent episodes of mania and depression. To date, the association of biological and psychopathological processes in BPD has not been extensively studied on a cognitive and cortical basis at the same time. We investigated whether brain atrophy (in prefrontal, temporal and occipital cortices) was associated with cognitive, biological and clinical processes in patients with BPD and healthy controls (HCs). A total of 104 participants (56 with BPD) completed tasks that measured attention, memory, information processing speed, inhibitory control, visuospatial working memory and cognitive flexibility. In addition, structural brain scans were obtained using high-resolution MRI. Outcomes of the measurements were examined using robust multiple mediation analyses. BPD patients showed greater cortical atrophy across all regions of interest when compared to HCs, linked to cognitive decline. BPD patients had slower reaction times and markedly increased errors of commission on the tasks. The outcomes were significantly influenced by medication use, symptomatology and illness duration. The findings showcase the complexity of brain structures and networks as well as the physiological mechanisms underlying diverse BPD symptomatology and endophenotypes. These differences were pronounced in patients with BPD, motivating further investigations of pathophysiological mechanisms involved in brain atrophy and cognitive decline.

Association of childhood trauma with cognitive impairment and structural brain alterations in remitted patients with bipolar disorder

BACKGROUND

Cognitive impairment affects many patients with bipolar disorder (BD). No pro-cognitive treatment with robust efficacy exists partly due to limited insight into underlying neurobiological abnormalities.

METHODS

This magnetic resonance imaging (MRI) study investigates structural neuronal correlates of cognitive impairment in BD by comparing brain measures in a large sample of cognitively impaired versus cognitively intact patients with BD or cognitively impaired patients with major depressive disorder (MDD) and healthy controls (HC). Participants underwent neuropsychological assessments and MRI scans. The cognitively impaired and - intact BD and MDD patient groups were compared with each other and HC regarding prefrontal cortex measures, hippocampus shape/volume, and total cerebral white (WM) and grey matter (GM).

RESULTS

Cognitively impaired BD patients showed lower total cerebral WM volume than HC, which scaled with poorer global cognitive performance and more childhood trauma. Cognitively impaired BD patients also showed lower adjusted GM volume and thickness in the frontopolar cortex than HC but greater adjusted GM volume in the temporal cortex than cognitively normal BD patients. Cognitively impaired BD patients showed decreased cingulate volume than cognitively impaired MDD patients. Hippocampal measures were similar across all groups.

LIMITATIONS

The cross-sectional study design prevented insights into causal relationships.

CONCLUSIONS

Lower total cerebral WM and regional frontopolar and temporal GM abnormalities may constitute structural neuronal correlates of cognitive impairment in BD, of which the WM deficits scale with the degree of childhood trauma. The results deepen the understanding of cognitive impairment in BD and provide a neuronal target for pro-cognitive treatment development.

Clinical characteristics and prescriptions associated with a 2-year course of rapid cycling and euthymia in bipolar disorder: a multicenter treatment survey for bipolar disorder in psychiatric clinics

Objective

In patients with bipolar disorder (BD), rapid cycling (RC) presents a risk for a more severe illness, while euthymia (EUT) has a better prognosis. This study focused on the progression of RC and EUT, which are contrasting phenomenology, and aimed to clarify the influence of patient backgrounds and prescription patterns on these different progressions, using a large sample from the first and second iterations of a multicenter treatment survey for BD in psychiatric clinics (MUSUBI).

Methods

In the cross-sectional study (MUSUBI), a questionnaire based on a retrospective medical record survey of consecutive BD cases (N = 2,650) was distributed. The first survey was conducted in 2016, and the second one in 2017. The questionnaire collected information on patient backgrounds, current episodes, and clinical and prescribing characteristics.

Results

In the first survey, 10.6% of the participants had RC and 3.6% had RC for two consecutive years, which correlated with BP I (Bipolar disorder type I), suicidal ideation, duration of illness, and the use of lithium carbonate and antipsychotic medications. Possible risk factors for switching to RC were comorbid developmental disorders and the prescription of anxiolytics and sleep medication. Moreover, 16.4% of the participants presented EUT in the first survey, and 11.0% presented EUT for two consecutive years. Possible factors for achieving EUT included older age; employment; fewer psychotic symptoms and comorbid personality disorders; fewer antidepressants, antipsychotics, and anxiolytics, and more lithium prescriptions.

