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

Cognitive reserve and cognition in mood disorders: A systematic review and meta-analysis

Cognitive functioning heterogeneity is a well-recognized phenomenon in individuals diagnosed with mood disorders. Cognitive Reserve (CR) has been linked to multiple positive outcomes, including cognitive performance in these patients. This systematic review and meta-analysis aim to provide a comprehensive analysis of the relationship between CR and cognitive functioning in individuals with mood disorders, including bipolar disorder and depressive disorders. Following PRISMA guidelines, a systematic review and meta-analysis was conducted of original research exploring the relationship between CR and cognitive performance in adult individuals with mood disorders. The literature search was conducted on PubMed, Scopus, and Web of Science, from 2002 to September 2023, and the Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of studies. Overall, 17 studies met the inclusion criteria for the systematic review and 11 for the meta-analysis. Both qualitative and quantitative findings suggested a positive relationship between CR measures and cognitive domains. CR emerges as a possible protective factor for cognitive functioning in adult individuals with mood disorders, potentially helping to mitigate the cognitive impairments associated with the disorder. These findings underscore the importance of the fact that promoting and enhancing CR could help in the cognitive prognosis of this population.

Impact of cognitive reserve on bipolar disorder: a systematic review

Background

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

Methods

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

Results

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

Conclusion

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

Systematic review registration

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

Impact of cognitive reserve in clinical, neurocognitive and lifestyle factors in chronic schizophrenia and early stages of schizophrenia

INTRODUCTION

Although there is evidence that higher cognitive reserve (CR) is a protective factor and it has been related to better prognosis, there have been no studies to date that have explored the CR level and its impact in clinical, neurocognitive and lifestyle outcomes according to the stage of the disease: early stage of psychosis (ESP) or chronic schizophrenia (SCZ).

MATERIAL AND METHODS

A total of 60 patients in the ESP and 225 patients with SCZ were enrolled in the study. To test the predictive capacity of CR for each diagnostic group, a logistic regression analysis was conducted. Hierarchical linear regression analyses were performed to explore the associations between CR and different outcomes. The mediation analyses were performed according to the principles of Baron and Kenny.

RESULTS

Patients with SCZ showed lower CR than those in the ESP (p<0.001). CR correctly classified 79.6% of the cases (p<0.001; Exp(B)=1.062). In ESP group, CR was related to working memory (p=0.030) and negative symptoms (p=0.027). CR (t=3.925, p<0.001) and cannabis use (t=2.023, p=0.048) explained 26.7% of the variance on functioning (p=0.003). In patients with SCZ, CR predicted all cognitive domains, negative symptoms (R2=0.091, p=0.001) and functioning (R2=0.074, p=0.005). In both ESP and SCZ groups, higher CR was associated with lower body mass index and circumference. In ESP group, the effect of adherence to Mediterranean diet on functioning (p=0.037) was mediated by CR level (p=0.003).

CONCLUSIONS

The implications of CR depend on the stage of the disease (ESP vs. SCZ), with a greater effect on neurocognition and negative symptoms in patients with chronic SCZ.

The relationship between cognitive reserve focused on leisure experiences and cognitive functions in bipolar patients

Bipolar disorder (BP) is characterized by cognitive decline. Individual differences exist in maintaining cognitive function due to daily physical activity and sleep. We examined the relationship between leisure experiences as proxies for cognitive reserve (CR) and cognitive function in patients with bipolar disorder after adjusting for daily physical activity and sleep. The CR of patients with BP (n = 24) and healthy study controls (HC) (n = 24) was assessed using premorbid IQ, years of education, and leisure activity history. Performance-based neuropsychological tests were performed to evaluate cognitive function. A self-reported scale was used to assess resilience. Physical activity and sleep were measured using an activity meter. Verbal fluency, story memory, and verbal memory were significantly positively correlated with the kinds of leisure experiences in patients with BP. A hierarchical regression analysis accounting for confounding factors showed that verbal fluency and memory were associated with the kinds of leisure experiences. Neither years of education nor resilience were significantly associated with neuropsychological scores. Various leisure experiences in patients with BP are associated with higher language-related cognitive functioning. Engaging in various leisure experiences may affect higher cognitive functions related to language.

Effectiveness of enhancing cognitive reserve in children, adolescents and young adults at genetic risk for psychosis: Study protocol for a randomized controlled trial

BACKGROUND

Offspring of patients diagnosed with bipolar disorder and schizophrenia (Off-BDSZ) have a high genetic risk of developing a mental illness. The aim of this project is to develop and investigate the efficacy of an intervention aimed at this population, based on the concept of cognitive reserve.

METHODS

This is a multicenter randomized trial with an experimental test-retest design study with control group. Two groups will be included: a community comparison group (CC) and a Off-BDSZ group. A total of 108 Off-BDSZ and 65 CC aged between 6 and 25 years will be recruited. Off-BDSZ participants will be randomized to receive either Cognitive Reserve EnhAncement ThErapy (CREATE) (n=54), or a supportive approach (n=54). The CC group will be assessed at baseline. The duration of the intervention will be 3 months, with 12 weekly group sessions. The primary outcome will be the improvement in CR measured according to change in the Cognitive Reserve Assessment Scale in Health (CRASH) and Cognitive Reserve scale for Adolescents (CORE-A). All participants will be blindly evaluated using clinical, cognitive and neuroimaging measures at baseline, at three months (after the psychological intervention), and at twelve-month follow-up after treatment completion.

DISCUSSION

The results will provide insight into whether the CREATE-Offspring version may enhance cognitive reserve (CR) in child, adolescent and young adult Off-BDSZ as well as advance knowledge about changes in clinical manifestations, neuropsychological performance and brain structure and function associated with improving CR. This novel and cost-effective intervention represents an advance in the framework of preventive interventions in mental health.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03722082. Registered on 26 October 2018.

Biomarkers as proxies for cognitive reserve: The role of high density lipoprotein cholesterol in first episode of psychosis

INTRODUCTION

The proxies used to compose cognitive reserve (CR) for patients of a first episode of psychosis (FEP) have varied in the literature. The development of FEP is linked to peripheral pathways of the central nervous system, yet despite this knowledge, no research has considered the introduction of biomarkers as proxies for CR. Meanwhile, schizophrenia has been linked to the metabolic system, indicating that alterations in the levels of biological parameters, in particular high-density lipoproteins (HDL), cause worse global functioning and cognitive impairment. For these reasons, the present study aimed to create a quantifiable and objective CR index that adjusts for the multifactorial nature of FEP.

MATERIALS AND METHODS

We included 668 FEP patients and 217 healthy controls. Participants were assessed for sociodemographic information, years of education, employment status, premorbid IQ and biological parameters: waist circumference, hypertension, and levels of HDL, triglycerides, and glucose.

RESULTS

The findings suggest that the years of education proxy showed correlational and higher relationship with HDL levels for both FEP patients (r=0.23, b=0.185) and controls (r=0.31, b=0.342). We found that the CR index composed of years of education and HDL levels showed a higher explanatory power for the phenomenon than the classic CR index composed of years of education, employment status and premorbid IQ.

CONCLUSIONS

This article proposes an objective and quantifiable method to measure CR that is more the multifactorial nature of FEP.

Cognitive reserve in patients with mood disorders: Validation study of the Chinese version of the cognitive reserve assessment scale in health

BACKGROUND

Cognitive reserve (CR) is closely associated with cognitive and functional outcome, disease severity, progression and prognosis in psychiatric patients; however, it has not been extensively tested in mood disorders. This study examined the psychometric properties of the Cognitive Reserve Assessment Scale in Health (CRASH) in mood disorder patients.

