Neuropsychological performance in euthymic Indian patients with bipolar disorder type I: correlation between quality of life and global functioning

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.

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.

Neural Responses to a Working Memory Task in Acute Depressed and Remitted Phases in Bipolar Patients

(1) Cognitive impairments such as working memory (WM) deficits are amongst the most common dysfunctions characterizing bipolar disorder (BD) patients, severely contributing to functional impairment. We aimed to investigate WM performance and associated brain activation during the acute phase of BD and to observe changes in the same patients during remission. (2) Frontal brain activation was recorded using functional near-infrared spectroscopy (fNIRS) during n-back task conditions (one-back, two-back and three-back) in BD patients in their acute depressive (n = 32) and remitted (n = 15) phases as well as in healthy controls (n = 30). (3) Comparison of BD patients during their acute phase with controls showed a trend (p = 0.08) towards lower dorsolateral prefrontal cortex (dlPFC) activation. In the remitted phase, BD patients showed lower dlPFC and ventrolateral prefrontal cortex (vlPFC) activation (p = 0.02) compared to controls. No difference in dlPFC and vlPFC activation between BD patients' phases was found. (4) Our results showed decreased working memory performance in BD patients during the working memory task in the acute phase of disease. Working memory performance improved in the remitted phase of the disease but was still particularly attenuated for the more demanding conditions.

Relationship between advanced glycated end products and maternal cognition in gestational diabetes: a case control study

OBJECTIVE

Gestational diabetes (GDM) is a form of glucose intolerance which manifests during pregnancy. There is lack of literature regarding the study of cognitive functions in GDM. Recent evidences suggests an increase in accumulation of serum Advanced glycated end products (AGE'S) during GDM. Accumulation of AGE's in brain can induce changes in permeability of blood brain barrier and creates oxidative stress and inflammation that can alter cognitive functions. In this study we hypothesize that diagnosis of GDM in pregnancy is related to lower cognitive scores which is correlated to increased serum AGE's level.

METHOD

This was a cross sectional case control study which recruited 60 participants in total consisting of two groups with 30 participants in each - diagnosed cases of GDM and healthy pregnant controls. Subjects were recruited from OPD of Obstetrics & Gynecology department in a tertiary care hospital in South India at gestational age of 32-36 weeks. On the first appointment, biochemical parameters of Fasting plasma glucose (FPG) & HbA1C was measured in both groups. Serum was obtained for testing levels of N Carboxy methyl lysine (N-CML) (a form of AGE). On second appointment, pen and paper neurocognitive tests including Montreal cognitive tests (MOCA) and Trail making test (TMT A & B) was presented. Event related potentials (ERP's) are time locked EEG wave signals produced in response to a sensory, motor or cognitive event. P300 is an "endogenous" ERP produced by cognitive processing in response to a stimuli presented to subject. P300 wave Latency and amplitude was recorded in both the groups as an objective marker of cognitive processing. Above mentioned biochemical and neurocognitive parameters were compared between both the groups and correlation analysis between serum AGE levels and neurocognitive parameters was performed using SPSS software.

RESULTS

Biochemical parameters of HbAIC & N-CML(A form of AGE) levels were increased in GDM group (HbA1C 6.01±0.30 and N CML 236.25 ± 68.9) vs Control group (HbA1C 4.11 ± 0.68 and NCML 198.42 ± 44.2). Scores in MOCA were significantly lower in GDM (28 (27-29)) group as compared to controls (24 (23-25)). GDM subjects took significantly greater time to perform TMT A (24.59 ± 2.60 s) test than controls (29.7 ± 1.72 s). Significant changes were not found in P300 Latency & amplitude in GDM group. Decreased MOCA scores and increased duration of TMT A attempt were correlated with increased serum AGE concentration in GDM group.

CONCLUSIONS

Our study indicates the vulnerability of women suffering from GDM to cognitive impairment during pregnancy. Lower scores in cognitive tests were correlated to AGE accumulation in GDM women.

Quality of life in euthymic bipolar patients: A systematic review and meta-analysis

BACKGROUND

Patients with bipolar disorder, even euthymic, could suffer an impairment in their quality of life compared to healthy controls. Since no previous systematic review and meta-analysis has been conducted, the aim of the current study is to conduct a systematic review and meta-analysis of cross-sectional case-controlled studies on quality of life in adult euthymic Bipolar Disorder patients.

