Computerized assessment of cognition in schizophrenia: Promises and pitfalls of CANTAB

Exercise Leads to Better Clinical Outcomes in Those Receiving Medication Plus Cognitive Behavioral Therapy for Major Depressive Disorder

OBJECTIVE

The aim of this study is to investigate the effects of exercise as an add-on therapy with antidepressant medication and cognitive behavioral group therapy (CBGT) on treatment outcomes in low-active major depressive disorder (MDD) patients. We also explored whether exercise reduces the residual symptoms of depression, notably cognitive impairment and poor sleep quality, and aimed to identify putative biochemical markers related to treatment response.

METHODS

Sixteen low-active MDD patients were recruited from a mental health day treatment program at a local hospital. Eight medicated patients performed an 8-week exercise intervention in addition to CBGT, and eight medicated patients attended the CBGT only. Twenty-two low-active, healthy participants with no history of mental health illness were also recruited to provide normal healthy values for comparison.

RESULTS

Results showed that exercise resulted in greater reduction in depression symptoms (p = 0.007, d = 2.06), with 75% of the patients showing either a therapeutic response or a complete remission of symptoms vs. 25% of those who did not exercise. In addition, exercise was associated with greater improvements in sleep quality (p = 0.046, d = 1.28) and cognitive function (p = 0.046, d = 1.08). The exercise group also had a significant increase in plasma brain-derived neurotrophic factor (BDNF), p = 0.003, d = 6.46, that was associated with improvements in depression scores (p = 0.002, R² = 0.50) and sleep quality (p = 0.011, R² = 0.38).

CONCLUSION

We provide evidence that exercise as an add-on to conventional antidepressant therapies improved the efficacy of standard treatment interventions. Our results suggest that plasma BDNF levels and sleep quality appear to be good indicators of treatment response and potential biomarkers associated with the clinical recovery of MDD.

Attentional set-shifting and social abilities in children with schizotypal and comorbid autism spectrum disorders

OBJECTIVE

While diagnostically independent, autism and schizotypal disorders can co-occur. Their concurrent impact on outcomes and phenotypes has not been investigated. We investigated the impact of comorbid autism and schizotypal disorders in children on executive functioning and socio-pragmatic skills - core features of both disorders.

METHOD

Executive functioning (assessed with the Cambridge Neuropsychological Test Automated Battery) and socio-pragmatic skills (assessed using the Melbourne Assessment of Schizotypy in Kids) were investigated in a total of 67 (6-12 year old) children with autism ( n = 15; M/F = 10/5), schizotypal disorder ( n = 8; M/F = 5/3) and comorbid autism and schizotypal disorder ( n = 12; M/F = 5/7) and typically developing children ( n = 32; M/F = 17/15).

RESULTS

Both the autism and schizotypal disorder groups performed more poorly than the typically developing group on socio-pragmatic skills and overall performance (i.e. number of stages completed) of the intra-/extra-dimensional set-shifting task (all ps < 0.001). Clear distinctions between the autism and schizotypal groups were present in the intra-/extra-dimensional task relative to the typically developing group - the autism group had difficulties with extra-dimensional shifts ( p < 0.001), and the schizotypal disorder group with intra-dimensional shifts ( p = 0.08). Interestingly, the overall performance of the comorbid group on the intra-/extra-dimensional task was not significantly different from the typically developing group, and they were superior to both the autism ( p = 0.019) and schizotypal disorder ( p = 0.042) groups on socio-pragmatic skills.

CONCLUSION

The phenotypical overlap between autism and schizotypal disorders may be precipitated by different cognitive styles and/or mechanisms associated with attention and information processing. We propose that sustaining and switching attention represent two poles of irregularities across the autism and schizotypal spectra, which appear to converge in a compensatory manner in the comorbid group. Our findings highlight the importance of investigating children with a dual diagnosis of autism and schizotypal disorders, and raise intriguing questions about possible mechanisms to explain the attenuated impairment observed in the group of children with comorbid autism and schizotpyal disorders.