METHODS

Altogether 166 subjects were recruited, 44 with major depressive disorder (MDD), 64 with bipolar disorder (BD), and 58 healthy controls. CR was assessed using the CRASH and the Cognitive Reserve Questionnaire (CRQ).

RESULTS

Internal consistency (Cronbach's alpha) was 0.779 for the CRASH. The Receiver Operating Characteristic (ROC) curve analysis revealed an area under the ROC curve (AUC) value of 0.73 (95 % CI: 0.647-0.809). The optimal cut-off score of 51 generated the best combination of sensitivity (0.78) and specificity (0.43) for discriminating between patients with mood disorders and healthy controls. The CRASH score was highly correlated with the CRQ score in both mood disorder patients (r_s = 0.586, P < 0.001) and healthy controls (r_s = 0.627, P < 0.001), indicating acceptable convergent validity for the CRASH. Within the mood disorder sample, the CRASH score was associated with functional outcomes (FAST: r_s = -0.243, P = 0.011).

CONCLUSIONS

The CRASH is a useful tool to measure CR in mood disorder with acceptable psychometric properties and could be used in both research and clinical practice.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cognitive reserve profiles are associated with outcome in schizophrenia

Cognitive reserve (CR), the brain's ability to cope with brain pathology to minimize symptoms, could explain the heterogeneity of outcomes in neuropsychiatric disorders, however it is still rarely investigated in schizophrenia. Indeed, this study aims to classify CR in this disorder and evaluate its impact on neurocognitive and socio-cognitive performance and daily functioning. A group of 106 patients diagnosed with schizophrenia was enrolled and assessed in these aereas: neurocognition, Theory of Mind (ToM) and daily functioning. A composite CR score was determined through an integration of the intelligence quotient and education and leisure activities. CR profiles were classified with a two-step cluster analysis and differences among clusters were determined with an analysis of variance (ANOVA). The cluster analysis was identified with three CR profiles characterized, respectively, by high, medium and low CR. ANOVA analysis showed significant differences on neurocognition, ToM and daily functioning between the clusters: people with higher CR reached significantly superior scores. This study suggests that greater general cognitive resources could act as a buffer against the effect of brain pathology, allowing patients to have a better cognitive performance, social outcome and quality of life.

Data-driven cognitive phenotypes in subjects with bipolar disorder and their clinical markers of severity

BACKGROUND

Subjects with bipolar disorder (BD) show heterogeneous cognitive profile and that not necessarily the disease will lead to unfavorable clinical outcomes. We aimed to identify clinical markers of severity among cognitive clusters in individuals with BD through data-driven methods.

METHODS

We recruited 167 outpatients with BD and 100 unaffected volunteers from Brazil and Spain that underwent a neuropsychological assessment. Cognitive functions assessed were inhibitory control, processing speed, cognitive flexibility, verbal fluency, working memory, short- and long-term verbal memory. We performed hierarchical cluster analysis and discriminant function analysis to determine and confirm cognitive clusters, respectively. Then, we used classification and regression tree (CART) algorithm to determine clinical and sociodemographic variables of the previously defined cognitive clusters.

RESULTS

We identified three neuropsychological subgroups in individuals with BD: intact (35.3%), selectively impaired (34.7%), and severely impaired individuals (29.9%). The most important predictors of cognitive subgroups were years of education, the number of hospitalizations, and age, respectively. The model with CART algorithm showed sensitivity 45.8%, specificity 78.4%, balanced accuracy 62.1%, and the area under the ROC curve was 0.61. Of 10 attributes included in the model, only three variables were able to separate cognitive clusters in BD individuals: years of education, number of hospitalizations, and age.

CONCLUSION

These results corroborate with recent findings of neuropsychological heterogeneity in BD, and suggest an overlapping between premorbid and morbid aspects that influence distinct cognitive courses of the disease.

Neuropsychological functioning in post-ICU patients after severe COVID-19 infection: The role of cognitive reserve

Background

Cognitive manifestations associated with Severe Acute Respiratory Syndrome by Coronavirus 2 (SARS-CoV-2) are yet to be described in the existing literature. The aim of this exploratory study is to analyze the impact of severe SARS-CoV-2 infection on neuropsychological performance 6 months following hospital discharge, and to identify which medical variables predict worse outcome. In this context, we study if cognitive reserve (CR) may play a protective role on cognitive impairment.

Methods

We enrolled a cohort of 102 severe SARS-CoV-2 survivors who had been admitted to the Intensive Care Unit (ICU) and were contacted 6-months post discharge. A total of 58 agreed to participate in this 6-month follow-up study. Patients with previously known cognitive impairment were excluded. Demographic, clinical and laboratory data were collected. Firstly, to test the magnitude of neurocognitive sequalae two standard deviations below normative group were considered. Secondly, to analyze the main effects of medical variables on cognition and the interaction with cognitive reserve, ANCOVA analyses were performed.

Results

53.4% obtained a score below the cutoff point (<26) in the screening test MOCA. ICU variables including mechanical ventilation, days of sedation or high CRP days were related with cognition. Cognitive Reserve (CR) interacted with delirium (F ​= ​6.8, p ​= ​0.01) and sedation days (F ​= ​9.40, p ​= ​0.003) to predict verbal memory and interacted with high CRP to predict phonemic fluency (F ​= ​6.47, p ​= ​0.01). Finally, no differences in neuropsychological performance were found depending on subjective cognitive impairment (SCI). However, patients with SCI had a higher score in the HAD anxiety subscale (t ​= ​−2.2; p ​< ​0.05).

Conclusions

In our cohort, cognitive dysfunction was related with ICU variables such as delirium, mechanical ventilation, and inflammation. CR modulated the impact of these variables on cognition. Cognitive complaints were related with anxiety but not with cognitive performance. Despite some limitations, including the need of replication of the findings with larger samples and control groups, our study suggests that high CR may be protective for severe COVID-19-related cognitive impairment.

Is the effect of cognitive reserve in longitudinal outcomes in first-episode psychoses dependent on the use of cannabis?

BACKGROUND

Cognitive reserve (CR) is a protective factor against cognitive and functional impairment in first-episode psychosis (FEP). The aim of this study was to evaluate the differences in clinical presentation according to the use of cannabis (cannabis users vs non-users) among patients presenting a FEP (non-affective vs affective psychosis), to investigate the impact of CR and cannabis use on several outcomes and to explore the potentially mediatory role played by CR in the relationship between cognitive domains or clinical status and functionality, depending on the use of cannabis.

METHODS

Linear regression analysis models were carried out to assess the predictive value of CR on clinical, functional and cognitive variables at baseline and at two-year follow-up. The mediation analyzes were performed according to the principles of Baron and Kenny.

RESULTS

CR was associated with better cognitive performance, regardless of cannabis consumption or diagnosis. In both diagnoses, CR was associated with better clinical and functional outcomes in those patients who did not use cannabis. In terms of mediation procedure, CR mediates the relationship between some cognitive domains and functioning at follow-up only in patients without cannabis use.

LIMITATIONS

The small sample size of the affective group.

CONCLUSIONS

CR plays a differential role in the outcome of psychoses according to whether patients are cannabis users or not. Both in affective and non-affective groups CR exerted a greater effect in patients without cannabis use. Our results suggest that the deleterious effect of cannabis use on functioning in FEP surpasses the protective effect of CR.