Conclusion

RC and EUT generally exhibit conflicting characteristics, and the conflicting social backgrounds and factors contributing to their outcomes were distinctive. Understanding these clinical characteristics may be helpful in clinical practice for management of patients with BD.

Neural basis of memory impairments and relation to functional disability in fully or partially remitted patients with affective disorders

Bipolar disorder (BD) and major depressive disorder (MDD) are associated with cognitive and functional impairment. Cognitive impairment is often associated with dorsal prefrontal cortex (dPFC) hypo-activity, but the neuronal correlates of functional disability is largely unknown. In this study, 91 patients with affective disorders in full or partial remission (BD, n = 67; MDD, n = 24) with objectively verified cognitive impairment and substantial functional disability underwent neuropsychological assessment and functional magnetic resonance imaging (fMRI) scan during which they completed a strategic picture-encoding task. For comparison, 36 matched healthy controls underwent an identical test protocol. Patients showed encoding-related hypo-activity in the dPFC compared to controls. In patients, lower right dlPFC activity was associated with poorer overall functioning and more antipsychotic drug use. In conclusion, memory impairments were underpinned by failure to recruit the dPFC during task performance which was associated with impaired functioning in fully or partially remitted patients with affective disorders. This aberrant neurocircuitry activity has implications for the design of future pro-cognitive interventions that aim to improve not only cognition but also real-world functioning.

The relationship between sleep disturbance and cognitive impairment in mood disorders: A systematic review

BACKGROUND

Cognitive impairment experienced by people with bipolar disorders (BD) or major depressive disorder (MDD) is associated with impaired psychosocial function and poorer quality of life. Sleep disturbance is another core symptom of mood disorders which may be associated with, and perhaps worsen, cognitive impairments. The aim of this systematic review was to critically assess the relationship between sleep disturbance and cognitive impairment in mood disorders.

METHODS

In this systematic review, relevant studies were identified using electronic database searches of PsychINFO, MEDLINE, Embase and Web of Science.

FINDINGS

Fourteen studies were included; eight investigated people with BD, five investigated people with MDD, and one included both people with MDD and people with BD. One study was an intervention for sleep disturbance and the remaining thirteen studies used either a longitudinal or cross-sectional observational design. Ten studies reported a significant association between subjectively measured sleep disturbance and cognitive impairment in people with MDD or BD after adjusting for demographic and clinical covariates, whereas no such association was found in healthy participants. Two studies reported a significant association between objectively measured (actigraphy or polysomnography) sleep abnormalities and cognitive impairment in mood disorders. One study of cognitive behavioural therapy for insomnia modified for BD (CBTI-BD) found an association between improvements in sleep and cognitive performance in BD.

INTERPRETATION

There is preliminary evidence to suggest a significant association between sleep disturbance and cognitive impairment in mood disorders. These findings highlight the need for further research of sleep disturbances and cognitive impairment in people with mood disorders.

Emotional cognition subgroups in unaffected first-degree relatives of patients with mood disorders

BACKGROUND

Patients with major depressive disorder (MDD) or bipolar disorder (BD) exhibit difficulties with emotional cognition even during remission. There is evidence for aberrant emotional cognition in unaffected relatives of patients with these mood disorders, but studies are conflicting. We aimed to investigate whether emotional cognition in unaffected first-degree relatives of patients with mood disorders is characterised by heterogeneity using a data-driven approach.

METHODS

Data from 94 unaffected relatives (33 of MDD patients; 61 of BD patients) and 203 healthy controls were pooled from two cohort studies. Emotional cognition was assessed with the Social Scenarios Test, Facial Expression Recognition Test and Faces Dot-Probe Test. Hierarchical cluster analysis was conducted using emotional cognition data from the 94 unaffected relatives. The resulting emotional cognition clusters and controls were compared for emotional and non-emotional cognition, demographic characteristics and functioning.

