Systematic review of appropriate cognitive assessment instruments used in clinical trials of schizophrenia, major depressive disorder and bipolar disorder

A comparative study of cognitive function in young patients with bipolar disorder with and without non-suicidal self-injury

OBJECTIVE

Bipolar disorder (BD) is a chronic mental disorder characterized by alternating or mixed episodes of mania or hypomania and depression. Cognitive function impairment is a frequent associated feature of the disease. While many BD patients also engage in non-suicidal self-injury (NSSI), there is a lack of studies on the cognitive function of BD patients with NSSI. This study aimed to evaluate cognitive functioning of BD patients with NSSI and provide a clinical basis for the differential diagnosis and treatment of BD and NSSI.

METHODS

A total of 60 BD patients with NSSI, 60 BD patients without NSSI, and 60 healthy controls (HC) were selected for the study. All participants met the inclusion criteria and were not taking any medications, excluding the potential effects of medication on cognitive functions. The following neurocognitive tests were used to measure the cognitive functions in areas such as speed of processing, reasoning and problem solving, attention/vigilance, working memory, visual learning, and verbal learning: The Trail Making Test (TMT), Category Fluency, Digit Symbol Coding Test (DSCT), Brief Visuospatial Memory Test-Revised (BVMT-R), The Neuropsychological Assessment Battery Mazes (NABM), Wechsler Memory Scale Third Edition Spatial Span Test (WMS III-SST), Hopkins Verbal Learning Test-Revised (HVLTR) and Continuous Performance Test and Identical Prs (CPT-IP).

RESULTS

The findings indicated that BD patients with NSSI exhibited cognitive impairment in all measured cognitive domains. On the other hand, BD patients without NSSI showed less pronounced impairment in terms of speed of processing, but exhibited significant cognitive impairment in the remaining five areas compared to the HC group.

CONCLUSION

The study underscores the presence of cognitive impairment in BD, and the cognitive impairment is more severe in BD patients with NSSI compared to those without NSSI. In conclusion, both individuals with NSSI and those without NSSI in BD exhibit cognitive impairment, which provides ideas and strategies for using cognitive-behavioral therapy to treat BD and NSSI.

Neuropsychological instruments for bipolar disorders: A systematic review on psychometric properties

BACKGROUND

Cognitive deficits are a core feature of bipolar disorder (BD) that persist during the euthymic phase and affect global functioning. However, nowadays, there is no consensus on the optimal tool to capture cognitive deficits in BD. Therefore, this review aims to examine the psychometric properties of tools commonly used to assess cognitive functioning in BD.

METHODS

Literature search was conducted on PubMed and Web of Science databases on August 1, 2022 and on April 20, 2023, yielding 1758 de-duplicated records. Thirteen studies fulfilled the inclusion criteria and were included in the review.

RESULTS

All tools examined showed acceptable-to-good psychometric properties suggesting that both brief cognitive screeners and comprehensive batteries may be appropriate for detecting or monitoring cognitive changes in BD.

LIMITATIONS

Methodological differences between the included studies precluded a direct comparison of the results. Further research is needed to investigate the psychometric properties of cognitive tools that assess also affective and social cognition.

CONCLUSIONS

The tools examined appear sensitive enough to distinguish between BD patients with versus without cognitive deficits, however, an optimal tool has not yet been identified. The applicability and clinical utility of the tools may depend on multiple factors such as available resources. That said, web-based instruments are expected to become the first-choice instrument for cognitive screening as they can be applied on a large scale and at an affordable cost. As for second-level assessment instruments, the BACA shows robust psychometric properties and tests both affective and non-affective cognition.

A comparative study of cognitive functions between schizophrenia and obsessive-compulsive disorder

Background

Schizophrenia (SZ) and obsessive-compulsive disorder (OCD) are closely linked, have a high comorbidity rate, and their differential diagnosis is challenging in clinic. Some studies have found common cognitive deficits in some domains between them. The goal of this research was to compare the cognitive functions of SZ and OCD in order to offer a clinical foundation for differential diagnosis and treatment of the two disorders.

Methods

A control design was used in this study, which comprised 61 patients with SZ, 60 individuals with OCD, and 51 healthy controls (HC). We assessed patients' cognitive functions by testing six domains, including visual learning, reasoning and problem solving, verbal learning, attention/vigilance, speed of processing and working memory.

Results

The results showed that patients with SZ had cognitive impairments in all areas except attention/vigilance, while patients with OCD only had cognitive impairment in reasoning and problem-solving. Overall, patients with SZ did not perform as well as patients with OCD in all domains.

Conclusions

In terms of neurocognition, both of SZ and OCD patients have defects in reasoning and problem solving. In addition to this, SZ patients also performed worse than HC in other areas such as speed of processing, working memory, verbal learning and visual learning. On the overall level, cognitive performance is better in OCD patients than in SZ patients. The field of reasoning and problem solving can be used as a new goal to study the relationship and treatment strategies between them in the future.

Cross-Cultural Adaptation and Validation of the Serbian Version of the Brief Assessment of Cognition in Schizophrenia Scale

The Brief Assessment of Cognition in Schizophrenia (BACS) scale was developed for the assessment of cognitive function in patients with schizophrenia. The objective of this study was to cross-culturally adapt and validate the BACS in to the Serbian language. The study was conducted at the Laza Lazarevic Clinic for Mental Disorders and the Clinic for Psychiatry of the University Clinical Center of Serbia from March 2021 to January 2022. The study enrolled 61 inpatients diagnosed with schizophrenia and 61 healthy controls matched for age and sex. Compared with the healthy control group, the schizophrenia patient group had worse cognitive function in all dimensions measured using BACS (p < 0.001 for all measures). The mean standardized composite BACS score was z = -2.46, and symbol coding (z = -2.54) was the most deficient function. Principal component analysis suggests a two-factor structure, where the first factor consisted of loading the measures of verbal and working memory, attention, speed of information processing, and executive function, while the second factor regarded the loading of motor speed. Cronbach's alpha coefficient demonstrated an excellent level of internal consistency (0.798). These outcomes suggest that the Serbian BACS neurocognitive battery's psychometric properties are satisfactory, with good overall discriminant validity and high internal consistency. The Serbian BACS appears to be a quick and reliable neuropsychological instrument for evaluating global cognition in schizophrenia patients in Serbia.

Correlation of Health-Related Quality of Life with Negative Symptoms Assessed with the Self-Evaluation of Negative Symptoms Scale (SNS) and Cognitive Deficits in Schizophrenia: A Cross-Sectional Study in Routine Psychiatric Care

(1) Background: Schizophrenia is a severe mental disorder characterized by various symptom groups that tremendously affect health-related quality of life (HRQoL). We aimed to specify whether negative symptoms and cognitive deficits of schizophrenia correlate and can predict HRQoL. (2) Methods: Patients diagnosed with paranoid schizophrenia were invited to participate in the study. Participants were evaluated using the Montreal Cognitive Assessment (MoCA) and the Brief Psychiatric Rating Scale (BPRS) and were asked to fill out the Self-evaluation of Negative Symptoms scale (SNS) and the Medical Outcomes Short Form Survey (SF-36). Pearson's and Spearman's correlations were used to calculate the correlations between cognitive deficits and negative symptoms. We performed the receiver operating characteristic (ROC) analysis for the variables correlated with SF-36 scores. (3) Results: HRQoL correlated significantly with the negative symptoms; however, it did not correlate with cognitive deficits. ROC analysis showed that the abulia subscore of the SNS showed the most significant predictive potential of HRQoL. (4) Conclusions: Negative symptoms correlate more significantly with the HRQoL than cognitive symptoms. The SNS offers the possibility of predicting the HRQoL of patients with schizophrenia and is useful as a screening tool in clinical practice.

