Neurocognitive Impairments (NCI) in bipolar disorder: Comparison with schizophrenia and healthy controls

Evaluation des Troubles Cognitifs Chez des Patients Tunisiens Atteints de Trouble Bipolaire en Rémission : Étude Cas-Témoins: Assessment of Cognitive Impairment in Tunisian Patients With Bipolar Disorder in Remission: A Case-Control Study

OBJECTIVES

Our aims were to assess cognitive impairment in bipolar patients in remission compared with healthy controls, and to study its connection to clinical and therapeutic factors.

METHODOLOGY

This was a case-control study of patients with bipolar disorder (BD) in remission and matched healthy controls. It was carried out at the Hédi Chaker University Hospital in Sfax, Tunisia. The Screen for Cognitive Impairment in Psychiatry (SCIP) scale was used to assess cognitive function in patients and controls. This scale comprises subtests for verbal learning with immediate (VLT-I) and delayed (VLT-D) recall, working memory (WMT), verbal fluency (VFT) and information processing speed (PST).

RESULTS

We recruited 61 patients and 40 controls. Compared with controls, patients had significantly lower scores on the overall SCIP scale and on all SCIP subtests (p < 0.001 throughout) with moderate to high effects. In multivariate analysis, the presence of psychotic characteristics correlated with lower scores on the overall SCIP (p = 0.001), VLT-I (p = 0.001) and VLT-D (p = 0.007), WMT (p = 0.002) and PST (p = 0.008). Bipolar II correlated with lower LTV-I scores (p = 0.023). Age of onset and duration of the disorder were negatively correlated with PST scores (p < 10-3 and p = 0.007, respectively). Predominantly manic polarity correlated with lower VFT scores (p = 0.007).

CONCLUSIONS

Our study showed that bipolar patients in remission presented significantly more marked cognitive impairments, affecting various cognitive domains, than the controls. These cognitive impairments appear to be linked to clinical and therapeutic factors that are themselves considered to be factors of poor prognosis in BD.

Cognitive Function in Patients with Psychotic and Affective Disorders: Effects of Combining Pharmacotherapy with Cognitive Remediation

Background: Cognitive impairment is a relevant problem in psychiatry and can be well assessed with a cross-diagnostic test such as the Screen for Cognitive Impairment in Psychiatry (SCIP). The aim of our pilot study is to assess cognitive impairment in acute psychiatric inpatients diagnosed with psychotic disorders, bipolar disorder and depression using the German version of the SCIP (SCIP-G). We also investigate whether cognitive dysfunction improves over the course of the inpatient treatment, where patients are offered a combination of pharmacological treatment and cognitive remediation. Methods: A total of 143 adult inpatients were included in the study. Cognitive testing was performed using two different forms of the SCIP-G. All patients received state-of-the-art pharmacotherapy and cognitive remediation using the COGPACK® software package version 6.06. Results: Based on the ICD-10 Criteria for Research, 54 patients were given an F2 diagnosis (schizophrenia and schizotypal and delusional disorders). Thirty-nine patients met the criteria for bipolar disorder (F30 and F31) and fifty for depression (F32 and F33). At baseline, a significant difference was observed between the SCIP total scores of the F2 and F32/33 patients (p < 0.001) and between the F2 and F30/31 groups (p = 0.022). At the second measurement time point, the SCIP total score showed significant improvement in all three groups (p < 0.001), and there was no statistically significant interaction between SCIP total score and diagnostic groups (p = 0.860). Conclusions: Cognitive dysfunction is present in psychiatric disorders and can be easily assessed during an inpatient hospital stay. In our sample, patients with a psychotic disorder were more cognitively impaired at baseline than patients with an affective disorder. Inpatient treatment, consisting of pharmacotherapy and cognitive remediation, improved cognitive deficits. Patients with psychotic disorders, bipolar disorder and depression showed similar improvements in cognitive performance.

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.

