Specific executive dysfunction in patients with first-episode medication-naïve schizophrenia

Increased and sex-differentiated medial prefrontal cortex activation during the MATRICS Consensus Cognitive Battery in schizophrenia: A fNIRS study

Executive impairment in schizophrenia is common, but the mechanism remains unclear. This is the first study to use simultaneously functional near-infrared spectroscopy (fNIRS) to monitor the hemodynamic response in schizophrenia during the MATRICS Consensus Cognitive Battery (MCCB). Here, we monitored relative changes in oxyhemoglobin concentration in the medial prefrontal cortex (mPFC) during Trail Making Test, Symbol Coding Test and Mazes Test of the MCCB in 63 patients (29 females) with schizophrenia and 32 healthy controls (15 females). Results showed that patients with schizophrenia scored lower than healthy controls on all three tests (P < 0.001), but mPFC activation was significantly higher during the test (P < 0.03). Higher activation of the mPFC may reflect abnormal information processing in schizophrenia. In addition, the results also showed sex differences in hemodynamic activation during the task in patients with schizophrenia, and fNIRS has the potential to be a clinical adjunct to screening for cognitive function in schizophrenia.

Associations of resilience, white matter topological organization, and cognitive functions in first-episode, drug-naïve schizophrenia patients: A moderated mediation analysis

BACKGROUND

Cognitive deficits are core symptoms of schizophrenia (SZ) and are associated with impaired resilience to stress. Different cognitive functions appeared to be interrelated, and the mechanism may involve neural alterations. The disrupted topological organization indicated abnormalities in the segregation and integration of brain networks that support various cognitive processes in SZ patients. Therefore, this study aimed to assess the direct and indirect effects of resilience on cognitive functions. We hypothesized that topological properties would moderate these associations.

METHODS

Forty-nine SZ patients and fifty-two healthy controls (HCs) were recruited in this study. The Connor-Davidson Resilience Scale and the MATRICS Consensus Cognitive Battery were used to examine resilience and cognitive functions, respectively, and a graph theory approach was used to assess white matter topological organization.

RESULTS

Compared to HCs, SZ patients showed lower levels of resilience and cognitive functions in multiple domains as well as abnormal global properties and nodal metrics. In addition, shorter characteristic path length was associated with a stronger indirect effect of resilience on working memory through processing speed in SZ patients.

CONCLUSION

Characteristic path length might moderate the mediating effects of processing speed in the relationship between resilience and working memory in schizophrenia patients.

Strain-level structure of gut microbiome showed potential association with cognitive function in major depressive disorder: A pilot study

BACKGROUND

Although the association between gut microbiota and the pathogenesis of major depressive disorder (MDD) has been well studied, it is unclear whether gut microbiota affects cognitive function in patients with MDD. In this study, we explored the association between gut microbiota and cognitive function in MDD and its possible mechanisms.

METHODS

We enrolled 57 patients with MDD and 30 healthy controls (HCs) and used 16S rRNA gene sequencing analysis and shotgun metagenomic sequencing analysis to determine gut microbial composition.

RESULTS

The richness and diversity of gut microbiota in patients with MDD were the same as those in HCs, but there were differences in the abundance of Bifidobacterium and Blautia. Compared with HCs, two strains (bin_32 and bin_55) were significantly increased, and one strain (bin_31) was significantly decreased in patients with MDD based on the strain-level meta-analysis. Time to complete the Stroop-C had significant negative correlations with bin_31 and bin_32. Bin_55 had significant negative correlations with time to complete the Stroop-C, time to complete the Stroop-CW, and repeated animal words in 60 s but significant positive correlations with correct answers in 120 s on the Stroop-CW.

LIMITATIONS

This study only tested the cognitive function of MDD in a small sample, which may have caused some bias.

CONCLUSIONS

Based on our strain-level analysis, we found that gut microbiota may be associated with the pathogenesis of MDD and may have potential effects on cognitive function.

Correlations between Negative Symptoms and Cognitive Deficits in Individuals at First Psychotic Episode or at High Risk of Psychosis: A Systematic Review

The present review aims to identify correlations between negative symptoms (NS) and deficits in neurocognition and social cognition in subjects with first-episode psychosis (FEP) and at-high-risk populations (HR). A systematic search of the literature published between 1 January 2005 and 31 December 2022 was conducted on PubMed, Scopus, and PsycInfo. Out of the 4599 records identified, a total of 32 studies met our inclusion/exclusion criteria. Data on a total of 3086 FEP and 1732 HR were collected. The available evidence shows that NS correlate with executive functioning and theory of mind deficits in FEP subjects, and with deficits in the processing speed, attention and vigilance, and working memory in HR subjects. Visual learning and memory do not correlate with NS in either FEP or HR subjects. More inconsistent findings were retrieved in relation to other cognitive domains in both samples. The available evidence is limited by sample and methodological heterogeneity across studies and was rated as poor or average quality for the majority of included studies in both FEP and CHR populations. Further research based on shared definitions of first-episode psychosis and at-risk states, as well as on more recent conceptualizations of negative symptoms and cognitive impairment, is highly needed.

Şizofreni hastalarında TSH, fT3 ve fT4 düzeylerinin nörobilişsel belirtiler üzerine etkisi

Amaç: Bu çalışmamızda ötiroid psikoz hastalarında tiroid hormon düzeyleri ile pozitif, negatif, genel ve bilişsel belirtiler arasındaki ilişkiyi incelemeyi amaçladık. Gereç ve Yöntem: Çalışmaya 33 şizofreni hastası dahil edildi. Katılımcıların sosyodemografik ve klinik verileri, Pozitif ve Negatif Belirtileri Değerlendirme Ölçeği (PANSS), İşlevselliğin Genel Değerlendirilmesi Ölçeği (IGD), Klinik Global İzlenim Ölçeği (KGI) skorları kaydedildi. İz sürme, Sözel Akıcılık Testi, İleri ve Geri Sayı Menzili ile Wisconsin Kart Sayma Testinden (WKST) oluşan bir nörobilişsel batarya uygulanan hastaların bilişsel performanslarının TSH, sT3 ve sT4 düzeyleri ile ilişkisi araştırıldı. Bulgular: sT4 düzeyleri ile İz Sürme B (r=-,376; p=0,031) ve Sözel Akıcılık test (p=,355; p=0,043) performansları arasında anlamlı derecede ilişki saptandı. Linear regresyon modelinde sT3 düzeylerinin WKST- tamamlanan kategori sayısını (UB=1.680; p=0.029) anlamlı derecede yordadığı saptandı.. Sonuç: Çalışmamızın sonuçları sT3 ün özellikle yürütücü işlevler üzerinde sT4’e kıyasla daha belirleyici etkileri olduğunu düşündürmüştür. İleride yapılacak daha geniş katılımlı araştırmalar, bilişsel belirtilerin tedavisinde tiroid hormon replasmanının etkinliğini belirlemek açısından önemli görünmektedir.

Executive deficits in schizophrenia: mediation by processing speed and its relationships with aging

BACKGROUND

Executive deficits are a core characteristic of schizophrenia. Yet, the origin of these impairments remains unclear as they may be caused by processing slowing. This issue is of particular interest for aging insofar as cognitive aging is also associated with a decline in executive functioning and a slowing of processing speed. As schizophrenia patients' life expectancy increases, a better understanding of the origin of older patients' cognitive deficits becomes essential so that healthcare can be adapted to suit them. This study aims to determine whether processing speed mediates how schizophrenia affects executive functions and whether these relationships are moderated by age.