Remote cognitive assessment in severe mental illness: a scoping review

Many individuals living with severe mental illness, such as schizophrenia, present cognitive deficits and reasoning biases negatively impacting clinical and functional trajectories. Remote cognitive assessment presents many opportunities for advancing research and treatment but has yet to be widely used in psychiatric populations. We conducted a scoping review of remote cognitive assessment in severe mental illness to provide an overview of available measures and guide best practices. Overall, 34 studies (n = 20,813 clinical participants) were reviewed and remote measures, psychometrics, facilitators, barriers, and future directions were synthesized using a logic model. We identified 82 measures assessing cognition in severe mental illness across 11 cognitive domains and four device platforms. Remote measures were generally comparable to traditional versions, though psychometric properties were infrequently reported. Facilitators included standardized procedures and wider recruitment, whereas barriers included imprecise measure adaptations, technology inaccessibility, low patient engagement, and poor digital literacy. Our review identified several remote cognitive measures in psychiatry across all cognitive domains. However, there is a need for more rigorous validation of these measures and consideration of potentially influential factors, such as sex and gender. We provide recommendations for conducting remote cognitive assessment in psychiatry and fostering high-quality research using digital technologies.

The screen for cognitive impairment in psychiatry in patients with borderline personality disorder

Cognitive deficits are common in borderline personality disorder (BPD) and appear to be associated with psychopathology, functioning and outcome. The availability of a cognitive screening instrument could be of use in clinical settings in order to assess neurocognition in BPD patients. The Screen for Cognitive Impairment for Psychiatry (SCIP) proved to be reliable in different psychiatric populations, but it has not yet been validated in personality disorders. The purpose of this study is therefore to evaluate its psychometric properties in a sample of 58 BPD patients. The SCIP was validated against the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Trail Making Test A and B (TMT A and B). The receiver operator curve analysis displayed an acceptable convergent validity (total score AUC: 0.78, 95% CI: 0.70-0.86; Se: 75%, Sp: 72%). A cut-off total score of 80 identified 81% of patients as cognitively impaired. The exploratory factor analysis displayed a one-factor solution explaining 55.8% of the total variance. The SCIP displayed adequate psychometric properties in BPD and could be integrated in the routine clinical assessment to provide a preliminary evaluation of cognitive features for BPD.

A critical overview of tools for assessing cognition in bipolar disorder

Cognitive deficits are prevalent in bipolar disorder even during the euthymic phase, having a negative impact on global functioning and quality of life. As such, more and more mental health professionals agree that neuropsychological assessment should be considered an essential component of the clinical management of bipolar patients. However, no gold standard tool has been established so far. According to bipolar disorder experts targeting cognition, appropriate cognitive tools should be brief, easy to administer, cost-effective and validated in the target population. In this commentary, we critically appraised the strengths and limitations of the tools most commonly used to assess cognitive functioning in bipolar patients, both for screening and diagnostic purposes.

The prevalence and characteristics of MCCB cognitive impairment in unmedicated patients with bipolar II depression and major depressive disorder

BACKGROUND

Cognitive impairment has been acknowledged as a core clinical manifestation of bipolar disorder (BD) as well as major depressive disorder (MDD). Determining the prevalence and characteristics of cognitive impairment is important for clinical interventions. This study investigated the prevalence and characteristics of cognitive impairment based on the Measurement and Treatment Research to Improve Cognition Schizophrenia Consensus Cognitive Battery (MCCB) in both BD and MDD.

METHOD

One hundred and forty-nine BD II depression, 147 MDD, and 124 demographically matched healthy controls (HC) underwent MCCB cognitive assessment. The prevalence of MCCB cognitive impairment and group difference comparisons were performed. Additionally, association analysis was performed to investigate the relationship between cognitive performance and clinical variables.

RESULTS

Compared to the HC group, both BD II depression and MDD groups had a significantly reduced performance for all MCCB cognitive domains (all p < 0.05). The numerical scores for visual learning were lower in the BD II depression group compared to the MDD group. 32.89% of the BD II depression patients had clinically significant impairment (>1.5 SD below the normal mean) in two or more MCCB domains compared to 23.13% for MDD patients.

CONCLUSIONS

A high percent of patients in the BD II depression and MDD group exhibited MCCB cognitive impairments with clinical significance. Cognitive impairments were more common in BD II depression patients compared to MDD patients, particularly for visual learning. These findings suggest that clinicians should be aware of the severe cognitive impairment in mood disorders and establish effective cognitive screening and intervention strategies.

Application of computerized cognitive test battery in major depressive disorder: a narrative literature review

BACKGROUND

Major depressive disorder (MDD) is a chronic and debilitating relapsing-remitting mood disorder, characterized by psychological, cognitive, and behavioral disturbances. The assessment of cognitive dysfunction in individuals with MDD has increasingly become a topic of concern in recent years.

AIMS

To pool and compare the characteristics of various cognition evaluation tools.

METHOD

Overview of recent research in application of computerized cognitive test battery in MDD.

RESULTS

With recent technological advances in mobile health technologies and the ubiquity of smartphones, the use of traditional tools is no longer sufficient to monitor the dynamic changes of an individual's cognitive performance, which may be influenced by many factors, including, but not limited to, disease course and medications. Computerized tests have many advantages over traditional neuropsychological testing, chiefly in terms of time and cost savings, accurate recording of multiple response components, and the ability to automatically store and compare performance between testing sessions. In the following review, we summarized cognitive impairment characteristics of MDD, introduced traditional assessment tools of cognitive function in MDD, and reviewed the development of the current computerized cognitive test batteries for MDD. The comparisons among cognitive function evaluation tools were also performed.

CONCLUSIONS

It is our belief that the improvement of existing novel computerized cognitive test batteries, the development of more comprehensive and easy-to-operate scales, verification techniques and multiple follow-up surveys among large sample populations may provide valuable clues for the evaluation and tracking of cognitive function in individuals with MDD.

Cognitive Considerations in Major Depression: Evaluating the Effects of Pharmacotherapy and ECT on Mood and Executive Control Deficits

Deficits in the executive control of attention greatly impact the quality of life of patients diagnosed with major depressive disorder (MDD). However, attentional deficits are often underemphasized in clinical contexts compared with mood-based symptoms, and a comprehensive approach for specifically evaluating and treating them has yet to be developed. The present study evaluates the efficacy of bifrontal electroconvulsive therapy (ECT) combined with drug therapy (DT) in alleviating mood-related symptomatology and executive control deficits in drug-refractory MDD patients and compares these effects with those observed in MDD patients undergoing DT only. The Hamilton Rating Scale for Depression and the Lateralized Attentional Network Test-Revised were administered across two test sessions to assess treatment-related changes in mood-based symptoms and conflict processing, respectively, in patients undergoing ECT + DT (n = 23), patients undergoing DT (n = 33), and healthy controls (n = 40). Although both groups showed an improvement in mood-based symptoms following treatment and a deficit in conflict processing estimated on error rate, a post-treatment reduction of an executive control deficit estimated on RT was solely observed in the ECT + DT patient group. Furthermore, Bayesian correlational analyses confirmed the dissociation of mood-related symptoms and of executive control measures, supporting existing literature proposing that attentional deficits and mood symptoms are independent aspects of MDD. The cognitive profile of MDD includes executive control deficits, and while both treatments improved mood-based symptoms, only ECT + DT exerted an effect on both measures of the executive control deficit. Our findings highlight the importance of considering the improvement in both mood and cognitive deficits when determining the efficacy of therapeutic approaches for MDD.

Assessing cognition in people with severe mental disorders in low- and middle-income countries: a systematic review of assessment measures

BACKGROUND

Cognitive difficulties are common in people with severe mental disorders (SMDs) and various measures of cognition are of proven validity. However, there is a lack of systematic evidence regarding the psychometric properties of these measures in low- and middle-income countries (LMICs).

OBJECTIVE

To systematically review the psychometric properties of cognitive measures validated in people with SMDs in LMICs.

METHODS

We conducted a systematic review of the literature by searching from four electronic databases. Two authors independently screened studies for their eligibility. Measurement properties of measures in all included studies were extracted. All eligible measures were assessed against criteria set for clinical and research recommendations. Results are summarized narratively and measures were grouped by measurement type and population.