Minocycline as adjunct therapy for a male patient with deficit schizophrenia

The pathophysiology of schizophrenia may involve increased production of inflammatory cytokines by activated microglia. Minocycline can inhibit activated microglia and may improve secondary negative symptoms and/or cognitive functions when used as adjuvant to antipsychotics. Effects on minocycline on primary and enduring negative symptoms in deficit schizophrenia (DS) are unknown. We present a male patient with a 3-year history of DS. He was treated for 12 weeks with risperidone at a maximal dose of 6 mg per day, then for 10 weeks with olanzapine at 20 mg per day. Symptoms did not improve, and body mass index increased from 20.41 to 22.84 kg/m². Serum levels of several inflammatory cytokines were elevated, so we prescribed minocycline as adjunct to aripiprazole for 12 weeks. Negative symptoms and cognitive impairment improved, and serum levels of inflammatory cytokines decreased. Our case suggests that clinicians may consider minocycline as adjunct therapy to antipsychotics in patients with DS with elevated serum levels of inflammatory cytokines. This highlights the need for further research into possible relationships of minocycline with negative symptoms and cognitive function in patients with DS.

Passive Double-Sensory Evoked Coherence Correlates with Long-Term Memory Capacity

HIGHLIGHTS Memory correlates with the difference between single and double-sensory evoked steady-state coherence in the gamma range (ΔC).The correlation is most pronounced for the anterior brain region (ΔC_A ).The correlation is not driven by birth size, education, speed of processing, or intelligence.The sensitivity of ΔC_A for detecting low memory capacity is 90%. Cerebral rhythmic activity and oscillations are important pathways of communication between cortical cell assemblies and may be key factors in memory. We asked whether memory performance is related to gamma coherence in a non-task sensory steady-state stimulation. We investigated 40 healthy males born in 1953 who were part of a Danish birth cohort study. Coherence was measured in the gamma range in response to a single-sensory visual stimulation (36 Hz) and a double-sensory combined audiovisual stimulation (auditive: 40 Hz; visual: 36 Hz). The individual difference in coherence (ΔC) between the bimodal and monomodal stimulation was calculated for each subject and used as the main explanatory variable. ΔC in total brain were significantly negatively correlated with long-term verbal recall. This correlation was pronounced for the anterior region. In addition, the correlation between ΔC and long-term memory was robust when controlling for working memory, as well as a wide range of potentially confounding factors, including intelligence, length of education, speed of processing, visual attention and executive function. Moreover, we found that the difference in anterior coherence (ΔC_A ) is a better predictor of memory than power in multivariate models. The sensitivity of ΔC_A for detecting low memory capacity is 92%. Finally, ΔC_A was also associated with other types of memory: verbal learning, visual recognition, and spatial memory, and these additional correlations were also robust enough to control for a range of potentially confounding factors. Thus, the ΔC is a predictor of memory performance may be useful in cognitive neuropsychological testing.

Neurocognitive Graphs of First-Episode Schizophrenia and Major Depression Based on Cognitive Features

Neurocognitive deficits are frequently observed in patients with schizophrenia and major depressive disorder (MDD). The relations between cognitive features may be represented by neurocognitive graphs based on cognitive features, modeled as Gaussian Markov random fields. However, it is unclear whether it is possible to differentiate between phenotypic patterns associated with the differential diagnosis of schizophrenia and depression using this neurocognitive graph approach. In this study, we enrolled 215 first-episode patients with schizophrenia (FES), 125 with MDD, and 237 demographically-matched healthy controls (HCs). The cognitive performance of all participants was evaluated using a battery of neurocognitive tests. The graphical LASSO model was trained with a one-vs-one scenario to learn the conditional independent structure of neurocognitive features of each group. Participants in the holdout dataset were classified into different groups with the highest likelihood. A partial correlation matrix was transformed from the graphical model to further explore the neurocognitive graph for each group. The classification approach identified the diagnostic class for individuals with an average accuracy of 73.41% for FES vs HC, 67.07% for MDD vs HC, and 59.48% for FES vs MDD. Both of the neurocognitive graphs for FES and MDD had more connections and higher node centrality than those for HC. The neurocognitive graph for FES was less sparse and had more connections than that for MDD. Thus, neurocognitive graphs based on cognitive features are promising for describing endophenotypes that may discriminate schizophrenia from depression.