METHODS

A systematic review and meta-analysis that followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) was conducted. Major electronic databases were searched on August 2018 to assess the variables associated with quality of life in euthymic bipolar disorder patients. After selecting case-control studies, data collection, quality assessment and subsequently statistical analysis were done.

RESULTS

66 studies were finally selected for systematic review and meta-analysis. Four different quality of life instruments were used among the different studies. Effect size analysis showed that there were significant differences in quality of life outcomes between euthymic bipolar disorder patients and healthy controls (d=-0.922; SE=0.316; 95%CI=-1.541--0.303; p=.004), with lower quality of life in the euthymic patients. Furthermore, time since euthymia explained 15.62% of variability, and age of control group explained 29.6% of variability. No other moderators were statiscally significant.

LIMITATIONS

The instruments used were heterogeneous. Moreover, the role of other clinical moderators could not be included due to the lack of this information in most of the articles.

CONCLUSIONS

Quality of life is lower in euthymic bipolar patients than in healthy controls. However, longer time in euthymia is associated with better outcomes.

Executive Functions in Insomnia Disorder: A Systematic Review and Exploratory Meta-Analysis

Background: Executive functions (EFs) are involved in the control of basic psychological processes such as attention and memory and also contribute to emotion regulation. Research on the presence of EFs impairments in insomnia yielded inconsistent results. Therefore, we performed a systematic review of the literature on three EFs: inhibitory control, working memory, and cognitive flexibility in adults with insomnia in order to investigate the presence and magnitude of insomnia-related EFs impairments. Methods: PubMed, Scopus, Medline, and PsycINFO were searched. Risk of bias assessment of included studies was performed by two independent researchers. Findings were summarised using both a narrative approach and meta-analysis. Cohen's d was calculated at 95% confidence interval (CI) as effect size of between groups differences. Results: Twenty-eight studies comparing adult individuals with a diagnosis of insomnia and healthy controls on neuropsychological measures of EFs were included. Narrative synthesis revealed substantial variability across study findings. Factors that were primarily hypothesised to account for this variability are: objective sleep impairments and test sensitivity. Exploratory meta-analysis showed impaired performance of small to moderate magnitude in individuals with insomnia as compared to controls in reaction times, but not accuracy rates, of inhibitory control (d = -0.32, 95% CI: -0.52 to -0.13) and cognitive flexibility tasks (d = -0.30, 95% CI: -0.59 to -0.01). Performance in working memory tasks was also significantly impacted (d = -0.19, 95% CI: -0.38 to -0.00). Effects sizes were larger when insomnia was associated with objective sleep impairments, rather than normal sleep. Conclusions: We gathered evidence supporting small to moderate deficits in EFs in individuals with insomnia. Due to the small sample size results should be considered preliminary and interpreted carefully.

Assessment of cognitive functions in bipolar I disorder: A 1-year naturalistic follow-up study

OBJECTIVE

Available findings from cross-sectional studies have demonstrated cognitive impairments in bipolar I disorder (BD-I) during various phases of illness. However, very little is known about the longitudinal course of these cognitive impairments. The purpose of the study was to explore the longitudinal pattern of changes in cognitive functioning of BD-I patients.

METHODS

A total of 129 BD-I subjects (manic, depressed and euthymic groups) and 49 healthy controls were recruited using predefined selection criteria. All four study groups were assessed on various clinical and cognitive parameters (for attention, memory, executive functions and working memory) at study intake and at 3-monthly intervals over the next year.

RESULTS

All three patient groups performed poorly compared to controls on all cognitive measures at study intake and on some cognitive measures at the 3-, 6-, 9- and 12-month assessments. No significant time effects were observed for any cognitive test. A significant group by time interaction effect was found for executive functions (β = -44.74; P = .018) and working memory (β = 0.77; P ≤ .019) in the depressed group at 12 months; for visual memory (β = 1.21; P = .039) and working memory (β = 1.17; P ≤ .029) in the manic group at 12 months; and for working memory (β = -0.52; P ≤ .036) in the euthymic group at 12 months.

CONCLUSION

The patient groups showed significant impairments in all or some test domains relative to controls at all time-points. The cognitive functions largely remained stable in all patient groups, with slight improvement over time in a few tests. Further investigation is warranted in larger samples in longitudinal studies.

Potential biomarkers for bipolar disorder: Where do we stand?