RESULTS

Two distinct clusters of unaffected relatives were identified: a relatively 'emotionally preserved' cluster (55%; 40% relatives of MDD probands) and an 'emotionally blunted' cluster (45%; 29% relatives of MDD probands). 'Emotionally blunted' relatives presented with poorer neurocognitive performance (global cognition p = 0.010), heightened subsyndromal mania symptoms (p = 0.004), lower years of education (p = 0.004) and difficulties with interpersonal functioning (p = 0.005) than controls, whereas 'emotionally preserved' relatives were comparable to controls on these measures.

CONCLUSIONS

Our findings show discrete emotional cognition profiles that occur across healthy first-degree relatives of patients with MDD and BD. These emotional cognition clusters may provide insight into emotional cognitive markers of genetically distinct subgroups of individuals at familial risk of mood disorders.

The longitudinal trajectory of emotional cognition in subgroups of recently diagnosed patients with bipolar disorder

Although cross-sectional studies show heterogeneity in emotional cognition in bipolar disorder (BD), the temporal course within subgroups is unclear. In this prospective, longitudinal study we assessed the trajectories of emotional cognition subgroups within a 16-month follow-up period in recently diagnosed BD patients compared to healthy controls (HC). Recently diagnosed BD patients and HC underwent comprehensive emotional and non-emotional testing at baseline and again at follow-up. We employed hierarchical cluster analysis at baseline to identify homogenous emotional cognition subgroups of patients, and changes across the subgroups of BD and HC were assessed with linear mixed-model analyses. We found two emotional cognition subgroups: subgroup 1 (65%, n = 179), showing heightened negative emotional reactivity in neutral and negative social scenarios and faster recognition of emotional facial expressions than HC (ps<0.001, n = 190), and subgroup 2 (35%, n = 96) showing blunted reactivity in positive social scenarios, impaired emotion regulation, poorer recognition of positive and slower recognition of all facial expressions than HC (ps≤.03). Subgroup 1 exhibited normalization of the initial emotional cognition abnormalities in follow-up. In contrast, subgroup 2 showed a lack of improvement in reactivity positively-valenced emotional information. Patients in subgroup 2 presented more and longer mixed episodes during the follow-up time and were more often prescribed lithium. One third of patients display blunted emotional reactivity, impaired emotion regulation abilities and facial expression recognition difficulties also show persistent impairments and poorer course of illness. This subgroup may indicate a need for earlier and more targeted therapeutic interventions.

An update on potential pharmacotherapies for cognitive impairment in bipolar disorder

INTRODUCTION

Cognitive impairment is a core feature of bipolar disorder (BD) that impedes recovery by preventing the return to optimal socio-occupational functioning and reducing quality of life. Presently, there are no efficacious treatments for cognitive impairment in BD, but many pharmacological interventions are being considered as they have the potential to target the underlying pathophysiology of the disorder.

AREAS COVERED

This review summarizes the available evidence for pharmacological interventions for cognitive impairment in bipolar disorder. We searched PubMed, MedLine, and PsycInfo from inception to December 1^st, 2022. Traditional treatments, such as lithium, anticonvulsants (lamotrigine), antipsychotics (aripiprazole, asenapine, cariprazine, lurasidone, and olanzapine), antidepressants (vortioxetine, fluoxetine, and tianeptine) and psychostimulants (modafinil), and emerging interventions, such as acetylcholinesterase inhibitors (galantamine and donepezil), dopamine agonists (pramipexole), erythropoietin, glucocorticoid receptor antagonists (mifepristone), immune modulators (infliximab, minocycline and doxycycline), ketamine, metabolic agents (insulin, metformin, and liraglutide), probiotic supplements, and Withania somnifera are discussed.

EXPERT OPINION

The investigation of interventions for cognitive impairment in BD is a relatively under-researched area. In the past, methodological pitfalls in BD cognition trials have also been a critical limiting factor. Expanding on the existing literature and identifying novel pharmacological and non-pharmacological treatments for cognitive impairment in BD should be a priority.