METHODS

Sixty-two schizophrenia patients (27 women) and 62 healthy comparison subjects matched for age (range: 18-76 years), gender and education performed neurocognitive tests to evaluate their executive functions (shifting, updating, inhibition and access) and processing speed.

RESULTS

Processing speed mediated the effect of schizophrenia on the four specific executive functions, and age moderated this mediation for shifting, updating and access, but in different ways. Age moderated the effect of processing speed on shifting, the direct effect of schizophrenia on access, and both the effect of processing speed and the direct effect of schizophrenia on updating.

CONCLUSIONS

This research highlights the need to evaluate processing speed routinely during therapeutic follow-up, as it is easy and simple to assess and appears to be at the heart of the cognitive deficits in schizophrenia. Finally, processing speed abilities yield information about the evolution of cognition with aging in schizophrenia.

Interactive effects of maintenance decay and interference on working memory updating in schizophrenia

BACKGROUND

Deficits in working memory have been identified as a core cognitive impairment in schizophrenia. Prior work has identified a unique pattern of rapidly decreasing accuracy following intact encoding and updating of a single visuospatial target in patients with schizophrenia. Understanding whether these deficits are related to disruption of working memory stores following retrieval or part of a broader maintenance dysfunction may help elucidate the specific subprocesses underlying working memory deficits in schizophrenia.

METHODS

Participants were 71 patients with a schizophrenia spectrum disorder and 43 healthy controls who completed a working memory paradigm that parametrically varied maintenance demands from 1000 to 8000 ms.

RESULTS

Patients with a schizophrenia spectrum disorder were comparable to healthy controls at delays of 1000 ms. However, when delays were extended to 2000 and 4000 ms, the patient group showed significantly decreased accuracy. Additionally, the patient group showed a greater decline in accuracy following a second delay.

CONCLUSIONS

These findings suggest that early encoding of one item is intact in patients with a schizophrenia spectrum disorder, but information rapidly decays from working memory stores with extended delays. Accuracy further decreased when information was retrieved from working memory, suggesting that working memory stores may also be susceptible to disruption from internal stimuli. Thus, working memory stores in patients with a schizophrenia spectrum disorder may be vulnerable to both rapid decay and interference.

Executive functions in 7-year-old children of parents with schizophrenia or bipolar disorder compared with controls: The Danish High Risk and Resilience Study-VIA 7, a population-based cohort study

Cognitive impairments are strongly associated with schizophrenia (SZ) and bipolar disorder (BP) with executive functions (EF) impairments as a likely key feature. Studies of everyday behavior rated EF in young children at familial high risk of SZ (FHR-SZ) are scarce and, to our knowledge, non-existent in young children at familial high risk of BP (FHR-BP). We aimed to compare everyday behavior-rated EF of FHR-SZ, FHR-BP, and control children. A nationwide population-based cohort of 522 7-year-old children with parents diagnosed with either SZ (N = 202) or BP (N = 120) and matched controls (N = 200) were recruited using the Danish national registries. The children's EF were assessed with the Behavior Rating Inventory of Executive Functions questionnaire rated by primary caregivers and teachers. According to primary caregiver assessments, FHR-SZ children displayed widespread EF impairments and had an odds ratio of 3.7 (2.0-6.9) of having clinically significant global EF impairments compared to controls. FHR-BP children were most severely impaired regarding EF related to emotional control and had an odds ratio of 2.5 (1.2-5.1) of clinically significant global EF impairments compared to controls. Teacher assessments were overall comparable to primary caregiver assessments but teachers rated more difficulties in the FHR-SZ group than primary caregivers. Already at age 7, children with a parental history of SZ or BP displayed significant impairments of EF in everyday-life situations. FHR-SZ children displayed widespread significant impairments of EF, whereas FHR-BP children were most severely impaired on emotional control. Clinicians should be aware of potential EF impairments in FHR children.

A network analysis and empirical validation of executive deficits in patients with psychosis and their healthy siblings

BACKGROUND

Psychopathological symptoms and cognitive impairment are core features of patients with psychotic disorders. Executive dysfunctions are commonly observed and typically assessed using tests like the Wisconsin Card Sorting Test (WCST). However, the structure of executive deficits remains unclear, and the underlying processes may be different. This study aimed to explore and compare the network structure of WCST measures in patients with psychosis and their unaffected siblings and to empirically validate the resulting network structure of the patients.

METHODS

The subjects were 298 patients with a DSM 5 diagnosis of a psychotic disorder and 89 of their healthy siblings. The dimensionality and network structure of the WCST were examined by means of exploratory graph analysis (EGA) and network centrality parameters.

RESULTS

The WCST network structure comprised 4 dimensions: perseveration (PER), inefficient sorting (IS), failure to maintain set (FMS) and learning (LNG). The patient and sibling groups showed a similar network structure, which was reliably estimated. PER and IS showed common and strong associations with antecedent, concurrent and outcome validators. The LNG dimension was also moderately associated with these validators, but FMS did not show significant associations.

CONCLUSIONS

Four cognitive processes underlying WCST performance were identified by the network analysis. PER, IS and LNG were associated with and shared common antecedent, concurrent and outcome validators, while FMS was not associated with external validators. These four underlying dysfunctions might help disentangle the neurofunctional basis of executive deficits in psychosis.

Cognitive correlates of 'Formal Thought Disorder' in a non-clinical sample with elevated schizotypal traits

Different dimensions of formal thought disorder (FTD) are distinguished by different patterns of cognitive dysfunction in patients with schizophrenia; however, inconsistent findings may relate to patient-related confounds. To avoid these confounds, we examined relationships between FTD dimensions and cognitive domains in a non-clinical sample with attenuated schizophrenia-like traits, or schizotypal traits, on the Schizotypal Personality Questionnaire (N = 91). To our knowledge, no study has done this. FTD dimension scores were derived following principal component analysis of the Scale for the Assessment of Thought, Language and Communication (TLC dimensions: Disorganisation, Verbosity, Emptiness) and the Thought and Language Index (TLI dimensions: Negative, Idiosyncratic). The sample completed a comprehensive neuropsychological battery. Findings indicate that higher-order reasoning, executive function (set shift and generative ability) and language/semantic functioning are the primary drivers of FTD in our non-clinical sample with elevated schizotypal traits, in line with schizophrenia research. FTD may have shared aetiology along the schizophrenia spectrum.

Evaluation of a computer-assisted cognitive remediation program for young people with psychosis: A pilot study

Background

People with psychosis have a range of neuropsychological impairments that impact their functional abilities and rehabilitation outcomes. We designed a Computer-Assisted Cognitive Remediation (CACR) program to help young people with psychosis to restore their cognitive function. The program combines the drill-and-practice approach and the strategic approach to remediation, with sixteen sessions of computerized cognitive training, two sessions of psychoeducation, and four session of coaching on applying cognitive skills to daily life.

Method

This was a randomized, single-blind, controlled study in which the outcomes of the CACR program were compared with outcomes of a treatment-as-usual (TAU) control group. Pre-intervention and post-intervention measures were compared.

Results

When compared with the control group, the intervention group had significant increases in their MCCB neurocognitive composite scores, and specifically in the areas of verbal learning and speed of processing at posttest. They also had significant increases in their secondary outcome measures of mental well-being and perceived occupational competence. There were no significant differences in functional status between the two groups at post-test.

Conclusions

The CACR program was effective in improving overall cognitive function and in the specific domains of verbal learning, speed of processing, and effect sizes were small. Participants also experienced positive changes in mental well-being and perceived competence.