Bipolar disorder (BD) is a severe, recurrent mood disorder, associated with a significant morbidity and mortality, with high rates of suicides and medical comorbidities. There is a high risk of mood disorders among the first-degree relatives of patients with BD. In the current clinical practice, the diagnosis of BD is made by history taking, interview and behavioural observations, thereby lacking an objective, biological validation. This approach may result in underdiagnosis, misdiagnosis and eventually poorer outcomes. Due to the heterogeneity of BD, the possibility of developing a single, specific biomarker is still remote; however, there is a set of promising biomarkers which may serve as predictive, prognostic or treatment markers in the future. The review presents a critical appraisal and update on some of the most promising candidates for biomarkers, namely, neuroimaging markers, peripheral biomarkers and genetic markers, including a brief discussion on cognitive endophenotypes as indicative of genetic risk. The lessons learnt from other fields and specialties in medicine need to be applied to psychiatry to translate the knowledge from ‘bench to bedside’ by means of clinically useful biomarkers. Overall, the biomarkers may help in pushing the shift towards personalized medicine for psychiatric patients.

Executive functioning deficits among adults with Bipolar Disorder (types I and II): A systematic review and meta-analysis

BACKGROUND

Executive functioning (EF) deficits contribute to a significant proportion of the burden of disease associated with bipolar disorder (BD). Yet, there is still debate in the literature regarding the exact profile of executive functioning in BD. The purpose of the present project was to assess whether EF deficits exist among adults suffering BD, and whether these deficits (if apparent) differ by BD subtype.

METHODS

A systematic search identified relevant literature. Randomised controlled trials that used neuropsychological assessment to investigate EF among adults 16-65 years) with a remitted DSM diagnosis of BD (type I or II) were included. Studies were published between 1994 and 2015. A systematic review and meta-analysis were undertaken. For individual studies, standardised mean differences (Cohen's d) and 95% confidence intervals were calculated and represented in forest plots to illustrate differences in executive performance between groups. Summary effects were produced and tests of heterogeneity employed to assess the dispersion and generalisability of results.

RESULTS

Thirty-six studies met criteria for inclusion. Six domains of EF were identified: Set-shifting (SS), inhibition (INH), planning (PLA), verbal fluency (VF), working memory (WM), and attention (ATT). BD1s performed worse than HCs in all domains. BD2s demonstrated impairment in VF, WM, SS, and ATT. The results were mixed for comparisons between BD1s and BD2s, but revealed that BD2s can experience similar (or sometimes greater) EF impairment.

LIMITATIONS

Only a limited number of studies that included BD2 samples were available for inclusion in the current study. Subgroup analysis to elucidate potential moderators of within-study variance was not undertaken.

CONCLUSION

This is the first systematic review and meta-analysis to have compared the EF of remitted BD1s, BD2s, and HCs. The results provided useful insight into the EF profile of patients with BD, and offered commentary as to some of the contradictory results reported in the literature. A standardised methodological protocol for assessment of EF in BD was proposed. The information in this review could enhance our understanding of EF impairment inherent in BD, and the methods and efficacy with which clinicians assess and treat this population.

Performance of Bipolar Disorder Patients in Attention Testing: Comparison with Normal Controls and Among Manic, Depressive, and Euthymic Phases

Several studies on cognition in bipolar disorder (BD) have been developed on the last decade. Neuropsychological evaluation of attention in BD patients is fundamental since alterations in attention affect other cognitive functions. Evaluate if performance of BD patients in attention tests varies according to each phase of the disease and verify if there are differences in attention when comparing BD patients with normal controls. The study included 101 BD patients, with ages between 18 and 65 years, being 52 euthymic, 22 manic and 27 depressive, besides 30 normal controls. All subjects were evaluated though Hamilton Depression Scale, Young Mania Rating Scale and Global Assessment of Functioning, bipolar version (CGI-BP). Attention was evaluated through a neuropsychological battery. Normal controls had a better performance in selective attention tests than BD patients. No differences were found among manic, depressive and euthymic phases. Attention is markedly impaired in BD. Nevertheless, the results of this study do not imply that the severity of the attention deficit in BD patients varies according to decease phase.

Effects of resilience on quality of life in patients with bipolar disorder

BACKGROUND

Few studies have examined the effects of resilience on quality of life (QOL) in patients with bipolar disorder (BD). Therefore, this study investigated the association between resilience and QOL in patients with BD and compared it to the relationship between resilience and QOL in healthy individuals.