Clinical and developmental characteristics of cognitive subgroups in a transdiagnostic sample of schizophrenia spectrum disorders and bipolar disorder

Evidence suggests that neurocognitive dysfunction is a transdiagnostic feature of individuals across the continuum between schizophrenia and bipolar disorder. However, there is significant heterogeneity of neuropsychological and social-cognitive abilities in schizophrenia, schizoaffective disorder, and bipolar disorder. The current study aimed to investigate the clinical and developmental characteristics of cognitive subgroups within the schizo-bipolar spectrum. 147 clinically stable patients with schizophrenia, schizoaffective or bipolar disorder were assessed using clinical rating scales for current psychotic and affective symptoms, and a comprehensive neuropsychological battery including measures of social cognition (Hinting and Reading the mind from the Eyes (RMET) task)). Developmental history and premorbid academic functioning were also evaluated. The study also included 36 healthy controls. Neurocognitive subgroups were investigated using latent class analysis (LCA). The optimal number of clusters was determined based on the Bayesian information criterion. A logistic regression analysis was conducted to investigate the predictors of membership to the globally impaired subgroup. LCA revealed two neurocognitive clusters including globally impaired (n = 89, 60.5%) and near-normal cognitive functioning (n = 58, 39.5%) subgroups. The near-normal cognitive functioning subgroup was not significantly different from healthy controls. The globally impaired subgroup had a higher score of developmental abnormalities (p<0.001), poorer premorbid academic functioning, mothers who were less educated and more severe disorganized speech (p = 0.001) and negative symptoms (p = 0.004) compared to the near-normal cognitive functioning group. History of developmental abnormalities and persistent disorganization rather than diagnosis are significant predictors of the subgroup of individuals with global cognitive impairment in the schizophrenia-bipolar disorder continuum.

Does cognitive improvement translate into functional changes? Exploring the transfer mechanisms of cognitive remediation therapy for euthymic people with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is associated with cognitive and functional difficulties, persistent beyond mood episodes. Cognitive remediation (CR) is a psychological therapy targeting cognitive and functioning difficulties. Recent evidence suggests that CR may enhance long-term functioning but transfer mechanisms on functional outcomes have not been explored. We aim to investigate whether and how cognitive gains after CR transfer to functional improvement.

METHODS

We considered data from a randomized controlled trial comparing CR (n = 40) to treatment-as-usual (TAU; n = 40) in euthymic people with BD. Treatment outcomes included individual cognitive domains and global cognition, psychosocial functioning, and goal attainment. Regression-based mediation and moderation modelling were used to assess whether and how post-treatment cognitive changes translate into functional improvement at follow-up, three months after treatment end.

RESULTS

Cognitive gains after CR transferred to functional changes three months later: improvement in post-treatment global cognition partially mediated the effect of CR on psychosocial functioning (standardized indirect effect: -0.23, 95% CI -0.51 to -0.04). Goal attainment was not significantly mediated by changes in cognition, but post-treatment cognitive performance moderated the effect of CR on the GAS at follow-up (interaction effect: 0.78, 95% CI 0.08-1.55).

CONCLUSIONS

Our findings suggest that cognitive improvements contribute to functional improvement but transfer mechanisms differ between psychosocial functioning and idiosyncratic recovery goals. Cognition accounted for only a proportion of the total CR effect on functional outcomes. Future studies should consider other variables, such as metacognition, that may drive the transfer of CR effects to functional outcomes.

Fire and Darkness: On the Assessment and Management of Bipolar Disorder

Bipolar disorder is characterized by recurrent mood episodes, affecting 1% to 2% of the population. Although its defining features are manic and hypomanic episodes, its course is dominated by depressive syndromes. Diagnosis can be challenging owing to symptom overlap with other disorders. Management goals include early and complete remission of acute episodes and the prevention of relapse between episodes. We present an overview of bipolar disorder and its subtypes, including algorithms and suggestions for screening, assessment, and treatment.

A five-year follow-up of the verbal memory performance of individuals with bipolar disorder and schizophrenia: evidence of unchanging deficits under treatment

OBJECTIVE

Bipolar disorder (BD) and schizophrenia (SZ) are chronic and heterogeneous mental disorders that present cognitive and functional impairments. Verbal memory is considered an important predictor of functioning and a domain vulnerable to the aging process. However, only few studies investigate the progression of memory longitudinally in BD and SZ, especially in lower- and middle-income countries. Therefore, we aim to evaluate the course of verbal memory in individuals with BD and SZ.