RESULTS

We identified 23 unique measures from 28 studies. None of these was from low-income settings. Seventeen of the measures were performance-based. The majority (n = 16/23) of the measures were validated in people with schizophrenia. The most commonly reported measurement properties were: known group, convergent, and divergent validity (n = 25/28). For most psychometric property, studies of methodological qualities were found to be doubtful. Among measures evaluated in people with schizophrenia, Brief Assessment of Cognition in Schizophrenia, Cognitive Assessment Interview, MATRICS Consensus Cognitive Battery, and CogState Schizophrenia Battery were with the highest scores for clinical and research recommendation.

CONCLUSIONS

Studies included in our review provide only limited quality evidence and future studies should consider adapting and validating measures using stronger designs and methods. Nonetheless, validated assessments of cognition could help in the management and allocating therapy in people with SMDs in LMICs.

European Psychiatric Association guidance on assessment of cognitive impairment in schizophrenia

Background

Impairment in a wide range of cognitive abilities has been consistently reported in individuals with schizophrenia. Both neurocognitive and social cognitive deficits are thought to underlie severe functional disabilities associated with schizophrenia. Despite the key role in schizophrenia outcome, cognition is still poorly assessed in both research and clinical settings.

Methods

In this guidance paper, we provide a systematic review of the scientific literature and elaborate several recommendations for the assessment of cognitive functions in schizophrenia both in research settings and in real-world clinical practice.

Results

Expert consensus and systematic reviews provided guidance for the optimal assessment of cognitive functions in schizophrenia. Based on the reviewed evidence, we recommend a comprehensive and systematic assessment of neurocognitive and social cognitive domains in schizophrenia, in all phases of the disorder, as well as in subjects at risk to develop psychosis. This European Psychiatric Association guidance recommends not only the use of observer reports but also self-reports and interview-based cognitive assessment tools. The guidance also provides a systematic review of the state of the art of assessment in the first episode of psychosis patients and in individuals at risk for psychosis.

Conclusion

The comprehensive review of the evidence and the recommendations might contribute to advance the field, allowing a better cognitive assessment, and avoiding overlaps with other psychopathological dimensions. The dissemination of this guidance paper may promote the development of shared guidelines concerning the assessment of cognitive functions in schizophrenia, with the purpose to improve the quality of care and to obtain recovery.

A randomized, multicenter, crossover psychometric evaluation study of an iPad-administered cognitive test battery in participants with major depressive disorder who responded to treatment with oral antidepressants

BACKGROUND

Performance validity and test-retest reliability of ReVeRe.D, an iPad-administered cognitive test battery in major depressive disorder (MDD) were analyzed.

METHODS

Participants aged 18-59 years had DSM-5 diagnosis of MDD with adequate visual and hearing acuity. All had responded to oral antidepressant treatment for a major depressive episode within the most recent 24-months and were stable with no greater than mild depressive symptoms as evidenced by Montgomery Asberg Depression Rating Scale total score <17. Participants were randomly assigned to 1 of 2 test sequences (AABB or BBAA; A=ReVeRe.D; B=examiner-administered tests) in a crossover design.

RESULTS

244 randomized participants (AABB: n=123; BBAA: n=121) had mean age of 38.3 years; 54.9% had a college, baccalaureate, or higher education. At first administration, Pearson correlation coefficients (PCC) for 6/10 pairs of corresponding ReVeRe.D vs examiner-administered tests exceeded the pre-specified acceptance criterion (PCC=0.53) for the primary analysis; 8 test score pairs had PCC exceeding 0.40. At second administration, PCC for 9/10 test scores pairs exceeded PCC=0.53. Together, the series of PCCs supports the concurrent validity for ReVeRe.D. Test-retest reliability for ReVeRe.D test scores was generally moderate to high.

LIMITATIONS

The study included stable participants with MDD who had responded to oral antidepressant treatment, with most in at least partial remission. The sample was limited to English-speaking participants, and skewed towards white, college-educated women. Further studies in acutely ill MDD patients who represent a broader demographic, are warranted.

CONCLUSIONS

iPad-administered ReVeRe.D is a valid and reliable computerized test battery for assessment of cognitive performance in MDD.

Cross-cultural adaptation and validation of the Arabic version of the BACS scale (the brief assessment of cognition in schizophrenia) among chronic schizophrenic inpatients

BACKGROUND

Assessment of cognitive disorders in schizophrenia is becoming a part of clinical and research practice by using batteries that differ widely in their content. The Brief Assessment of Cognition in Schizophrenia (BACS) was developed to cover the main cognitive deficits of schizophrenia. The objective of this study was to assess concurrent validity of the Arabic version of the BACS with a standard neurocognitive battery of tests in Lebanese patients with schizophrenia and healthy controls.

METHODS

A sample of 120 stable inpatients diagnosed with schizophrenia and 60 healthy controls received the Arabic version of the BACS in a first session, and a standard battery in a second session.

RESULTS

Mean duration of completion for the BACS was 31.2 ± 5.4 min in patients with schizophrenia. All tests demonstrated significant differences between controls and patients (p < .01). Principal components analysis demonstrated that a one-factor solution best fits our dataset (64.8% of the variance). High Cronbach alpha was found (.85). The BACS composite scores were significantly correlated with the standard battery composite scores in patients (r = .73, p < .001) and healthy controls (r = .78, p < .001). Also, correlation analysis between the BACS sub-scores and the standard battery sub-scores showed significant results (p < .05).

CONCLUSION

Results showed that the Arabic version of the BACS demonstrated high ability to discriminate patients with schizophrenia from healthy controls and it is a useful tool for assessing cognition in patients with schizophrenia and could be used in clinical practice in Lebanon.

Cognitive Enhancers in Schizophrenia: A Systematic Review and Meta-Analysis of Alpha-7 Nicotinic Acetylcholine Receptor Agonists for Cognitive Deficits and Negative Symptoms

Background: Schizophrenia is a severe and enduring disease and is one of the leading causes of disability worldwide. Cognitive impairment is a core clinical symptom that plays a crucial role in functional outcomes and prognosis, thus making it a relevant treatment target. The aim of this study was to assess the efficacy of alpha-7 nicotinic acetylcholine receptor agonists (α7 nAChR) as adjunctive treatment to enhance cognition and ameliorate negative symptoms in patients with schizophrenia. Methods: A search strategy was developed for MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials up to May 2019. We included randomized controlled trials (RCTs) that compared antipsychotic treatment plus α7 nAChR agonists with antipsychotic treatment plus placebo and determined their effects on the main cognitive domains proposed by the MATRICS initiative and on negative symptoms. Two authors independently reviewed study eligibility and data extraction and assessed the risk of bias of the studies included. According to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework, we used a random-effects model and assessed the quality of the evidence. Results: Thirteen studies were included in the quantitative analysis. No differences were found in any of the cognitive domains assessed in four RCTs (n = 414). In contrast, nine RCTs (n = 978) presented a small effect in support of α7 nAChR agonists for negative symptoms [standardized mean difference -0.28, 95% CI (-0.56 to -0.00); P = 0.05], even though the confidence to support this evidence is low according to the GRADE system. Conclusions: Current evidence is too weak to consider α7 nAChR agonists as an effective add-on treatment to antipsychotics to enhance cognition and negative symptoms.

A systematic review of research on neuropsychological measures in psychotic disorders from low and middle-income countries: The question of clinical utility

INTRODUCTION

Several studies of neuropsychological measures have been undertaken in patients with psychotic disorders from low- and middle-income countries (LMICs). It is, however, unclear if the measures used in these studies are appropriate for cognitive screening in clinical settings. We undertook a systematic review to determine if measures investigated in research on psychotic disorders in LMICs meet the clinical utility criteria proposed by The Working Group on Screening and Assessment.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses were employed. We determined if tests had been validated against a comprehensive test battery, the duration and scope of the tests, the personnel administering the tests, and the means of administration.

