Psychometric characteristics of the MATRICS Consensus Cognitive Battery in a large pooled cohort of stable schizophrenia patients

Location-based differences in cognition and functional capacity: Consistent levels of impairment in participants with schizophrenia compared to healthy controls

Cognitive performance manifests regional differences, correlated with education. There is less information available about regional differences in performance-based measures of functional capacity. In multi-national trials focused on cognitive enhancement, it may be impossible to validate every measure in all locations. It is unknown if regional differences in healthy controls' (HC) performance affects relative levels of impairment in participants with schizophrenia (SCZ). A multi-site study comparing SCZ and HC administered the MATRICS Consensus Cognitive Battery (MCCB) and Virtual Reality Functional Capacity Assessment Tool (VRFCAT) to 164 HC participants and 164 with SCZ across three sites (Columbia, SC, Miami, and San Diego) and a representative sample of HC (n = 390) completed the VRFCAT in Durham, NC. Performance was compared between HC and SCZ participants at the validation sites. There were statistically significant cross-site differences in HC performance on both the MCCB and VRFCAT. Differences between HC and SCZ on MCCB and VRFCAT were substantial at all three sites, indicating that regional variations in HC performance did not induce reduced differences from SCZ participants. Regional differences were smaller than diagnostic group differences, suggesting that relative impairments of participants with SCZ is consistently preserved across performance differences in HC.

PsyCog: A computerised mini battery for assessing cognition in psychosis

Despite the functional impact of cognitive deficit in people with psychosis, objective cognitive assessment is not typically part of routine clinical care. This is partly due to the length of traditional assessments and the need for a highly trained administrator. Brief, automated computerised assessments could help to address this issue. We present data from an evaluation of PsyCog, a computerised, non-verbal, mini battery of cognitive tests. Healthy Control (HC) (N = 135), Clinical High Risk (CHR) (N = 233), and First Episode Psychosis (FEP) (N = 301) participants from a multi-centre prospective study were assessed at baseline, 6 months, and 12 months. PsyCog was used to assess cognitive performance at baseline and at up to two follow-up timepoints. Mean total testing time was 35.95 min (SD = 2.87). Relative to HCs, effect sizes of performance impairments were medium to large in FEP patients (composite score G = 1.21, subtest range = 0.52-0.88) and small to medium in CHR patients (composite score G = 0.59, subtest range = 0.18-0.49). Site effects were minimal, and test-retest reliability of the PsyCog composite was good (ICC = 0.82-0.89), though some practice effects and differences in data completion between groups were found. The present implementation of PsyCog shows it to be a useful tool for assessing cognitive function in people with psychosis. Computerised cognitive assessments have the potential to facilitate the evaluation of cognition in psychosis in both research and in clinical care, though caution should still be taken in terms of implementation and study design.

Measuring Cognitive Impairments Associated With Schizophrenia in Clinical Practice: Overview of Current Challenges and Future Opportunities

BACKGROUND

Cognitive impairment associated with schizophrenia (CIAS) negatively impacts daily functioning, quality of life, and recovery, yet effective pharmacotherapies and practical assessments for clinical practice are lacking. Despite the pivotal progress made with establishment of the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) for clinical research, implementation of the full MCCB is too time-consuming and cost-ineffective for most clinicians in clinical practice.

STUDY DESIGN

Here we discuss current assessments in relation to delivery format (interview-based and performance-based), validity, ease of use for clinicians and patients, reliability/reproducibility, cost-effectiveness, and suitability for clinical implementation. Key challenges and future opportunities for improving cognitive assessments are also presented.

STUDY RESULTS

Current assessments that require 30 min to complete would have value in clinical settings, but the associated staff training and time required might preclude their application in most clinical settings. Initial profiling of cognitive deficits may require about 30 min to assist in the selection of evidence-based treatments; follow-up monitoring with brief assessments (10-15 min in duration) to detect treatment-related effects on global cognition may complement this approach. Guidance on validated brief cognitive tests for the strategic monitoring of treatment effects on CIAS is necessary.

CONCLUSIONS

With increased advancements in technology-based and remote assessments, development of validated formats of remote and in-person assessment, and the necessary training models and infrastructure required for implementation, are likely to be of increasing clinical relevance for future clinical practice.

The MATRICS consensus cognitive battery for the assessment of cognitive impairment in schizotypal personality disorder

Cognitive deficits are a core impairment across the range of schizophrenia (SZ) spectrum disorders, including schizotypal personality disorder (SPD). The MATRICS Consensus Cognitive Battery (MCCB) was developed to be a robust, specific, and valid cognitive assessment battery to assess cognition in clinical trials for treating cognitive impairments in SZ. Despite the similarity of cognitive impairments shown in SPD and SZ and the clear relevance of uniform assessment across a diagnostic spectrum, the MCCB has yet to be validated in SPD. As such, this is the first study to evaluate the sensitivity of the MCCB for the assessment of cognitive function in individuals with SPD. Participants were 30 individuals with SPD and 54 healthy controls (HC) assessed with the MCCB and supplemental neurocognitive assessments (Trails B, DOT test, Paced Auditory Serial Addition Test (PASAT), AX Continuous Performance Task (AX-CPT), and N-back). Individuals with SPD performed worse than HC participants on all MCCB subtests, as well as on converging supplemental tasks including Trails B, DOT test, PASAT, AX-CPT, and N-back. These results indicate that the MCCB was sensitive to cognitive impairment in SPD compared to controls. SPD participants demonstrate impairments similar to data of SZ participants within the literature, although to a slightly lesser degree of severity. Taken together, these results highlight the generalizability of using the MCCB across SZ spectrum diagnostic groups to assess cognition. Such findings allow for further comparison across disorders, greater understanding of the cognitive characteristics in the spectrum, and use of uniform assessment within cognitive intervention research.