METHODS

We assessed 31 individuals with BD and 27 individuals with SZ under treatment at outpatient clinics at baseline and after five years. They were assessed through a sociodemographic questionnaire, memory and estimated IQ (eIQ) instruments, and clinical scales.

RESULTS

Individuals with SZ showed worse verbal memory performance in comparison to BD, however, we did not observe changes over time within patient groups. Individuals with BD with higher eIQ showed a better verbal memory performance, while no effect of eIQ was found for subjects with SZ.

CONCLUSION

Patients with SZ and BD showed different levels of verbal memory impairment, although they had similar unchanging trajectories after 5 years under psychiatric treatment. This finding indicates a relative stable cognitive course for both disorders.

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.

Interactive relationships of Type 2 diabetes and bipolar disorder with cognition: evidence of putative premature cognitive ageing in the UK Biobank Cohort

Type 2 diabetes (T2D) is disproportionately prevalent in bipolar disorder (BD) and is associated with cognitive deficits in psychiatrically healthy cohorts. Whether there is an interaction effect between T2D and BD on cognition remains unclear. Using the UK Biobank, we explored interactions between T2D, BD and cognition during mid and later life; and examined age-related cognitive performance effects in BD as a function of T2D. Data were available for 1511 participants with BD (85 T2D), and 81,162 psychiatrically healthy comparisons (HC) (3430 T2D). BD and T2D status were determined by validated measures created specifically for the UK Biobank. Diagnostic and age-related associations between T2D status and cognition were tested using analyses of covariance or logistic regression. There was a negative association of T2D with visuospatial memory that was specific to BD. Processing speed and prospective memory performance were negatively associated with T2D, irrespective of BD diagnosis. Cognitive deficits were evident in BD patients with T2D compared to those without, with scores either remaining the same (processing speed) or improving (visuospatial memory) as a function of participant age. In contrast, cognitive performance in BD patients without T2D was worse as participant age increased, although the age-related trajectory remained broadly equivalent to the HC group. BD and T2D associated with cognitive performance deficits across the mid-life period; indicating comorbid T2D as a potential risk factor for cognitive dysfunction in BD. In comparison to BD participants without T2D and HCs, age-independent cognitive impairments in BD participants with comorbid T2D suggest a potential premature deterioration of cognitive functioning compared to what would normally be expected.

Relationship between baseline cognition and 18-month treatment response in bipolar disorder

BACKGROUND

To date, few studies have examined baseline cognitive function as a predictor of clinical outcome following treatment in bipolar disorder (BD). The aim of this analysis was therefore to examine the relationship between baseline cognitive function and treatment outcome in a sample of young adults with BD receiving Interpersonal Social Rhythm Therapy (IPSRT) or Specialist Supportive Care (SSC) with adjunctive pharmacotherapy.

METHODS

Eighty-six BD patients underwent baseline cognitive testing and completed 18 months of IPSRT or SCC. Univariate analyses examined the relationship between baseline cognitive function (global and individual cognitive domains) and change in mood symptom burden, and psychosocial functioning, from baseline to treatment-end.

RESULTS

Baseline global cognition was not predictive of change in mood symptom burden over 18 months of treatment. However, poorer baseline psychomotor speed performance was associated with less improvement in mood symptom burden at treatment-end. Neither baseline global cognition nor individual cognitive domain scores were associated with change in psychosocial functioning.

LIMITATIONS

Due to the exploratory nature of the study, correction was not made for multiple comparisons. Data was obtained from a relatively small sample and has been the subject of prior analysis, thereby increasing the likelihood of chance findings.

CONCLUSION

Although global cognition was not associated with outcome, when examining individual domains, poorer baseline psychomotor speed predicted less change in mood symptom burden following 18-months of psychotherapy and pharmacotherapy. This suggests that pre-treatment measures of psychomotor speed may help to identify those who require additional, and more targeted, intervention. Further large-scale research is required.

Predictors of functional impairment in bipolar disorder: Results from 13 cohorts from seven countries by the global bipolar cohort collaborative

OBJECTIVES

Persistent functional impairment is common in bipolar disorder (BD) and is influenced by a number of demographic, clinical, and cognitive features. The goal of this project was to estimate and compare the influence of key factors on community function in multiple cohorts of well-characterized samples of individuals with BD.