METHODS

Participants were 68 euthymic patients with BD and 68 age-, sex-, and length of education-matched controls. Sociodemographic characteristics and clinical variables of the two groups were obtained using face-to-face interviews, and all participants completed the Connor-Davidson Resilience Scale, the World Health Organization QOL-Brief Form.

RESULTS

The QOL of the BD group was significantly impaired compared with that of the controls. Degree of resilience, number of depressive episodes, Clinical Global Impression scores, degree of impulsivity, and length of education were significantly correlated with QOL in the BD group. Resilience was significantly associated with overall QOL, physical subdomains of QOL, psychological subdomains of QOL, social subdomains of QOL, and environmental subdomains of QOL in the BD group, even after controlling for confounders. In the control group, resilience was significantly associated with overall QOL, the physical subdomains of QOL, psychological subdomains of QOL, and social subdomains of QOL.

LIMITATIONS

The number of participants in each group was 68, which is a relatively small sample size.

CONCLUSIONS

Resilience in patients with BD was independently and positively correlated with various areas of QOL. Various strategies to reinforce resilience in patients with BD are needed to improve the low QOL in this population.

Systematic Review of Cognitive Function in Euthymic Bipolar Disorder and Pre-Surgical Temporal Lobe Epilepsy

BACKGROUND

Bipolar disorder (BD) and temporal lobe epilepsy (TLE) overlap in domains including epidemiology, treatment response, shared neurotransmitter involvement and temporal lobe pathology. Comparison of cognitive function in both disorders may indicate temporal lobe mediated processes relevant to BD. This systematic review examines neuropsychological test profiles in euthymic bipolar disorder type I (BD-I) and pre-surgical TLE and compares experimental designs used.

METHODS

A search of PubMed, PsychINFO, and Scopus using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. Inclusion criteria were comparison group or pre- to post-surgical patients; reported neuropsychological tests; participants aged 18-60 years. Fifty six studies met criteria: 27 BD-I; 29 TLE.

RESULTS

Deficits in BD-I compared to healthy controls (HC) were in executive function, attention span and verbal memory. Deficits in TLE compared to HC were in executive function and memory. In the pre- to post-surgical comparisons, verbal memory in left temporal lobe (LTL) and, less consistently, visuospatial memory in right temporal lobe (RTL) epilepsy declined following surgery. BD-I studies used comprehensive test batteries in well-defined euthymic patients compared to matched HC groups. TLE studies used convenience samples pre- to post-surgery, comparing LTL and RTL subgroups, few included comparisons to HC (5 studies). TLE studies typically examined a narrow range of known temporal lobe-mediated neuropsychological functions, particularly verbal and visuospatial memory.

CONCLUSION

Both disorders exhibit deficits in executive function and verbal memory suggestive of both frontal and temporal lobe involvement. However, deficits in TLE are measured pre- to post-surgery and not controlled at baseline pre-surgery. Further research involving a head-to-head comparison of the two disorders on a broad range of neuropsychological tests is needed to clarify the nature and extent of cognitive deficits and potential overlaps.

Proxy-reported quality of life in adolescents and adults with dyskinetic cerebral palsy is associated with executive functions and cortical thickness

PURPOSE

Quality of life (QOL) is a key outcome for people with cerebral palsy (CP), and executive functioning is an important predictor of QOL in other health-related conditions. Little is known about this association in CP or about its neural substrate. We aim to analyze the influence of executive functioning (including cognitive flexibility) as well as that of other psychological, motor, communication and socioeconomic variables on QOL and to identify neuroanatomical areas related to QOL in adolescents and adults with CP.

METHODS

Fifty subjects diagnosed with dyskinetic CP (mean age 25.96 years) were recruited. Their caregivers completed the primary caregiver proxy report version of the CP QOL-Teen questionnaire. Motor status, communication, IQ, four executive function domains, anxiety/depression and socioeconomic status were evaluated. Correlations and multiple linear regression models were used to relate CP QOL domains and total score to these variables. Thirty-six participants underwent an MRI assessment. Correlations were examined between cortical thickness and CP QOL total score and between cortical thickness and variables that might predict the CP QOL total score.

RESULTS

Executive functions predict scores in four domains of CP QOL (General well-being and participation, Communication and physical health, Family health and Feelings about functioning) in the regression model. Among the cognitive domains that comprise executive function, only cognitive flexibility measured in terms of performance on the Wisconsin card sorting test (WCST) predicts the CP QOL total score. Monthly income, fine motor functioning and communication ability predict scores on the domains Access to services and Family Health, Feelings about functioning and School well-being, respectively. The clusters resulting from the correlation between cortical thickness and both CP QOL total score and WCST performance overlapped in the posterior cingulate and precuneus cortices.