RESULTS

A total of 31 articles were included in the review, of which 11 were from Africa. The studies included 3254 participants with psychosis and 1331 controls. 3 studies reported on the validation of the test against a comprehensive cognitive battery. Assessments took 1 h or less to administer in 6/31 studies. The average number of cognitive domains assessed was four. Nonspecialized staff were used in only 3/31 studies, and most studies used pen and paper tests (17/31).

CONCLUSION

Neuropsychological measures used in research on psychotic disorders in LMICs typically do not meet the Working Group on Screening and Assessment clinical utility criteria for cognitive screening. Measures that have been validated in high-income countries but not in LMICs that do meet these criteria, such as the Brief Assessment of Cognition in Schizophrenia, therefore deserve further study in LMIC settings.

Comparison of cognitive dysfunction between schizophrenia and bipolar disorder patients: A meta-analysis of comparative studies

OBJECTIVE

Cognitive dysfunction is common in both schizophrenia and bipolar disorder. This is a meta-analysis of studies that compared cognitive dysfunction between schizophrenia and bipolar disorder.

METHODS

Both international and Chinese databases were systematically searched. Studies that compared cognitive function between schizophrenia and bipolar disorder with the MATRICS Consensus Cognitive Battery (MCCB) were analyzed using the random-effects model.

RESULTS

Twelve studies with 9,518 participants (4,411 schizophrenia and 5,107 bipolar patients) were included in the analyses. Schizophrenia patients performed significantly worse than bipolar patients on the MCCB total scores with a large effect size (SMD=-0.80, 95%CI: -1.21 to -0.39), as well as on all the 7 subscale scores; attention (SMD=-2.56, 95%CI: -3.55 to -1.57) and social cognition (SMD=-0.86, 95%CI: -1.13 to -0.58) with large effect sizes; and speed of processing (SMD=-0.75, 95%CI: -1.00 to -0.49), working memory (SMD=-0.68, 95%CI: -0.91 to -0.45), verbal learning (SMD=-0.78, 95%CI: -0.95 to -0.61), visual learning (SMD=-0.65, 95%CI: -0.83 to -0.48), and reasoning and problem solving (SMD=-0.61, 95%CI: -0.93 to -0.29) with medium effect sizes.

CONCLUSION

Compared to bipolar patients, patients with schizophrenia had more severe cognitive dysfunction in this meta-analysis, particularly in attention and social cognition. Timely assessment and treatment of cognitive dysfunction should be part of standard management protocols in both schizophrenia and bipolar disorder.

Screening for cognitive impairment in non-affective psychoses: A comparison between the SCIP and the MoCA

BACKGROUND

Neuropsychological performance has a strong impact on real-life functioning and clinical outcomes in psychosis. However, conducting lengthy cognitive assessments may not be feasible in routine clinical practice. Brief, reliable and cost-effective tools are highly needed, but few studies are available to guide clinician choice.

METHODS

The purpose of this study was to compare the performance of two widely used, short instruments: the Screen for Cognitive Impairment in Psychiatry (SCIP) and the Montreal Cognitive Assessment (MoCA). These instruments were validated in a sample of patients with psychotic disorders and healthy controls, using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and other instruments to assess executive functions, as comparators.

RESULTS

Patients fared worse than controls across almost all cognitive domains, with effect sizes ranging from 0 (MoCA naming) to 2.08 (SCIP total). Receiver Operator Curve analysis of patient and control performance suggested a better convergent validity for the SCIP (total score AUC: 0.85; 95%CI: 0.79-0.90; Se: 76%, Sp: 83%, PPV: 85%, NPV: 73%) than the MoCA (AUC: 0.78; 95%CI: 0.72-0.85; Se: 69%, Sp: 76%, PPV: 78.7%, NPV 66%).

CONCLUSIONS

The Screen for Cognitive Impairment in Psychiatry seems to be a more sensitive and specific screening tool than the MoCA to identify cognitive impairment among patients with psychotic disorders.

A systematic review of factors that influence the efficacy of cognitive remediation therapy in schizophrenia

OBJECTIVE

Cognitive remediation therapy is a moderately effective intervention for ameliorating cognitive deficits in individuals with schizophrenia-related disorders. With reports of considerable variability in individual response to cognitive remediation therapy, we need to better understand factors that influence cognitive remediation therapy efficacy to realise its potential. A systematic review was conducted to identify and evaluate predictors of cognitive outcome.

METHODS

An electronic database search was conducted identifying peer-reviewed articles examining predictors of cognitive response to cognitive remediation therapy.

RESULTS

A total of 40 articles accounting for 1681 cognitive remediation therapy participants were included; 81 distinct predictors of cognitive response were identified. Data synthesis and discussion focused on 20 predictors examined a minimum three times in different studies. Few of the examined predictors of cognitive outcome following cognitive remediation therapy were significant when examined through systematic review. A strong trend was found for baseline cognition, with reasoning and problem solving and working memory being strongly predictive of within-domain improvement. Training task progress was the most notable cross-domain predictor of cognitive outcome.

CONCLUSION

It remains unclear why a large proportion of participants fail to realise cognitive benefit from cognitive remediation therapy. However, when considering only those variables where a majority of articles reported a statistically significant association with cognitive response to cognitive remediation therapy, three stand out: premorbid IQ, baseline cognition and training task progress. Each of these relates in some way to an individual's capacity or potential for change. There is a need to consolidate investigation of potential predictors of response to cognitive remediation therapy, strengthening the evidence base through replication and collaboration.

Longitudinal course of cognitive function across treatment in patients with MDD: A meta-analysis

BACKGROUND

The longitudinal change of cognitive function across psychological treatment remains unclear. The aim of this meta-analysis was to synthesize results from longitudinal studies of cognitive deficits in MDD patients across treatment to examine change and determine domains that are most sensitive to change.

METHODS

A literature search was conducted using PsycINFO, MEDLINE, Science direct, and Google scholar databases. The main analysis included 16 studies and examined the change of cognitive function in 859 patients with MDD by calculating overall test-retest effect sizes (Hedges' g) and using a random effects model. Further analyses were conducted on studies of MDD patients that included a healthy control group, and effect sizes were compared.

RESULTS

The effect size estimates suggest significant small improvements in all cognitive measures (g = 0.17-0.35). Studies including healthy controls revealed no significant differences in cognitive function between MDD patients and healthy controls, except for the improvements in verbal memory. Moderator analyses revealed that mean age influenced change in some cognitive domains. The change in depression severity did not affect the results.

LIMITATIONS

Treatments differed with regard to the type and duration of psychological intervention and the influence of additional pharmacological treatment could not be controlled. Due to the small number of included studies, the results should be regarded as preliminary.

CONCLUSIONS

Cognitive abilities improved during treatments, which included psychological interventions. The improvements may be due to practice effects rather than cognitive recovery, except for verbal memory.

Impact of subjective vs. objective remission status on subjective cognitive impairments in depression

OBJECTIVE

The impact of subjective vs. objective illness severity on subjective cognitive impairment in patients with depression has not been addressed.

METHODS

This study is a post-hoc analysis of our cross-sectional study in Japanese outpatients with depressive disorder (ICD-10) (Ozawa et al., 2017). The participants received assessments with the Japanese version of the Perceived Deficits Questionnaire (J-PDQ), Quick Inventory of Depressive Symptomatology (QIDS), and Montgomery-Asberg Depression Rating Scale (MADRS). First, multiple regression analysis was conducted to examine the effects of demographic and clinical characteristics, including illness severity and medications (e.g., antidepressants and benzodiazepines), on the PDQ total score. Next, we categorized the participants into 4 groups based on the presence/absence of subjective and objective symptom remission (i.e., QIDS total score of ≤5 and MADRS total score of ≤9, respectively), and compared the differences in PDQ total scores between the QIDS- and MADRS-remitted group and the QIDS-non-remitted but MADRS-remitted group.

RESULTS

102 participants were included (45 men; mean ± SD age, 50.5 ± 14.7 years). Higher QIDS and MADRS total scores were significantly associated with a greater PDQ total score (both p's < 0.001), while other factors did not exhibit any associations. The QIDS-non-remitted but MADRS-remitted group showed a significantly higher PDQ total score than that of the QIDS- and MADRS-remitted group (median 10.0 [8.0-12.0] vs. 3.0 [range: 2.0-4.0], p < 0.001).