METHODS

Thirteen cohorts from 7 countries included n = 5882 individuals with BD across multiple sites. The statistical approach consisted of a systematic uniform application of analyses across sites. Each site performed a logistic regression analysis with empirically derived "higher versus lower function" as the dependent variable and selected clinical and demographic variables as predictors.

RESULTS

We found high rates of functional impairment, ranging from 41 to 75%. Lower community functioning was associated with depressive symptoms in 10 of 12 of the cohorts that included this variable in the analysis. Lower levels of education, a greater number of prior mood episodes, the presence of a comorbid substance use disorder, and a greater total number of psychotropic medications were also associated with low functioning.

CONCLUSIONS

The bipolar clinical research community is poised to work together to characterize the multi-dimensional contributors to impairment and address the barriers that impede patients' complete recovery. We must also identify the core features which enable many to thrive and live successfully with BD. A large-scale, worldwide, prospective longitudinal study focused squarely on BD and its heterogeneous presentations will serve as a platform for discovery and promote major advances toward optimizing outcomes for every individual with this illness.

The role of glutamate and GABA in cognitive dysfunction in schizophrenia and mood disorders - A systematic review of magnetic resonance spectroscopy studies

Epidemiologic, genetic, and neurobiological studies suggest considerable overlap between schizophrenia and mood disorders. Importantly, both disorders are associated with a broad range of cognitive deficits as well as altered glutamatergic and GABAergic neurometabolism. We conducted a systematic review of magnetic resonance spectroscopy (MRS) studies investigating the relationship between glutamatergic and GABAergic neurometabolites and cognition in schizophrenia spectrum disorders and mood disorders. A literature search in Pubmed of studies published before April 15, 2019 was conducted and 37 studies were deemed eligible for systematic review. We found that alterations in glutamatergic and GABAergic neurotransmission have been identified relatively consistently in both schizophrenia and mood disorders. However, because of the vast heterogeneity of published studies in terms of illness stage, medication exposure, MRS acquisition parameters and data post-processing strategies, we still do not understand the relationship between those neurotransmitters and cognitive dysfunction in mental illness, which is a critical initial step for rational drug development. Our findings emphasize the need for coordinated multi-center studies that characterize cognitive function and its biological substrates in large and well-defined clinical populations, using harmonized imaging sequences and analytical methods with the goal to elucidate the underlying pathophysiological mechanisms and to inform future clinical trials.

Facial processing in bipolar disorder is mediated by clinical and biological aspects

OBJECTIVE

The process of detecting faces can be considered one of the initial steps in face recognition, which is essential for human interaction. We sought to investigate whether a face perception task reliably detects subtle perceptual disturbances between patients with bipolar disorder (BD) and healthy controls.

METHODS

In this multisite study, we examined differences between BD patients and matched healthy controls. Participants were instructed to detect the orientation (either left or right) of a face when it was presented as a face/non-face pair on a computer screen using Bayesian entropy estimation. Data analyses compared performance between the groups.

RESULTS

Overall, BD patients exhibited more perceptual disturbances compared with controls. BD patients who took olanzapine had better performance and faster reaction times (RTs) than patients who took lithium or were medication-naive. BD patients who took lithium had better performance and faster RTs than medication-naive patients. The medication-naive BD group exhibited greater disturbances than all other groups.

CONCLUSION

These findings highlight the reliability of the face perception task used herein and may be important for public health initiatives and follow-up studies that seek to understand the diverse effects of other variables that can affect sensory processing in this population.

Peripheral insulin sensitivity predicting cognitive function in euthymic bipolar disorder patients

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cognitive subgroups and their longitudinal trajectories in bipolar disorder

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Aging in bipolar disorder: Cognitive performance and clinical factors based on an adulthood-lifespan perspective

BACKGROUND

The evolution of cognitive performance throughout the lifespan in bipolar disorder (BD) is understudied. This cross-sectional study aims to describe the cognitive performance across age groups.