The relationships between cognitive reserve, cognitive functioning and quality of life in first-episode schizophrenia spectrum disorders

Cognitive reserve (CR) has been conceptualized as an individual's ability to optimize or maximize performance through differential recruitment of brain networks. As such, CR may contribute to the heterogeneity of cognitive deficits observed in schizophrenia. This study aimed to assess the relationships between CR, cognition and quality of life in first-episode (FES) patients. A total of 137 patients with either ICD-10 schizophrenia or "acute and transient psychotic disorders" diagnosis, and 62 healthy controls had completed a comprehensive assessment of six cognitive domains: speed of processing, attention, working memory/flexibility, verbal memory, visual memory, and abstraction/executive functioning. CR was calculated from the participants' education, premorbid IQ, and socioeconomic status. The results suggested that in patients, CR was positively related to cognitive performance in all domains, explaining 42.6% of the variance observed in cognition overall. Effects of CR in the control group were limited to three domains: speed of processing, abstraction/executive function and working memory/flexibility. These results suggest that CR largely contributes to cognitive variations present in FES patients. In addition, CR was negatively related to the social construct of patients' quality of life, and positively to symptom severity and general functioning.

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.

Cognition in older adults with bipolar disorder: An ISBD task force systematic review and meta-analysis based on a comprehensive neuropsychological assessment

OBJECTIVES

We aim to characterize the cognitive performance in euthymic older adults with bipolar disorder (OABD) through a comprehensive neuropsychological assessment to obtain a detailed neuropsychological profile.

METHODS

We conducted a systematic search in MEDLINE/Pubmed, Cochrane, and PsycInfo databases. Original studies assessing cognitive function in OABD (age ≥50 years ) containing, at a minimum, the domains of attention/processing speed, memory, and executive functions were included. A random-effects meta-analysis was conducted to summarize differences between patients and matched controls in each cognitive domain. We also conducted meta-regressions to estimate the impact of clinical and socio-demographic variables on these differences.

RESULTS

Eight articles, providing data for 328 euthymic OABD patients and 302 healthy controls, were included in the meta-analysis. OABD showed worse performance in comparison with healthy controls, with large significant effect sizes (Hedge's g from -0.77 to -0.89; p < 0.001) in verbal learning and verbal and visual delayed memory. They also displayed statistically significant deficits, with moderate effect size, in processing speed, working memory, immediate memory, cognitive flexibility, verbal fluency, psychomotor function, executive functions, attention, inhibition, and recognition (Hedge's g from -0.52 to -0.76; p < 0.001), but not in language and visuoconstruction domains. None of the examined variables were associated with these deficits.

CONCLUSIONS

Cognitive dysfunction is present in OABD, with important deficits in almost all cognitive domains, especially in the memory domain. Our results highlight the importance of including a routine complete neuropsychological assessment in OABD and also considering therapeutic strategies in OABD.

Cognitive reserve and its correlates in child and adolescent offspring of patients diagnosed with schizophrenia or bipolar disorder

AIM

To analyze cognitive reserve (CR) in child and adolescent offspring of patients diagnosed with schizophrenia (SZ-off) or bipolar disorder (BD-off) and compare them with a group of community controls (CC-off). We also aimed to investigate whether there was an association between CR and clinical and neuropsychological variables according to group.

METHODS

The study included 46 SZ-off, 105 BD-off and 102 CC-off. All participants completed assessments regarding CR and clinical, neuropsychological and psychosocial functioning. CR was measured with a proxy based on premorbid intelligence, parental occupational level, educational attainment, developmental milestones and sociability. The clinical assessment included the Kiddie Schedule for Affective Disorders and Schizophrenia, Present and Lifetime, the Semi-structured Interview for Prodromal Syndromes, and the Global Assessment Functioning scale. The neuropsychological assessment included measures of executive functioning, attention, verbal memory, working memory and processing speed.

RESULTS

SZ-off showed a lower level of CR compared to BD-off and CC-off, while BD-off showed an intermediate level of CR between SZ-off and CC-off. Moreover, an association between higher CR and less lifetime psychopathology, fewer prodromal psychotic symptoms, higher psychosocial functioning, and a higher working memory score was observed in all groups, but it was stronger in SZ-off.

CONCLUSIONS

CR seemed to be associated with psychopathology, clinical symptoms, psychosocial functioning, and some cognitive functions. SZ-off appeared to benefit more from a higher CR, therefore it could be considered a protective factor against the development of clinical symptomatology and cognitive impairment.

The impact of cognitive reserve, cognition and clinical symptoms on psychosocial functioning in first-episode psychoses

BACKGROUND

Functional impairment is a defining feature of psychotic disorders. A range of factors has been shown to influence functioning, including negative symptoms, cognitive performance and cognitive reserve (CR). However, it is not clear how these variables may affect functioning in first-episode psychosis (FEP) patients. This 2-year follow-up study aimed to explore the possible mediating effects of CR on the relationship between cognitive performance or specific clinical symptoms and functional outcome.

METHODS

A prospective study of non-affective FEP patients was performed (211 at baseline and 139 at follow-up). CR was entered in a path analysis model as potential mediators between cognitive domains or clinical symptoms and functioning.

RESULTS

At baseline, the relationship between clinical variables or cognitive performance and functioning was not mediated by CR. At follow-up, the effect of attention (p = 0.003) and negative symptoms (p = 0.012) assessed at baseline on functioning was partially mediated by CR (p = 0.032 and 0.016), whereas the relationship between verbal memory (p = 0.057) and functioning was mediated by CR (p = 0.014). Verbal memory and positive and total subscales of PANSS assessed at follow-up were partially mediated by CR and the effect of working memory on functioning was totally mediated by CR.

CONCLUSIONS

Our results showed the influence of CR in mediating the relationship between cognitive domains or clinical symptoms and functioning in FEP. In particular, CR partially mediated the relationship between some cognitive domains or clinical symptoms and functioning at follow-up. Therefore, CR could improve our understanding of the long-term functioning of patients with a non-affective FEP.

Modifiable lifestyle factors and cognitive reserve: A systematic review of current evidence

This systematic review aims to summarize cognitive reserve (CR) evaluation approaches and to examine the role of seven selected modifiable lifestyle factors (diet, smoking, alcohol consumption, physical activity, cognitive leisure activity, sleep, and meditation) in mitigating the impacts of age- or disease-related brain changes on cognition. Eighteen population-based English empirical studies were included. We summarize the study designs and identify three CR models that were broadly used in these studies, including a residual model assessing lifestyle factors in relation to unexplained variance in cognition after accounting for brain markers, a moderation model testing whether lifestyle factors moderate the relationship between brain status and cognition, and a controlling model examining the associations between lifestyle factors and cognition when controlling for brain measures. We also present the findings for the impact of each lifestyle factor. No studies examined diet, sleep, or meditation, and only two studies focused on smoking and alcohol consumption each. Overall, the studies suggest lifestyle activity factors (physical and cognitive leisure activities) may contribute to CR and attenuate the damaging impact of brain changes on cognition. Standardized measurements of lifestyle factors and CR are needed, and mechanisms underlying CR need to be further addressed as well.

Long-term outcome predictors after functional remediation in patients with bipolar disorder

BACKGROUND

Improving functioning in patients with bipolar disorder (BD) is one of the main objectives in clinical practice. Of the few psychosocial interventions that have been specifically developed to enhance the psychosocial outcome in BD, functional remediation (FR) is one which has demonstrated efficacy. The aim of this study was to examine which variables could predict improved functional outcome following the FR intervention in a sample of euthymic or subsyndromal patients with BD.