Cognitive and Clinical Predictors of Prefrontal Cortical Thickness Change Following First-Episode of Psychosis

The association of neuroanatomical progression with cognitive and clinical deterioration after first-episode of psychosis remains uncertain. This longitudinal study aims to assess whether i)impaired executive functioning and emotional intelligence at first presentation are associated with progressive prefrontal and orbitofrontal cortical thinning ii)negative symptom severity is linked to progressive prefrontal cortical thinning. 1.5T MRI images were acquired at baseline and after 3.5 years for 20 individuals with first-episode psychosis and 18 controls. The longitudinal pipeline of Freesurfer was employed to parcellate prefrontal cortex at two time points. Baseline cognitive performance was compared between diagnostic groups using MANCOVA. Partial correlations investigated relationships between cognition and negative symptoms at baseline and cortical thickness change over time. Patients displayed poorer performance than controls at baseline in working memory, reasoning/problem solving and emotional intelligence. In patients, loss of prefrontal and orbitofrontal thickness over time was predicted by impaired working memory and emotional intelligence respectively at baseline. Moreover, exploratory analyses revealed that the worsening of negative symptoms over time was significantly related to prefrontal cortical thinning. Results indicate that specific cognitive deficits at the onset of psychotic illness are markers of progressive neuroanatomical deficits and that worsening of negative symptoms occurs with prefrontal thickness reduction as the illness progresses.

Advancing study of cognitive impairments for antipsychotic-naïve psychosis comparing high-income versus low- and middle-income countries with a focus on urban China: Systematic review of cognition and study methodology

BACKGROUND

Comparing the course of antipsychotic-naïve psychosis in low- and middle-income countries (LMIC) may help to illuminate core pathophysiologies associated with this condition. Previous reviews-primarily from high-income countries (HIC)-identified cognitive deficits in antipsychotic-naïve, first-episode psychosis, but did not examine whether individuals with psychosis with longer duration of untreated psychosis (DUP > 5 years) were included, nor whether LMIC were broadly represented.

METHOD

A comprehensive search of PUBMED from January 2002-August 2018 identified 36 studies that compared cognitive functioning in antipsychotic-naïve individuals with psychosis (IWP) and healthy controls, 20 from HIC and 16 from LMIC.

RESULTS

A key gap was identified in that LMIC study samples were primarily shorter DUP (<5 years) and were primarily conducted in urban China. Most studies matched cases and controls for age and gender but only 9 (24%) had sufficient statistical power for cognitive comparisons. Compared with healthy controls, performance of antipsychotic-naïve IWP was significantly worse in 81.3% (230/283) of different tests of cognitive domains assessed (90.1% in LMIC [118/131] and 73.7% [112/152] in HIC).

CONCLUSIONS

Most LMIC studies of cognition in antipsychotic-naïve IWP adopted standardized procedures and, like HIC studies, found broad-based impairments in cognitive functioning. However, these LMIC studies were often underpowered and primarily included samples typical of HIC: primarily male, young-adult, high-school educated IWP, in their first episode of illness with relatively short DUP (<5 years). To enhance understanding of the long-term natural course of cognitive impairments in untreated psychosis, future studies from LMIC should recruit community-dwelling IWP from rural areas where DUP may be longer.

Executive functions in schizophrenia aging: Differential effects of age within specific executive functions

There are common cognitive and brain abnormalities in schizophrenia and healthy aging which may cumulate in schizophrenia aging. However, the course of executive deficits in late-life schizophrenia is still controversial as it remains unclear whether schizophrenia patients show accelerated aging. The use of specific models of executive functions might help to shed new lights on this issue. The aim of this study was then to determine how each of the four specific executive functions (shifting, updating, inhibition and access to long-term memory) is affected by aging in schizophrenia compared to healthy aging. 20 younger (age 18-34), 17 middle-aged (age 35-49) and 25 older (age 59-76) schizophrenia patients and 62 healthy comparison participants matched for gender, age and education performed a neurocognitive battery evaluating the four specific executive functions. Schizophrenia patients performed worse than comparison participants on shifting, updating and access, whereas inhibition appeared preserved. Age affected the four functions with increased degradation of shifting and access in schizophrenia patients, whereas updating and inhibition showed a normal decline with age. These results suggest a vulnerability of prefrontal and cingulate cortexes in schizophrenia aging. Moreover, as age affected the specific executive functions differently, remediation programs should be adapted to older patients. Models of specific executive functions are useful for understanding the complexity of cognition in schizophrenia and its course during later life so that healthcare can be adapted accordingly.

Executive dysfunctions differentially predict amotivation in first-episode schizophrenia-spectrum disorder: a prospective 1-year follow-up study

Amotivation is a major determinant of functional outcome in schizophrenia but it is understudied in the early course of illness. There is a paucity of longitudinal research investigating predictors of amotivation. In this study, we aimed to examine baseline cognitive and clinical predictors of amotivation at 6 and 12 months of follow-up in patients aged 18-55 years presenting with first-episode DSM-IV schizophrenia-spectrum disorder (FES). Of 145 patients recruited at intake, 116 and 113 completed assessments at 6- and 12-month follow-up, respectively. Amotivation was measured by avolition-apathy and anhedonia-asociality subscale scores of the Scale of the Assessment of Negative Symptoms. Cognitive assessment was administered at baseline. As executive dysfunction has been more consistently found to be associated with negative symptoms and amotivation in prior literature, we adopted fractionated approach to subdivide executive function into distinct components encompassing switching and flexibility, response initiation, response inhibition, planning and strategy allocation, sustained attention and working memory. Our results showed that baseline amotivation (p = 0.01) and switching and flexibility (p = 0.01) were found to independently predict amotivation at 6 months follow-up. Baseline amotivation (p < 0.01) and switching and flexibility (albeit with trend-wise significance, p = 0.06) were also retained in final multivariate regression model for 12-month amotivation prediction. No other executive components or cognitive domains predicted amotivation at follow-up. Findings of our study thus indicate amotivation at initial presentation as a critical determinant of subsequent motivational deficits over 1 year of treatment for FES patients. Cognitive flexibility might be specifically related to the development of amotivation in the early stage of illness.

Objective and subjective cognitive functioning in relation to psychopathology among women with early psychosis

BACKGROUND

Subjective cognitive impairment (SCI) among early psychosis is under-recognized and under-studied. However, SCI is as important as objective impairment to be understood, since it assesses cognitive difficulties in real-life situations from a personal perspective and is therefore an essence of individualized medicine. This study aims to explore the associations between the objective and subjective measures of cognitive impairments and to identify factors contributing to SCI among people with early psychosis.

METHODS

Participants were 60 females (mean age 24.57 ± 8.28) who had a diagnosis of psychotic-spectrum disorder within 5 years. They completed a battery of neuropsychological tests assessing a range of cognitive functions including verbal learning, memory, attention, and executive functions. The Subjective Cognitive Impairment Scale (SCIS) was used to assess their perceived cognitive decline. Psychotic symptoms and depression were also assessed.

RESULTS

SCIS was not correlated with any of the objective cognitive tests results. It was positively correlated with depression and positive symptoms. A hierarchical multiple regression model revealed that positive symptoms and depression together explained 31.9% of the total variance in SCIS and only depression significantly predicted SCI. Performances on the memory tests were correlated with, and predicted by negative symptoms.

CONCLUSIONS

There was no correlation between SCI and objective cognitive performances in patients with early psychosis. Treatments should not only focus on symptomatic remission and performance of cognitive tests, but also place emphasis on improving moods and subjective cognitive functions of individuals with early psychosis.