CONCLUSIONS

These findings suggest that objective remission in the absence of subjective remission may not be adequate to improve subjective cognitive functioning.

The Relationship Between Cognitive Dysfunction and Symptom Dimensions Across Schizophrenia, Bipolar Disorder, and Major Depressive Disorder

Background: Cognitive dysfunction is considered a core feature among schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). Despite abundant literature comparing cognitive dysfunction among these disorders, the relationship between cognitive dysfunction and symptom dimensions remains unclear. The study aims are a) to identify the factor structure of the BPRS-18 and b) to examine the relationship between symptom domains and cognitive function across SZ, BD, and MDD. Methods: A total of 716 participants [262 with SZ, 104 with BD, 101 with MDD, and 249 healthy controls (HC)] were included in the study. One hundred eighty participants (59 with SZ, 23 with BD, 24 with MDD, and 74 HC) completed the MATRICS Consensus Cognitive Battery (MCCB), and 507 participants (85 with SZ, 89 with BD, 90 with MDD, and 243 HC) completed the Wisconsin Card Sorting Test (WCST). All patients completed the Brief Psychiatric Rating Scale (BPRS). Results: We identified five BPRS exploratory factor analysis (EFA) factors ("affective symptoms," "psychosis," "negative/disorganized symptoms," "activation," and "noncooperation") and found cognitive dysfunction in all of the participant groups with psychiatric disorders. Negative/disorganized symptoms were the most strongly associated with cognitive dysfunctions across SZ, BD, and MDD. Conclusions: Our findings suggest that cognitive dysfunction severity relates to the negative/disorganized symptom domain across SZ, BD, and MDD, and negative/disorganized symptoms may be an important target for effective cognitive remediation in SZ, BD, and MDD.

Cognitive improvement of acetylcholinesterase inhibitors in schizophrenia

BACKGROUND

Schizophrenia is a severe, persistent mental disorder, and a leading cause of disability worldwide. Cognitive impairments presented in schizophrenia lead to a worse prognostic, thus treatments targeted to enhance cognition in schizophrenia may be clinically relevant.

AIMS

The purpose of this study was to assess the efficacy of acetylcholinesterase inhibitors as add-on medication to antipsychotics on cognition in patients with schizophrenia.

METHODS

Search strategies were developed for Medline, Embase and Cochrane Central Register of Controlled Trials, and are current to March 2018. We included randomised controlled trials that compared antipsychotics plus acetylcholinesterase inhibitors versus antipsychotics plus placebo on prespecified cognitive domains (speed of processing, attention and working memory). Two review authors independently evaluated study eligibility, extracted data and assessed the risk of bias of included studies. We used random-effects model for meta-analyses and assessed the quality of evidence using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

We included nine randomised controlled trials. Six randomised controlled trials ( n=219) presented evidence that acetylcholinesterase inhibitors improve speed of processing (standardised mean difference -0.52, 95% confidence interval (-0.79 to -0.25); p value=0.0002). However, eight randomised controlled trials ( n=252) did find placebo was better than acetylcholinesterase inhibitors in the attention domain (-0.43, (-0.72 to -0.13); p value=0.005) and eight randomised controlled trials ( n=273) did not find differences in the working memory (-0.14, (-0.51 to 0.24), p value=0.47).

CONCLUSIONS

The current evidence is too weak to base recommendations on the use of acetylcholinesterase inhibitors as adjunctive treatments to antipsychotics to improve basic cognitive functions. We have limited confidence in the effect estimates.

Neurocognitive dysfunction in subjects at clinical high risk for psychosis: A meta-analysis

Findings of neurocognitive dysfunction in subjects at Clinical High Risk for Psychosis (CHR-P) have been controversial. This meta-analysis systematically examined studies of neurocognitive functions using the MATRICS Consensus Cognitive Battery (MCCB) in CHR-P. An independent literature search of both English and Chinese databases was conducted by two reviewers. Standardized mean difference (SMD) was calculated using a random effects model to evaluate the effect size of the meta-analytic results. Six case-control studies (n = 396) comparing neurocognitive functions between CHR-P subjects (n = 197) and healthy controls (n = 199) using the MCCB were identified; 4 (66.7%) studies were rated as "high quality". Compared to healthy controls, CHR-P subjects showed impairment with large effect size in overall cognition (n = 128, SMD = -1.00, 95%CI: -1.38, -0.63, P < 0.00001; I² = 2%), processing speed (SMD = -1.21) and attention/vigilance (SMD = -0.83), and with medium effect size in working memory (SMD = -0.76), reasoning and problem solving (SMD = -0.71), visual (SMD = -0.68) and verbal learning (SMD = -0.67). No significant difference between CHR-P subjects and controls was found regarding social cognition (SMD = -0.33, 95%CI: -0.76, 0.10, P = 0.14; I² = 70%) with small effect size. Apart from social cognition, CHR-P subjects performed worse than healthy control in all MCCB cognitive domains, particularly in processing speed, attention/vigilance and working memory.

The Chinese Version of the Brief Assessment of Cognition in Schizophrenia: Data of a Large-Scale Mandarin-Speaking Population

Objective

The Brief Assessment of Cognition in Schizophrenia (BACS) is a cognitive assessment tool used to measure the broad aspects of cognition that are most frequently impaired in patients with schizophrenia. This study aims to develop the normative data of the Chinese version of the BACS among the Mandarin-speaking population.

Method

This cross-sectional study included 382 healthy participants (age range: 19-79 years; mean age: 48.0 ± 16.7 years, 47.6% men) in Taiwan, who were evaluated with the BACS. Means and standard deviations of subtests and composite scores were arranged by age group and gender. The Z-scores calculated based on the U.S. norms were compared to our scores based on the norms established in this study.

Results

The raw scores of all the BACS tests (verbal memory, digit sequencing, token motor test, verbal fluency, symbol coding, and Tower of London) were negatively correlated with participants' age. Women were superior to men in verbal memory, but inferior to them in executive function. Furthermore, applying the U.S. norms of the BACS to determine the performance of the Chinese BACS results in bias with regard to verbal memory, token motor test, verbal fluency, symbol coding, Tower of London and composite score.

Conclusions

These findings demonstrate that directly applying western cognitive norms to a Mandarin-speaking population can cause biased interpretations. The results of this study can be an important reference for clinical settings and research related to cognitive assessments in Mandarin-speaking Chinese populations.

Cognitive complaints and predictors of perceived cognitive dysfunction in adults with major depressive disorder: Findings from the Cognitive Dysfunction in Asians with Depression (CogDAD) study

BACKGROUND

Several studies have described the presence of perceived cognitive dysfunction amongst Asian patients with major depressive disorder (MDD). To date, no study has been conducted investigating the predictors of perceived cognitive dysfunction amongst Asian MDD patients.

METHODS

This was a post-hoc analysis of the Cognitive Dysfunction in Asian patients with Depression (CogDAD) study. Descriptive statistics were used to describe the most common cognitive complaints by patients. Univariate and multivariate analyses were performed to determine variables associated with perceived cognitive dysfunction (Perceived Deficit Questionnaire-Depression, PDQ-D).

RESULTS

The CogDAD study population is comprised of MDD patients with mild-to-moderate depression (Patient Health Questionnaire 9-item [PHQ-9]: 11.3 ± 6.9) who reported perceived cognitive dysfunction (PDQ-D = 22.6 ± 16.2). The most common cognitive complaints were: mind drifting (42.3%), trouble making decision (39.6%) and trouble concentrating (38.0%). Predictors of perceived cognitive dysfunction were: being Southeast Asians (vs. Taiwanese) (p < 0.001), current episode longer than 8 weeks (vs. 1-8 weeks) (p < 0.05), the presence of disability (vs. no disability) (p < 0.05), younger age (p < 0.01), and higher PHQ-9 total scores (p < 0.001).