METHODS

A total of 92 euthymic outpatients were included in this longitudinal study, with 62 completers. Partial correlations controlling for the functional outcome at baseline were calculated between demographic, clinical and neurocognitive variables, and functional outcome at endpoint was assessed by means of the Functioning Assessment Short Test scale. Next, a multiple regression analysis was run in order to identify potential predictors of functional outcome at 2-year follow-up, using the variables found to be statistically significant in the correlation analysis and other variables related to functioning as identified in the previous scientific literature.

RESULTS

The regression model revealed that only two independent variables significantly contributed to the model (F(6,53): 4.003; p = 0.002), namely verbal memory and inhibitory control. The model accounted for 31.2% of the variance. No other demographic or clinical variable contributed to the model.

CONCLUSIONS

Results suggest that patients with better cognitive performance at baseline, especially in terms of verbal memory and executive functions, may present better functional outcomes at long term follow-up after receiving functional remediation.

Psychoeducation in bipolar disorder: A systematic review

BACKGROUND

Bipolar disorder (BD) is a severe psychiatric disorder characterized by mood swings. Psychosocial interventions, such as psychoeducation, play an essential role in promoting social rehabilitation and improving pharmacological treatment.

AIM

To investigate the role of psychoeducation in BD.

METHODS

A systematic review of original studies regarding psychoeducation interventions in patients with BD and their relatives was developed. A systematic literature search was performed using the Medline, Scopus, and Lilacs databases. No review articles or qualitative studies were included in the analysis. There were no date restriction criteria, and studies published up to April 2021 were included.

RESULTS

A total of forty-seven studies were selected for this review. Thirty-eight studies included patients, and nine included family members. Psychoeducation of patients and family members was associated with a lower number of new mood episodes and a reduction in number and length of stay of hospitalizations. Psychoeducational interventions with patients are associated with improved adherence to drug treatment. The strategies studied in patients and family members do not interfere with the severity of symptoms of mania or depression or with the patient's quality of life or functionality. Psychoeducational interventions with family members do not alter patients' adherence to pharmacotherapy.

CONCLUSION

Psychoeducation as an adjunct strategy to pharmacotherapy in the treatment of BD leads to a reduction in the frequency of new mood episodes, length of hospital stay and adherence to drug therapy.

Cognitive reserve in patients with first-episode psychosis as outcome predictor at 5-year follow-up

Cognitive reserve (CR) is the premorbid brain capacity to cope with neural damage. People with good CR can tolerate higher levels of pathological brain injuries before displaying clinical symptoms than others. This study aimed to analyze CR in a sample of patients diagnosed with first-episode psychosis (FEP) during childhood or adolescence, comparing them to a community control group (CC) and assessing the predictive value of CR regarding psychosocial functioning, clinical symptoms and neuropsychological variables at the 5-year follow-up. 57 patients diagnosed with FEP during childhood or adolescence and 37 controls completed clinical, neuropsychological, and psychosocial functioning assessments at baseline and 5-year follow-up. CR was assessed in both groups at baseline. The FEP group showed lower CR scores than the CC group. Higher CR in the FEP group was associated with fewer psychotic negative symptoms, total psychotic symptoms and depressive symptoms, higher psychosocial functioning, and less impaired memory and attention at the 5-year follow-up. CR is associated with long-term clinical, neuropsychological and psychosocial functioning outcomes in patients diagnosed with FEP during childhood or adolescence.

Cognitive reserve may outperform age, mood and psychiatric comorbidities as a predictor of executive functioning in bipolar disorder and healthy adults

INTRODUCTION

Cognitive reserve plays a protective role against executive dysfunction in healthy adults and individuals with psychiatric illnesses such as bipolar disorder. However, the magnitude of the influence of cognitive reserve on specific executive functions (EFs), and its impact relative to variables such as depressive symptoms, age and psychiatric comorbidities, is unexplored. This study aimed to quantify the influence of cognitive reserve on specific EFs, and compare its impact with that of depressive symptoms, age and psychiatric comorbidities, in separate models for patients with bipolar disorder and healthy adults.

METHOD

This was a cross-sectional study of 121 adults with no mood disorders and 109 with bipolar disorder, all of whom underwent a comprehensive psychiatric assessment and evaluation of the EFs. Cognitive reserve was measured using years of education, IQ and reading and writing habits. The association between EFs and predictors (cognitive reserve, depressive symptoms, age and psychiatric comorbidities) was evaluated through structural equation modeling. Four models were constructed for each group independently (bipolar disorder and control), one each for working memory, verbal fluency, inhibition and flexibility, due to group differences in age and cognitive reserve.

RESULTS

Working memory, inhibition and flexibility were most significantly predicted by cognitive reserve and age. Verbal fluency was only predicted by cognitive reserve. Comorbidities and depressive symptoms were not significant in any of the models. Cognitive reserve had a positive influence on all EFs in models for patients with bipolar disorder and models for control participants. Age had a negative impact on three of the four EFs tested.

CONCLUSION

Fostering cognitive reserve through continued education and cognitively stimulating leisure activities may be an effective intervention for executive dysfunction in patients and non-patients alike. In some cases, the effects of these interventions may outweigh the negative cognitive impact of aging, depressive symptoms and psychiatric conditions.

Cognitive impairment in euthymic patients with bipolar disorder: Prevalence estimation and model selection for predictors of cognitive performance

Objectives Although cognitive dysfunction is a prominent feature of bipolar disorder (BD), previous research presents limitations in estimating the proportion of euthymic patients experiencing clinically relevant deficits and identifying predictors of cognitive difficulties. We explored the relevance of recommended definitions of clinically significant cognitive impairment for functional outcomes, estimated its prevalence, and identified patient characteristics associated with cognition. Methods We assessed cognitive performance across four domains in 80 euthymic participants with BD. Participants were categorized based on two criteria for clinically significant cognitive impairment and we assessed the ability of these criteria to differentiate participant performance on established functional outcomes. Variable selection with elastic net regression was used to identify sociodemographic and clinical factors associated with cognitive performance. Selected variables were examined as predictors of clinically significant cognitive impairment with logistic regression. Results According to the selected criterion, 34% presented with clinically significant cognitive impairment. Poorer current cognitive performance was associated with older age, lower estimated premorbid IQ, more currently prescribed psychotropic medications, fewer previous psychological therapies, and current use of antipsychotics. A model with premorbid IQ, psychotropic medications and previous psychological therapies as predictors of cognitive impairment correctly classified 75% of the participants. Conclusions This is one of the first studies to use a model selection approach to identify factors associated with cognitive difficulties in BD. Our findings offer the initial steps towards a predictive model for cognitive impairment. This could improve treatment decisions and prioritization for euthymic patients with BD, particularly the implementation of cognitive interventions.

Cognitive performance in older-age bipolar disorder: Investigating psychiatric characteristics, cardiovascular burden and psychotropic medication

OBJECTIVE

This study aimed to explore a large range of candidate determinants of cognitive performance in older-age bipolar disorder (OABD).

METHODS

A cross-sectional study was performed in 172 BD patients aged ≥50 years. Demographics, psychiatric characteristics and psychotropic medication use were collected using self-report questionnaires and structured interviews. The presence of cardiovascular risk factors was determined by combining information from structured interviews, physical examination and laboratory assessments. Cognitive performance was investigated by an extensive neuropsychological assessment of 13 tests, covering the domains of attention, learning/ memory, verbal fluency and executive functioning. The average of 13 neuropsychological test Z-scores resulted in a composite cognitive score. A linear multiple regression model was created using forward selection with the composite cognitive score as outcome variable. Domain cognitive scores were used as secondary outcome variables.