Meta-analysis of cognitive function in Chinese first-episode schizophrenia: MATRICS Consensus Cognitive Battery (MCCB) profile of impairment

Background

Compromised neurocognition is a core feature of schizophrenia. With increasing studies researching cognitive function of Chinese patients with first-episode schizophrenia (FES) using MATRICS Consensus Cognitive Battery (MCCB), it is not clear about the level and pattern of cognitive impairment among this population.

Aim

To provide a meta-analysis systematically analysing studies of neurocognitive function using MCCB in Chinese patients with FES.

Methods

An independent literature search of both Chinese and English databases up to 13 March 2019 was conducted by two reviewers. Standardised mean difference (SMD) was calculated using the random effects model to evaluate the effect size.

Results

56 studies (FES=3167, healthy controls (HC)=3017) were included and analysed. No study was rated as 'high quality' according to Strengthening the Reporting of Observational Studies in Epidemiology. Compared with HCs, Chinese patients with FES showed impairment with large effect size in overall cognition (SMD=-1.60, 95% CI -1.82 to -1.38, I ²=67%) and all seven cognitive domains, with the SMD ranging from -0.87 to -1.41. In nine MCCB subtests, patients with FES showed significant difference in Symbol Coding (SMD=-1.90), Trail Making Test (TMT) (SMD=-1.36), Continuous Performance Test-Identical Pairs (SMD=-1.33), Hopkins Verbal Learning Test (SMD=-1.24), Brief Visuospatial Memory Test (SMD=-1.18), Mazes (SMD=-1.16), Category Fluency (SMD=-1.01), Spatial Span (SMD=-0.69) and Mayer-Salovey-Caruso Emotional Intelligence Test (SMD=-0.38).

Conclusions

Our meta-analysis demonstrates that Chinese patients with FES show neurocognitive deficits across all seven MCCB cognitive domains and all nine subtests, particularly in two neurocognitive domains: speed of processing and attention/vigilance, with the least impairment shown in social cognition. Symbol Coding and TMT may be the most sensitive tests to detect cognitive deficit in Chinese patients with FES.

A meta-analysis of executive dysfunction in patients with schizophrenia: Different degree of impairment in the ecological subdomains of the Behavioural Assessment of the Dysexecutive Syndrome

We performed meta-analyses of studies using the 6 subtests of the neuropsychological test battery, the Behavioural Assessment of the Dysexecutive Syndrome (BADS), in order to assess and compare subdomains of executive dysfunction in stable phase patients with schizophrenia relative to healthy controls. The meta-analyses were performed according to the PRISMA statement. A systematic literature search was performed yielding 10 studies for inclusion (N_SCH= 375; N_HC = 541). Meta-analyses were done using Stata IC 14. Due to large heterogeneity and the few number of studies a random-effects model was used along with Hedges' g. Results showed that relative to healthy controls, patients with schizophrenia overall performed significantly worse in all subtests of BADS. However, moderate effect sizes were seen with regard to temporal estimation and strategy-forming, while very large effect sizes were seen regarding complex forward planning, inhibition, cognitive flexibility and novel problem solving. The findings from this meta-analysis demonstrate a significant difference between patients with (primarily) longer lasting schizophrenia and healthy control subjects on all subdomains of executive functions (EF). But some aspects of EF seem to be more severely affected than others. Future research and clinical interventions need to differentiate between subdomains of EF.

Assessment of executive function using the Tinkertoy test

The Tinkertoy test (TTT) has often been used to assess executive function. Despite its clinical importance, there are few published normative data for it. Thus, the primary aim of this study was to fill this gap. Moreover, as there exists a sex difference in many cognitive abilities and neuropsychological tests, a secondary aim was to examine whether sex influences TTT performance. We administered the TTT to 25 healthy men and 25 healthy women whose average age was 28 years. Performances were scored based upon Lezak's (1982) original TTT criteria. On average, our participants used 43 pieces to complete their construction (SD=8), with a range of 21-50, and their complexity scores ranged from 7 to 12, with a mean score of 9.68 (SD=1.35). Overall performance did not differ based on sex; yet, when examining individual scoring criteria, we found that men scored significantly higher on the symmetry measure. Efforts towards the development of adequate normative data for the TTT and different tests of executive functioning are crucial to neuropsychologists' and other healthcare providers' ability to reliably diagnose and treat disorders of cognition that affect executive function. The present data go some way towards enhancing the utility of the TTT.

Duration of untreated psychosis and neurocognitive functioning in first-episode psychosis: a systematic review and meta-analysis

BACKGROUND

Previous reviews suggest there is minimal evidence for an association between duration of untreated psychosis (DUP) and neurocognition. This is based on tallied findings of studies with small samples and neurocognition viewed as a single construct. We aimed to conduct a systematic review and meta-analysis examining the association between DUP and individual neurocognitive domains and tests in first-episode psychosis (FEP).

METHOD

MOOSE and PRISMA guidelines were followed. Forty-three studies involving 4647 FEP patients were included. For studies providing correlations between DUP and neurocognition, 12 separate meta-analyses were performed based on neurocognitive domains/indices. The influence of demographic/clinical variables was tested using weighted linear meta-regression analyses.

RESULTS

The relationship between DUP and most neurocognitive domains/indices was not significant. Longer DUP was associated with a larger cognitive deterioration index, i.e. current minus premorbid intellectual functioning (N = 4; mean ES -0.213, 95% confidence interval (CI) (-0.344 to -0.074), p = 0.003). Findings were homogeneous, with no evidence of publication bias or significant influence from moderators. For studies providing mean and standard deviations for neurocognitive measures and DUP, 20 meta-regressions were performed on individual neurocognitive tests. One significant finding emerged showing that longer DUP was associated with fewer Wisconsin Card Sorting Test-perseverative errors (mean ES -0.031, 95% CI (-0.048 to -0.013), p < 0.001). Exploratory meta-regressions in studies with mean DUP <360 days showed longer DUP was significantly associated with poorer performance on Trail Making Test A and B and higher Full-Scale IQ.

CONCLUSION

There may not be a generalised association between DUP and neurocognition, however, specific cognitive functions may be associated with longer DUP or delayed help-seeking.

High-functioning autism patients share similar but more severe impairments in verbal theory of mind than schizophrenia patients

BACKGROUND

Evidence suggests that autism and schizophrenia share similarities in genetic, neuropsychological and behavioural aspects. Although both disorders are associated with theory of mind (ToM) impairments, a few studies have directly compared ToM between autism patients and schizophrenia patients. This study aimed to investigate to what extent high-functioning autism patients and schizophrenia patients share and differ in ToM performance.

METHODS

Thirty high-functioning autism patients, 30 schizophrenia patients and 30 healthy individuals were recruited. Participants were matched in age, gender and estimated intelligence quotient. The verbal-based Faux Pas Task and the visual-based Yoni Task were utilised to examine first- and higher-order, affective and cognitive ToM. The task/item difficulty of two paradigms was examined using mixed model analyses of variance (ANOVAs). Multiple ANOVAs and mixed model ANOVAs were used to examine group differences in ToM.

RESULTS

The Faux Pas Task was more difficult than the Yoni Task. High-functioning autism patients showed more severely impaired verbal-based ToM in the Faux Pas Task, but shared similar visual-based ToM impairments in the Yoni Task with schizophrenia patients.