Social cognition and psychosocial functioning in schizophrenia and bipolar disorder: Theory of mind as a key to understand schizophrenia dysfunction

Functional impairment is a common symptom in schizophrenia (SZ) and bipolar disorder (BD). Pharmacological treatments have limited functional recovery in both disorders. Social cognition, a cognitive process, has been associated with functioning in mental disorders. Theory of mind (ToM) is considered a key factor in understanding the social cognitive deficits in SZ and BD. Our study aimed to investigate the relationship between ToM and functioning in SZ, BD, and healthy controls (HC) and compare ToM and functioning impairments between groups. A total of 208 participants (HC n = 69; BD n = 89; SZ n = 50) were evaluated with the Functioning Assessment Short Test (FAST), Reading the Mind in the Eyes Test (RMET), the Vocabulary subtest of the Wechsler Abbreviated Scale for Intelligence (WASI) and the Hopkins Verbal Learning Test - Revised (HVLT-R). Comparisons of RMET between low- and high-functioning individuals and multiple linear regression analyses were conducted for each group. Multiple regression analysis revealed that the association between ToM and psychosocial functioning was observed only in SZ (β = -1.352, p = 0.008). Low-functioning SZ participants showed a lower ToM performance compared to participants with high-functioning SZ (t = 1.80, p = 0.039, Cohen's d = 0.938). No significant associations were found in the other groups. ToM is essential to understand the functional impairment in SZ, more than in BD. Furthermore, ToM may be a primary target for intervention strategies in improving functioning in SZ.

Better than expected: the gap between self-reported and objective measures of cognitive performance in remitted bipolar disorder

Background

Studies comparing objective and self-reported cognitive functioning as well as influencing factors in individuals with remitted bipolar disorder are scarce and contradictory.

Methods

The aim of this study was to compare executive functioning and other objective and self-reported cognitive impairment between 26 individuals with remitted bipolar disorder (15 BD I) and 24 healthy controls using a cross-sectional design. Executive functions were measured by the TAP Go/No-go subtest as well as the Stroop Task. Self-rated functioning was assessed using the Attention Deficit Experience Questionnaire. In addition, possible predictors of self-reported and objective cognitive functioning were examined to perform regression analyses.

Results

Individuals with remitted bipolar disorder did not differ significantly in executive functions or other objective cognitive domains from the healthy control group, but showed a significantly lower level of self-reported cognitive functioning and self-esteem. While self-esteem was the strongest predictor in healthy controls for self-reported cognitive functioning, severity of illness and subthreshold depressive mood were the most important predictors in individuals with remitted bipolar disorder.

Conclusion

The results once again demonstrate the cognitive heterogeneity in bipolar disorder. In the treatment of cognitive deficits, factors such as subthreshold depressive symptomatology and self-esteem should be focused on in addition to cognitive training in remitted patients.

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

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

Different Frequency of Heschl’s Gyrus Duplication Patterns in Neuropsychiatric Disorders: An MRI Study in Bipolar and Major Depressive Disorders

An increased prevalence of duplicated Heschl’s gyrus (HG) has been repeatedly demonstrated in various stages of schizophrenia as a potential neurodevelopmental marker, but it remains unknown whether other neuropsychiatric disorders also exhibit this macroscopic brain feature. The present magnetic resonance imaging study aimed to examine the disease specificity of the established finding of altered HG patterns in schizophrenia by examining independent cohorts of bipolar disorder (BD) and major depressive disorder (MDD). Twenty-six BD patients had a significantly higher prevalence of HG duplication bilaterally compared to 24 age- and sex-matched controls, while their clinical characteristics (e.g., onset age, number of episodes, and medication) did not relate to HG patterns. No significant difference was found for the HG patterns between 56 MDD patients and 33 age- and sex-matched controls, but the patients with a single HG were characterized by more severe depressive/anxiety symptoms compared to those with a duplicated HG. Thus, in keeping with previous findings, the present study suggests that neurodevelopmental pathology associated with gyral formation of the HG during the late gestation period partly overlaps between schizophrenia and BD, but that HG patterns may make a somewhat distinct contribution to the phenomenology of MDD.

Serum levels of olanzapine are associated with acute cognitive effects in bipolar disorder

Bipolar (BPD) patients have deficits in cognition, but there are still controversies about the effects of some medications on their cognitive performance. Here, we investigated the relationship between cognition in terms of executive functions, memory, and attention in both first-episode medication-naive BPD patients and BPD patients taking olanzapine. Forty-one healthy controls, 40 unmedicated drug-naive BPD patients, and 34 BPD patients who took only olanzapine were recruited for the study. Cognitive performance was assessed using the Flanker test, Stroop test, and Corsi-block test. Bayesian multivariate regression analysis was run considering maximum robustness to avoid bias and to predict the outcomes. Our results revealed that unmedicated medication-naive BPD patients performed worse than healthy controls and the olanzapine group in some tasks. Additionally, BPD patients who took olanzapine had better cognitive performance than healthy controls and unmedicated BPD patients. The acute cognitive effects were predicted by olanzapine dosage and serum levels (i.e., large effects). The potential pro-cognitive effects of olanzapine in BPD patients should be carefully interpreted by considering various other clinical variables. We expect that our findings will contribute to further research in this area, with the goal of helping other researchers, patients, and the population.