Changes in BDNF methylation patterns after cognitive remediation therapy in schizophrenia: A randomized and controlled trial

Although cognitive remediation therapy (CRT) produces cognitive benefits in schizophrenia, we do not yet understand whether molecular changes are associated with this cognitive improvement. A gene central to synaptic plasticity, the BDNF, has been proposed as one potential route. This study assesses whether BDNF methylation changes following CRT-produced cognitive improvement are detected. A randomized and controlled trial was performed with two groups (CRT, n = 40; TAU: Treatment as Usual, n = 20) on a sample of participants with schizophrenia. CRT was delivered by trained therapists using a web-based computerized program. Mixed Models, where the interaction of treatment (CRT, TAU) by time (T0: 0 weeks, T1: 16 weeks) was the main effect were used. Then, we tested the association between the treatment and methylation changes in three CpG islands of the BDNF gene. CRT group showed significant improvements in some cognitive domains. Between-groups differential changes in 5 CpG units over time were found, 4 in island 1 (CpG1.2, CpG1.7, CpG1.10, CpG1.17) and 1 in island 3 (CpG3.2). CRT group showed increases in methylation in CpG1.2, CpG1.7 and decreases in pG1.10, CpG1.17, and CpG3.2. Differences in the degree of methylation were associated with changes in Speed of Processing, Working Memory, and Verbal Learning within the CRT group. Those findings provide new data on the relationship between cognitive improvement and changes in peripheral methylation levels of BDNF gene, a key factor involved in neuroplasticity regulation. Trial Registration: NCT04278027.

Large-scale mechanism hypothesis and research prospects of cognitive impairment in schizophrenia based on magnetic resonance imaging

Cognitive impairments in schizophrenia are pivotal clinical issues that need to be solved urgently. However, the mechanism remains unknown. It has been suggested that cognitive impairments in schizophrenia are associated with connectome damage, and are especially relevant to the disrupted hub nodes in the frontal and parietal lobes. Activating the dorsolateral prefrontal cortex (DLPFC) via repetitive transcranial magnetic stimulation (rTMS) could result in improved cognition. Based on several previous magnetic resonance imaging (MRI) studies on schizophrenia, we found that the first-episode patients showed connectome damage, as well as abnormal activation and connectivity of the DLPFC and inferior parietal lobule (IPL). Accordingly, we proposed that DLPFC-IPL pathway destruction might mediate connectome damage of cognitive impairments in schizophrenia. In the meantime, with the help of multimodal MRI and noninvasive neuromodulation tool, we may not only validate the hypothesis, but also find IPL as the potential intervention target for cognitive impairments in schizophrenia.

The social cognitive and neural mechanisms that underlie social functioning in individuals with schizophrenia - a review

In many individuals with a diagnosis of schizophrenia social functioning is impaired across the lifespan. Social cognition has emerged as one of the possible factors that may contribute to these challenges. Neuroimaging research can give further insights into the underlying mechanisms of social (cognitive) difficulties. This review summarises the evidence on the associations between social cognition in the domains of theory of mind and emotion perception and processing, and individuals' social functioning and social skills, as well as associated neural mechanisms. Eighteen behavioural studies were conducted since the last major review and meta-analysis in the field (inclusion between 7/2017 and 1/2022). No major review has investigated the link between the neural mechanisms of social cognition and their association with social functioning in schizophrenia. Fourteen relevant studies were included (from 1/2000 to 1/2022). The findings of the behavioural studies showed that associations with social outcomes were slightly stronger for theory of mind than for emotion perception and processing. Moreover, performance in both social cognitive domains was more strongly associated with performance on social skill measures than questionnaire-based assessment of social functioning in the community. Studies on the underlying neural substrate of these associations presented mixed findings. In general, higher activation in various regions of the social brain was associated with better social functioning. The available evidence suggests some shared regions that might underlie the social cognition-social outcome link between different domains. However, due to the heterogeneity in approaches and findings, the current knowledge base will need to be expanded before firm conclusions can be drawn.

Accuracy of immediate self-assessment of neurocognitive test performance: Associations with psychiatric diagnosis and longitudinal psychotic symptoms

Participants with schizophrenia (SCZ) and bipolar disorder (BD) have challenges in self-evaluation of their cognitive and functional abilities, referred to as introspective accuracy (IA). Although psychotic symptoms are commonly found to be uncorrelated with cognitive performance, many models of the development of delusions focus on failures in self-assessment and responses biases during momentary monitoring. We performed a single 4-test cognitive assessment on 240 participants (schizophrenia n = 126; bipolar disorder n = 114) and asked them to make a judgment about their performance immediately after completion of each task. We related performance and these judgments to results of Ecological Momentary Assessments (EMA) of the momentary occurrence of psychotic symptoms (Voices, paranoid ideas, other delusions) collected over up to 90 surveys over a 30 days prior to the single cognitive assessment. We examined test performance and the accuracy of self-assessment at that assessment, looking at diagnostic differences in performance and mis-estimation of performance. Participants with bipolar disorder had better cognitive performance, but there were no differences in mis-estimation. Analyses of the correlation between cognitive performance and self-assessment were all significant and better cognitive performance predicted reduced errors in self-assessment. Examination of the 30-day course of psychotic symptoms and IA could only be performed in participants with schizophrenia, revealing correlations between more common occurrences of all three psychotic symptoms and increased absolute values for IA errors. These data are consistent with theories of cognitive response biases and the formation of delusions.