CONCLUSIONS

The findings that individuals with high-functioning autism shared similar but more severe impairments in verbal ToM than individuals with schizophrenia support the autism-schizophrenia continuum. The finding that verbal-based but not visual-based ToM was more impaired in high-functioning autism patients than schizophrenia patients could be attributable to the varied task/item difficulty between the two paradigms.

Following Instructions in Patients With Schizophrenia: The Benefits of Actions at Encoding and Recall

The ability to follow spoken instructions is important to everyday functioning but has seldom been studied in patients with schizophrenia (SZ). Recent evidence suggests that action-based processing may facilitate the ability to follow instructions, which relies largely on working memory. In this study, we tested the hypothesis that SZ patients may also benefit from action-based advantages in following instructions. Forty-eight clinically stable SZ patients and 48 demographic- and IQ-matched controls completed a following spoken instruction span task involving varied encoding and recall conditions. While SZ patients were impaired in the overall performance of following spoken instructions, this deficit could be attributed to working memory impairment. More importantly, SZ patients showed action-based advantages both at the encoding and retrieval stage to the same extent as healthy controls. Specifically, both healthy controls and SZ patients showed improved memory performance when they additionally performed the actions, or watched the experimenter carrying out the actions compared with simply listening to spoken instructions during the encoding stage. During the retrieval stage, memory was improved when they recalled the instructions by physical enactment compared with oral repetition. The present study provides the first empirical evidence for the impairment in the ability to follow instructions in SZ. We have shown that involving action-based processing in the encoding and retrieval stage facilitated memory of instructions, indicating that the enactment advantage in working memory also applies to SZ patients. These findings provide useful insights for clinical interventions and cognitive remediation for SZ patients.

First episode psychosis moderates the effect of gray matter volume on cognition

Patients with first episode psychosis (FEP) present with cognitive deficits and volume differences in certain brain areas. Brain volumetric information further correlates with cognitive testing, and multiple brain areas shows different strengths of correlation with the cognitive functions being tested. Traditionally, these cognitive functions are independently related to volumetric differences, but these functions share variance. Failing to account for this aspect of cognition hinders the proper representation of cognition in neuroimaging studies. We used modeling methods which account for this shared variance to investigate the differences of correlations between cognitive abilities and brain areas. A multiple-groups structured equation model (SEM) approach was used to design and test a model representing the relation between gray matter volumetric data and neuropsychological test scores in a sample of 100 Brazilian FEP patients and 94 controls. Models with a latent variable formed by neurological measures and reflecting cognitive measures performed better on fit tests. FEP moderated the relation between gray matter volumes and cognition by altering the profile of correlations between groups. This moderation had a large effect size. SEM provides a fine grained picture of the interdependence of structural brain changes and cognition.

Executive Functions in Students With Depression, Anxiety, and Stress Symptoms

Introduction:

This study aimed to investigate and compare the executive functions of students with depression, anxiety, and stress symptoms with those functions in healthy ones.

Methods:

This study was a comparative and non-clinical analysis. The study population comprised all students of Shahid Beheshti University, Tehran, Iran. A total of 448 students were recruited using convenience sampling method. They were also screened using the Depression Anxiety Stress Scales (DASS) test comprising 21 items. Of study participants, 30 people were depressed, 27 had anxiety, and 15 suffered from stress. Then, 50 control people were matched with them. Next, both groups were compared using the Stroop test, Wisconsin card sorting, and cognitive ability test.

Results:

Using MANOVA test, data analysis revealed no significant differences among 4 groups with regard to selective attention and shifting attention. Depressed group reacted rapidly as opposed to the anxiety group with regard to measures of shifting attention and cognitive abilities; it was observed that the memory, inhibition control, planning, and flexibility of the healthy group were better than those of the 3 other groups.

Conclusion:

The findings of this research raised specific issues in relation to the role of depression, anxiety, and stress in the disruption of the executive functions of sufferers. Selective and shifting attention and cognitive abilities are specifically affected in this regard. Meanwhile, the role of stress in impairing decision making and the major role of anxiety in impairing sustained attention was shown to be considerable.

Cognitive Pragmatic Rehabilitation Program in Schizophrenia: A Single Case fMRI Study

Introduction. The present study was intended to evaluate the effects of a rehabilitative training, the Cognitive Pragmatic Treatment (CPT), aimed at improving communicative-pragmatic abilities and the related cognitive components, on the cerebral modifications of a single case patient diagnosed with schizophrenia. Methods. The patient underwent two functional magnetic resonance imaging (fMRI) sessions, before and after the treatment. In order to assess brain changes, we calculated the Amplitude of Low Frequency Fluctuation (ALFF) index of the resting-state fMRI signal, which is interpreted as reflecting the intensity of the spontaneous regional activity of the brain. Behavioural measures of the patient's communicative performance were also gathered before and after training and at follow-up. Results. The patient improved his communicative performance in almost all tests. Posttraining stronger ALFF signal emerged in the superior, inferior, and medial frontal gyri, as well as the superior temporal gyri. Conclusions. Even if based on a single case study, these preliminary results show functional changes at the cerebral level that seem to support the patient's behavioural improvements.

Performance of Verbal Fluency as an Endophenotype in Patients with Familial versus Sporadic Schizophrenia and Their Parents

What’s the neurocognitive deficit as an endophenotype to familial schizophrenia? Here, we investigate the neurocognitive endophenotype in first-episode patients with familial schizophrenia (FS) and sporadic schizophrenia (SS), and their parents. 98 FS patients and their 105 parents; 190 SS patients and their 207 parents; 195 controls matched with patients, and 190 controls matched with the patients’ parents, were assessed with the short version of the Wechsler Adult Intelligence Scale-Revised in China (WAIS-RC), the immediate and delayed logical memory tests from the Wechsler Memory Scale-Revised in China (WMS-RC), the Verbal Fluency Test (VFT), the Trail Making Test Parts A and B-Modified (TMA, TMB-M), and the Modified Wisconsin Card Sorting Test (WCST-M). The results showed that with age, gender, and education as covariates, after controlling for false discovery rates, the FS group and their parent group performed worse than the SS group and their parent group on VFT. No significant differences were found for other neurocognitive tests between the FS and SS patient groups, and their respective parent groups. Our findings suggest the patients with familial and sporadic schizophrenia and their respective parent groups may have a different genetic predisposition in relation to a cognitive endophenotype.

Theory of mind in adolescents with early-onset schizophrenia: correlations with clinical assessment and executive functions

OBJECTIVE

We examined Theory of Mind (ToM) abilities in adolescents with early-onset schizophrenia (EOS) and their correlation with clinical findings and Executive Functions (EF).

METHODS

The ToM abilities of 12 adolescents with EOS were compared with those of healthy participants matched in age and educational level. The Moving Shapes Paradigm was used to explore ToM abilities in three modalities: random movement, goal-directed movement and ToM - scored on the dimensions of intentionality, appropriateness and length of each answer. EF was tested using Davidson's Battery and the clinical psychopathology with the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Adolescents with EOS were significantly more impaired than controls in the three dimensions evaluated for the goal-directed and ToM modalities. Regarding the random movement modality, the only difference was in appropriateness (p<0.01). No correlation with age or level of education was evident for ToM skills. Total PANSS score was negatively correlated with appropriateness score for the goal-directed (p=0.02) and ToM modalities (p=0.01). No correlation existed between performance in the ToM Animated Tasks and positive, negative or disorganisation PANSS subscores. No correlations were found among the three scores in the Moving Shapes Paradigm and any measures of the accuracy of the three tasks assessing EF.