The relations between executive functions and occupational functioning in individuals with bipolar disorder: a scoping review

Background

Patients with bipolar disorder experience impairments in their occupational functioning, despite remission of symptoms. Previous research has shown that neurocognitive deficits, especially deficits in executive functions, may persist during euthymia and are associated with diminished occupational functioning.

Objectives

The aim of this scoping review was to identify published studies that report on the relationships between executive functions and occupational functioning in BD to review current knowledge and identify knowledge gaps. In addition to traditional neuropsychological approaches, we aimed to describe executive functioning from a self-regulation perspective, including emotion regulation.

Methods

We applied the methodological framework as described by Arksey and O’Malley (Int J Soc Res Methodol Theory Pract 8:19–32, 2005) and Levac et al. (Implement Sci 5:1–9, 2010). We searched PubMed and psycINFO for literature up to November 2021, after which we screened papers based on inclusion criteria. Two reviewers independently performed the screening process, data charting process, and synthesis of results.

Results

The search yielded 1202 references after deduplication, of which 222 remained after initial screening. The screening and inclusion process yielded 82 eligible papers in which relationships between executive functions and occupational functioning are examined.

Conclusion

Neurocognitive deficits, including in executive functions and self-regulation, are associated with and predictive of diminished occupational functioning. Definitions and measurements for neurocognitive functions and occupational functioning differ greatly between studies, which complicates comparisons. Studies on functional remediation show promising results for improving occupational functioning in patients with BD. In research and clinical practice more attention is needed towards the quality of work functioning and the various contexts in which patients with BD experience deficits.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40345-022-00255-7.

The significance of sleep quality in euthymic bipolar patients from Nigeria

Background

Bipolar disorder is highly under-researched in Africa. Existing studies show that racial/ethnic disparities exist for sleep quality. Poor sleep quality in bipolar disorder causes significant morbidity and mortality even during periods of euthymia.

Aim

This study aimed to assess sleep quality and its correlates amongst euthymic patients with bipolar I disorder from Nigeria.

Setting

The study was carried out in a teaching hospital, and state hospital, in Ibadan, Nigeria.

Method

This cross-sectional study was conducted amongst 76 euthymic bipolar patients aged between 18 and 60 years, meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) diagnostic criteria for bipolar disorder. Euthymia was defined as having a score of ≤ 5 on the Young Mania Rating Scale and < 8 on the Hamilton Depression Rating Scale. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI).

Results

A total of 37 (48.7%) participants had poor quality sleep. Sleep quality was associated with marital status (p = 0.013) and suicide plan (p = 0.047). Participants with good sleep quality had higher total sleep duration, lower time to fall asleep (sleep latency), better subjective quality of sleep, were less likely to use sleep medications and had less daytime dysfunction than participants with poor sleep quality. All p-values were < 0.05. Subjective quality of sleep, ongoing use of sleep medication, daytime dysfunction were independently associated with poor sleep quality.

Conclusion

Poor sleep quality frequently persists during euthymic periods in patients with bipolar disorder. The correlates identified can be targeted for intervention during treatment.

Neurocognition, functional outcome, and quality of life in remitted and non-remitted schizophrenia: A comparison with euthymic bipolar I disorder and a control group