Effectiveness of KarXT (xanomeline-trospium) for cognitive impairment in schizophrenia: post hoc analyses from a randomised, double-blind, placebo-controlled phase 2 study

The muscarinic receptor agonist xanomeline improved cognition in phase 2 trials in Alzheimer's disease and schizophrenia. We present data on the effect of KarXT (xanomeline-trospium) on cognition in schizophrenia from the 5-week, randomised, double-blind, placebo-controlled EMERGENT-1 trial (NCT03697252). Analyses included 125 patients with computerised Cogstate Brief Battery (CBB) subtest scores at baseline and endpoint. A post hoc subgroup analysis evaluated the effects of KarXT on cognitive performance in patients with or without clinically meaningful cognitive impairment at baseline, and a separate outlier analysis excluded patients with excessive intraindividual variability (IIV) across cognitive subdomains. ANCOVA models assessed treatment effects for completers and impairment subgroups, with or without removal of outliers. Sample-wide, cognitive improvement was numerically but not statistically greater with KarXT (n = 60) than placebo (n = 65), p = 0.16. However, post hoc analyses showed 65 patients did not exhibit clinically meaningful cognitive impairment at baseline, while eight patients had implausibly high IIV at one or both timepoints. Significant treatment effects were observed after removing outliers (KarXT n = 54, placebo n = 63; p = 0.04). Despite the small sample size, a robust (d = 0.50) and significant effect was observed among patients with cognitive impairment (KarXT n = 23, placebo n = 37; p = 0.03). These effects did not appear to be related to improvement in PANSS total scores (linear regression, R2 = 0.03). Collectively, these findings suggest that KarXT may have a separable and meaningful impact on cognition, particularly among patients with cognitive impairment.

N-Acetylcysteine (NAC) in Schizophrenia Resistant to Clozapine: A Double-Blind, Randomized, Placebo-Controlled Trial Targeting Negative Symptoms

BACKGROUND AND HYPOTHESIS

Clozapine is the most effective antipsychotic for treatment-resistant schizophrenia, yet a significant proportion of individuals on clozapine continue to experience disabling symptoms, despite being treated with an adequate dose. There is a need for adjunct treatments to augment clozapine, notably for negative and cognitive symptoms. One such potential agent is the glutathione precursor N-acetylcysteine (NAC).

STUDY DESIGN

A randomized double-blind, multi-center, placebo-controlled trial for clozapine patients with enduring psychotic symptoms (n = 84) was undertaken to investigate the efficacy of adjunctive NAC (2 g daily) for negative symptoms, cognition and quality of life (QoL). Efficacy was assessed at 8, 24, and 52 weeks.

STUDY RESULTS

NAC did not significantly improve negative symptoms (P = .62), overall cognition (P = .71) or quality of life (Manchester quality of life: P = .11; Assessment of quality of life: P = .57) at any time point over a 1-year period of treatment. There were no differences in reported side effects between the groups (P = .26).

CONCLUSIONS

NAC did not significantly improve schizophrenia symptoms, cognition, or quality of life in treatment-resistant patients taking clozapine. This trial was registered with "Australian and New Zealand Clinical Trials" on the 30 May, 2016 (Registration Number: ACTRN12615001273572).

An Update on Treatment of Cognitive Impairment Associated with Schizophrenia

Cognitive impairment associated with schizophrenia (CIAS) is widely regarded as a critically important treatment target for schizophrenia. Despite major efforts and a number of promising findings, we do not yet have an approved drug for CIAS. Similarly, promising cognitive remediation approaches are limited in their ability to help patients achieve real-world functional gains on a wide scale. This article provides an update and critical evaluation of recent treatment development activities for CIAS. First, we provide update on pharmacological approaches, which include a glutamatergic drug that is currently in Phase III trials for CIAS, and discuss factors that may have impacted past efforts to identify efficacious drugs. Second, we review positive findings, limitations, and current trends involving cognitive remediation approaches. Third, we consider newer transdiagnostic approaches aimed at looking beyond, or identifying more homogenous subgroups within, the diagnostic category schizophrenia to advance treatment development. Despite its many challenges, treatment development for CIAS remains a major public health issue and research continues to push forward on several encouraging fronts.

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.

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.

The Association Between Lentiform Nucleus Function and Cognitive Impairments in Schizophrenia

Introduction: Cognitive decline is the core schizophrenia symptom, which is now well accepted. Holding a role in various aspects of cognition, lentiform nucleus (putamen and globus pallidus) dysfunction contributes to the psychopathology of this disease. However, the effects of lentiform nucleus function on cognitive impairments in schizophrenia are yet to be investigated.

Objectives: We aim to detect the fractional amplitude of low-frequency fluctuation (fALFF) alterations in patients with schizophrenia, and examine how their behavior correlates in relation to the cognitive impairments of the patients.

Methods: All participants underwent magnetic resonance imaging (MRI) and cognitive assessment (digit span and digit symbol coding tests). Screening of brain regions with significant changes in fALFF values was based on analysis of the whole brain. The data were analyzed between Jun 2020 and Mar 2021. There were no interventions beyond the routine therapy determined by their clinicians on the basis of standard clinical practice.

Results: There were 136 patients (75 men and 61 women, 24.1 ± 7.4 years old) and 146 healthy controls (82 men and 64 women, 24.2 ± 5.2 years old) involved in the experiments seriatim. Patients with schizophrenia exhibited decreased raw scores in cognitive tests (p < 0.001) and increased fALFF in the bilateral lentiform nuclei (left: 67 voxels; x = −24, y = −6, z = 3; peak t-value = 6.90; right: 16 voxels; x = 18, y = 0, z = 3; peak t-value = 6.36). The fALFF values in the bilateral lentiform nuclei were positively correlated with digit span-backward test scores (left: r = 0.193, p = 0.027; right: r = 0.190, p = 0.030), and the right lentiform nucleus was positively correlated with digit symbol coding scores (r = 0.209, p = 0.016).

Conclusion: This study demonstrates that cognitive impairments in schizophrenia are associated with lentiform nucleus function as revealed by MRI, involving working memory and processing speed.

Preliminary evidence for the phosphodiesterase type-4 inhibitor, roflumilast, in ameliorating cognitive flexibility deficits in patients with schizophrenia

BACKGROUND

Cognitive flexibility deficits are present in patients with schizophrenia and are strong predictors of functional outcome but, as yet, have no pharmacological treatments.