RESULTS

The final multivariable model (N = 125), which controlled for age and education level, included number of depressive episodes, number of (hypo)manic episodes, late onset, five or more psychiatric admissions, lifetime smoking, metabolic syndrome and current use of benzodiazepines. Together, these determinants explained 43.0% of the variance in composite cognitive score. Late onset and number of depressive episodes were significantly related to better cognitive performance whereas five or more psychiatric admissions and benzodiazepine use were significantly related to worse cognitive performance.

CONCLUSION

Psychiatric characteristics, cardiovascular risk and benzodiazepine use are related to cognitive performance in OABD. Cognitive variability in OABD thus seems multifactorial. Strategies aimed at improving cognition in BD should include cardiovascular risk management and minimizing benzodiazepine use.

Evaluation of neurotrophic factors and education level as predictors of cognitive decline in alcohol use disorder

Cognitive reserve (CR) is the capability of an individual to cope with a brain pathology through compensatory mechanisms developed through cognitive stimulation by mental and physical activity. Recently, it has been suggested that CR has a protective role against the initiation of substance use, substance consumption patterns and cognitive decline and can improve responses to treatment. However, CR has never been linked to cognitive function and neurotrophic factors in the context of alcohol consumption. The present cross-sectional study aims to evaluate the association between CR (evaluated by educational level), cognitive impairment (assessed using a frontal and memory loss assessment battery) and circulating levels of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) in patients with alcohol use disorder (AUD). Our results indicated that lower educational levels were accompanied by earlier onset of alcohol consumption and earlier development of alcohol dependence, as well as impaired frontal cognitive function. They also suggest that CR, NT-3 and BDNF may act as compensatory mechanisms for cognitive decline in the early stages of AUD, but not in later phases. These parameters allow the identification of patients with AUD who are at risk of cognitive deterioration and the implementation of personalized interventions to preserve cognitive function.

Influence of social cognition as a mediator between cognitive reserve and psychosocial functioning in patients with first episode psychosis

BACKGROUND

Social cognition has been associated with functional outcome in patients with first episode psychosis (FEP). Social cognition has also been associated with neurocognition and cognitive reserve. Although cognitive reserve, neurocognitive functioning, social cognition, and functional outcome are related, the direction of their associations is not clear. Therefore, the main aim of this study was to analyze the influence of social cognition as a mediator between cognitive reserve and cognitive domains on functioning in FEP both at baseline and at 2 years.

METHODS

The sample of the study was composed of 282 FEP patients followed up for 2 years. To analyze whether social cognition mediates the influence of cognitive reserve and cognitive domains on functioning, a path analysis was performed. The statistical significance of any mediation effects was evaluated by bootstrap analysis.

RESULTS

At baseline, as neither cognitive reserve nor the cognitive domains studied were related to functioning, the conditions for mediation were not satisfied. Nevertheless, at 2 years of follow-up, social cognition acted as a mediator between cognitive reserve and functioning. Likewise, social cognition was a mediator between verbal memory and functional outcome. The results of the bootstrap analysis confirmed these significant mediations (95% bootstrapped CI (-10.215 to -0.337) and (-4.731 to -0.605) respectively).

CONCLUSIONS

Cognitive reserve and neurocognition are related to functioning, and social cognition mediates in this relationship.

"Influence of modifiable and non-modifiable variables on functioning in bipolar disorder: a path analytical study"

OBJECTIVE

The aim of this study was to investigate the influence of modifiable (mood, cognitive reserve, cognitive performance) and non-modifiable factors (diagnosis, suicide attempts, substance use, age) on self-reported functioning in BD.

METHODS

103 adults with no mood disorders and 95 individuals with BD completed the WHODAS 2.0, in addition to a neuropsychological battery and diagnostic assessments. Path analysis was then used to analyse the relationships between modifiable and non-modifiable predictors of functioning in the sample.

RESULTS

Cognitive reserve and age had an indirect influence on individual functioning, mediated by cognitive performance. The influence of diagnosis and depressive symptoms on functioning was partly direct, and partly mediated by cognition. The presence of psychiatric comorbidities in addition to BD also had a significant influence on individual functioning.

CONCLUSIONS

Initiatives focussed on modifiable factors such as depressive symptoms and cognitively stimulating activities, which increase cognitive reserve, may be a useful complement to existing treatments and help patients achieve functional recovery. KEY POINTS Individual functioning was influenced by cognitive performance, cognitive reserve, age, diagnosis and depressive symptoms. Executive functioning mediated the influence of age and cognitive reserve on individual functioning. Interventions focussed on depressive symptoms and cognitive stimulation may help patients achieve functional recovery.

Cognitive reserve-mediated neural modulation of emotional control and regulation in people with late-life depression

Late-life depression (LLD) is an affective disorder that is highly prevalent among older people. Cognitive reserve (CR) refers to an active process that facilitates the flexibility and efficiency of the neural networks to compensate for impairments that emerge in consequence of brain pathology. The current functional magnetic resonance imaging study investigated whether and how CR affects emotional regulation, level of depression severity and neural activity associated with affective control during emotional Stroop (eStroop) task. Altogether, 90 older people participated in this study, 50 of whom suffered from LLD. We used years of education and verbal fluency capacity as proxies for CR. Clinical participants with relatively higher CR presented with milder degrees of depression, better eStroop performance and stronger neural activity in the middle frontal gyrus (MFG) involved with exercising affective control. Results of the mediation analysis indicated that both education and verbal fluency significantly mediated the association between the depression severity and MEG activity. These results suggest a negative association between CR and age-related clinical symptoms of emotional dysregulation. Our neurobehavioral findings provide supportive evidence that CR implies efficiency of top-down emotional regulation and operates as a protective factor against emotional and cognitive vulnerability in the aging brain.

Clinical and Neurocognitive Predictors of Functional Outcome in Depressed Patients with Partial Response to Treatment: One Year Follow-Up Study

BACKGROUND

Cognitive dysfunction represents a distinct biological and clinical dimension in major depression disorders (MDD) and cognitive performance strongly affects psychosocial functioning in patients diagnosed with MDD.

OBJECTIVE

To assess which neurocognitive variables at baseline predict the functional outcome of MDD patients in a 1-year follow-up study as assessed by Functioning Assessment Short Test (FAST) and whether the improvement observed on affective and cognitive symptoms in our 12 week-prospective observational study after treatment with selective serotonin reuptake inhibitors (SSRIs) and selective noradrenalin reuptake inhibitors (SNRIs) can affect the following long-term psychosocial functional outcome at 1 year in the same MDD patients.

METHODS

We recruited a total of 31 patients (8 males; 23 females) with MDD who had previously completed a pharmacological treatment with SSRIs (n = 22) or SNRIs (n = 9) for 12 weeks, and then continued the same pharmacological treatment for 1 year. After an average 1-year follow-up, they were interviewed with the FAST to assess functional outcome. Multivariate analyses were applied to identify clinical and neurocognitive predictors of functional outcome.

RESULTS

Total Montreal Cognitive Assessment (MoCA), Digit Span forward (Span F) and backward (Span B), and 15 Rey words immediate recall (Rey I) scores significantly correlated with FAST. However, after performing regression models only Rey immediate recall score was useful to predict long-term functional outcome (Pearson correlation coefficient R= -0.68, p < 0.001) in four specific subdomains of FAST. When considering changes in affective and cognitive symptoms at the end of the 12 weeks of pharmacological treatment with SSRI or SNRIs (T1-T0) by multiple regression analysis, we found that Span F-test predicted scores in the FAST leisure domain, whereas, changes in Span F, Frontal Assessment Battery (FAB) and Rey I predicted psychosocial functioning in the specific "cognitive" subdomains of FAST.

