The influence of cognitive reserve on psychosocial and neuropsychological functioning in bipolar disorder

Methodological recommendations for cognition trials in bipolar disorder by the International Society for Bipolar Disorders Targeting Cognition Task Force

OBJECTIVES

To aid the development of treatment for cognitive impairment in bipolar disorder, the International Society for Bipolar Disorders (ISBD) convened a task force to create a consensus-based guidance paper for the methodology and design of cognition trials in bipolar disorder.

METHODS

The task force was launched in September 2016, consisting of 18 international experts from nine countries. A series of methodological issues were identified based on literature review and expert opinion. The issues were discussed and expanded upon in an initial face-to-face meeting, telephone conference call and email exchanges. Based upon these exchanges, recommendations were achieved.

RESULTS

Key methodological challenges are: lack of consensus on how to screen for entry into cognitive treatment trials, define cognitive impairment, track efficacy, assess functional implications, and manage mood symptoms and concomitant medication. Task force recommendations are to: (i) enrich trials with objectively measured cognitively impaired patients; (ii) generally select a broad cognitive composite score as the primary outcome and a functional measure as a key secondary outcome; and (iii) include remitted or partly remitted patients. It is strongly encouraged that trials exclude patients with current substance or alcohol use disorders, neurological disease or unstable medical illness, and keep non-study medications stable. Additional methodological considerations include neuroimaging assessments, targeting of treatments to illness stage and using a multimodal approach.

CONCLUSIONS

This ISBD task force guidance paper provides the first consensus-based recommendations for cognition trials in bipolar disorder. Adherence to these recommendations will likely improve the sensitivity in detecting treatment efficacy in future trials and increase comparability between studies.

Are patients with bipolar disorder and comorbid attention-deficit hyperactivity disorder more neurocognitively impaired?

OBJECTIVE

Research on neurocognitive impairment in adult patients with comorbid bipolar disorder (BD) and attention-deficit hyperactivity disorder (ADHD) is very scarce. This study assessed the neurocognitive profile of a comorbid group (BD+ADHD) compared with that of pure BD (pBD) group, pure ADHD (pADHD) group and healthy controls (HCs).

METHODS

This was a three-site study comprising 229 subjects: 70 patients with pBD, 23 with BD+ADHD, 50 with pADHD, and 86 HCs. All patients with BD had been euthymic for at least 6 months. Neuropsychological performance was assessed using a comprehensive neurocognitive battery.

RESULTS

Our results showed that all the clinical groups had poorer performance than the HCs in all the neurocognitive domains except for executive functions. No significant differences were observed between the pBD and BD+ADHD groups in any of the cognitive domains, with these two groups showing greater impairment than the pADHD group in executive functions and visual memory.

CONCLUSIONS

Our results, although preliminary, suggest that the BD+ADHD group showed the same neurocognitive profile as pBD patients, most likely reflecting the same neurobiological basis. On the other hand, the pADHD group showed a more selective moderate impairment in attention.

Impact of childhood trauma on cognitive profile in bipolar disorder

OBJECTIVES

Bipolar Disorder (BD) is associated with cognitive impairment even during remission periods. Nonetheless, this impairment seems to adjust to different profiles of severity. Our aim was to examine the potential impact of childhood trauma (CT) on cognitive performance and, more specifically, on neurocognitive profile membership.

METHODS

Using a data-driven strategy, 113 euthymic bipolar patients were grouped according to their cognitive performance using a hierarchical clustering technique. Patients from the three resulting clusters, the so-called "low", "average", and "high performance" groups, were then compared in terms of main sociodemographic, clinical and functioning variables, including CT measures. One-way ANOVA, a chi-square test and partial correlations were used for this purpose, as appropriate. A multinomial logistic regression model was used to determine which variables contributed to neurocognitive clustering membership.

RESULTS

Patients from the three neurocognitive clusters differed in terms of sociodemographic, clinical, functioning and CT variables. Scores on the Childhood Trauma Questionnaire (CTQ), especially on the physical negligence subscale, were also associated with a poor cognitive performance. The multinomial regression model indicated that CTQ total scores and the estimated intelligence quotient (IQ) significantly contributed to differentiation among the three neurocognitive groups.

CONCLUSIONS

Our results confirmed that CT significantly impacts on cognitive performance during adulthood in BD. The data obtained suggest that a history of CT could act as a liability marker for cognitive impairment. A higher estimated IQ may act as a protective factor against cognitive decline in this group of patients.

Social cognition in bipolar disorder: Focus on emotional intelligence

BACKGROUND

The present study aims to characterize emotional intelligence (EI) variability in a sample of euthymic bipolar disorder (BD) patients through the Mayer- Salovey-Caruso Emotional Intelligence Test (MSCEIT).