The effect of the muscarinic M1 receptor antagonist biperiden on cognition in medication free subjects with psychosis

The acetylcholine muscarinic M₁ receptor has been implicated in both psychosis and cognition. Post-mortem research has shown reduced muscarinic M₁ receptor density in 25% of chronic patients with schizophrenia. It is unknown whether reduced M₁ receptor density is related to cognitive symptoms of psychosis. We investigated the role of the M₁ receptor in separate cognitive domains in subjects with a psychotic disorder using a muscarinic M₁ antagonist as an acute pharmacological challenge. 33 young subjects with a psychotic disorder and 30 gender, age and IQ matched healthy controls were enrolled. All participants completed a comprehensive cognitive test battery twice: once after placebo and once after oral administration of 4mg. biperiden (M₁ antagonist). The order of drug administration was counterbalanced. Biperiden significantly negatively influenced both verbal (p< 0.001 and p=0.032) and visual learning and memory (p=0.028) in both groups. A medication x group interaction effect was found for reasoning and problem solving (p=0.005). No main or interaction effects were found for other cognitive domains. These results provide further in-vivo evidence that the M₁ receptor is involved in cognitive functioning, particularly verbal and visual memory processes. Lack of differential effects of biperiden between psychotic subjects and healthy controls may suggest that decreased M₁ receptor density is only present in chronic, older schizophrenia patients. However, it remains possible that differential effects of biperiden would be present in more severe cognitive impaired subjects with psychosis after several doses of biperiden instead of a single administration.

Two subgroups of antipsychotic-naive, first-episode schizophrenia patients identified with a Gaussian mixture model on cognition and electrophysiology

Deficits in information processing and cognition are among the most robust findings in schizophrenia patients. Previous efforts to translate group-level deficits into clinically relevant and individualized information have, however, been non-successful, which is possibly explained by biologically different disease subgroups. We applied machine learning algorithms on measures of electrophysiology and cognition to identify potential subgroups of schizophrenia. Next, we explored subgroup differences regarding treatment response. Sixty-six antipsychotic-naive first-episode schizophrenia patients and sixty-five healthy controls underwent extensive electrophysiological and neurocognitive test batteries. Patients were assessed on the Positive and Negative Syndrome Scale (PANSS) before and after 6 weeks of monotherapy with the relatively selective D₂ receptor antagonist, amisulpride (280.3±159 mg per day). A reduced principal component space based on 19 electrophysiological variables and 26 cognitive variables was used as input for a Gaussian mixture model to identify subgroups of patients. With support vector machines, we explored the relation between PANSS subscores and the identified subgroups. We identified two statistically distinct subgroups of patients. We found no significant baseline psychopathological differences between these subgroups, but the effect of treatment in the groups was predicted with an accuracy of 74.3% (P=0.003). In conclusion, electrophysiology and cognition data may be used to classify subgroups of schizophrenia patients. The two distinct subgroups, which we identified, were psychopathologically inseparable before treatment, yet their response to dopaminergic blockade was predicted with significant accuracy. This proof of principle encourages further endeavors to apply data-driven, multivariate and multimodal models to facilitate progress from symptom-based psychiatry toward individualized treatment regimens.

Treatment-Resistant Schizophrenia: Treatment Response and Resistance in Psychosis (TRRIP) Working Group Consensus Guidelines on Diagnosis and Terminology

OBJECTIVE

Research and clinical translation in schizophrenia is limited by inconsistent definitions of treatment resistance and response. To address this issue, the authors evaluated current approaches and then developed consensus criteria and guidelines.

METHOD

A systematic review of randomized antipsychotic clinical trials in treatment-resistant schizophrenia was performed, and definitions of treatment resistance were extracted. Subsequently, consensus operationalized criteria were developed through 1) a multiphase, mixed methods approach, 2) identification of key criteria via an online survey, and 3) meetings to achieve consensus.

RESULTS

Of 2,808 studies identified, 42 met inclusion criteria. Of these, 21 studies (50%) did not provide operationalized criteria. In the remaining studies, criteria varied considerably, particularly regarding symptom severity, prior treatment duration, and antipsychotic dosage thresholds; only two studies (5%) utilized the same criteria. The consensus group identified minimum and optimal criteria, employing the following principles: 1) current symptoms of a minimum duration and severity determined by a standardized rating scale; 2) moderate or worse functional impairment; 3) prior treatment consisting of at least two different antipsychotic trials, each for a minimum duration and dosage; 4) systematic monitoring of adherence and meeting of minimum adherence criteria; 5) ideally at least one prospective treatment trial; and 6) criteria that clearly separate responsive from treatment-resistant patients.