AIMS

The purpose of this study was to investigate whether the phosphodiesterase type-4 inhibitor, roflumilast, can improve cognitive flexibility performance and functional brain activity in patients with schizophrenia.

METHODS

This was a within-subject, randomised, double-blind, placebo-controlled, three-period crossover study using a version of the Intradimensional/Extradimensional (ID/ED) task, optimised for functional magnetic resonance imaging (fMRI), in 10 patients with schizophrenia who were scanned after receiving placebo, 100 µg or 250 µg roflumilast for 8 consecutive days. Data from an additional fMRI ID/ED study of 18 healthy participants on placebo was included to contextualise the schizophrenia-related performance and activations. The fMRI analyses included a priori driven region of interest (ROI) analysis of the dorsal frontoparietal attention network.

RESULTS

Patients on placebo demonstrated broad deficits in task performance compared to the healthy comparison group, accompanied by preserved network activity for solution search, but reduced activity in left ventrolateral prefrontal cortex (VLPFC) and posterior parietal cortex for attentional set-shifting and reduced activity in left dorsolateral prefrontal cortex (DLPFC) for reversal learning. These ROI deficits were ameliorated by 250 µg roflumilast, whereas during solution search 100 µg roflumilast reduced activity in the left orbitofrontal cortex, right DLPFC and bilateral PPC, which was associated with an improvement in formation of attentional sets.

CONCLUSIONS

The results suggest roflumilast has dose-dependent cognitive enhancing effects on the ID/ED task in patients with schizophrenia, and provides sufficient support for larger studies to test roflumilast's role in improving cognitive flexibility deficits in this clinical population.

The normative data study of the Czech MATRICS consensus cognitive battery

OBJECTIVE

The MATRICS consensus cognitive battery (MCCB) is a widely used neuropsychological battery for the assessment of cognitive dysfunction in schizophrenia. However, the accuracy of measurement is dependent on suitable normative data which are in the Czech Republic lacking.

METHOD

The Czech academic research translation of the MCCB battery was administered to a sample of healthy volunteers aged 17 to 62 years (N = 573) and the effects of age, education and sex were examined. In addition, a comparison was made to examine the differences between the US and current normative data.

RESULTS

Consistent with previous studies, significant effects of age, sex and education were found, however, in sex and education in distinct MCCB-domains. By comparing the original and current normative data, significant differences with small to large effect sizes were revealed in all domains except for Verbal Learning.

CONCLUSIONS

We present nationally specific MCCB regression-based and tabular normative data applicable in research and clinical settings.

Efficacy and safety of the novel glycine transporter inhibitor BI 425809 once daily in patients with schizophrenia: a double-blind, randomised, placebo-controlled phase 2 study

BACKGROUND

Cognitive impairment associated with schizophrenia predicts poor functional outcomes, but currently no approved pharmacotherapy is available. This study investigated whether the glycine transporter-1 inhibitor BI 425809 improves cognition in patients with schizophrenia.

METHODS

This phase 2, randomised, double-blind, placebo-controlled, parallel-group trial (81 centres, 11 countries), randomly assigned outpatients (aged 18-50 years) with schizophrenia on stable treatment to add-on once-daily oral BI 425809 2 mg, 5 mg, 10 mg, or 25 mg or placebo (1:1:1:1:2) for 12 weeks. Treatment was assigned in blocks using interactive response technology; patients, investigators, and all trial personnel were masked to group assignment. The primary endpoint was change from baseline in MATRICS Consensus Cognitive Battery (MCCB) overall composite T-score at week 12. Six predefined dose-response models were evaluated using a multiple comparison procedure and modelling approach with mixed model repeated measures to assess evidence for a non-flat dose-response relationship for cognitive improvements with BI 425809. Adverse events were monitored. Safety analyses included all randomly allocated patients who received one or more doses of trial medication; efficacy analyses included patients from this set who also had available baseline data and at least one post-baseline on-treatment measurement for the primary or secondary endpoint. This study is registered with ClinicalTrials.gov, number NCT02832037.

FINDINGS

509 patients were randomly assigned between April 25, 2018, and Oct 4, 2019 (BI 425809 2 mg, n=85; 5 mg, n=84; 10 mg, n=85; 25 mg, n=85; placebo, n=170 444 (87%) completed the 12-week treatment. Five of six dose-response models showed a statistically significant benefit of BI 425809 over placebo (linear [t=2·55, p=0·015], linear in log [t=2·56, p=0·015]; Emax [t=2·75, p=0·0089], sigmoid Emax [t=2·98, p=0·0038], logistic [t=2·77, p=0·0085]). Pairwise comparisons showed greater mean improvement from baseline in MCCB overall composite T-score at week 12 with BI 425809 10 mg and 25 mg versus placebo (adjusted mean difference 1·98 [95% CI 0·43-3·53] for 10 mg and 1·73 [0·18-3·28] for 25 mg; standardised effect size 0·34 for 10 mg and 0·30 for 25 mg). Adverse events were balanced across groups, reported in 50 (59%) of 85 patients on BI 425809 2 mg, 44 (52%) of 84 on 5 mg, 35 (41%) of 85 on 10 mg, 36 (42%) of 85 on 25 mg, and 74 (44%) of 170 on placebo.

INTERPRETATION

BI 425809 improved cognition after 12 weeks in patients with schizophrenia; doses of 10 mg and 25 mg showed the largest separation from placebo. If these encouraging results are confirmed in phase 3 trials, BI 425809 could provide an effective treatment for cognitive impairment associated with schizophrenia.

FUNDING

Boehringer Ingelheim.