LIMITATIONS

The causal relationship between predictive variables and PDQ-D could not be tested due to the cross-sectional nature of the study. Furthermore, a neuropsychological test was not included in the CogDAD study and use of concomitant medications, including anti-depressants, could have impacted patient's perceived cognitive ability.

CONCLUSIONS

The present study results suggest a potential role for subjective cognitive assessment in patients with MDD who are young, with long durations of depression or severe depression.

Cognitive impairment in schizophrenia and depression: A comparison of stability and course

Cognitive deficits are clinically relevant features in schizophrenia and depression, yet little comparative data on changes in both disorders is available. This study compares cognitive performance of inpatients with schizophrenia (N = 52) and unipolar major depression (N = 67) during psychiatric treatment, assessing performance twice: after admission to hospital (acute) and prior to discharge (postacute) on average seven weeks later. A group of healthy controls was tested at comparable intervals. Data was analyzed using a multivariate linear model. Patients with schizophrenia and depression showed significantly impaired performance compared to healthy controls. On follow-up both patient groups showed improved performance. Contrary to expectation, patients with schizophrenia showed greater improvement in verbal memory, visual memory, and psychomotor speed than depressive patients. Verbal fluency presented as a possible candidate to differentiate between both disorders. Similar profiles of generalized cognitive deficits were observed in both patient-groups on acute and postacute assessment, which might indicate trait-like deficits with persistent functional implications in both disorders. Findings do not support assumptions of greater cognitive impairment in schizophrenia compared to depression. A distinction of the disorders on the grounds of cognitive functioning seems to be less specific than presumed.

Cognitive Performance in Euthymic Patients with Bipolar Disorder vs Healthy Controls: A Neuropsychological Investigation

OBJECTIVES

Cognitive impairment may affect patients with Bipolar Disorder (BD) beyond the acute episodes, qualifying as a potential endophenotype. However, which cognitive domains are specifically affected in euthymic patients with BD and the potential influence of confounding factors (e.g., age and concomitant pharmacological treatment) are still a matter of debate. The present study was, therefore, conducted to assess cognitive performance across specific domains in euthymic bipolar patients, not older than 50 years (to avoid potential age-related bias) versus healthy controls (HCs).

METHODS

A cognitive task battery, including the Wisconsin Card Test, Span Attention Test, Tower of London, Trail Making Test, Verbal Fluency Test, Matrices Scores and N-Back, was administered to 62 subjects (30 bipolar patients and 32 matched HCs) and differences between the groups analyzed.

RESULTS

Bipolar patients performed significantly worse than HCs in the Span Forward task, in the expression of Verbal Fluency Test (Category) and in the N-Back task (all p<.05), with marginal differences between BD I and BD II patients.

CONCLUSION

The present study pointed out significant differences in terms of cognitive performance between euthymic bipolar patients and HCs, supporting the notion that specific cognitive functions may remain impaired even after the resolution of the acute episodes in subjects suffering from BD. Future studies on larger samples are warranted to confirm the present results and further explore potential differences in cognitive impairment across specific bipolar subtypes.

Internal consistency and concurrent validity of the Montreal Cognitive Assessment in individuals with major depressive disorder

This study aimed to determine the internal consistency and concurrent validity of the Montreal Cognitive Assessment (MoCA), as well as its subtests, in patients with major depressive disorder (MDD). Participants were patients with DSM-IV MDD aged between 21 and 65 years. Neurocognitive function was assessed by using the MoCA and 12 neurocognitive tests. The composite z-score of 12 neurocognitive tests, which indicated the global cognitive performance, was calculated. Participants were 57 outpatients with MDD. Except the MoCA Orientation, each of the MoCA subtests showed a wide range of scores. The average inter-item correlation and the Cronbach's alpha of MoCA were 0.24 and 0.64, respectively. The MoCA total score was significantly and highly associated with the composite z-score of 12 neurocognitive tests (Pearson's r=0.78, p<0.001). The score of each MoCA subtest was significantly and moderately correlated with the z-score of its analogous neuropsychological test (absolute Spearman's r_s's=0.33-0.56, p's≤0.01). The MoCA and its subtests are reliable and valid for assessing global and specific cognitive performance in patients with MDD and could be a tool for screening neurocognitive deficits in depressed patients.

EPICOG-SCH: A brief battery to screen cognitive impact of schizophrenia in stable outpatients

Brief batteries in schizophrenia, are needed to screen for the cognitive impact of schizophrenia. We aimed to validate and co-norm the Epidemiological Study of Cognitive Impairment in Schizophrenia (EPICOG-SCH) derived brief cognitive battery. A cross-sectional outpatient evaluation was conducted of six-hundred-seventy-two patients recruited from 234 centers. The brief battery included well-known subtests available worldwide that cover cognitive domains related to functional outcomes: WAIS-III-Letter-Number-Sequencing-LNS, Category Fluency Test-CFT, Logical-Memory Immediate Recall-LM, and Digit-Symbol-Coding-DSC. CGI-SCH Severity and WHO-DAS-S were used to assess clinical severity and functional impairment, respectively. Unit Composite Score (UCS) and functional regression-weighted Composite Scores (FWCS) were obtained; discriminant properties of FWCS to identify patients with different levels of functional disability were analyzed using receiver-operating characteristic (ROC) technique. The battery showed good internal consistency, Cronbach's alpha = 0.78. The differences between cognitive performance across CGI-SCH severity level subscales ranged from 0.5 to 1 SD. Discriminant capacity of the battery in identifying patients with up to moderate disability levels showed fair discriminant accuracy with areas under the curve (AUC) > 0.70, p < 0.0001. An FWCS mean cut-off score ≥ 100 showed likelihood ratios (LR) up to 4.7, with an LR + of 2.3 and a LR - of 0.5. An FWCS cut-off ≥ 96 provided the best balance between sensitivity (0.74) and specificity (0.62). The EPICOG-SCH proved to be a useful brief tool to screen for the cognitive impact of schizophrenia, and its regression-weighted Composite Score was an efficient complement to clinical interviews for confirming patients' potential functional outcomes and can be useful for monitoring cognition during routine outpatient follow-up visits.

Prefronto-cerebellar tDCS enhances neurocognition in euthymic bipolar patients. Findings from a placebo-controlled neuropsychological and psychophysiological investigation

OBJECTIVES

The present double blind placebo-controlled study aimed at investigating the efficacy of 3-weeks prefronto-cerebellar transcranial direct current stimulation (tDCS) on neurocognitive functioning in euthymic BD patients.

METHODS

Forty-two outpatients with BD were randomly assigned to receive either active (n=21) or sham (n=21) prefronto-cerebellar tDCS for 3 consecutive weeks. Neurocognitive abilities were assessed with both neuropsychological testing and psychophysiological evaluation with a P300 novelty task.

RESULTS

Our results showed that (i) Trail Making Test-B, a measure of executive functioning, decreased significantly in the active but not in the sham group, (ii) Rey Complex Figure Test Delay Recall, a measure of visuospatial memory, increased significantly in both groups with a greater increase in the active compared to the sham group, and (iii) P3b latency, a measure of brain information processing stream, decreased significantly in the active but not in the sham group. No significant changes were observed in the other explored neuropsychological and psychophysiological measures.

CONCLUSIONS

The study suggests that concomitant prefrontal-excitatory and cerebellar-inhibitory tDCS in euthymic BD patients may lead to better neurocognitive performance, quantified through neuropsychological and psychophysiological measures.

Use of the MATRICS consensus cognitive battery (MCCB) to evaluate cognitive deficits in bipolar disorder: A systematic review and meta-analysis

BACKGROUND

The Measurement and Treatment Research to Improve Cognition Schizophrenia Consensus Cognitive Battery (MCCB) has also been proposed for use in clinical trials to assess cognitive deficits in patients with bipolar disorder (BD). The aim of this study was to evaluate cognitive function assessed by the MCCB in BD.