CONCLUSION

Our data suggest that long-term psychosocial functioning can be influenced by neurocognitive performance at baseline, with verbal memory playing a key role in overall functioning. Furthermore, improvement in verbal memory can predict functional outcome at one year in MDD patients with a recent history of partial response to antidepressants.

The effects of cognitive reserve on predicting and moderating the cognitive and psychosocial functioning of patients with bipolar disorder

BACKGROUND

Cognitive reserve (CR) reflects the resilience of the brain to cope with neuropathological changes and minimize clinical manifestations. In the present study, we explore the association between CR and cognitive and psychosocial functioning, and examined the potential moderating role of CR in patients with bipolar disorder (BD).

METHODS

One hundred and twenty-five outpatients with BD type I and sixty healthy individuals were recruited. All participants were assessed with a neuropsychological battery examining attention and processing speed, working memory, visual memory and executive functioning, the Global Assessment of Functioning scale and the Cognitive Complaints in Bipolar Disorder Rating Assessment. Proxies for cognitive reserve included premorbid intelligence and educational level.

RESULTS

Patients with bipolar disorder presented with worse cognitive performance and psychosocial functioning than healthy controls. Multiple regression models revealed that educational level negatively associated with all assessed domain-specific cognition scores and premorbid intelligence predicted attention and processing speed and psychosocial functioning. Notably, premorbid intelligence significantly moderated the associations between the number of episodes (total, hypo/manic and depressed) and neurocognitive functioning, and the educational level also moderated the relationships between the numbers of hypo/manic and total episodes and subjective cognitive functioning.

CONCLUSIONS

Cognitive reserve contributes to functional outcomes in patients with BD and may emerge as a key factor contributing to the course and prognosis of patients with BD. In the future, cognitive reserve must be considered in both research and clinical interventions related to bipolar disorder.

Lifetime Psychotic Symptoms, Subthreshold Depression and Cognitive Impairment as Barriers to Functional Recovery in Patients with Bipolar Disorder

(1) Background: bipolar disorder (BD) is a chronic disease that often leads to functional impairment. The objective of this study is to elucidate which variables are associated with better functional outcomes in a sample of euthymic patients with BD. (2) Methods: patients were recruited at the Hospital Clinic of Barcelona and they underwent a clinical interview, a functional assessment, and a comprehensive neuropsychological evaluation. After that, patients were divided into two groups according to the Functioning Assessment Short Test total score: functionally remitted vs. functionally impaired. Following this, a multivariate logistic regression was run in order to identify clinical, demographic and cognitive factors associated with functional remission. (3) Results: a total of 420 euthymic patients with BD were assessed for this study, distributed as follows: functionally remitted (n = 221) and functionally impaired (n = 199). Finally, the multivariate logistic regression revealed that only five variables significantly contributed to the model, including: lifetime history of psychotic symptoms (the variable that contributed the most to the model), followed by the Hamilton Depression total score, and cognitive performance (executive functions and verbal memory). (4) Conclusions: treatments to ensure a good functional outcome in BD should specially prevent psychosis, target subthreshold depressive symptoms and enhance cognition, more specifically executive functions and verbal memory.

Cognitive Reserve Assessment Scale in Health (CRASH): Its Validity and Reliability

(1) Background: The cognitive reserve (CR) concept has not been precisely defined in severe mental disorders and has been estimated using heterogeneous methods. This study aims to investigate and develop the psychometric properties of the Cognitive Reserve Assessment Scale in Health (CRASH), an instrument designed to measure CR in people with severe mental illness; (2) Methods: 100 patients with severe mental illness (non-affective psychoses and affective disorders) and 66 healthy controls were included. The internal consistency and convergent validity of CRASH were assessed. Spearman's correlations coefficients were also performed to examine the relationship between CRASH and neuropsychological tests, psychosocial functioning, and clinical course; (3) Results: The internal consistency was high (Cronbach's alpha coefficient = 0.903). The CRASH global score had a large positive correlation with the Cognitive reserve questionnaire total score (r = 0.838, p < 0.001), demonstrating good convergent validity. The correlation coefficients between the CRASH total scores and clinical, functional, and neuropsychological performance were different between groups. In order to provide clinical interpretation, severity classification based on diagnosis (non-affective psychotic disorders, affective disorders, and healthy controls) have been created; (4) Conclusions: CRASH is the first CR measure developed specifically for patients with severe mental illness, facilitating reliable and valid measurement of this construct. The scale may aid in the stratification of patients and the implementation of personalized interventions.

Improving Functioning, Quality of Life, and Well-being in Patients With Bipolar Disorder

People with bipolar disorder frequently experience persistent residual symptoms, problems in psychosocial functioning, cognitive impairment, and poor quality of life. In the last decade, the treatment target in clinical and research settings has focused not only on clinical remission, but also on functional recovery and, more lately, in personal recovery, taking into account patients' well-being and quality of life. Hence, the trend in psychiatry and psychology is to treat bipolar disorder in an integrative and holistic manner. This literature review offers an overview regarding psychosocial functioning in bipolar disorder. First, a brief summary is provided regarding the definition of psychosocial functioning and the tools to measure it. Then, the most reported variables influencing the functional outcome in patients with bipolar disorder are listed. Thereafter, we include a section discussing therapies with proven efficacy at enhancing functional outcomes. Other possible therapies that could be useful to prevent functional decline and improve functioning are presented in another section. Finally, in the last part of this review, different interventions directed to improve patients' well-being, quality of life, and personal recovery are briefly described.

Neurococognitive and neuroimaging correlates of obesity and components of metabolic syndrome in bipolar disorder: a systematic review

BACKGROUND

Individuals with bipolar disorder (BD) have a higher prevalence of obesity and metabolic syndrome (MetS) compared with the general population. Obesity and MetS are associated with cognitive deficits and brain imaging abnormalities in the general population. Obesity and components of MetS might potentially associate with neuroimaging and neurocognitive findings in BD.

METHODS

A literature search of studies investigating the association between obesity (and other components of MetS) and neurocognitive and neuroimaging findings in BD was conducted. In addition to a systematic review, a random-effects meta-analysis was conducted when sufficient data were available.

RESULTS

Twenty-three studies were included in the current systematic review. Overweight/obese patients were significantly associated with impaired neurocognition compared normal weight individuals with BD (d = 0.37). The most robust association between obesity and cognitive deficits in BD was observed in the cognitive subdomain of executive functions (d = 0.61). There was also evidence for a significant relationship between cognitive impairment in BD and other components of MetS including hypertension, dyslipidemia, and diabetes. Overweight/obese individuals with BD had more pronounced brain imaging abnormalities than normal weight individuals with BD.

CONCLUSIONS

Obesity and related cardiovascular risk factors significantly are associated with more severe cognitive and brain imaging abnormalities in BD. Medical co-morbidities can potentially contribute to functional decline observed in some patients throughout the course of BD.

Cognitive variability in bipolar I disorder: A cluster-analytic approach informed by resting-state data

BACKGROUND

While the presence of cognitive performance deficits in bipolar disorder I (BD-I) is well established, there is no consensus about which cognitive abilities are affected. Heterogeneous phenotypes displayed in BD-I further suggest the existence of subgroups among the disorder. The present study sought to identify different cognitive profiles among BD-I patients as well as potentially underlying neuronal network changes.