CONCLUSIONS

Cognitive flexibility predicts proxy report CP QOL-Teen total score in dyskinetic CP. This relationship has its anatomical correlate in the posterior cingulate and precuneus cortices.

Increased Beta Frequency (15-30 Hz) Oscillatory Responses in Euthymic Bipolar Patients Under Lithium Monotherapy

The effect of lithium on neurocognition is not still fully explored. Brain oscillatory activity is altered in bipolar disorder. We aimed to assess the oscillatory responses of euthymic bipolar patients and how they are affected by lithium monotherapy. Event-related oscillations in response to visual target stimulus during an oddball paradigm in 16 euthymic drug-free and 13 euthymic lithium-treated bipolar patients were compared with 16 healthy controls. The maximum peak-to-peak amplitudes were measured for each subject's averaged beta (15-30 Hz) responses in the 0- to 300-ms time window over frontal (F3, Fz, F4), central (C3, Cz, C4), temporal (T7, T8), temporo-parietal (TP7, TP8), parietal (P3, Pz, P4), and occipital (O1, Oz, O2) areas. Patients under lithium monotherapy had significantly higher beta responses to visual target stimuli than healthy controls (P=.017) and drug-free patients (P=.015). The increase in beta response was observed at all electrode locations, however, the difference was statistically significant for the left (T7; P=.016) and right (T8; P=.031) temporal beta responses. Increased beta responses in drug-free patients and further significant increase in lithium-treated patients may be indicative of a core pathophysiological process of bipolar disorder and how it is affected by lithium. Whether the finding corresponds to lithium's corrective effect on the underlying pathology or to its neurocognitive side effect remains to be further explored. In either case, the finding is a sign that the oscillatory activity may be useful in tracking medication effect in bipolar disorder.

Residual symptoms and specific functional impairments in euthymic patients with bipolar disorder

OBJECTIVES

The aims of the present study were to confirm the impact of residual symptoms on overall functioning in a large sample of euthymic patients with bipolar disorder in real-life conditions and to explore the relationship between residual symptoms and specific areas of functional impairment.

METHODS

This was a multicenter, cross-sectional, non-interventional study of euthymic outpatients with bipolar disorder. The Functioning Assessment Short Test was used to assess overall and specific domains of functioning (autonomy, occupational functioning, cognitive functioning, financial issues, interpersonal relationships, and leisure time). Various residual symptoms were assessed (residual mood symptoms, emotional dysregulation, sleep and sexual disorders, stigma, and perceived cognitive impairment). Logistic regression was used to determine the best model of association between functional domains and residual symptoms.

RESULTS

Almost half of the 468 patients included (42%) had poor overall functioning. Residual depressive symptoms appeared to have an impact on overall functioning and in nearly all areas of functioning. In addition, specific residual symptoms had significantly more negative effects on some domains of functioning in euthymic patients with bipolar disorder (residual manic symptoms and occupational stigma on autonomy, emotional inhibition on occupational functioning, residual manic symptoms on financial issues, family stigma on interpersonal relationships, and sexual function and occupational stigma on leisure time).

CONCLUSIONS

Our findings highlight the importance of evaluating overall functioning in clinical practice as well as functional domains. They also indicate that some residuals symptoms in patients with bipolar disorder should be targeted in personalized treatment plans, in order to improve functioning in the domains in which the patient is most impaired.

Emotion regulation strategies can predict task-switching abilities in euthymic bipolar patients

This study examined task-switching abilities and emotion regulation strategies in euthymic bipolar patients (EBP). Forty EBP and 40 healthy individuals performed face categorization tasks where they switched between emotion and non-emotion (i.e., gender) features among faces and completed emotion regulation questionnaire (Gross and John, 2003). Subject groups showed substantial differences in task-switching abilities and emotion regulation strategies: (1) there was a dissociation between emotion and gender classification in EBP. The switch cost was larger [i.e., higher reaction times (RTs) on switch as compared to no-switch trials] for gender categorization as compared to the emotion categorization task. In contrast, such asymmetries were absent among healthy participants. The differential pattern of task switching reflected functional disturbances in frontotemporal neural system and an attentional bias to emotion features of the faces in EBP. This suggests that when a euthymic bipolar patient is preoccupied with emotion recognition, an instruction to perform gender categorization results in greater cost on RTs. (2) In contrast to healthy individuals, EBP reported more frequent use of emotion suppression and lesser use of cognitive reappraisal as emotion regulation strategy. (3) Emotion regulation was found to be a significant predictor of task-switching abilities. It is argued that task switching deficits rely on maladaptive emotion regulation strategies in EBP specifically when tasks of emotional significance are involved.