High-intensity interval training and active video gaming improve neurocognition in schizophrenia: a randomized controlled trial

There is a need for treatments targeting neurocognitive dysfunctions in schizophrenia. The aim of this study was to investigate the neurocognitive effect of aerobic high-intensity interval training (HIIT). A comparison group performed sport simulating active video gaming (AVG). We anticipated that HIIT would improve neurocognition beyond any effect of AVG, due to engagement in higher intensity cardiorespiratory demands. Recent research on the beneficial neurocognitive effect of AVG challenges this expectation but added new relevance to comparing the two interventions. This is an observer-blinded randomized controlled trial. Eighty-two outpatients diagnosed with schizophrenia were allocated to HIIT (n = 43) or AVG (n = 39). Both groups received two supervised sessions per week for 12 weeks. The attrition rate was 31%, and 65% of the participants were defined as protocol compliant study completers. Intention-to-treat analyses showed significant improvements in the neurocognitive composite score from baseline to post-intervention and from baseline to 4 months follow-up in the total sample. The same pattern of results was found in several subdomains. Contrary to our hypothesis, we found no interaction effects of time and group, indicating equal effects in both groups. Separate within-group analysis unexpectedly showed trends of differential effects in the learning domain, as HIIT showed post-intervention improvement in verbal but not visual learning, while AVG showed improvement in visual but not verbal learning. HIIT and AVG improve neurocognition equally, suggesting that both interventions may be applied to target neurocognition in schizophrenia. Future research should investigate trends towards possible differential effects of exercise modes on neurocognitive subdomains. NCT02205684, 31.07.14.

Relationship of Change in Plasma Clozapine/N-desmethylclozapine Ratio with Cognitive Performance in Patients with Schizophrenia

OBJECTIVE

The clozapine/N-desmethylclozapine (NDMC) ratio is proposed to be used as a predictor of cognitive performance in clozapine-treated patients, as its principal metabolite, NDMC, has an opposite action with clozapine on the cholinergic system. The aim of this study is to determine whether clozapine has influence on cognitive performance in accordance with changes in the clozapine/NDMC in patients with schizophrenia.

METHODS

The data of fifteen patients with schizophrenia, who had initial and follow-up assessments after starting clozapine treatment, were retrospectively collected. The assessments included clinical scale, cognitive battery, and pharmacological data including plasma concentrations of clozapine and NDMC. The data were analyzed with Pearson correlation and stepwise multiple regression analyses.

RESULTS

ΔAttention/vigilance, Δsocial cognition, and Δcomposite score had a significant correlation with Δclozapine/NDMC ratio, while ΔWorking memory had correlation with Δclozapine concentration and ΔNDMC concentration, and Δsocial cognition had association with Δclozapine concentration. Multiple regression analysis showed that Δattention/vigilance had negative association with Δclozapine/NDMC ratio, Δworking memory had negative relation with Δclozapine concentration, and that Δsocial cognition had negative association with Δclozapine concentration.

CONCLUSION

This finding implicates that lowering the clozapine/NDMC ratio could enhance cognition in patients with schizophrenia treated with clozapine.

The psychometric properties of the Self-Evaluation of Negative Symptoms Scale (SNS) in treatment-resistant schizophrenia (TRS)

BACKGROUND

Clinician-administered measures of negative symptoms may not capture patients' subjective experiences. The Self-Evaluation of Negative Symptoms (SNS) has shown good psychometric properties when used in outpatients with higher-level functioning schizophrenia. We aimed to evaluate the psychometric properties of the SNS in low functioning participants with treatment-resistant schizophrenia (TRS).

METHODS

Participants were assessed using the following measures at two time-points; time-point 1: SNS, Wide Range Achievement Test, 4th Edition Reading Subtest (WRAT-4), and Brief Assessment of Cognition in Schizophrenia (BACS). Time-point 2 (within a week of time-point 1): SNS, Negative Symptom Assessment 16 items (NSA-16), Scale to Assess Unawareness in Mental Disorder-Abbreviated (SUMD-A), Clinical Global Impression Severity Scale (CGI-S), Simpson Angus Scale (SAS), Calgary Depression Scale for Schizophrenia (CDSS), and the Patient Feasibility Questionnaire.

RESULTS

Fifty participants with TRS were enrolled, a mean age of 43.8 years (SD = 11.19, min = 25, max = 64), a mean IQ of 80.62 (SD = 17.12, min = 65, max = 110), and a mean BACS Composite T-Score of 14.08 (SD = 17.16, min = -27, max = 49). Participants responded to SNS prompts with moderate consistency across two time-points. There were no significant correlations between the SNS and the NSA-16 Global Symptom score (Pearson r = 0.207, p = .150, Spearman r = 0.101, p = .483), NSA-16 Global Functioning score (Pearson r = 0.209, p = .145, Spearman r = 0.126, p = .384), nor the NSA-16 total score (Pearson r = 0.149, p = .302, Spearman r = 0.116, p = .421). However, when participants were stratified by BACS Composite T-score, there was a significant positive correlation between the SNS total and the NSA-16 Global Functioning score (Pearson r = 0.500, p = .048, Spearman r = 0.546, p = .029) among participants who demonstrated higher cognitive functioning.

CONCLUSION

Participants with TRS and low functioning were able to respond to questions on the SNS regarding their subjective assessment of negative symptoms. However, self-reported and clinician-rated negative symptoms were not equivalent, except in a subgroup with higher cognitive functioning. This discrepant self-reporting appeared to relate to their low levels of insight and cognitive impairments.

mGluR5 receptor availability is associated with lower levels of negative symptoms and better cognition in male patients with chronic schizophrenia

Consistent findings postulate disturbed glutamatergic function (more specifically a hypofunction of the ionotropic NMDA receptors) as an important pathophysiologic mechanism in schizophrenia. However, the role of the metabotropic glutamatergic receptors type 5 (mGluR5) in this disease remains unclear. In this study, we investigated their significance (using [¹¹C]ABP688) for psychopathology and cognition in male patients with chronic schizophrenia and healthy controls. In the patient group, lower mGluR5 binding potential (BP_ND) values in the left temporal cortex and caudate were associated with higher general symptom levels (negative and depressive symptoms), lower levels of global functioning and worse cognitive performance. At the same time, in both groups, mGluR5 BP_ND were significantly lower in smokers (F_[27,1] = 15.500; p = .001), but without significant differences between the groups. Our findings provide support for the concept that the impaired function of mGluR5 underlies the symptoms of schizophrenia. They further supply a new perspective on the complex relationship between tobacco addiction and schizophrenia by identifying glutamatergic neurotransmission—in particularly mGluR5—as a possible connection to a shared vulnerability.