CONCLUSION

Our results confirm previous findings of ToM deficits in adult individuals with schizophrenia and attest the severity of these deficits in patients with EOS.

The erotetic theory of delusional thinking

INTRODUCTION

In this paper, we argue for a novel account of one cognitive factor implicated in delusional cognition. According to the erotetic theory of delusion we present, the central cognitive factor in delusion is impaired endogenous question raising.

METHOD

After presenting the erotetic theory, we draw on it to model three distinct patterns of reasoning exhibited by delusional and schizophrenic patients, and contrast our explanations with Bayesian alternatives.

RESULTS

We argue that the erotetic theory has considerable advantages over Bayesian models. Specifically, we show that it offers a superior explanation of three phenomena: the onset and persistence of the Capgras delusion; recent data indicating that schizophrenic subjects manifest superior reasoning with conditionals in certain contexts; and evidence that schizophrenic and delusional subjects have a tendency to "jump to conclusions." Moreover, since the cognitive mechanisms we appeal to are independently motivated, we avoid having to posit distinct epistemic states that are intrinsically irrational in order to fit our model to the variety of data.

CONCLUSION

In contrast to Bayesian models, the erotetic theory offers a simple, unified explanation of a range of empirical data. We therefore conclude that it offers a more plausible framework for explaining delusional cognition.

Patients with bipolar disorder show differential executive dysfunctions: A case-control study

Executive deficits in euthymic bipolar I disorder were examined in a fractionated manner based on the "Supervisory Attentional System" (SAS) model, and the relationship between the degree of executive impairment and the demographic and clinical characteristics of bipolar I participants was explored. A battery of neurocognitive tests capturing specific components of executive function was administered on 30 patients with bipolar I disorder in euthymic state, and compared with 30 healthy controls who were matched by age, gender and IQ. A differential impairment in executive function was demonstrated in euthymic bipolar I participants by using a fractionated approach of the SAS. Euthymic bipolar I patients were found to have significantly poorer performance in immediate and delayed visual memory; and in the executive domains of "initiation", "sustained attention", and "attention allocation and planning". Those with a greater number of executive impairments had lower IQ and higher negative sub-scores on PANSS. These findings might provide a the basis for further studies on identifying the executive components that are associated with particular disease characteristics of bipolar disorder, and those with poorer functional outcome, so that rehabilitation can be focused on the selective domains concerned.

Application of the Audio Recorded Cognitive Screen and its relation to functioning in schizophrenia

OBJECTIVE

This study investigated the ability of the Audio Recorded Cognitive Screen (ARCS) to detect cognitive deficit in individuals with schizophrenia, relative to the Mini Mental State Examination (MMSE) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and explored the associations between the ARCS and functional outcomes. We hypothesised that the ARCS would be able to better discriminate between individuals with schizophrenia and healthy controls than the MMSE, and that ARCS performance would be correlated with measures of social and vocational functioning.

METHODS

The participants were 19 community-dwelling individuals with schizophrenia or schizoaffective disorder and 19 healthy controls recruited from the Australian Schizophrenia Research Bank (ASRB). Participants completed the ARCS, MMSE, and self-report measures of social and vocational functioning. Clinical and diagnostic data stored by the ASRB were also utilised.

RESULTS

The schizophrenia group performed worse than the control group on the ARCS, with memory, t(36)=2.49, p=0.02, 95% CI [-1.84, -18.79] and fluency, t(36)=2.40, p=0.02, 95% CI [-1.87, -22.24] domains being the main discriminating measures. The RBANS also discriminated between the two groups, and ARCS and RBANS total scores were moderately to strongly correlated. There was no difference between the two groups on the MMSE after controlling for demographic variables. ARCS performance was associated with employment status [χ2(1)=7.16, p=0.007].

CONCLUSION

The ARCS may be sensitive to the cognitive deficits in outpatients with schizophrenia and an indicator of functional outcomes in this population.

Theory of mind impairments in patients with first-episode schizophrenia and their unaffected siblings

BACKGROUND

Theory of mind (ToM) impairment has been consistently demonstrated in patients with schizophrenia, but whether ToM impairments exist in unaffected siblings of patients with schizophrenia remains unclear. Few studies have examined the affective and cognitive components of ToM in schizophrenia. This study aimed to examine whether ToM impairments exist in patients with first-episode schizophrenia and their unaffected siblings, and whether there is any dissociation between the affective and cognitive components of ToM.

METHOD

We adopted a family-based case-control design. Participants were 41 patients with first-episode schizophrenia, 43 unaffected siblings, and 42 healthy controls. The Yoni Task which measures the participants' ability to understand first- and second-order affective versus cognitive ToM and the Faux Pas Task which taps into integration of the affective and cognitive components of ToM were administered. Multivariate and univariate ANCOVAs were used to examine the group differences in ToM, while controlling for other neurocognitive functions.

RESULTS

Compared with controls, patients with schizophrenia and their unaffected siblings performed poorer on the Faux Pas Task (p<0.001), with siblings having intermediate performance between patients and controls. Patients with schizophrenia performed worse than controls on second-order affective condition of the Yoni Task (p=0.004), but their unaffected siblings did not (p=0.063). We did not find any significant Group-by-Condition interaction in the Yoni Task (p=0.358).

CONCLUSION

Patients with first-episode schizophrenia and their unaffected siblings exhibit ToM impairments, but no dissociation between affective and cognitive component of ToM was found. Our findings support the notion that ToM deficit may be a trait marker of schizophrenia.

Executive function as predictors of persistent thought disorder in first-episode schizophrenia: a one-year follow-up study

Language disorganization is an important clinical indicator of acute psychosis, yet the longitudinal course and pathogenesis are not well understood. Executive dysfunction has been suggested as a vital contributor to formal thought disorder (FTD) and may serve as a stable predictor of symptomatic risk. The paper reports a one-year prospective study of language disorganization in sixty patients with first-episode schizophrenia-spectrum disorders and investigates executive function as a predictor of persistent FTD one year after illness onset. FTD was captured using the Clinical Language Disorder Rating Scale (CLANG), which segregates language abnormalities into three empirically validated levels: syntactic, semantic, and production. After one year, patients' syntactic and semantic deficits were substantially reduced, but production impairments persisted. Patients' improvement of semantic impairment was associated with reduced disorganized symptoms while production impairment was associated with negative symptoms. We further identified two different patterns of baseline executive function predictors for both residual semantic and production impairment. We found that sustained FTD at the semantic level was predicted by both sustained attention and planning at illness onset, while residual production failure was only predicted by sustained attention. In conclusion, the present paper documents the distinct characteristics of psycholinguistic levels in FTD and isolates two different patterns of executive function predictors for persistent semantic and production language disorganization at follow-up. The findings help to disentangle FTD dimensions at different levels of language production processes, which provide clinical implications for targeting patients at risk for prolonged FTD concordant upon executive dysfunction at illness onset.

Meta-analysis of cognitive performance in drug-naïve patients with schizophrenia

Cognitive deficits represent a significant characteristic of schizophrenia. However, a majority of the clinical studies have been conducted in antipsychotic drug treated patients. Thus, it remains unclear if significant cognitive impairments exist in the absence of medication. This is the first meta-analysis of cognitive findings in drug-naïve patients with schizophrenia. Cognitive data from 23 studies encompassing 1106 patients and 1385 controls published from 1992 to 2013 were included. Tests were to a large extent ordered in cognitive domains according to the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) battery. Analysis was performed with STATA using the random-effects model and heterogeneity as well as Egger's publication bias was assessed. Overall the results show that patients performed worse than healthy controls in all cognitive domains with medium to large effect sizes. Verbal memory, speed of processing and working memory were three of the domains with the greatest impairments. The pattern of results is in line with previous meta-analytic findings in antipsychotic treated patients. The present meta-analysis confirms the existence of significant cognitive impairments at the early stage of the illness in the absence of antipsychotic medication.