METHOD

A total of 134 euthymic BD outpatients were recruited and divided into three groups according to the total Emotional Intelligence Quotient (EIQ) score of the MSCEIT, following a statistical criterion of scores 1.5SDs above/below the normative group mean, as follows: a low performance (LP) group (EIQ <85), a normal performance (NP) group (85≤EIQ≤115), and a high performance (HP) group (EIQ >115). Afterwards, main sociodemographic, clinical, functional and neurocognitive variables were compared between the groups.

RESULTS

Three groups were identified: 1) LP group (n=16, 12%), 2) NP group (n=93, 69%) and 3) HP group (n=25, 19%). There were significant differences between the groups in premorbid intelligence quotient (IQ) (p=0.010), axis II comorbidity (p=0.008), subthreshold depressive symptoms (p=0.027), general functioning (p=0.013) and in four specific functional domains: autonomy, occupation, interpersonal relations and leisure time. Significant differences in neurocognitive performance were found between groups with the LP group showing the lowest attainments.

LIMITATIONS

The cross-sectional design of the study.

CONCLUSION

Our results suggest that EI variability among BD patients, assessed through MSCEIT, is lower than expected. EI could be associated with premorbid IQ, subthreshold depressive symptoms, neurocognitive performance and general functioning. The identification of different profiles of SC may help guide specific interventions for distinct patient subgroups aimed at improving social cognition, neurocognitive performance and psychosocial functioning.

Relationship Between Cognitive Function and Clinical Features in Patients With Bipolar I Disorder

INTRODUCTION

Previous studies suggest that the severity of alterations in cognitive functions in people with a diagnosis of bipolar I disorder (BP-I) are directly related to the deterioration in overall functioning and life quality. Altered cognitive function is associated with a worse prognosis of BP-I, however little is known about the relationship between cognitive functions and the clinical features of BP-I.

OBJECTIVE

To establish possible associations between cognitive function and the clinical and socio-demographic characteristics of patients with BP-I.

METHODS

Cognitive function was evaluated by applying a neuropsychological battery to a group of patients with a BP-I diagnosis, who did not have affective episodes for at least 6 months, and who were outpatients treated at the San Juan de Dios Clinic in Manizales. The statistical analysis involved using clustering methocology in order to divide those patients with the best and worst cognitive function and it was later correlated with the clinical and socio-demographic variables.

RESULTS

A statistically significant corrrelation was found between the number of years of education and the age the disorder started with alterations in the level of cognitive function (P=.002 and P=.017 respectively). No significant correlations were found with other variables.

CONCLUSIONS

An early onset of the pathology and fewer years of education seems to be risk factors associated with poorer cognitive function in patients with BP-I.

White Matter Tract Integrity in Alzheimer's Disease vs. Late Onset Bipolar Disorder and Its Correlation with Systemic Inflammation and Oxidative Stress Biomarkers

Background: Late Onset Bipolar Disorder (LOBD) is the development of Bipolar Disorder (BD) at an age above 50 years old. It is often difficult to differentiate from other aging dementias, such as Alzheimer's Disease (AD), because they share cognitive and behavioral impairment symptoms.

Objectives: We look for WM tract voxel clusters showing significant differences when comparing of AD vs. LOBD, and its correlations with systemic blood plasma biomarkers (inflammatory, neurotrophic factors, and oxidative stress).

Materials: A sample of healthy controls (HC) (n = 19), AD patients (n = 35), and LOBD patients (n = 24) was recruited at the Alava University Hospital. Blood plasma samples were obtained at recruitment time and analyzed to extract the inflammatory, oxidative stress, and neurotrophic factors. Several modalities of MRI were acquired for each subject,

Methods: Fractional anisotropy (FA) coefficients are obtained from diffusion weighted imaging (DWI). Tract based spatial statistics (TBSS) finds FA skeleton clusters of WM tract voxels showing significant differences for all possible contrasts between HC, AD, and LOBD. An ANOVA F-test over all contrasts is carried out. Results of F-test are used to mask TBSS detected clusters for the AD > LOBD and LOBD > AD contrast to select the image clusters used for correlation analysis. Finally, Pearson's correlation coefficients between FA values at cluster sites and systemic blood plasma biomarker values are computed.

Results: The TBSS contrasts with by ANOVA F-test has identified strongly significant clusters in the forceps minor, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and cingulum gyrus. The correlation analysis of these tract clusters found strong negative correlation of AD with the nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) blood biomarkers. Negative correlation of AD and positive correlation of LOBD with inflammation biomarker IL6 was also found.

Conclusion: TBSS voxel clusters tract atlas localizations are consistent with greater behavioral impairment and mood disorders in LOBD than in AD. Correlation analysis confirms that neurotrophic factors (i.e., NGF, BDNF) play a great role in AD while are absent in LOBD pathophysiology. Also, correlation results of IL1 and IL6 suggest stronger inflammatory effects in LOBD than in AD.