Practice Effects and Test–Retest Reliability of the Continuous Performance Test, Identical Pairs Version in Patients with Schizophrenia over Four Serial Assessments

Objective

The purposes of this study were to examine the practice effects and test–retest reliability of the Continuous Performance Test, Identical Pairs version (CPT-IP) over four serial assessments in patients with schizophrenia.

Method

Fifty-six patients with schizophrenia were assessed with the CPT-IP four times, once per week. The CPT-IP contains four indices: “2-digit score,” “3-digit score,” “4-digit score,” and “total score.”

Results

The four indices showed trivial-to-small practice effects (Cohen’s d = −0.13–0.24), good-to-excellent test–retest reliability (ICC = 0.62–0.88), and unacceptable random measurement error (MDC% = 33.8%–110.8%).

Conclusions

The total score had the best reliability among the four indices. Although practice effects of the four indices all appeared cumulative, all four CPT-IP indices reached a plateau after the second assessment. These results indicate that clinicians should interpret the change scores of the CPT-IP conservatively and use the total-score index in their routine repeated assessments.

Six month durability of targeted cognitive training supplemented with social cognition exercises in schizophrenia

Background

Deficits in cognition, social cognition, and motivation are significant predictors of poor functional outcomes in schizophrenia. Evidence of durable benefit following social cognitive training is limited. We previously reported the effects of 70 h of targeted cognitive training supplemented with social cognitive exercises (TCT + SCT) verses targeted cognitive training alone (TCT). Here, we report the effects six months after training.

Methods

111 participants with schizophrenia spectrum disorders were randomly assigned to TCT + SCT or TCT-only. Six months after training, thirty-four subjects (18 TCT + SCT, 16 TCT-only) were assessed on cognition, social cognition, reward processing, symptoms, and functioning. Intent to treat analyses was used to test the durability of gains, and the association of gains with improvements in functioning and reward processing were tested.

Results

Both groups showed durable improvements in multiple cognitive domains, symptoms, and functional capacity. Gains in global cognition were significantly associated with gains in functional capacity. In the TCT + SCT group, participants showed durable improvements in prosody identification and reward processing, relative to the TCT-only group. Gains in reward processing in the TCT + SCT group were significantly associated with improvements in social functioning.

Conclusions

Both TCT + SCT and TCT-only result in durable improvements in cognition, symptoms, and functional capacity six months post-intervention. Supplementing TCT with social cognitive training offers greater and enduring benefits in prosody identification and reward processing. These results suggest that novel cognitive training approaches that integrate social cognitive exercises may lead to greater improvements in reward processing and functioning in individuals with schizophrenia.

A novel approach to evaluate the pharmacodynamics of a selective dopamine D1/D5 receptor partial agonist (PF-06412562) in patients with stable schizophrenia

BACKGROUND

PF-06412562 is an orally bioavailable, selective dopamine D1/D5 receptor partial agonist with a non-catechol structure under evaluation for treatment of cognitive impairment in schizophrenia.

AIMS

This randomized, double-blind, placebo-controlled, parallel-group, Phase 1b study examined the pharmacokinetics and pharmacodynamics of three doses of PF-06412562 (3 mg, 9 mg, and 45 mg twice daily) over 15 days in patients with schizophrenia receiving antipsychotics.

METHODS

Primary endpoints included adjunctive safety/tolerability and effects on MATRICS Consensus Cognitive Battery Working Memory domain and reward processing (Monetary Incentive Delay) tasks. Exploratory endpoints included other behavioral/neurophysiological tasks, including the N-back task.

RESULTS

Among 95 subjects (78% male; mean age 34.8 years), baseline characteristics were similar across groups. The MATRICS Consensus Cognitive Battery Working Memory composite change from baseline on Day 13 improved in all groups, the smallest improvement was observed in the 45 mg group and was significantly smaller than that in the placebo group (two-sided p=0.038). For the Monetary Incentive Delay task (change from baseline in blood-oxygen-level-dependent functional magnetic resonance imaging activation in anterior ventral striatum for the contrast of cue gain>cue no gain on Day 15), no PF-06412562 dose was significantly different from placebo. No doses of PF-06412562 showed a significant difference on two-back task accuracy versus placebo.

CONCLUSIONS

Adjunctive treatment with PF-06412562 was safe and well tolerated in patients with schizophrenia. PF-06412562 failed to show clinical benefit relative to placebo on assessments of cognition or reward processing in symptomatically stable patients over a 15-day treatment period. Numerous limitations due to the safety study design warrant further efficacy evaluation for this drug mechanism.

Evaluation of the Efficacy, Safety, and Tolerability of BI 409306, a Novel Phosphodiesterase 9 Inhibitor, in Cognitive Impairment in Schizophrenia: A Randomized, Double-Blind, Placebo-Controlled, Phase II Trial

BACKGROUND

Patients with cognitive impairment associated with schizophrenia may benefit from treatments targeting dysfunctional glutamatergic neurotransmission. BI 409306, a potent and selective phosphodiesterase 9 inhibitor, was assessed in patients with schizophrenia using a learn-and-confirm adaptive trial design.

METHODS

This double-blind, parallel-group trial randomized patients 2:1:1:1:1 to once-daily placebo or BI 409306 (10, 25, 50, or 100 mg) for 12 weeks. Stage 1 (learn) assessed change from baseline in Cambridge Neuropsychological Test Automated Battery (CANTAB) scores (week 12) to identify ≥1 meaningful endpoints for stage 2 (confirm). If no domains showed efficacy, change from baseline in Measurements and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) composite scores (week 12) was the primary endpoint. The key secondary endpoint was change from baseline in Schizophrenia Cognition Rating Scale (SCoRS) total score. Safety was monitored.