There are discrepancies about if the severity of the symptomatology in schizophrenia is related to neurocognitive performance, functional outcome, and quality of life (QoL). Also, there are controversial data about the comparison between euthymic bipolar patients and different subgroups of schizophrenia in neurocognition, functioning, and QoL level. The present study aimed to compare the neurocognitive performance, functional outcome, and QoL of remitted and non-remitted patients with SC with respect to a group of euthymic patients with BD, and a control group. It included 655 subjects: 98 patients with schizophrenia in remission (SC-R), 184 non-remitted patients with schizophrenia (SC-NR), 117 euthymic patients with bipolar I disorder (BD), and 256 healthy subjects. A comprehensive clinical, neurocognitive (six cognitive domains), functional, and QoL assessment was carried out. Remission criteria of Andreasen were used to classify schizophrenia patients as remitted or non-remitted. Compared with control subjects all groups of patients showed impaired neurocognitive performance, functioning and QoL. SC-R patients had an intermediate functioning between control subjects and SC-NR, all at a neurocognitive, functional, or QoL level. There were no significant differences between SC-R and BD. These results suggest that reaching clinical remission is essential to achieve a better level of psychosocial functioning, and QoL. Likewise, the results of this study suggest that euthymic patients with bipolar disorder and patients with schizophrenia in remission are comparable at the neurocognitive and functional levels, which might have implications in the pathophysiology of both disorders.

Number of episodes and duration of illness associated with hypertension and 10-year cardiovascular risk in patients with bipolar disorder type I

Severe Mental Illnesses, including bipolar disorder (BD) and schizophrenia (SCZ), are burdened with an increased mortality and a significantly reduced life expectancy than general population, and cardiovascular diseases (CVD) are considered the most contributing conditions. The aim of the present study is to evaluate 10-year CV risk and the associated clinical characteristics in patients with SCZ, BD type I and II. Patients were consecutively recruited from two Italian psychiatric acute units. Single CV risk factors were assessed, and 10-year CV risk calculated by means of the CUORE Project 10-year CV risk algorithm, based on the combination of the following risk factors: age, systolic blood pressure, total and high-density lipoprotein cholesterol, diabetes, smoking habit, and hypertensive treatment. Three hundred patients were included. Patients with BD type I showed a higher prevalence of hypertension and 10-year CV risk score compared to the other groups. In subjects with BD type I, we found a significant correlation between duration of illness and number of mood episodes and both hypertension and 10-year CV risk score. Several preventive strategies should be provided to these vulnerable populations, such as correcting unhealthy lifestyles, prescribing medications at lower CV and metabolic risk, enhancing access to care.

Graph Analysis of Verbal Fluency Tests in Schizophrenia and Bipolar Disorder

Verbal Fluency Tests (VFT) are one of the most common neuropsychological tasks used in bipolar disorder (BD) and schizophrenia (SZ) research. Recently, a new VFT analysis method based on graph theory was developed. Interpreting spoken words as nodes and every temporal connection between consecutive words as edges, researchers created graph structures, allowing the extraction of more data from participants’ speech, called Speech Graph Attributes (SGA). The aim of our study was to compare speech graphs, derived from Phonemic and Semantic VFT, between SZ, BD, and healthy controls (HC). Twenty-nine SZ patients, twenty-nine BD patients, and twenty-nine HC performed Semantic and Phonemic VFT. Standard measures (SM) and 13 SGA were analyzed. SZ patients’ Semantic VFT graphs showed lower total word count and correct responses. Their graphs presented less nodes and edges, higher density, smaller diameter, average shortest path (ASP), and largest strongly connected component than the HC group. SM did not differentiate BD and HC groups, and patients’ Semantic VFT graphs presented smaller diameter and ASP than HC. None of the parameters differentiated BD and SZ patients. Our results encourage the use of speech graph analysis, as it reveals verbal fluency alterations that remained unnoticed in the routine comparisons of groups with the use SM.

Association between abnormal glycolipid level and cognitive dysfunction in drug-naïve patients with bipolar disorder

OBJECTIVES

Cognitive impairment and abnormal glycolipid metabolism are common clinical features of bipolar disorder (BD). The purpose of this study was to investigate the relationship between conventional glycolipid metabolism indicators and cognitive impairment in patients with BD.

METHODS

A total of 132 drug-naïve patients with BD and 129 healthy controls (HC) were recruited in the study. Five serum glycolipid metabolism indicators were measured and cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Stroop Color-Word Test (Stroop test) for each participant.