METHODS

A literature search of the PubMed, Embase, PsycINFO, SCI, Cochrane Library databases and the Cochrane Controlled Trials Register was conducted. Case reports, reviews and meta-analyses were excluded and a systematic review of the remaining studies of cognitive function in BD was carried out. The cognitive outcome measure was the MCCB, including 7 domains and overall cognition. A random-effects model was applied.

RESULTS

Eighty eight studies were initially identified. Seven clinical studies comprising a total of 487 patients and 570 healthy controls (HC) were included in the meta-analysis. Patients with BD performed worse than HC in overall cognition and processing speed with a large effect size of >0.8; with a medium effect size (0.5-0.8) in attention, working memory, verbal learning and visual learning; and with a small effect size (0.2-0.5) in reasoning and problem solving and social cognition.

CONCLUSION

Patients with BD performed worse than HC in overall cognition and all cognitive domains of the MCCB. Cognitive deficits in domains of processing speed and working memory are prominent in patients with BD. Our findings suggest that MCCB can be usefully applied in BD.

Cognitive dysfunction in major depression and bipolar disorder: Assessment and treatment options

Cognitive dysfunction is a recognized feature of mood disorders, including major depressive disorder (MDD) and bipolar disorder (BD). Cognitive impairment is associated with poor overall functional outcome and is therefore an important feature of illness to optimize for patients' occupational and academic outcomes. While generally people with BD appear to have a greater degree of cognitive impairment than those with MDD, direct comparisons of both patient groups within a single study are lacking. There are a number of methods for the assessment of cognitive function, but few are currently used in clinical practice. Current symptoms, past course of illness, clinical features, such as the presence of psychosis and comorbid conditions, may all influence cognitive function in mood disorders. Despite the general lack of assessment of cognitive function in clinical practice, clinicians are increasingly targeting cognitive symptoms as part of comprehensive treatment strategies. Novel pharmacological agents may improve cognitive function, but most studies of standard mood stabilizers, such as lithium and the anticonvulsants, have focused on whether or not the medications impair cognition. Non-pharmacological strategies, such as cognitive remediation and exercise, are increasingly studied in patients with mood disorders. Despite the growing interest in strategies to manage cognitive function, there is a paucity of high-quality trials examining either pharmacological or non-pharmacological modes of intervention.

[Cognition - the core of major depressive disorder]

Cognitive deficits have been only recently recognized as a major phenotype determinant of major depressive disorder, although they are an integral part of the definition of the depressive state. Congruent evidence suggest that these cognitive deficits persist beyond the acute phase and may be identified at all ages. The aim of the current study was to review the main meta-analyses on cognition and depression, which encompasses a large range of cognitive domains. Therefore, we discuss the "cold" (attention, memory, executive functions) and "hot" (emotional bias) cognitive impairments in MDD, as well as those of social cognition domains (empathy, theory of mind). Several factors interfere with cognition in MDD such as clinical (melancholic, psychotic...) features, age, age of onset, illness severity, medication and comorbid condition. As still debated in the literature, the type of relationship between the severity of cognitive symptoms and functioning in depression is detailed, thus highlighting their predictive value of functional outcome, independently of the affective symptoms. A better identification of the cognitive deficits in MDD and a monitoring of the effects of different treatments require appropriate instruments, which may be developed by taking advantage of the increasing success of computing tools. Overall, current data suggest a core role for different cognitive deficits in MDD, therefore opening new perspectives for optimizing the treatment of depression.

Assessing and measuring cognitive function in major depressive disorder

Cognitive dysfunction is a major component of major depressive disorder (MDD). No 'gold-standard' tool exists for the assessment of cognitive dysfunction for adults with MDD. The use of measurement-based care to improve treatment outcomes invites the need for a systematic screening, evaluation and measurement tool. The aim herein was to provide a succinct summary of literature documenting clinical implication of cognitive dysfunction in MDD, and a review of available screening, diagnostic and measurement tools for cognitive dysfunction in MDD is provided. We also take the opportunity to introduce a screening tool (ie, the THINC-it tool) targeted at addressing the unmet needs. We found that there are limitations to the current measurement scales; for example, many are not targeted for MDD and not all digitally available tests are free of charge. Furthermore, the spectrum of cognitive dysfunction in MDD is poorly represented by the existing tests and as such, there is a lack of sensitivity in the ability to screen a patient with MDD for a cognitive dysfunction. Recognising and addressing the limitations in the current screening techniques for cognitive dysfunction as well as being presented with the current tools available provides the ability to perform an educated cognitive screening for a patient with MDD.

Consensus paper of the WFSBP Task Force on Biological Markers: Criteria for biomarkers and endophenotypes of schizophrenia part II: Cognition, neuroimaging and genetics

OBJECTIVES

Schizophrenia is a group of severe psychiatric disorders with high heritability but only low odds ratios of risk genes. Despite progress in the identification of pathophysiological processes, valid biomarkers of the disease are still lacking.

METHODS

This comprehensive review summarises recent efforts to identify genetic underpinnings, clinical and cognitive endophenotypes and symptom dimensions of schizophrenia and presents findings from neuroimaging studies with structural, functional and spectroscopy magnetic resonance imaging and positron emission tomography. The potential of findings to be biomarkers of schizophrenia is discussed.

RESULTS

Recent findings have not resulted in clear biomarkers for schizophrenia. However, we identified several biomarkers that are potential candidates for future research. Among them, copy number variations and links between genetic polymorphisms derived from genome-wide analysis studies, clinical or cognitive phenotypes, multimodal neuroimaging findings including positron emission tomography and magnetic resonance imaging, and the application of multivariate pattern analyses are promising.

CONCLUSIONS

Future studies should address the effects of treatment and stage of the disease more precisely and apply combinations of biomarker candidates. Although biomarkers for schizophrenia await validation, knowledge on candidate genomic and neuroimaging biomarkers is growing rapidly and research on this topic has the potential to identify psychiatric endophenotypes and in the future increase insight on individual treatment response in schizophrenia.

Neurocognitive profile in major depressive disorders: relationship to symptom level and subjective memory complaints

BACKGROUND

The MATRICS Consensus Cognitive Battery (MCCB) was developed for schizophrenia patients, but is also being used to assess neurocognitive function in bipolar disorder. This study aims to describe neurocognitive differences in major depressive disorder patients and healthy controls with the MCCB, and to describe the relationship between depression symptom severity, subjective cognitive complaints, and objective cognitive test performance.

METHODS

Thirty-three patients with major depressive disorder and 33 pairwise matched healthy controls were assessed with the MCCB. The patients were also assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Everyday Memory Questionnaire (EMQ).

RESULTS

On all neurocognitive domains, the depression patients scored significantly lower than the controls. The level of impairment ranged from 21.0% (Working Memory) to 58.0% (Speed of Processing). There were significant associations between neurocognitive test performance and depression symptom severity, but not with subjective cognitive complaints.

CONCLUSIONS

The MCCB was applicable in this study of major depressive disorder, and revealed significant neurocognitive dysfunction in this group. At least one fifth of the patients were impaired on all cognitive domains, with Speed of Processing and Reasoning/Problem Solving being most strongly affected. The objective test scores were significantly related to depression severity, but not to subjective cognitive complaints.

Cognitive Dysfunction in Major Depressive Disorder: Assessment, Impact, and Management

Cognitive dysfunction is increasingly being recognized as an important clinical dimension in major depressive disorder. This review summarizes the existing data on the epidemiology, assessment, and treatment of cognitive dysfunction among nonelderly adults with the disorder. Overall, cognitive dysfunction is prevalent, persists through periods of symptom remission, and may be independently associated with functional outcomes. However, although the evidence increasingly suggests that clinicians should be heedful of their patients' cognitive functioning, there is as yet no consensus on how best to monitor cognition clinically. In addition, although most studies have reported improved cognition with antidepressant medications, psychotherapy, and neuromodulation, the clinical significance of these improvements is unclear, and high-level evidence to guide decision making is limited. Nonetheless, given the important functional implications, clinicians should assess and monitor cognition and optimize both medication and psychological treatments to mitigate cognitive dysfunction among patients with major depressive disorder.