Cognitive performance and quality of life early in the course of bipolar disorder

BACKGROUND

Several studies have reported cognitive functioning as a significant predictor of quality of life (QoL) in patients with established bipolar disorder (BD), in addition to mood symptoms. However, it is unclear whether cognitive functioning predicts QoL early in the course of illness. The purpose of this study was therefore to evaluate the relationship between mood and neuropsychological variables and self-reported QoL early in the course of BD.

METHODS

Patients with BD-I (n=54) completed a neuropsychological battery and clinical assessment within 3 months of resolution of their first manic episode. QoL was assessed 6 months later using the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q). Cognitive predictors of QoL were assessed through Pearson correlations and hierarchical multiple regression.

RESULTS

After accounting for mood rating scores at the time of cognitive testing (ΔR²=.27, p<.001), measures of sustained attention (ΔR²=.08, p<.05), verbal memory (ΔR²=.09, p<.01), working memory (ΔR²=.06, p<.05), and executive functioning (ΔR²=.08, p<.05) each predicted QoL when entered independently in separate regression models. When entered simultaneously, the cognitive domains explained 15% (R(2)=.42, p<.05) of the variance in QoL beyond mood.

LIMITATIONS

Some aspects of QoL that are particularly important in BD may be missing as a result of using the Q-LES-Q, because the measure was not specifically developed to assess QoL in BD.

CONCLUSIONS

In addition to mood symptoms, poorer cognitive functioning is a significant predictor of reduced QoL early in the course of BD. Recently diagnosed patients with BD may benefit from early cognitive-enhancing interventions to maintain or restore their QoL.

Inflammatory mediators of cognitive impairment in bipolar disorder

OBJECTIVES

Recent studies have pointed to neuroinflammation, oxidative stress and neurotrophic factors as key mediators in the pathophysiology of mood disorders. Little is however known about the cascade of biological episodes underlying the cognitive deficits observed during the acute and euthymic phases of bipolar disorder (BD). The aim of this review is to assess the potential association between cognitive impairment and biomarkers of inflammation, oxidative stress and neurotrophic activity in BD.

METHODS

Scopus (all databases), Pubmed and Ovid Medline were systematically searched with no language or year restrictions, up to November 2013, for human studies that collected both inflammatory markers and cognitive data in BD. Selected search terms were bipolar disorder, depression, mania, psychosis, inflammatory, cognitive and neurotrophic.

RESULTS

Ten human studies satisfied the criteria for consideration. The findings showed that high levels of peripheral inflammatory-cytokine, oxidative stress and reduced brain derived neurotrophic factor (BDNF) levels were associated with poor cognitive performance. The BDNF val66met polymorphism is a potential vulnerability factor for cognitive impairment in BD.

CONCLUSIONS

Current data provide preliminary evidence of a link between the cognitive decline observed in BD and mechanisms of neuroinflammation and neuroprotection. The identification of BD specific inflammatory markers and polymorphisms in inflammatory response genes may be of assistance for therapeutic intervention.

Sustained attention in psychosis: Neuroimaging findings

To provide a systematic review of scientific literature on functional magnetic resonance imaging (fMRI) studies on sustained attention in psychosis. We searched PubMed to identify fMRI studies pertaining sustained attention in both affective and non-affective psychosis. Only studies conducted on adult patients using a sustained attention task during fMRI scanning were included in the final review. The search was conducted on September 10^th, 2013. 15 fMRI studies met our inclusion criteria: 12 studies were focused on Schizophrenia and 3 on Bipolar Disorder Type I (BDI). Only half of the Schizophrenia studies and two of the BDI studies reported behavioral abnormalities, but all of them evidenced significant functional differences in brain regions related to the sustained attention system. Altered functioning of the insula was found in both Schizophrenia and BDI, and therefore proposed as a candidate trait marker for psychosis in general. On the other hand, other brain regions were differently impaired in affective and non-affective psychosis: alterations of cingulate cortex and thalamus seemed to be more common in Schizophrenia and amygdala dysfunctions in BDI. Neural correlates of sustained attention seem to be of great interest in the study of psychosis, highlighting differences and similarities between Schizophrenia and BDI.