The predictive role of daily cognitive stimulation on executive functions in bipolar disorder

This study aimed to estimate the predictive role of clinical and demographic variables on the three core executive functions (EF) - working memory (WM), inhibitory control (IC) and cognitive flexibility (CF) - in bipolar disorder (BD). The sample consisted of 38 patients with BD type I, 39 with BD type II, and 106 control participants with no mood disorders. Subjects completed the Hayling Test, Trail Making Test, Digit Span Backwards, Sentence Word Span Test, and Stroop Color-Word Test. Composite scores for WM, IC and CF were calculated, and their correlations with clinical and demographic variables were analyzed. Stepwise hierarchical regression models including all significant correlates, gender, and diagnosis, revealed that the frequency of reading and writing habits (FRWH), IQ and diagnosis predicted 38.1% of the variance in IC. Diagnosis and IQ predicted 24.9% of the variance in WM scores. CF was predicted by the FRWH only, which accounted for 7.6% of the variance in this construct. These results suggest that daily cognitive stimulation through reading and writing make a significant positive contribution to executive functioning in BD, even in the absence of continued education. These and other forms of routine cognitive stimulation should be further emphasized in intervention programs for BD.

Cognitive Impairment in Bipolar Disorder: Treatment and Prevention Strategies

Over the last decade, there has been a growing appreciation of the importance of identifying and treating cognitive impairment associated with bipolar disorder, since it persists in remission periods. Evidence indicates that neurocognitive dysfunction may significantly influence patients' psychosocial outcomes. An ever-increasing body of research seeks to achieve a better understanding of potential moderators contributing to cognitive impairment in bipolar disorder in order to develop prevention strategies and effective treatments. This review provides an overview of the available data from studies examining treatments for cognitive dysfunction in bipolar disorder as well as potential novel treatments, from both pharmacological and psychological perspectives. All these data encourage the development of further studies to find effective strategies to prevent and treat cognitive impairment associated with bipolar disorder. These efforts may ultimately lead to an improvement of psychosocial functioning in these patients.

Do patients with bipolar disorder and subsyndromal symptoms benefit from functional remediation? A 12-month follow-up study

We analyzed the efficacy of functional remediation, in a sample of patients with bipolar disorder who presented with subsyndromal symptoms. From a total sample of 239 patients with bipolar I and II disorder, according to DSM-IV-TR diagnostic criteria, entering a randomized clinical trial, those patients who presented with subsyndromal symptoms were selected based on a method already described by Berk and colleagues was applied. It consists of using the Clinical Global Impression-Bipolar version (CGI-BP) to establish the scores of the Hamilton Depression Rating Scale (HAM-D) and of the Young Mania Rating Scale (YMRS) that correspond with 1 in the CGI-BP. Functional outcome and mood symptoms were assessed at 6 and at 12-month follow-up. A total of 99 patients were selected for this post-hoc analysis, allocated as follows: functional remediation (n=33); psychoeducation (n=37) and treatment as usual (TAU,n=29). The repeated-measures analyses at 12-month follow-up revealed a significant group x time interaction in favour of the patients who received functional remediation when compared to psychoeducation and TAU (F=2.93; p=0.02) at improving psychosocial functioning. Finally, mood symptoms did not significantly change in any of the three groups at any time of follow-up, as shown by the non-significant group x time interaction effect in HAM-D scores (F=1.57; p=0.18) and YMRS scores (F=1.51; p=0.20). Bipolar patients with subsyndromal symptoms improve their functional outcome when exposed to functional remediation regardless of the persistence of mood symptomatology.

The effect of premorbid intelligence on neurocognitive and psychosocial functioning in bipolar disorder

BACKGROUND

The aim of this study was to assess if premorbid IQ moderates the association between measures of clinical severity and neurocognitive or psychosocial functioning in euthymic patients with bipolar disorder.

METHODS

One hundred and nineteen outpatients and forty healthy controls were included. The length of illness, number of previous hypo/manic and depressive episodes, episode density, and history of psychosis assessed clinical severity. Performances in verbal memory, attention, and executive functions, as well as level of psychosocial functioning were used as outcomes.

RESULTS

The negative relationship between number of hypo/manic episodes and performance in executive functions decreased as a function of higher values of premorbid IQ. No other influences of premorbid IQ were found in the association between clinical severity measures and neurocognitive and psychosocial functioning.

CONCLUSIONS

Premorbid IQ might moderate the relationship between the number of hypo/manic episodes and executive functioning in bipolar disorder. Possible interpretations of this finding are discussed.

Influence of cognitive reserve on neuropsychological functioning in bipolar disorder: Findings from a 5-year longitudinal study

OBJECTIVES

The present study examined the 5-year longitudinal course of cognitive functioning in a large sample of well-characterized patients with bipolar disorder (BP), compared to healthy controls (HCs), and the influence of cognitive reserve factors (e.g., education and IQ) on cognitive change over time.

METHODS

Participants included 159 individuals diagnosed with BP and 54 HCs recruited as part of a longitudinal naturalistic study of BP who had completed neuropsychological testing at the time of their enrollment and again 5 years later.