RESULTS

Five hundred eighteen patients were randomized. In stage 1, CANTAB did not differentiate between BI 409306 and placebo (n = 120), so the primary endpoint of change from baseline in MCCB composite score was analyzed in 450 patients in stage 2. There was no significant difference between BI 409306 (1.2-2.8) and placebo (2.5) in MCCB composite score change. BI 409306 did not significantly improve change from baseline in SCoRS total score (-3.1 to -2.0) vs placebo (-2.5). Adverse events were dose-dependent, increasing from 33.3% (10 mg) to 53.5% (100 mg), vs 36.4% for placebo.

CONCLUSION

The primary endpoint of cognitive function improvement was not met. BI 409306 was well-tolerated, with an acceptable safety profile.

The continuing story of schizophrenia and schizoaffective disorder: One condition or two?

Although schizophrenia and schizoaffective disorder remain separable in diagnostic systems, the validity of the distinction is uncertain. This study asked whether schizophrenia and schizoaffective disorder are distinguishable on selected cognitive, social cognitive and structural social brain measures. Outpatients with a diagnosis of schizophrenia (n = 44) or schizoaffective disorder (n = 29) and non-psychiatric control participants (n = 62) were studied. Patients were assessed clinically (Positive and Negative Syndrome Scale) and all participants were administered a battery of cognitive (MATRICS Consensus Cognitive Battery; Wechsler Abbreviated Scale of Intelligence, Wide Range Achievement Reading) and social cognitive (Reading the Mind in the Eyes, Mayer-Salovey-Caruso Emotional Intelligence Test; MSCEIT) tasks. In addition, participants underwent structural magnetic resonance imaging (MRI) to yield cortical thickness data for 42 regions associated with the social brain network. Results showed no significant differences between patient groups on 17/18 cognitive/social cognitive and social brain cortical thickness measures. In contrast, schizophrenia and schizoaffective disorder patients differed from controls on 16/18 and 11/18 measures respectively. Schizoaffective disorder patients outperformed schizophrenia patients on an emotion regulation task (MSCEIT). Schizophrenia and schizoaffective disorder are largely indistinguishable on key cognitive, social cognitive and neural measures. The continuing separation of these syndromes in diagnostic systems and disease models requires is questionable and requires further attention.

A randomized controlled trial of cognitive remediation for a national cohort of forensic patients with schizophrenia or schizoaffective disorder

BACKGROUND

Evidence is accumulating that Cognitive Remediation Training (CRT) is effective for ameliorating cognitive deficits experienced by patients with schizophrenia and accompanying functional impairment. There has been no randomized controlled trial of CRT using a nationally representative population of forensic patients, despite the significant cognitive deficits frequently present within this group.

METHODS

Sixty-five patients with schizophrenia or schizoaffective disorder were enrolled in a single blind randomized controlled trial of CRT versus treatment as usual (TAU); representing 94% of those eligible within a national forensic cohort. The primary outcome measure was the composite score of the MATRICS Consensus Cognitive Battery (MCCB). Secondary outcome measures included neurocognitive and social cognitive domains, symptoms, and 'real world' functioning. Patient satisfaction was examined using an exit interview. Participants were reassessed at 8 months follow up. All data were analyzed using an intention to treat design (ITT).

RESULTS

For the primary outcome measure, the MCCB composite score, there were significant differences between those who participated in CRT and those receiving TAU at both end of treatment and 8 months follow up (Cohen's d = 0.34. Significant improvements were observed in visual and working memory. Mediation analysis found that those who cognitively benefited from CRT had corresponding improved functioning, and more net positive therapeutic moves i.e. moves to units with lower security within the hospital. Ninety-six percent believed their cognitive gains positively affected their daily lives.

CONCLUSIONS

CRT may be an acceptable and efficacious intervention for forensic patients with schizophrenia or schizoaffective disorder.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02360813 . Trial registered Feb 4th 2015, last updated May 1st 2015.

The Use of Cognitive Screening in Pharmacotherapy Trials for Cognitive Impairment Associated With Schizophrenia

There are currently no regulatory approved pharmacological treatments for cognitive impairment associated with schizophrenia (CIAS). One possibility is that trial methodology itself is hindering their development. Emerging evidence suggests that patients with schizophrenia may show limited benefit from pro-cognitive interventions if they already exhibit intact cognitive performance, relative to normative thresholds. The aim of this report was to examine the extent to which objectively assessed cognitive performance has been used as an eligibility and/or stratification criterion in CIAS pharmacotherapy trials. On 16^th January 2019, we conducted a systematic search of studies listed on ClinicalTrials.gov to identify randomized, double-blind, placebo-controlled, add-on pharmacotherapy trials conducted in patients with a diagnosis of schizophrenia, in which a paper-and-pencil or computerized cognitive task (or battery) was specified as a primary outcome measure. Of the 87 trials that met our inclusion criteria, 10 (11.5%) required the presence of an objectively assessed cognitive deficit as part of their patient eligibility criteria. No studies reported stratifying patients according to the presence or degree of cognitive impairment they exhibited. These results suggest that the vast majority of CIAS trials may have been underpowered due to the inclusion of cognitively "normal" patients. Purposive screening for cognitive impairment could increase CIAS trial success.