METHODS

54 euthymic BD-I patients underwent cognitive testing and resting state neuroimaging. Hierarchical cluster-analysis was performed on executive function scores of bipolar patients. The derived clusters were compared against 54 age-, gender- and IQ-matched healthy controls (HC) to facilitate the interpretation of results. Further, resting state network properties were compared to identify differences probably underlying cognitive profiles.

RESULTS

A three-cluster solution emerged. Cluster 1 (n = 22) was characterized by deficits in cognitive flexibility and motor inhibition, cluster 2 (n = 12) displayed impulsive decision-making, while cluster 3 (n = 20) showed good visuospatial planning. Weaker connections in cluster 1 compared to cluster 2 were found between regions activated during tasks cluster 1 showed deficits on. Cluster 3 had a higher modularity than cluster 2, which correlated positively with problem solving performance and risk-taking in this cluster.

CONCLUSION

Obtained clusters showed distinct cognitive profiles, characterized by deficits and strengths, most of which remained precluded in a general comparison. Weaker interregional connections and separated subnetworks might underly behavioral deficits and strengths, respectively. The findings help explain the phenotypic heterogeneity observed in BD-I. This article is part of the Special Issue entitled 'Current status of the neurobiology of aggression and impulsivity'.

Identifying cognitive subgroups in bipolar disorder: A cluster analysis

BACKGROUND

Evidence has shown heterogeneity of cognitive function among patients with bipolar disorder (BD). Our study aims to replicate recent findings of cognitive subgroups, as well as we assessed subjective cognitive difficulties and functioning in each cluster.

METHODS

Hierarchical cluster analysis was conducted to examine whether there were distinct neurocognitive subgroups based on neurocognitive battery. Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA) and Functioning Assessment Short Test (FAST) were used to assess subjective cognitive difficulties and functional impairment.

RESULTS

We found three distinct subgroups: a first cluster with intact cognition (n = 30, 43.5%), a second cluster with selective cognitive impairment (n = 23, 33.3%), and a third cluster with globally cognitive impairment (n = 16, 23.3%). The intact group had more years of education (p < .001) and higher estimated IQ (p < .001) than globally and selectively impaired subgroups. Additionally, they were younger (p = .011), had an earlier age at bipolar diagnosis (p < .037) and earlier age of first hospitalization (p < .035) compared to individuals with globally cognitive impairment.

LIMITATIONS

This is a cross-sectional design with a small sample including only patients from a tertiary hospital.

CONCLUSION

Our results give support to the existence of a continuum of severity from patients without impairment to those with poor cognitive functioning. Patients in the intact group seem to have higher cognitive reserve than other two groups. However, they also experienced cognitive complaints and some degree of functional impairment. These findings suggest the importance of using a combo of instruments (e.g., objective and subjective cognitive measures plus functioning instruments) for a complete assessment of patients with BD.

Translational research on reserve against neurodegenerative disease: consensus report of the International Conference on Cognitive Reserve in the Dementias and the Alzheimer's Association Reserve, Resilience and Protective Factors Professional Interest Area working groups

BACKGROUND

The concept of reserve was established to account for the observation that a given degree of neurodegenerative pathology may result in varying degrees of symptoms in different individuals. There is a large amount of evidence on epidemiological risk and protective factors for neurodegenerative diseases and dementia, yet the biological mechanisms that underpin the protective effects of certain lifestyle and physiological variables remain poorly understood, limiting the development of more effective preventive and treatment strategies. Additionally, different definitions and concepts of reserve exist, which hampers the coordination of research and comparison of results across studies.

DISCUSSION

This paper represents the consensus of a multidisciplinary group of experts from different areas of research related to reserve, including clinical, epidemiological and basic sciences. The consensus was developed during meetings of the working groups of the first International Conference on Cognitive Reserve in the Dementias (24-25 November 2017, Munich, Germany) and the Alzheimer's Association Reserve and Resilience Professional Interest Area (25 July 2018, Chicago, USA). The main objective of the present paper is to develop a translational perspective on putative mechanisms underlying reserve against neurodegenerative disease, combining evidence from epidemiological and clinical studies with knowledge from animal and basic research. The potential brain functional and structural basis of reserve in Alzheimer's disease and other brain disorders are discussed, as well as relevant lifestyle and genetic factors assessed in both humans and animal models.

CONCLUSION

There is an urgent need to advance our concept of reserve from a hypothetical model to a more concrete approach that can be used to improve the development of effective interventions aimed at preventing dementia. Our group recommends agreement on a common dictionary of terms referring to different aspects of reserve, the improvement of opportunities for data sharing across individual cohorts, harmonising research approaches across laboratories and groups to reduce heterogeneity associated with human data, global coordination of clinical trials to more effectively explore whether reducing epidemiological risk factors leads to a reduced burden of neurodegenerative diseases in the population, and an increase in our understanding of the appropriateness of animal models for reserve research.

Cognitive reserve as an outcome predictor: first-episode affective versus non-affective psychosis

OBJECTIVE

Cognitive reserve (CR) refers to the brain's capacity to cope with pathology in order to minimize the symptoms. CR is associated with different outcomes in severe mental illness. This study aimed to analyze the impact of CR according to the diagnosis of first-episode affective or non-affective psychosis (FEP).

METHOD

A total of 247 FEP patients (211 non-affective and 36 affective) and 205 healthy controls were enrolled. To assess CR, common proxies have been integrated (premorbid IQ; education-occupation; leisure activities). The groups were divided into high and low CR.

RESULTS

In non-affective patients, those with high CR were older, had higher socioeconomic status (SES), shorter duration of untreated psychosis, and a later age of onset. They also showed greater performance in most cognitive domains. In affective patients, those with a greater CR showed a higher SES, better functioning, and greater verbal memory performance.

CONCLUSION

CR plays a differential role in the outcome of psychoses according to the diagnosis. Specifically, in order to address the needs of non-affective patients with low CR, cognitive rehabilitation treatments will need to be 'enriched' by adding pro-cognitive pharmacological agents or using more sophisticated approaches. However, a functional remediation therapy may be of choice for those with an affective psychosis and low CR.

Affective versus non-affective first episode psychoses: A longitudinal study

OBJECTIVE

This study aimed to assess (1) whether there were clinical, neuropsychological and functional differences between and within affective and non-affective psychoses at baseline and two years-follow-up and (2) to explore clinical and neuropsychological predictors of psychosocial functioning in the whole sample.

METHOD

This is a subanalysis from a multicentre, naturalistic, longitudinal prospective study ('Phenotype-genotype and environmental interaction. Application of a predictive model in first psychotic episodes'). The sample consisted of 192 patients with a first psychotic episode (FEP): 142 with non-affective psychoses and 50 with affective psychoses. Student t-tests, paired t-tests, Pearson correlations, ANOVAs and regression analyses were performed.

RESULTS

At baseline, the groups differed in perseverative errors (WCST), Premorbid Adjustment Scale (PAS), family history of psychiatric disorder, negative (PANSS) and manic symptoms (YMRS). At two years follow-up, the groups differed in all the PANSS subscales and in depressive symptoms assessed by the MADRS. When the whole sample was considered, the regression model which best explained the estimated variance in functioning at follow-up (41%) was composed by PANSS total score and verbal fluency assessed by the FAS (COWAT).

CONCLUSIONS

We found clinical and neurocognitive differences at baseline which decreased in the follow-up. Reduced performances at baseline in executive functions in combination with symptom severity (PANSS) were predictors of FEP patients' poor functional outcome.