RESULTS

The overall relative rate of change did not differ between the BP and HC groups. In total, 46.5% of the BP group and 37% of the HC group showed evidence of decline on at least one measure over time. T-test analyses did not find differences between BP 'decliners' and 'non-decliners' in cognitive reserve variables. However, we found that higher baseline intellectual ability was associated with more stability in cognitive test scores over time for the BP group. Results of linear regression modeling revealed that lower verbal IQ and education were related to increased cognitive decline in specific domains in the BP group.

CONCLUSIONS

This study has explored the influence of cognitive reserve on preservation of specific cognitive abilities over time in BP. The BP group did not demonstrate accelerated cognitive decline over 5 years compared to the HC group. Although the trajectory of cognitive change over time was similar between BP patients and HCs, higher overall intellectual ability may be a protective factor against cognitive decline, particularly for BP patients.

High cognitive reserve in bipolar disorders as a moderator of neurocognitive impairment

BACKGROUND

Cognitive reserve (CR) reflects the capacity of the brain to endure neuropathology, minimize clinical manifestations and successfully complete cognitive tasks. The present study aims to determine whether high CR may constitute a moderator of cognitive functioning in bipolar disorder (BD).

METHODS

102 patients with BD and 32 healthy controls were enrolled. All patients met DSM-IV criteria for I or II BD and were euthymic (YMRS≤6 and HDRS≤8) during a 6-month period. All participants were tested with a comprehensive neuropsychological battery, and a Cerebral Reserve Score (CRS) was estimated. Subjects with a CRS below the group median were classified as having low CR, whereas participants with a CRS above the median value were considered to have high CR.

RESULTS

Participants with BD with high CR displayed a better performance in measures of attention (digits forward: F=4.554, p=0.039); phonemic and semantic verbal fluency (FAS: F=9.328, p=0.004; and Animal Naming: F=8.532, p=0.006); and verbal memory (short cued recall of California Verbal Learning Test: F=4.236, p=0.046), after multivariable adjustment for potential confounders, including number of admissions and prior psychotic symptoms.

LIMITATIONS

The cross-sectional design of the study does not allow the establishment of causal inferences. Additionally, the small size of the sample may have limited some results.

CONCLUSIONS

High cognitive reserve may therefore be a valuable construct to explore for predicting neurocognitive performance in patients with BD regarding premorbid status.

Treatment of Functional Impairment in Patients with Bipolar Disorder

Traditionally, functional impairment has received little attention in bipolar disorder, despite the fact that many patients experience significant impairments in daily life. In the last decade, research has changed its focus from clinical remission to functional recovery in bipolar patients as a priority. A literature review of this topic will allow us provide an overview of the relevance of functional impairment as well as the potential factors that can predict or contribute to low functioning in bipolar disorder (BD). Treatment approaches should consider not only euthymia as a goal but also cognitive and functional improvement of patients with such a complex disorder. Functional remediation and psychoeducation among psychological interventions may help to enhance functioning. The combination of cognitive enhancers and cognitive/functional remediation programs may help in improving cognitive and functional impairments. Early interventions are essential to prevent cognitive deficits and disability.

Predictors of the discrepancy between objective and subjective cognition in bipolar disorder: a novel methodology

OBJECTIVE

The poor relationship between subjective and objective cognitive impairment in bipolar disorder (BD) is well-established. However, beyond simple correlation, this has not been explored further using a methodology that quantifies the degree and direction of the discrepancy. This study aimed to develop such a methodology to explore clinical characteristics predictive of subjective-objective discrepancy in a large BD patient cohort.

METHODS

Data from 109 remitted BD patients and 110 healthy controls were pooled from previous studies, including neuropsychological test scores, self-reported cognitive difficulties, and ratings of mood, stress, socio-occupational capacity, and quality of life. Cognitive symptom 'sensitivity' scores were calculated using a novel methodology, with positive scores reflecting disproportionately more subjective complaints than objective impairment and negative values reflecting disproportionately more objective than subjective impairment ('stoicism').

RESULTS

More subsyndromal depressive and manic symptoms, hospitalizations, BD type II, and being male positively predicted 'sensitivity', while higher verbal IQ predicted more 'stoicism'. 'Sensitive' patients were characterized by greater socio-occupational difficulties, more perceived stress, and lower quality of life.

CONCLUSION

Objective neuropsychological assessment seems especially warranted in patients with (residual) mood symptoms, BD type II, chronic illness, and/or high IQ for correct identification of cognitive deficits before commencement of treatments targeting cognition.

Cognitive reserve is associated with quality of life: A population-based study

OBJECTIVES

To assess the association between cognitive reserve (CR) and quality of life (QoL), as well as the role of depression, cognitive functioning, and disability in this association.

METHODS

Nationally-representative cross-sectional population-based data on 1973 individuals aged ≥50years from the Spanish sample of the Collaborative Research on Ageing in Europe (COURAGE) study were analysed. CR was a composite score ranging from 0 to 25 obtained from the Cognitive Reserve Questionnaire, which is composed of items on training courses, occupation, musical training, languages, reading activities, intellectual games, and level of education of the participants and their parents. QoL, ranging from 0 to 100, was assessed with the WHOQOL-AGE. Multiple linear regression and mediation analyses were performed.