Controversies in Computerized Cognitive Training

Computerized cognitive training (CCT) to improve cognitive functioning is of enormous interest and has been applied in a broad range of populations with goals of improving both cognition and community functioning. Recent reviews presenting negative conclusions about CCT efficacy have inconsistent definitions of the treatment targets and cognitive improvement. They do not present an accurate representation of the typical process of CCT and cognitive remediation (CR), especially as delivered in major mental illnesses such as schizophrenia. This review provides guidance on the definitions of CCT and CR, the uses of CCT and CR, and the definitions and measurements of cognitive and functional gains. The review focuses on schizophrenia and healthy aging, with each population receiving unique CCT or CR approaches and substantial extant literature with which to elucidate fundamental CCT and CR concepts and research findings. It is our conclusion that CCT has been shown in most studies to improve cognitive performance on untrained tests in healthy older people and in people with schizophrenia. Functional gains in schizophrenia appear to be limited to CR studies. Clearly defining CCT, CR, and levels of treatment-related gains will be critical for understanding the benefits of these widely used treatment programs.

Cognitive and functional deficits in people with schizophrenia: Evidence for accelerated or exaggerated aging?

Cognitive and functional deficits are commonly seen in people with schizophrenia. The profile of these impairments has a resemblance to the cognitive changes seen in healthy aging. In specific, many of the cognitive ability domains that change the most with aging in healthy people are the most salient of these deficits seen in people with schizophrenia, including prominent deficits in processing speed, working memory, and episodic memory. Functional deficits seen in schizophrenia are also similar to those seen in healthy aging. There is a relationship between multiple psychotic relapses and treatment resistance and longitudinal cognitive and functional changes in schizophrenia, with this relationship starting early in the course of illness. Cognitive performance in people with schizophrenia may be consistent with accelerated or premature aging. People with schizophrenia perform similarly to healthy people who are 3 or more decades older on indices of both cognition and their everyday functional skills. Some people with schizophrenia show exaggerated cognitive changes as well. Cognitive and functional performance worsens at the outset of the illness in schizophrenia compared to premorbid functioning, meaning that these deficits are not due to development disabilities. There are multiple medical and substance abuse comorbidities in schizophrenia and although these comorbidities affect cognitive functioning, they are not completely responsible for age-related changes.

Social Cognition and Neurocognition in Schizophrenia and Healthy Controls: Intercorrelations of Performance and Effects of Manipulations Aimed at Increasing Task Difficulty

Social cognition (SC) and neurocognition appear to predict different aspects of functional outcome in people with schizophrenia. However, the correlations between performance on these domains have not been tested extensively and compared cross-diagnostically with healthy controls. Further, some social cognitive measures appeared to have potential ceiling effects, particularly for healthy people, in previous research, so increasing their difficulty is of interest. In this paper we report on two studies wherein we examined the correlations between neurocognitive ability and performance on SC tests. In the first study the correlations between measures of social perception, emotion processing, and theory of mind and performance on a brief neuropsychological (NP) assessment were examined in 179 schizophrenia (SCZ) patients and 104 healthy controls (HC). In the second study, we instructed participants to perform a subset of the tasks as rapidly as possible in order to increase task difficulty, and we examined the effects of those instructions on task difficulty, task psychometrics, and correlations between SC and NP tests in 218 SCZ patients and 154 HC. In the first study, both HC and SCZ manifested a domain specific pattern of correlation between NP and SC test performance. Controlling for group differences in NP performance did not eliminate SC performance differences between the groups. In the second study, no differences in task performance, intercorrelations other SC tests, or test-retest stability were induced by the difficulty manipulation in the samples who performed the tasks with speed demands compared to the performance of the previous sample. These data suggest that simple manipulations aimed at increasing task difficulty may not have the desired effect and that despite consistent correlations between SC and NP test performance, impairments in social cognitive functioning are not fully explained by NP performance deficits.

Placebo Response and Practice Effects in Schizophrenia Cognition Trials

IMPORTANCE

Patients' previous experience with performance-based cognitive tests in clinical trials for cognitive impairment associated with schizophrenia can create practice-related improvements. Placebo-controlled trials for cognitive impairment associated with schizophrenia are at risk for these practice effects, which can be difficult to distinguish from placebo effects.

OBJECTIVES

To conduct a systematic evaluation of the magnitude of practice effects on the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) in cognitive impairment associated with schizophrenia and to examine which demographic, clinical, and cognitive characteristics were associated with improvement in placebo conditions.

DESIGN, SETTING, AND PARTICIPANTS

A blinded review was conducted of data from 813 patients with schizophrenia who were treated with placebo in 12 randomized placebo-controlled clinical trials conducted mostly in outpatient clinics in North America, Europe, Asia, and Latin America from February 22, 2007, to March 1, 2014. A total of 779 patients provided data for the primary outcome measure at baseline and at least 1 follow-up. Seven trials had prebaseline assessments wherein the patients knew that they were not receiving treatment, allowing a comparison of practice and placebo effects in the same patients.

INTERVENTIONS

Placebo compared with various experimental drug treatments.

MAIN OUTCOMES AND MEASURES

Composite score on the MCCB.

RESULTS

Of the 813 patients in the study (260 women and 553 men; mean [SD] age, 41.2 [11.5] years), the mean MCCB composite score at baseline was 22.8 points below the normative mean, and the mean (SEM) total change in the MCCB during receipt of placebo was 1.8 (0.2) T-score points (95% CI, 1.40-2.18), equivalent to a change of 0.18 SD. Practice effects in the 7 studies in which there was a prebaseline assessment were essentially identical to the postbaseline placebo changes. Baseline factors associated with greater improvements in the MCCB during receipt of placebo included more depression/anxiety (F1,438 = 5.41; P = .02), more motivation (F1,272 = 4.63; P = .03), and less improvement from screening to baseline (F1,421 = 59.32; P < .001).

CONCLUSIONS AND RELEVANCE

Placebo effects were minimal and associated with the number of postbaseline assessments and several patient characteristics. Given that the patients performed 2.28 SDs below normative standards on average at baseline, a mean placebo-associated improvement of less than 0.2 SD provides evidence that ceiling effects do not occur in these trials. These minimal changes in the MCCB could not be responsible for effective active treatments failing to separate from placebo.