Factors associated with poor functional outcome in bipolar disorder: sociodemographic, clinical, and neurocognitive variables

OBJECTIVE

The current investigation aimed at studying the sociodemographic, clinical, and neuropsychological variables related to functional outcome in a sample of euthymic patients with bipolar disorder(BD) presenting moderate-severe levels of functional impairment.

METHODS

Two-hundred and thirty-nine participants with BD disorders and with Functioning Assessment Short Test(FAST) scores equal or above 18 were administered a clinical and diagnostic interview, and the administration of mood measure scales and a comprehensive neuropsychological battery. Analyses involved preliminary Pearson bivariate correlations to identify sociodemographic and clinical variables associated with the FAST total score. Regarding neuropsychological variables, a principal component analysis (PCA) was performed to group the variables in orthogonal factors. Finally, a hierarchical multiple regression was run.

RESULTS

The best fitting model for the variables associated with functioning was a linear combination of gender, age, estimated IQ, Hamilton Depression Rating Scale (HAM-D), number of previous manic episodes, Factor 1 and Factor 2 extracted from the PCA. The model, including all these previous variables, explained up to 29.4% of the observed variance.

CONCLUSIONS

Male gender, older age, lower premorbid IQ, subdepressive symptoms, higher number of manic episodes, and lower performance in verbal memory, working memory, verbal fluency, and processing speed were associated with lower functioning in patients with BD.

Cognitive Reserve Profiles in Chronic Schizophrenia: Effects on Theory of Mind Performance and Improvement after Training

OBJECTIVES

Cognitive reserve (CR), defined as individual differences in the ability to cope with brain damage, seem to be associated to the several psychopathological features in psychiatric patients, such as the functional outcome. This study aims to identify different profiles of CR by combining intelligence quotient (IQ) and premorbid functioning, two measures independently associated to CR in previous works, as well as to explore CR effect on both Theory of Mind (ToM) baseline performance and improvement after socio-cognitive trainings.

METHODS

Sixty patients with chronic schizophrenia underwent a socio-cognitive rehabilitation. All patients were assessed for psychopathology, neurocognition, and ToM at baseline and post-treatment. CR profiles were explored with K-means cluster analysis, while differences between clusters in both baseline assessments and post-treatment ToM improvement, were analyzed by means of analysis of variance and repeated measures analysis of covariance.

RESULTS

The analysis revealed three CR profiles, respectively, characterized by low early premorbid functioning and mild intellectual impairment, average/high early premorbid functioning trend with moderate intellectual impairment and good early premorbid functioning associated to IQ within normal limits. Analyses showed a significant effect of CR on both baseline ToM performance and treatment outcome: patients with higher CR reached significantly better ToM scores.

CONCLUSIONS

These results underline the clinical relevance of defining CR profiles of patients to customize trainings: subjects with a lower CR may benefit from more intensive programs. A deeper knowledge about CR may considerably increase our understanding of individual differences and thus potentiate treatment outcome. (JINS, 2018, 24, 563-571).

Assessing and addressing cognitive impairment in bipolar disorder: the International Society for Bipolar Disorders Targeting Cognition Task Force recommendations for clinicians

OBJECTIVES

Cognition is a new treatment target to aid functional recovery and enhance quality of life for patients with bipolar disorder. The International Society for Bipolar Disorders (ISBD) Targeting Cognition Task Force aimed to develop consensus-based clinical recommendations on whether, when and how to assess and address cognitive impairment.

METHODS

The task force, consisting of 19 international experts from nine countries, discussed the challenges and recommendations in a face-to-face meeting, telephone conference call and email exchanges. Consensus-based recommendations were achieved through these exchanges with no need for formal consensus methods.

RESULTS

The identified questions were: (I) Should cognitive screening assessments be routinely conducted in clinical settings? (II) What are the most feasible screening tools? (III) What are the implications if cognitive impairment is detected? (IV) What are the treatment perspectives? Key recommendations are that clinicians: (I) formally screen cognition in partially or fully remitted patients whenever possible, (II) use brief, easy-to-administer tools such as the Screen for Cognitive Impairment in Psychiatry and Cognitive Complaints in Bipolar Disorder Rating Assessment, and (III) evaluate the impact of medication and comorbidity, refer patients for comprehensive neuropsychological evaluation when clinically indicated, and encourage patients to build cognitive reserve. Regarding question (IV), there is limited evidence for current evidence-based treatments but intense research efforts are underway to identify new pharmacological and/or psychological cognition treatments.

CONCLUSIONS

This task force paper provides the first consensus-based recommendations for clinicians on whether, when, and how to assess and address cognition, which may aid patients' functional recovery and improve their quality of life.

The role of premorbid adjustment in schizophrenia: Focus on cognitive remediation outcome

Premorbid adjustment has been associated with several outcomes in schizophrenia and has been proposed as an index of cognitive reserve. This study aims to comprehensively analyse the relation between premorbid adjustment and clinical, neurocognitive, socio-cognitive and functional assessments, as well as to investigate the effect of premorbid adjustment on cognitive improvements after a cognitive remediation therapy protocol. Seventy-nine clinically stabilised outpatients with schizophrenia underwent a combined intervention consisting of cognitive remediation therapy added to standard rehabilitation therapy. All patients were assessed at baseline for psychopathology, premorbid adjustment, intellectual level, cognition and functioning. Cognitive evaluations were also repeated after the intervention. At baseline, significant correlations were observed between premorbid adjustment and working memory. The global cognitive improvement after treatment was significantly predicted by age and premorbid adjustment. This study confirms the association between premorbid adjustment and cognitive impairment and is the first to highlight the possible role of premorbid adjustment on the capacity to recover from cognitive deficits through a cognitive remediation therapy protocol. The data suggest that cognitive remediation may be particularly effective for people in the early course and that the assessment of premorbid adjustment could be of value to design individualised interventions.

Functional impairment in adult bipolar disorder with ADHD

BACKGROUND

It is well established that patients with either bipolar disorder (BD) or attention-deficit/hyperactivity disorder (ADHD) present functional impairment even when in remission. Nevertheless, research on functional impairment with adult patients with bipolar disorder comorbid to ADHD (BD+ADHD) is very scarce. The main objective of the current report was to evaluate the overall and specific domains of functioning, in patients with BD+ADHD compared to patients with pure bipolar disorder (pBD) and healthy controls (HCs).

METHOD

162 subjects from 3 groups were compared: 63 pBD, 23 BD+ADHD and 76 HCs. All the patients with BD had been euthymic for at least 6 months and they were recruited at the Hospital Clinic of Barcelona. All the participants were assessed with the 17-item Hamilton Depression Rating Scale (HAM-D), the Young Mania Rating Scale (YMRS) and the Functioning Assessment Short Test (FAST). Clinical, and sociodemographic data were also recorded.

RESULTS

Clinical groups, pBD and BD+ADHD, showed lower overall functioning (p < 0.001) in each domain of the FAST scale compared to the HCs. Moreover, the Tukey post hoc test revealed that the BD+ADHD group showed a worse score than pBD in the cognitive domain of the FAST. However, after controlling for potential confounding variables, only the HDRS scores (p < 0.026) remained significant for the cognitive domain of the FAST.

LIMITATIONS

The small sample size of the comorbid BD+ADHD group.

CONCLUSIONS

Adult patients with BD+ADHD showed the worst scores in functioning compared with the HCs, but did not show more severe functional impairment than the pBD group except for the cognitive domain. Therefore our findings suggest that depressive symptoms in adults with BD+ADHD may negatively influence cognitive functioning. Further studies are needed to confirm our findings for the management of BD+ADHD.

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.