RESULTS

Higher levels of CR were associated with higher QoL, after controlling for potential confounders (Coef. 0.53; 95% CI=0.36, 0.70). The strongest mediator in this association was disability, which explained about half of the association, while depression and cognition explained 6-10% of this association.

DISCUSSION

CR is associated with higher QoL in older adults. Interventions targeting determinants of CR that can be modified or trained across the lifespan may lead to successful ageing by prolonging autonomous functioning and enhancing QoL.

Cognitive reserve lessens the burden of white matter lesions on executive functions in bipolar disorder

BACKGROUND

The concept of cognitive reserve (CR) hypothesizes that intellectually stimulating activities provide resilience against brain pathology/disease. Whereas brain abnormalities and cognitive impairment are frequently reported in bipolar disorder (BD), it is unknown whether the impact of brain alterations can be lessened by higher CR in BD.

METHOD

We tested if higher CR would reduce the influence of total volumes of deep white matter hypointensities (WMH), ventricular cerebrospinal fluid (CSF), and prefrontal cortex on memory, executive, and attention/speed functions in patients with BD (n = 75). Linear regression models with interaction terms for CR and brain volumes were applied to directly test if CR reduces the influence of brain pathology on cognitive domains.

RESULTS

CR reduced the influence of total volumes of deep WMH (β = -0.38, Q = 0.003) and ventricular CSF (β = -41, Q = 006) on executive functions.

CONCLUSIONS

The interactions between CR and total volumes of deep WMH/ventricular CSF appear to account for executive functioning in BD. The results suggest that the concept of CR is applicable in BD. Higher reserve capacity in BD alters the relationship between brain pathology and clinical presentation.

Cognitive enhancement treatments for bipolar disorder: A systematic review and methodological recommendations

Cognitive dysfunction is an emerging treatment target in bipolar disorder (BD). Several trials have assessed the efficacy of novel pharmacological and psychological treatments on cognition in BD but the findings are contradictory and unclear. A systematic search following the PRISMA guidelines was conducted on PubMed and PsychInfo. Eligible articles reported randomized, controlled or open-label trials investigating pharmacological or psychological treatments targeting cognitive dysfunction in BD. The quality of the identified randomized controlled trials (RCTs) was evaluated with the Cochrane Collaboration's Risk of Bias tool. We identified 19 eligible studies of which 13 were RCTs and six were open-label or non-randomized studies. The findings regarding efficacy on cognition were overall disappointing or preliminary, possibly due to several methodological challenges. For the RCTs, the risk of bias was high in nine cases, unclear in one case and low in three cases. Key reasons for the high risk of bias were lack of details on the randomization process, suboptimal handling of missing data and lack of a priori priority between cognition outcomes. Other challenges were the lack of consensus on whether and how to screen for cognitive impairment and on how to assess efficacy on cognition. In conclusion, methodological problems are likely to impede the success rates of cognition trials in BD. We recommend adherence to the CONSORT guidelines for RCTs, screening for cognitive impairment before inclusion of trial participants and selection of one primary cognition outcome. Future implementation of a 'neurocircuitry-based' biomarker model to evaluate neural target engagement is warranted.

The impact of cognitive reserve in the outcome of first-episode psychoses: 2-year follow-up study

The concept of cognitive reserve (CR) suggests that the premorbid intelligence quotient (IQ), years of education and leisure activities provide more efficient cognitive networks and therefore allow a better management of some conditions associated to cognitive impairment. Fifty-two DSM-IV diagnosed FEP subjects were matched with 41 healthy controls by age, gender and parental socio-economic status. All subjects were assessed clinically, neuropsychologically and functionally at baseline and after a two-year follow-up. To assess CR at baseline, three proxies have been integrated: premorbid IQ, years of education-occupation and leisure activities. Higher CR was associated with better cognitive, functional and clinical outcomes at baseline. The CR proxy was able to predict working memory, attention, executive functioning, verbal memory and global composite cognitive score accounting for 48.9%, 19.1%, 16.9%, 10.8% and 14.9% respectively of the variance at two-year follow-up. CR was also significantly predictive of PANSS negative scale score (12.5%), FAST global score (13.4%) and GAF (13%) at two-year follow-up. In addition, CR behaved as a mediator of working memory (B=4.123) and executive function (B=3.298) at baseline and of working memory (B=5.034) at 2-year follow-up. An additional analysis was performed, in order to test whether this mediation could be attributed mainly to the premorbid IQ. We obtained that this measure was not enough by itself to explain this mediation. CR may contribute to neuropsychological and functional outcome. Specific programs addressed to improve cognition and functioning conducted at the early stages of the illness may be helpful in order to prevent cognitive and functional decline.