INECO Frontal Screening: an Instrument to assess Executive Dysfunction in Schizophrenia

Although several brief sensitive screening tools are available to detect executive dysfunction, few have been developed to quickly assess executive functioning. The INECO Frontal Screening (IFS) is a brief tool which has proved be useful for the assessment of the executive functions in patients with dementia. The aim of this study was to explore whether the IFS is as sensitive and specific as the BADS, a battery designed to assess the dysexecutive syndrome, in schizophrenia. Our sample comprised a group of 34 schizophrenic patients (Mean age = 39.59, DP = 10.697) and 31 healthy controls (Mean age = 35.52, DP = 10.211). To all groups were administered the BADS, Wisconsin Card Sorting Test and IFS. The results suggest that schizophrenic patients performed significantly worse than the control group in all tests (p < .05). The IFS total score was 13.29 for the experimental group and 26.21 for the control group (p < .001). Considering a cut-off of 14 points, the IFS sensitivity was 100% and specificity 56% in detection of executive dysfunction in schizophrenia, compared with the BADS, that if we consider a cut-off of 11 points, was a sensitivity of 100% and a specificity of 50%. Thus, IFS is a brief, sensitive and specific tool for the detection of executive dysfunction in schizophrenia.

The relationship between executive functions and fluid intelligence in schizophrenia

An enduring question is unity vs. separability of executive deficits resulting from impaired frontal lobe function. In previous studies, we have asked how executive deficits link to a conventional measure of fluid intelligence, obtained either by standard tests of novel problem-solving, or by averaging performance in a battery of novel tasks. For some classical executive tasks, such as the Wisconsin Card Sorting Test (WCST), Verbal Fluency, and Trail Making Test B (TMTB), frontal deficits are entirely explained by fluid intelligence. However, on a second set of executive tasks, including tests of multitasking and decision making, deficits exceed those predicted by fluid intelligence loss. In this paper we discuss how these results shed light on the diverse clinical phenomenology observed in frontal dysfunction, and present new data on a group of 15 schizophrenic patients and 14 controls. Subjects were assessed with a range of executive tests and with a general cognitive battery used to derive a measure of fluid intelligence. Group performance was compared and fluid intelligence was introduced as a covariate. In line with our previous results, significant patient-control differences in classical executive tests were removed when fluid intelligence was introduced as a covariate. However, for tests of multitasking and decision making, deficits remained. We relate our findings to those of previous factor analytic studies describing a single principal component, which accounts for much of the variance of schizophrenic patients' cognitive performance. We propose that this general factor reflects low fluid intelligence capacity, which accounts for much but not all cognitive impairment in this patient group. Partialling out the general effects of fluid intelligence, we propose, may clarify the role of additional, more specific cognitive impairments in conditions such as schizophrenia.

Motor function deficits in schizophrenia: an fMRI and VBM study

INTRODUCTION

To investigate whether the motor functional alterations in schizophrenia (SZ) are also associated with structural changes in the related brain areas using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM).

METHODS

A sample of 14 right-handed SZ patients and 14 right-handed healthy control subjects matched for age, sex, and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during right index finger-tapping task in the same session.

RESULTS

fMRI results showed reduced functional activation in the motor areas (contralateral precentral and postcentral gyrus) and ipsilateral cerebellum in SZ subjects as compared to healthy controls (n = 14). VBM analysis also revealed reduced grey matter in motor areas and white matter reduction in cerebellum of SZ subjects as compared to controls.

CONCLUSION

The present study provides an evidence for a possible association between structural alterations in the motor cortex and disturbed functional activation in the motor areas in persons affected with SZ during a simple finger-tapping task.

A systematic review of cognitive function in first-episode psychosis, including a discussion on childhood trauma, stress, and inflammation

OBJECTIVE

To carry out a systematic review of the literature addressing cognitive functions in first-episode psychosis (FEP), divided into domains. Although this is not a full "cognitive-genetics-in-schizophrenia review," we will also include putative ideas of mechanism(s) behind these impairments, focusing on how early stress, and genetic vulnerability may moderate cognitive function in psychosis.

METHOD

Relevant studies were identified via computer literature searches for research published up to and including January 2013, only case-control studies were included for the neurocognitive meta-analysis.

RESULTS

Patients with FEP present global cognitive impairment compared to healthy controls. The largest effect size was observed for verbal memory (Cohen's d effect size = 2.10), followed by executive function (effect size = 1.86), and general IQ (effect size = 1.71). However, effect sizes varied between studies.

CONCLUSION

Cognitive impairment across domains, up to severe level based on Cohen's effect size, is present already in FEP studies. However, differences in levels of impairment are observed between studies, as well as within domains, indicating that further consolidation of cognitive impairment over the course of illness may be present. Cognitive abnormalities may be linked to a neurodevelopmental model including increased sensitivity to the negative effect of stress, as well as genetic vulnerability. More research on this field is needed.

Sensitivity, specificity and predictive value of the BADS to anterior executive dysfunction

In this study we investigated the validity of the BADS subtests to adequately discriminate anterior lesions (AL) from posterior lesions (PL). Therefore, we compared the performances of 30 AL patients, 22 PL patients and 29 healthy controls (HC) on the BADS subtests. Seven standard executive test variables were also examined. Our multiple comparisons showed that the BADS Zoo Map-Part 1 was not indicative for AL, whereas Rule Shifting, Action Programme, Key Search, Zoo Map-total score, and BADS-total score were found to be sensitive to AL. More importantly, the Modified Six Element Test (MSET), and the Zoo Map-Part 2 were highly specific for AL. In both BADS subtests AL patients performed significantly worse than either the PL or the HC groups, whereas no significant differences on the same variables were found between PL and HC individuals. Further logistic regression analysis revealed that the BADSMSET was the best predictor for distinguishing AL from PL patients, correctly classifying 78.8% of the patients. These results suggest that the BADSMSET is an accurate screening tool for the detection of anterior pathology. Poor performance on this BADS subtest is a significant indicator of executive dysfunctioning after anterior brain damage.

Gait control and executive dysfunction in early schizophrenia

Dysexecutive functioning, which is described as an enduring core feature of schizophrenia, has been associated with gait disorders. However, few studies have reported gait disorders in schizophrenia patients. The objective of this study was to examine the association between executive dysfunction and gait performance in recent-onset schizophrenia patients using the dual task paradigm. Thirty-two subjects participated to the study: 17 with recent-onset schizophrenia and 15 healthy age-matched controls. Executive functions were evaluated using the Frontal Assessment Battery, Stroop and Trail-Making tests. Mean values and coefficients of variation (CV) of the temporal gait parameters while single tasking (just walking) and while dual tasking (walking and forward counting, walking and backward counting, walking and verbal fluency) were measured using the SMTEC(®)-footswitch system. We focused on the CV of stride time as this measure has been shown to be the most representative parameter of higher gait control. A strong effect of the stride time was found in the group factor for the verbal fluency dual-task when compared to controls (Cohen's d mean = 1.28 and CV = 1.05). The effect was lower in the other dual tasks, and insignificant in the single task of walking. This study shows that patients exhibit higher stride-to-stride variability while dual tasking than controls. It also shows a stronger impact of verbal fluency on gait regularity compared to the other dual tasks revealing a relationship between the executive dysfunction and gait modification. Those results are in line with the idea that schizophrenia implies not only cognitive but also motor functioning and coordination impairment.