METHODS

A sample of 654 participants was recruited for this study (BD = 432 and healthy controls -HC- =222). Three subgroups, divided according to age range (18 to 35, 36 to 49, and ≥50 years old) were analyzed after administering a comprehensive neuropsychological battery including six cognitive domains. Demographic, clinical, and psychosocial functioning data were also analyzed. Generalized linear models (GLM) with age, diagnostic group, and age × group as main effects were carried out to examine their potential association on cognitive domains. Subsequently, a GLM in the BD sample was conducted to analyze interactions of several clinical variables by age on each cognitive domain.

RESULTS

Main effects of diagnostic group and age were found in all cognitive domains. Significant group × age effect interaction was found for attention domain (p = 0.02) demonstrating a worse cognitive evolution across age in BD, driven by older age, but not in HC. Significant interaction effects of higher number of manic episodes and older age were also found in attention and verbal memory. Older age was also associated with a longer duration of illness, higher number of episodes, more somatic comorbidities, and poorer psychosocial functioning.

CONCLUSIONS

These results suggest that older age was associated with a selective cognitive decline in BD in the attentional domain. These findings highlight the importance of developing interventions targeting cognitive dysfunction throughout the BD adulthood lifespan.

Can magnetic resonance imaging enhance the assessment of potential new treatments for cognitive impairment in mood disorders? A systematic review and position paper by the International Society for Bipolar Disorders Targeting Cognition Task Force

BACKGROUND

Developing treatments for cognitive impairment is key to improving the functioning of people with mood disorders. Neuroimaging may assist in identifying brain-based efficacy markers. This systematic review and position paper by the International Society for Bipolar Disorders Targeting Cognition Task Force examines the evidence from neuroimaging studies of pro-cognitive interventions.

METHODS

We included magnetic resonance imaging (MRI) studies of candidate interventions in people with mood disorders or healthy individuals, following the procedures of the Preferred Reporting Items for Systematic reviews and Meta-Analysis 2020 statement. Searches were conducted on PubMed/MEDLINE, PsycInfo, EMBASE, Cochrane Library, and Clinicaltrials.gov from inception to 30th April 2021. Two independent authors reviewed the studies using the National Heart, Lung, Blood Institutes of Health Quality Assessment Tool for Controlled Intervention Studies and the quality of neuroimaging methodology assessment checklist.

RESULTS

We identified 26 studies (N = 702). Six investigated cognitive remediation or pharmacological treatments in mood disorders (N = 190). In healthy individuals, 14 studies investigated pharmacological interventions (N = 319), 2 cognitive training (N = 73) and 4 neuromodulatory treatments (N = 120). Methodologies were mostly rated as 'fair'. 77% of studies investigated effects with task-based fMRI. Findings varied but most consistently involved treatment-associated cognitive control network (CCN) activity increases with cognitive improvements, or CCN activity decreases with no cognitive change, and increased functional connectivity. In mood disorders, treatment-related default mode network suppression occurred.

CONCLUSIONS

Modulation of CCN and DMN activity is a putative efficacy biomarker. Methodological recommendations are to pre-declare intended analyses and use task-based fMRI, paradigms probing the CCN, longitudinal assessments, mock scanning, and out-of-scanner tests.

Bipolar spectrum traits and the space between Madness and Genius: The Muse is in the Dose

Creativity has long been associated with the bipolar spectrum, particularly among unaffected first-degree relatives and those with milder expressions of bipolar traits, suggesting that some aspects of the bipolar spectrum may confer advantages for creativity. Here we took a multifaceted approach to better define the shared vulnerability between creativity and bipolar disorder. We recruited 135 individuals with bipolar disorder, 102 creative controls, and 103 non-creative controls for a total of 340 participants. All participants completed a comprehensive assessment battery that included several self-report temperament and personality questionnaires, a computerized test of cognitive function across multiple domains, and an evaluation of creative performance and achievement. Significant group differences were observed for the hypothesized shared vulnerability traits of hypomanic personality, cyclothymic temperament, impulsivity, and positive schizotypy. While both the creative and bipolar groups demonstrated superior creative ability, the creative group alone revealed enhanced cognitive performance. Accounting for intercorrelations between traits, a combination of openness, hypomanic personality, divergent thinking, and reasoning ability emerged as the strongest predictors of creativity, collectively explaining 34% of the variance in creative achievement and correctly classifying 85% of individuals with high achievement irrespective of diagnosis. These results confirm and extend earlier observations of a shared vulnerability between creativity and bipolar disorder and suggest that mild to moderate expressions of bipolar spectrum traits are associated with enhanced cognitive functioning and creative expression. Further investigation of these traits is needed to clarify the nature of this shared vulnerability and suggest individualized treatment strategies to improve clinical outcomes in bipolar disorder.