RESULTS

The scores of immediate memory, attention, language and delayed memory in BD group were significantly lower than those in HC group (P < 0.05). The triglyceride (TG) level in BD group was higher than that in HC group (P = 0.011), and the total cholesterol and high-density lipoprotein cholesterol (HDL) levels were lower than those in HC group (P = 0.026; P = 0.001). Regression analysis showed that TG level was significantly correlated with RBANS total score (β = 0.245, P = 0.008), attention (β = 0.289, P = 0.03) and delayed memory (β = 0.221, P = 0.023). Fasting blood glucose (FBG) level was significantly correlated with language subscale score (β = -0.187, P = 0.046) in BD.

LIMITATIONS

Cross-sectional design and limited control variables.

CONCLUSIONS

Elevated FBG and TG levels may be associated with cognitive dysfunction in BD patients. Improving glycolipid metabolism in patients with BD may help to improve certain domain-specific cognitive functions.

Body mass index (BMI) and obesity in Nigerians with schizophrenia

BACKGROUND

Few Nigerian studies have examined BMI in people with schizophrenia. The aims of the present study were to assess the prevalence and distribution of obesity in Nigerians with schizophrenia and to examine the clinical correlates of BMI and obesity.

METHODS

A total of 207 people with schizophrenia met the inclusion criteria and were evaluated for BMI.The Positive and Negative Syndrome Scale (PANSS), Hamilton Depression Rating Scale (HDRS), Social and Occupational Functioning Assessment Scale (SOFAS) were rated for all participants. Anthropometric measures such as weight and height were taken using a standard protocol.

RESULTS

The prevalence of obesity was 12.6%. The non-obese participants were made up of underweight 24 (11.7%), normal weight 118 (57%) and overweight 38 (18.4%). Compared to non-obese participants, obese participants were older, more educated, more likely to be employed, had higher incomes, lower PANSS score (negative subscale), had fewer female participants, and better social and occupational functioning (p < 0.05). BMI was positively correlated with age and monthly income. In the adjusted model, age, gender and education were independently associated with obesity while only age was associated with BMI.

CONCLUSION

The present study suggests that unlike in high-income countries, obese patients with schizophrenia in Nigeria have better social and psychological functioning than non-obese patients.

Spirituality and Suicidality Among Patients with Schizophrenia: A Cross-sectional Study from Nigeria

Studies which have explored the effect of spirituality on suicidality among patients with schizophrenia have been characterized by inconsistent results. The aim of this study was to examine the relationship between spirituality and suicidality among stable patients with schizophrenia in Nigeria. The Daily Spiritual Experience Scale was applied to measure spirituality. There was found a significant relationship between spirituality and having had suicidal thoughts in a lifetime. Spirituality was negatively correlated with the severity of negative symptoms, total positive and negative syndrome scale score (PANSS), the severity of depression, and positively correlated with functioning.

Sleep quality and cognitive impairments in remitted patients with schizophrenia in Nigeria

BACKGROUND

Despite the ubiquity of sleep disturbance in schizophrenia, it has generally been overlooked as a potential contributor to cognitive impairments. The main aim of this study was to find out if impaired sleep quality contributes to cognitive impairments in patients with a diagnosis of schizophrenia who are in remission.

METHODS

The study was conducted at the University College Hospital, Ibadan and State Hospital, Ibadan, Nigeria. The Pittsburgh Sleep Quality Index (PSQI) and Screen for Cognitive Impairment in Psychiatry (SCIP) were applied in this cross-sectional study, to all consecutive and consenting remitted outpatients with schizophrenia (N=130). Other instruments such as Hamilton Depression Rating Scale (HDRS), the Positive and Negative Syndrome Scale (PANSS), sociodemographic and clinical measures were also applied.

RESULTS

There were 130 participants made up of 69 females (53.1%) and 61males(46.9%). The mean age of the participants was 38.5±9.1 years. The prevalence of poor sleep quality in remitted patients with schizophrenia was 56.9%. Sleep quality was significantly negatively correlated with Verbal Learning Test-Immediate (VLT-I) (r(128)=-.18, P=.044) and Verbal Learning Test-Delayed (VLT-D) (r(128)=-.18, P=.037). The variables that independently predicted cognitive functioning were the VLT-I, odds ratio (OR) 0.66; 95% confidence interval ((CI) 0.49-0.88) and education (OR) 0.61;(CI) 0.40- 0.92).

CONCLUSION

Poor subjective sleep quality measured by the PSQI is linked to cognitive impairment in remitted patients with schizophrenia. We suggest that sleep quality in remitted patients with a diagnosis of schizophrenia should receive better attention by physicians.