Ten year neurocognitive trajectories in first-episode psychosis

Objective: Neurocognitive impairment is commonly reported at onset of psychotic disorders. However, the long-term neurocognitive course remains largely uninvestigated in first episode psychosis (FEP) and the relationship to clinically significant subgroups even more so. We report 10 year longitudinal neurocognitive development in a sample of FEP patients, and explore whether the trajectories of cognitive course are related to presence of relapse to psychosis, especially within the first year, with a focus on the course of verbal memory.

Method: Forty-three FEP subjects (51% male, 28 ± 9 years) were followed-up neurocognitively over five assessments spanning 10 years. The test battery was divided into four neurocognitive indices; Executive Function, Verbal Learning, Motor Speed, and Verbal Fluency. The sample was grouped into those relapsing or not within the first, second and fifth year.

Results: The four neurocognitive indices showed overall stability over the 10 year period. Significant relapse by index interactions were found for all indices except Executive Function. Follow-up analyses identified a larger significant decrease over time for the encoding measure within Verbal Memory for patients with psychotic relapse in the first year [F_{(4, 38)} = 5.8, p = 0.001, η² = 0.40].

Conclusions: Main findings are long-term stability in neurocognitive functioning in FEP patients, with the exception of verbal memory in patients with psychotic relapse or non-remission early in the course of illness. We conclude that worsening of specific parts of cognitive function may be expected for patients with on-going psychosis, but that the majority of patients do not show significant change in cognitive performance during the first 10 years after being diagnosed.

Impact of peripheral levels of chemokines, BDNF and oxidative markers on cognition in individuals with schizophrenia

OBJECTIVE

To investigate possible differences in peripheral levels of chemokines, BDNF and oxidative markers between patients with Schizophrenia (SZ) and matched healthy controls, and investigate the correlation of these biomarkers with cognitive performance.

METHODS

Thirty individuals with SZ and 27 healthy controls were included and the following plasmatic biomarkers' levels were determined according to manufacturers' instructions: BDNF, TBARS, protein carbonyl content (PCC) and the chemokines CXCL-10/IP-10, CXCL-8/IL-8, CCL-11, CCL-24/Eotaxin-2, CCL-2/MCP-1, CCL-3/MIP-1. Selected neuropsychological tasks were administered to assess verbal learning (Hopkins Verbal Learning Test), verbal fluency (FAS test), working memory (Visual Working Memory Task, Keep Track Task, Letter Memory Task), set shifting (Plus-minus task, Number-letter task), inhibition (Computerized Stroop Task, Semantic Generation Task) and complex executive function tasks (Tower of London and the shortened version of the WCST-64).

RESULTS

Compared with the healthy control group, individuals with SZ presented significantly higher levels of BDNF and the chemokine CCL-11, and lower levels of TBARS and the chemokine CXCL-10/IP-10. When we examined only the SZ group, BDNF levels were positively correlated with semantic generation tasks. Working memory ability was negatively correlated with PCC. Regarding chemokines, CCL-11 was negatively correlated to performance in working memory test, and positively correlated with cognitive flexibility task. CXCL-8/IL-8 was positively correlated with verbal fluency. CCL-24/Eotaxin-2 was positively correlated with semantic generation ability and letter memory task.

CONCLUSIONS

Our results indicate that cognitive performance in SZ is associated with mediators of neuroplasticity that can be measured peripherally.

Patients with bipolar disorders share similar but attenuated prospective memory impairments with patients with schizophrenia

BACKGROUND

Prospective memory (PM) refers to the ability to remember to carry out an intended action in the future. PM is consistently found to be impaired in individuals with schizophrenia. Bipolar disorder and schizophrenia may represent conditions along a continuum, and share similar neurocognitive and genetic architecture. This study aimed to compare the nature and extent of PM impairment in individuals with schizophrenia and bipolar disorder.

METHOD

Participants were 38 out-patients with schizophrenia and 40 out-patients with bipolar disorder in an early psychosis intervention programme, and 37 healthy controls. Time-, event- and activity-based PMs were assessed using a dual-task laboratory paradigm. Self-reported PM performance was gauged using the Prospective and Retrospective Memory Questionnaire. Analysis of covariance (ANCOVA), with intelligence quotient (IQ) and education included as covariates, was used to examine group difference on various types of PM. Repeated measures of ANCOVA were used to examine the group × PM type interaction effect. Correspondence between laboratory and self-reported PM measures was examined using correlational analysis.

RESULTS

The group × PM type interaction effect was not significant, but the main effect of group was significant. Patients with schizophrenia and patients with bipolar disorder both performed more poorly than healthy participants in PM. The two clinical groups did not significantly differ in PM. Laboratory and self-reported PM measures did not correlate significantly with each other.

CONCLUSIONS

Patients with bipolar disorder shared a similar PM impairment with those with schizophrenia. Findings of this study extended the similarity in neurocognitive impairments between the two psychiatric disorders to PM.

Prospective memory performance in patients with drug-naïve, first-episode psychosis

Schizophrenia is associated with an impairment of prospective memory (PM) which refers to the ability to remember to carry out an intended action in the future. However, most of these studies were limited to chronic samples. The current study examined the event-based PM and time-based PM using a dual-task paradigm in 22 drug-naïve, first-episode psychosis (FEP) patients and 23 healthy controls. Results indicated that FEP patients performed significantly poorer than healthy controls in both event-based and time-based PM. However, the significant difference in time-based PM disappeared after controlling for working memory. Correlation analysis indicated that both types of PM did not correlate with positive symptoms or negative symptoms, duration of illness, or duration of untreated psychosis. However, time-based PM was correlated with the general psychopathology subscale of the PANSS. Taken together, these findings suggest that PM deficits are present in drug-naïve FEP patients; impairment of event-based PM appears to occur independently, whereas time-based PM impairment may be, in part, a secondary consequence of a working memory deficit.

Executive functioning in schizophrenia spectrum disorder patients and their unaffected siblings: a ten-year follow-up study

Executive dysfunction represents a core deficit that is associated with schizophrenia spectrum disorders (SSDs). However, the longitudinal course of executive deficits in SSDs is still controversial. The aim of this study was to examine the executive performance of 34 SSD patients in relation to 34 of their unaffected siblings over a period of 10 years. Both groups completed psychopathological and executive assessments. Thirteen healthy controls were assessed using the same instruments. At baseline, the SSD patients differed significantly from siblings and controls in their performance on the Trail Making Test-B (TMT-B) and the number of categories in which they succeeded in the Wisconsin Card Sorting Test (WCST). They also differed significantly from the controls in the total number of errors in the WCST. The siblings did not differ in executive functioning from the controls over the follow-up. Longitudinally, the patients demonstrated significant improvement only for the TMT-B. However, only 14.71% of the patients showed reliable and clinically significant improvements for the TMT-B, and 8.82% made more errors on the WCST at the follow-up evaluation. Less than 3% of the patients showed either improved or worse results on the remaining measures of the WCST. A stabilisation pattern for the WCST was observed in the three groups. The patients performed worse than their siblings and controls on both executive tests. Some patients exhibited significant improvements in the TMT-B over time, but this improvement was reliable and clinically significant for less than 15% of the sample. Thus, we conclude that the patients exhibited stable impairments over time in the executive functions assessed.