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

BACKGROUND

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

The Italian version of the Brief Assessment of Cognition in Affective Disorders: performance of patients with bipolar disorder and healthy controls

OBJECTIVES

Cognitive deficits in Bipolar Disorder (BD) are significant enough to have an impact on daily functioning. Therefore, appropriate tools must be used to improve our understanding of the nature and severity of cognitive deficits in BD. In this study, we aimed to compare the cognitive profiles of patients with BD and healthy controls (HC) applying the Italian version of the Brief Assessment of Cognition in Affective Disorders (BAC-A).

METHODS

This cross-sectional study included 127 patients with BD and 134 HC. The participants' cognitive profiles were evaluated using the Italian version of the BAC-A, which assesses verbal memory, working memory, motor speed, verbal fluency, attention & processing speed, executive functions, and two new measures of affective processing. The BAC-A raw scores were corrected using the normative data for the Italian population. In addition, we explored whether intelligence quotient (IQ) and specific clinical variables would predict the BAC-A affective, non-affective, and total composite scores of patients with BD and HC.

RESULTS

HC performed better than patients with BD in all BAC-A subtests (all p < .001), except for subtests of the Affective Interference Test. (p ≥ .05). The effect sizes varied in magnitude and ranged between d = 0.02 and d = 1.27. In patients with BD, lower BAC-A composite scores were predicted by a higher number of hospitalizations. There was a significant association between IQ and BAC-A composite scores in both bipolar patients and HC.

CONCLUSIONS

The Italian BAC-A is sensitive to the cognitive impairments of patients with BD in both affective and non-affective cognitive domains.

Strategies and foundations for scientific discovery in longitudinal studies of bipolar disorder

Bipolar disorder (BD) is a complex and dynamic condition with a typical onset in late adolescence or early adulthood followed by an episodic course with intervening periods of subthreshold symptoms or euthymia. It is complicated by the accumulation of comorbid medical and psychiatric disorders. The etiology of BD remains unknown and no reliable biological markers have yet been identified. This is likely due to lack of comprehensive ontological framework and, most importantly, the fact that most studies have been based on small nonrepresentative clinical samples with cross-sectional designs. We propose to establish large, global longitudinal cohorts of BD studied consistently in a multidimensional and multidisciplinary manner to determine etiology and help improve treatment. Herein we propose collection of a broad range of data that reflect the heterogenic phenotypic manifestations of BD that include dimensional and categorical measures of mood, neurocognitive, personality, behavior, sleep and circadian, life-story, and outcomes domains. In combination with genetic and biological information such an approach promotes the integrating and harmonizing of data within and across current ontology systems while supporting a paradigm shift that will facilitate discovery and become the basis for novel hypotheses.

New drug targets in psychiatry: Neurobiological considerations in the genomics era

After a period of withdrawal, pharmaceutical companies have begun to reinvest in neuropsychiatric disorders, due to improvements in our understanding of these disorders, stimulated in part by genomic studies. However, translating this information into disease insights and ultimately into tractable therapeutic targets is a major challenge. Here we consider how different sources of information might be integrated to guide this process. We review how an understanding of neurobiology has been used to advance therapeutic candidates identified in the pre-genomic era, using catechol-O-methyltransferase (COMT) as an exemplar. We then contrast with ZNF804A, the first genome-wide significant schizophrenia gene, and draw on some of the lessons that these and other examples provide. We highlight that, at least in the short term, the translation of potential targets for which there is orthogonal neurobiological support is likely to be more straightforward and productive than that those relying solely on genomic information. Although we focus here on information from genomic studies of schizophrenia, the points are broadly applicable across major psychiatric disorders and their symptoms.