Longitudinal study of sustained attention in outpatients with bipolar disorder

Individuals with bipolar disorder (BD) may exhibit attentional deficits, however, the extent of impairment and long-term fluctuations in performance in attention are relatively unknown. We investigated the relationship between sustained attention and affective symptoms over time among BD patients. We also examined whether global differences in attentional capacity differed among BD versus normal comparison (NC) subjects. Participants included 106 outpatients with BD and 66 NC subjects who were administered symptom rating scales and a measure of sustained attention (Continuous Performance Test- Identical Pairs). Measures were repeated 6, 12, and 26 weeks post-baseline. Compared to NC subjects, participants with BD showed impairment in sustained attention across time. Within patient increases in manic symptoms were associated with increased false alarms; both manic and depressive symptoms were associated with worse discrimination. Neither manic nor depressive symptoms were related to hit rates. Our results indicate that the ability to inhibit a response to near miss stimuli (i.e., those that are close to but not identical to the target) is globally impaired among BD patients relative to NC subjects, as well as state-dependent, covarying with affective symptoms. Psychosocial interventions requiring high levels of attentional capacity may need to be adapted according to patients' current symptomatology.

Sleep quality during euthymia in bipolar disorder: the role of clinical features, personality traits, and stressful life events

Background

Poor sleep quality is known to precede the onset of mood episodes and to be associated with poor treatment outcomes in bipolar disorder (BD). We sought to identify modifiable factors that correlate with poor sleep quality in BD independent of residual mood symptoms.

Methods

A retrospective analysis was conducted to assess the association between the Pittsburgh Sleep Quality Index and clinical variables of interest in euthymic patients with DSM-IV BD (n = 119) and healthy controls (HC; n = 136) participating in the Prechter Longitudinal Study of Bipolar Disorder. Multivariable linear regression models were constructed to investigate the relationship between sleep quality and demographic and clinical variables in BD and HC participants. A unified model determined independent predictors of sleep quality.

Results and discussion

Euthymic participants with BD and HC differed in all domains. The best fitting unified multivariable model of poor sleep quality in euthymic participants with BD included rapid cycling (β = .20, p = .03), neuroticism (β = .28, p = 2 × 10⁻³), and stressful life events (β = .20, p = .02). Poor sleep quality often persists during euthymia and can be a target for treatment. Clinicians should remain vigilant for treating subjective sleep complaints independent of residual mood symptoms in those sensitive to poor sleep quality, including individuals with high neuroticism, rapid cycling, and recent stressful life events. Modifiable factors associated with sleep quality should be targeted directly with psychosocial or somatic treatment. Sleep quality may be a useful outcome measure in BD treatment studies.

The Relationship between Impulsivity and Quality of Life in Euthymic Patients with Bipolar Disorder

OBJECTIVE

Bipolar disorder (BD) is characterized by elevated impulsivity, even during periods of remission. Many recovered BD patients have functional impairments, which can lead to poor quality of life (QoL). The aim of this study was to investigate the association between impulsivity and QoL in euthymic BD patients.

METHODS

A total of 56 remitted or recovered patients with type I or II BD, diagnosed based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria, were recruited. Psychiatrists administered the Clinical Global Impression (CGI) for BD and the Global Assessment of Functioning (GAF) scales and then interviewed the subjects to assess clinical variables. Patients completed the Barratt Impulsiveness Scale (BIS-11) and the World Health Organization Quality of Life Assessment Instrument-Brief Form (WHOQoL-BREF). Pearson correlations, univariate regression analyses, and multiple linear regression analyses were performed.

RESULTS

The BIS-11 total score was significantly correlated with the WHOQoL-BREF total score (r=-0.55, p<0.01) and with the WHOQoL-BREF subscales. After controlling for GAF score and other clinical variables, the BIS-11 total score (β=-0.43, p=0.001) was independently associated with overall QoL. Additionally, the BIS-11 total score was particularly strongly associated with the physical, psychological, and social domains of the multi-dimensional QoL scale.

CONCLUSION

Our results suggest that high impulsivity is related to low QoL in euthymic BD patients. Further studies are needed to examine whether interventions for high impulsivity effectively improve QoL in patients with BD.