Improving Health Outcomes for Patients with Depression: A Population Health Imperative. Report on an Expert Panel Meeting

Improving Health Outcomes for Patients with Depression: A Population Health Imperative. Report on an Expert Panel Meeting Janice L. Clarke, RN, Alexis Skoufalos, EdD, Alice Medalia, PhD, and A. Mark Fendrick, MD Editorial: A Call to Action : David B. Nash, MD, MBA   S-2 OVERVIEW: Depression and the Population Health Imperative    S-3 Promoting Awareness of the Issues and Opportunities for Improvement    S-5 Cognitive Dysfunction in Affective Disorders    S-5 Critical Role of Employers in Improving Health Outcomes for Employees with Depression    S-6 Closing the Behavioral Health Professional and Process Gaps    S-6 Achieving the Triple Aim for Patients with Depressive Disorders    S-6 Improving the Experience of Care for Patients with Depression    S-6 Improving Quality of Care and Health Outcomes for Patients with Depression    S-7 Changing the Cost of Care Discussion from How Much to How Well    S-8 Panel Insights and Recommendations    S-9 Conclusion    S-10.

Executive dysfunction and cognitive subgroups in a large sample of euthymic patients with bipolar disorder

Bipolar disorder (BP), at the group level, is associated with significant but modest cognitive deficits, including executive dysfunction. Among executive functions, response inhibition deficits have been suggested to be particularly relevant to BP. However, BP is associated with significant heterogeneity in neurocognitive performance and level of functioning. Very few studies have investigated neurocognitive subgroups in BP with data-driven methods rather than arbitrarily defined criteria. Other than having relatively small sample sizes, previous studies have not taken into consideration the neurocognitive variability in healthy subjects. Five-hundred-fifty-six euthymic patients with BP and 416 healthy controls were assessed using a battery of cognitive tests and clinical measures. Neurocognitive subgroups were investigated using latent class analysis, based on executive functions. Four neurocognitive subgroups, including a good performance cluster, two moderately low-performance groups, which differ in response inhibition and reasoning abilities, and a severe impairment cluster were found. In comparison to healthy controls, BP patients were overrepresented in severe impairment cluster (27% vs 5.3%) and underrepresented in good performance cluster. BP patients with lower educational attainment and older age were significantly more likely to be members of cognitively impaired subgroups. Antipsychotic use was less common in good performance cluster. These results suggest that there is a considerable overlap of cognitive functions between BP and healthy controls. Neurocognitive differences between BP and healthy controls are driven by a subgroup of patients who have severe and global, rather than selective, cognitive deficits.

Cognitive reserve in bipolar disorder: relation to cognition, psychosocial functioning and quality of life

OBJECTIVE

Cognitive reserve (CR) is a concept that was postulated as a protective factor for some clinical symptoms after the observation that there is not a direct relationship between the degree of brain damage and its clinical manifestation. This study aimed to explore the association between CR and the main outcomes in bipolar disorder (BD): cognitive functions, psychosocial functioning and perceived quality of life.

METHOD

A sample of 224 euthymic bipolar patients was assessed with a neuropsychological battery, the Functioning Assessment Short Test and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). CR was calculated through three proxies: estimated premorbid Intelligent Quotient, educational level and occupational attainment. Relationships between CR and cognitive functions, psychosocial functioning and quality of life were assessed by multiple linear regression models.

RESULTS

Higher CR was associated with better cognitive functioning (P < 0.001 in processing speed, working memory, verbal and visual memory, and executive function; P = 0.026 in attention) and better psychosocial functioning (P = 0.008). For quality of life, CR was positively associated with the physical component of the SF-36 (P = 0.016) but negatively associated with the mental component (P = 0.004).

CONCLUSION

The results suggest that CR may play an important role in the course and prognosis of bipolar patients and it should be considered in both clinical and research settings related to BD.

Cognitive variability in bipolar II disorder: who is cognitively impaired and who is preserved

OBJECTIVES

Although it is well established that euthymic patients with bipolar disorder can have cognitive impairment, substantial heterogeneity exists and little is known about the extent and severity of impairment within the bipolar II disorder subtype. Therefore, the main aim of this study was to analyze cognitive variability in a sample of patients with bipolar II disorder.

METHODS

The neuropsychological performance of 116 subjects, including 64 euthymic patients with bipolar II disorder and 52 healthy control subjects, was examined and compared by means of a comprehensive neurocognitive battery. Neurocognitive data were analyzed using a cluster analysis to examine whether there were specific groups based on neurocognitive patterns. Subsequently, subjects from each cluster were compared on demographic, clinical, and functional variables.

RESULTS

A three-cluster solution was identified with an intact neurocognitive group (n = 29, 48.3%), an intermediate or selectively impaired group (n = 24, 40.0%), and a globally impaired group (n = 7, 11.6%). Among the three clusters, statistically significant differences were observed in premorbid intelligence quotient (p = 0.002), global functional outcome (p = 0.021), and leisure activities (p = 0.001), with patients in the globally impaired cluster showing the lowest attainments. No differences in other clinical characteristics were found among the groups.