Cognitive Dysfunction in Major Depressive Disorder. A Translational Review in Animal Models of the Disease

Major Depressive Disorder (MDD) is the most common psychiatric disease, affecting millions of people worldwide. In addition to the well-defined depressive symptoms, patients suffering from MDD consistently complain about cognitive disturbances, significantly exacerbating the burden of this illness. Among cognitive symptoms, impairments in attention, working memory, learning and memory or executive functions are often reported. However, available data about the heterogeneity of MDD patients and magnitude of cognitive symptoms through the different phases of MDD remain difficult to summarize. Thus, the first part of this review briefly overviewed clinical studies, focusing on the cognitive dysfunctions depending on the MDD type. As animal models are essential translational tools for underpinning the mechanisms of cognitive deficits in MDD, the second part of this review synthetized preclinical studies observing cognitive deficits in different rodent models of anxiety/depression. For each cognitive domain, we determined whether deficits could be shared across models. Particularly, we established whether specific stress-related procedures or unspecific criteria (such as species, sex or age) could segregate common cognitive alteration across models. Finally, the role of adult hippocampal neurogenesis in rodents in cognitive dysfunctions during MDD state was also discussed.

Italian psychiatrists' perception on cognitive symptoms in major depressive disorder

OBJECTIVE

Differently than Schizophrenia, the investigation of cognitive impairment in bipolar disorder and major depressive disorder (MDD) attracted the interest of research only recently. Therefore, it is worth understanding clinicians' perception about cognitive dysfunction in MDD and raising awareness about this issue.

METHODS

Between December 2014 and January 2015, 128 Italian psychiatrists participated in an on-line survey aiming at understanding psychiatrists' perception about cognitive symptoms in MDD. The questionnaire comprised three sections: the first investigating psychiatrists' socio-demographic profile, the second assessing cognitive symptoms relevance without mentioning that they represented the study focus and the third explicitly investigating cognitive symptoms.

RESULTS

Cognitive symptoms were considered as a relevant dimension of MDD and appeared among the most frequently cited residual symptoms influencing patients' work and relapse risk. About 70% of psychiatrists declared that cognitive symptoms significantly influence antidepressant choice. However, in the second questionnaire section cognitive symptoms appeared less frequently considered for antidepressant choice.

CONCLUSIONS

Results revealed a clear understanding of cognitive symptoms relevance in MDD. Nevertheless, the discrepancy between psychiatrists' perception and their therapeutical choices underlines the presence of an unmet-need that should be addressed increasing the awareness about the positive effects on cognitive symptoms of existing drugs, which could allow a more symptom-oriented therapeutical intervention. Key points Major depressive disorder (MDD) is a common mental disorder often associated with deficits in cognitive function. Psychiatrists considered cognitive symptoms among the most relevant residual symptoms in MDD patients that compromise patients working and influence the relapse risk. The importance given to residual cognitive symptoms seemed not to be reflected by psychiatrists' therapeutical choice. There is a gap between what psychiatrists know and what psychiatrists apply to their clinical practice reflecting the feeling of a therapeutical unmet need.

Validation of the Chinese version of Brief Assessment of Cognition in Schizophrenia

OBJECTIVE

A test battery that measures cognitive function impairment in patients with schizophrenia, the Brief Assessment of Cognition in Schizophrenia (BACS), has been translated into various languages and validated. This study aimed to test the reliability and validity of the Chinese version of the BACS in a Chinese-speaking population.

METHODS

All participants in this study (66 patients with schizophrenia [mean age: 41.2 years, 57.6% male] and 66 age- and sex-matched healthy controls) were from Taiwan and assessed using the BACS and the University of California, San Diego (UCSD) Performance-Based Skills Assessment, Brief Version (UPSA-B). Thirty-eight of the 66 patients with schizophrenia received a reassessment using the BACS.

RESULTS

The BACS had good test-retest reliability, and all BACS subtests had statistically insignificant practice effects. Principal components analysis demonstrated that a one-factor solution best fits our dataset (60.9% of the variance). In both patients and controls, the BACS composite scores were positively correlated with all BACS subscales (P<0.001) and UPSA-B scales (P<0.001). Furthermore, all BACS subtests (verbal memory, working memory, motor speed, verbal fluency, attention and processing speed, and executive function) significantly differentiated patients with schizophrenia from healthy controls (P<0.001), and the BACS composite score had the best discriminative validity (P<0.001).

CONCLUSION

The Chinese version of the BACS exhibits satisfactory psychometric properties, including high test-retest reliability, high internal consistency, acceptable concurrent validity, and good discriminant validity. We suggest that the BACS is a reliable and practical tool for assessing cognitive function in patients with schizophrenia.

Subjective memory and concentration deficits in medication-free, non-elderly Asians with major depressive disorder: prevalence and their correlates

BACKGROUND

Subjective cognitive impairment (SCI) in major depressive disorder (MDD) is prevalent and correlated with disability. This study aimed to examine the prevalence rates and correlates of subjective memory deficit (SMD) and subjective concentration deficit (SCD) in medication-free, non-elderly Asians with MDD.

METHODS

The SMD and SCD were assessed by using two items of the Symptom Checklist-90-Revised (SCL-90-R). Other measurements of interest included the Montgomery-Asberg Depression Rating Scale (MADRS), the Fatigue Severity Scale (FSS), the Sheehan Disability Scale (SDS), and the Short Form Health Survey (SF-36). Adjusted odds ratios with 95% confidence intervals were calculated.

RESULTS

Of 515 participants from China, Korea, Malaysia, Singapore, Taiwan, and Thailand, 347 (67.4%) and 377 (73.2%) had SMD and SCD, respectively. In total, 420 participants (81.6%) had SMD alone, SCD alone, and both deficits. Severe depression and poor mental health were significant correlates of SMD. Severe depression, clinically significant disability, poor physical health, and poor mental health were significantly independent correlates of SCD. Compared with young adults (18-34 years), older adults aged 50-65 years had a significantly lower risk of SCD (OR=.33, 95% CI: .19-.57).

LIMITATIONS

Only two SCL-90-R items were used to assess the SMD and SCD. The exclusion of MDD patients treated with psychotropic medications eliminated many patients commonly seen in typical clinic settings.

CONCLUSION

SMD and SCD are prevalent in medication-free, non-elderly Asians with MDD. Both deficits are correlated with depression and mental health status. The independent correlation between SCD and disability underscores the crucial role of SCI in MDD.

Theory of Mind in Bipolar Disorder, with Comparison to the Impairments Observed in Schizophrenia

Our ability to make sense of information on the potential intentions and dispositions of others is of paramount importance for understanding their communicative intent, and for judging what an appropriate reaction might be. Thus, anything that impinges on this ability has the potential to cause significant social impairment, and compromise an individual's level of functioning. Both bipolar disorder and schizophrenia are known to feature theory of mind impairment. We conducted a theoretical review to determine the extent and types of theory of mind impairment in bipolar disorder, and evaluate their relationship to medication and symptoms. We also considered possible mediatory mechanisms, and set out to discover what else could be learnt about the impairment in bipolar disorder by comparison to the profile of impairment in schizophrenia. The literature established that in bipolar disorder (i) some form of theory of mind impairment has been observed in all mood states, including euthymia, (ii) the form of theory of mind assessed and task used to make the assessment influence the impairment observed, and (iii) there might be some relationship to cognitive impairment, although a relationship to standard clinical variables was harder to establish. What also became clear in the literature on bipolar disorder itself was the possible relationship of theory of mind impairment to history of psychotic symptoms. Direct comparative studies, including patients with schizophrenia, were thus examined, and provided several important directions for future research on the bases of impairment in bipolar disorder. Particularly prominent was the issue of whether theory of mind impairment could be considered a candidate endophenotype for the psychoses, although current evidence suggests that this may be premature. The differences in impairment across schizophrenia and bipolar disorder may, however, have genuine differential effects on social functioning and the likely success of remediation.