CONCLUSIONS

These results confirm that neurocognitive variability is also present among patients with bipolar II disorder. Approximately one-half of the patients with bipolar II disorder were cognitively impaired, and among them 12% were severely and globally impaired. The identification of different cognitive profiles may help to develop cognitive remediation programs specifically tailored for each cognitive profile.

Low compliance to pharmacological treatment is linked to cognitive impairment in euthymic phase of bipolar disorder

BACKGROUND

Cognitive impairment and low compliance to pharmacological treatment are frequent complications in bipolar disorder. Moreover, low compliance in patients with bipolar disorder is one of the main reasons for relapse. This in turn, is associated with an increase in neurocognitive symptoms. The current study aimed to determine whether attention, memory, and executive function are related to the level of compliance to pharmacological treatment in individuals with bipolar disorder in euthymic phase.

METHOD

We examined 34 patients with bipolar disorder (12 with low compliance to the treatment and 22 with high compliance to the treatment) according to the DSM-IV criteria, in the range of 18-55 years. All patients were assessed through a neuropsychological battery in one single session. Analysis of covariance (ANCOVA) was used to compare neuropsychological test scores between low and high compliance patients. Clinical and sociodemographic characteristics were included as covariates in the study.

RESULTS

Patients with low level of compliance performed significantly worse than high treatment compliance on verbal memory immediate free recall (F (1)=12.14, p=.002), verbal memory immediate cued recall (F (1)=10.45, p=.003), verbal memory delayed free recall (F (1)=5.52, p=.027), and verbal memory delayed cued recall (F (1)=6.11, p=.021). Covariates such as number of manic episodes, history of psychosis and years of education were found significant for executive functions and processing speed.

CONCLUSION

We found that low compliance to pharmacological treatment is consistently linked to immediate and delayed verbal memory. In addition, executive function and processing speed were associated with clinical and demographic characteristics. Limitations of this study include the small sample size, a cross-sectional design that cannot address causality, and inability to account for pharmacologic effects.

Cognitive performance and psychosocial functioning in patients with bipolar disorder, unaffected siblings, and healthy controls

Objective:

To assess cognitive performance and psychosocial functioning in patients with bipolar disorder (BD), in unaffected siblings, and in healthy controls.

Methods:

Subjects were patients with BD (n=36), unaffected siblings (n=35), and healthy controls (n=44). Psychosocial functioning was accessed using the Functioning Assessment Short Test (FAST). A sub-group of patients with BD (n=21), unaffected siblings (n=14), and healthy controls (n=22) also underwent a battery of neuropsychological tests: California Verbal Learning Test (CVLT), Stroop Color and Word Test, and Wisconsin Card Sorting Test (WCST). Clinical and sociodemographic characteristics were analyzed using one-way analysis of variance or the chi-square test; multivariate analysis of covariance was used to examine differences in neuropsychological variables.

Results:

Patients with BD showed higher FAST total scores (23.90±11.35) than healthy controls (5.86±5.47; p < 0.001) and siblings (12.60±11.83; p 0.001). Siblings and healthy controls also showed statistically significant differences in FAST total scores (p = 0.008). Patients performed worse than healthy controls on all CVLT sub-tests (p < 0.030) and in the number of correctly completed categories on WCST (p = 0.030). Siblings did not differ from healthy controls in cognitive tests.

Conclusion:

Unaffected siblings of patients with BD may show poorer functional performance compared to healthy controls. FAST scores may contribute to the development of markers of vulnerability and endophenotypic traits in at-risk populations.

The Lithium Battery: assessing the neurocognitive profile of lithium in bipolar disorder

OBJECTIVE

The aim of the present study was to characterize the neurocognitive effects of lithium in bipolar disorder to inform clinical and research approaches for further investigation.

METHODS

Key words pertaining to neurocognition in bipolar disorder and lithium treatment were used to search recognized databases to identify relevant literature. The authors also retrieved gray literature (e.g., book chapters) known to them and examined pertinent articles from bibliographies.

RESULTS

A limited number of studies have examined the effects of lithium on neurocognition in bipolar disorder and, although in some domains a consistent picture emerges, in many domains the findings are mixed. Lithium administration appears to reshape key components of neurocognition - in particular, psychomotor speed, verbal memory, and verbal fluency. Notably, it has a sophisticated neurocognitive profile, such that while lithium impairs neurocognition across some domains, it seemingly preserves others - possibly those vulnerable to the effects of bipolar disorder. Furthermore, its effects are likely to be direct and indirect (via mood, for example) and cumulative with duration of treatment. Disentangling the components of neurocognition modulated by lithium in the context of a fluctuating and complex illness such as bipolar disorder is a significant challenge but one that therefore demands a stratified and systematic approach, such as that provided by the Lithium Battery.

CONCLUSIONS

In order to delineate the effects of lithium therapy on neurocognition in bipolar disorder within both research and clinical practice, a greater understanding and measurement of the relatively stable neurocognitive components is needed to examine those that indeed change with lithium treatment. In order to achieve this, we propose a Lithium Battery-Clinical and a Lithium Battery-Research that can be applied to these respective settings.

Discrimination between Alzheimer's Disease and Late Onset Bipolar Disorder Using Multivariate Analysis

Background

Late onset bipolar disorder (LOBD) is often difficult to distinguish from degenerative dementias, such as Alzheimer disease (AD), due to comorbidities and common cognitive symptoms. Moreover, LOBD prevalence in the elder population is not negligible and it is increasing. Both pathologies share pathophysiological neuroinflammation features. Improvements in differential diagnosis of LOBD and AD will help to select the best personalized treatment.

Objective

The aim of this study is to assess the relative significance of clinical observations, neuropsychological tests, and specific blood plasma biomarkers (inflammatory and neurotrophic), separately and combined, in the differential diagnosis of LOBD versus AD. It was carried out evaluating the accuracy achieved by classification-based computer-aided diagnosis (CAD) systems based on these variables.

Materials

A sample of healthy controls (HC) (n = 26), AD patients (n = 37), and LOBD patients (n = 32) was recruited at the Alava University Hospital. Clinical observations, neuropsychological tests, and plasma biomarkers were measured at recruitment time.

Methods

We applied multivariate machine learning classification methods to discriminate subjects from HC, AD, and LOBD populations in the study. We analyzed, for each classification contrast, feature sets combining clinical observations, neuropsychological measures, and biological markers, including inflammation biomarkers. Furthermore, we analyzed reduced feature sets containing variables with significative differences determined by a Welch’s t-test. Furthermore, a battery of classifier architectures were applied, encompassing linear and non-linear Support Vector Machines (SVM), Random Forests (RF), Classification and regression trees (CART), and their performance was evaluated in a leave-one-out (LOO) cross-validation scheme. Post hoc analysis of Gini index in CART classifiers provided a measure of each variable importance.

Results

Welch’s t-test found one biomarker (Malondialdehyde) with significative differences (p < 0.001) in LOBD vs. AD contrast. Classification results with the best features are as follows: discrimination of HC vs. AD patients reaches accuracy 97.21% and AUC 98.17%. Discrimination of LOBD vs. AD patients reaches accuracy 90.26% and AUC 89.57%. Discrimination of HC vs LOBD patients achieves accuracy 95.76% and AUC 88.46%.

Conclusion

It is feasible to build CAD systems for differential diagnosis of LOBD and AD on the basis of a reduced set of clinical variables. Clinical observations provide the greatest discrimination. Neuropsychological tests are improved by the addition of biomarkers, and both contribute significantly to improve the overall predictive performance.

Predictors of psychiatric re-hospitalization in older adults with severe mental illness

OBJECTIVE

Many patients with severe recurrent mental illness are approaching late life; however, little is known about psychiatric re-hospitalization in this population. Our objective was to identify predictors of psychiatric re-hospitalization.

METHODS

This was a retrospective cohort study of all 226 geriatric patients (age ≥65 years) admitted to a tertiary care Canadian inpatient psychiatric unit between 2003 and 2008. The main outcome was psychiatric re-hospitalization in 5-year follow-up post-discharge (e.g. 2008-2013 if a patient had been first admitted in 2008). Multivariate Cox regression analyses were used to identify potential predictors of re-hospitalization.

RESULTS

Over 5-year follow-up, 32.3% (73/226) required psychiatric re-hospitalization. Prior lifetime history of psychiatric admission, currently living in a supervised setting and bipolar disorder diagnosis all independently predicted a lower time to psychiatric re-hospitalization (HRs > 2.0, p < 0.05).

CONCLUSIONS

The rate of psychiatric re-hospitalization is high in older adults admitted for severe mental illness. Clinicians should be aware of the especially high rates of re-hospitalization in geriatric psychiatric inpatients with bipolar disorder, previous psychiatric admissions, or those living in a supervised setting. Future research could investigate approaches to prevent psychiatric re-hospitalization in these vulnerable sub-populations.

Staging bipolar disorder: what data and what models are needed?

Although bipolar disorder is increasingly recognised as a spectrum of multisystem disorders (ie, bipolar disorders), proposed staging models and theories of bipolar disease progression often fail to incorporate longitudinal data or data from multiple domains of dysfunction. We propose that bipolar disorders are best thought of as syndromes, with different trajectories of development and progression for various symptoms and demographic groups. This inherent complexity might be better suited to non-traditional modelling techniques, potentially derived from chaos theory. In this Personal View, we propose an allostatic load framework to account for biomarkers of physiological symptom progression. We then suggest integration of two potential domains of biobehavioural markers: sleep and wake and circadian rhythm regulation and the behavioural activation system. A satisfactory model should account for the effects of developmental stage as well as demographic characteristics, including but not limited to sex, culture, ethnicity, and socioeconomic status. The ultimate goal of a staging model has to be to inform the development of targeted, stage-appropriate interventions to reduce the substantial burden of bipolar disorders on individuals and societies.