CONCLUSIONS

There is considerable variation in current approaches to defining treatment resistance in schizophrenia. The authors present consensus guidelines that operationalize criteria for determining and reporting treatment resistance, adequate treatment, and treatment response, providing a benchmark for research and clinical translation.

Adjunctive memantine in clozapine-treated refractory schizophrenia: an open-label 1-year extension study

BACKGROUND

In a recent placebo-controlled, double-blind crossover trial (n = 52), significant beneficial effects on memory (d = 0.30) and negative symptoms (d = 0.29) were found after 12 weeks of memantine augmentation in patients with clozapine-refractory schizophrenia. In this open-label 1-year extension study we report the long-term effects and tolerability of memantine add-on therapy to clozapine.

METHOD

Completers of the first trial who experienced beneficial effects during 12 weeks of memantine treatment received memantine for 1 year. Primary endpoints were memory and executive function using the Cambridge Neuropsychological Test Automated Battery, the Positive and Negative Syndrome Scale (PANSS), and the Clinical Global Impression Severity Scale (CGI-S).

RESULTS

Of 31 randomized controlled trial completers who experienced beneficial effects from memantine, 24 received memantine for 1 year. The small improvement in memory found in the memantine condition in the placebo-controlled trial remained stable in the extension study. Executive function did not improve. After 26 weeks of memantine add-on therapy to clozapine, PANSS negative symptoms (r = 0.53), PANSS positive symptoms (r = 0.50) and PANSS total symptoms (r = 0.54) significantly improved. Even further significant improvement in all these measures was observed between 26 weeks and 52 weeks of memantine, with effect sizes varying from 0.39 to 0.51. CGI-S showed a non-significant moderate improvement at 26 weeks (r = 0.36) and 52 weeks (r = 0.34). Memantine was well tolerated without serious adverse effects.

CONCLUSIONS

In the 1-year extension phase the favourable effect of adjunctive memantine on memory was sustained and we observed further improvement of negative, positive and overall symptoms in patients with clozapine-treated refractory schizophrenia.

An optimal combination of MCCB and CANTAB to assess functional capacity in older individuals with schizophrenia

INTRODUCTION

Cognitive deficits predict functional capacity in patients with schizophrenia including in late life. The MATRICS Consensus Cognitive Battery (MCCB) and the Cambridge Neuropsychological Test Automated Battery (CANTAB) are widely used to assess cognition in this population. The aim of this study was to determine a minimal set of subtests across the two batteries that would be strongly associated with functional capacity in older patients with schizophrenia.

METHODS

Sixty participants age 50 years or older with a diagnosis of schizophrenia or schizoaffective disorder and 30 control participants were enrolled. Cognition was assessed using the MCCB and the CANTAB. Functional capacity was assessed using the USCD Performance-based Skills Assessment (UPSA). Stepwise linear regressions were performed to determine the best set of cognitive tests associated with functional capacity.

RESULTS

UPSA total score was negatively correlated with age and positively correlated with education and the MCCB global score. Most of the MCCB domains and subtests, and several of the CANTAB subtests correlated with UPSA total score. In the regression model, MCCB global score accounted for 42.5% of UPSA variance. In contrast, a combination of only four subtests (processing speed and verbal learning from the MCCB, and affective information processing and working memory from the CANTAB) accounted for 60% of UPSA variance.

CONCLUSIONS

Performance on MCCB and CANTAB is strongly associated with functional capacity in older patients with schizophrenia. A selective combination of MCCB and CANTAB subtests may be as effective in assessing functional capacity in late life schizophrenia. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Obsessive compulsive symptoms are associated with better functioning independently of cognition in schizophrenia

OBJECTIVES

Although the relationship of obsessive-compulsive symptoms (OCSs) with both cognition and social functioning (SF) has already been the focus of research in schizophrenia, the moderation of the relationship of OCSs with SF by cognition has not been explored to date. We investigated the association of OCSs with SF and its interaction with cognition in schizophrenia.

METHODS

We recruited 110 schizophrenia patients and assessed OCSs (Yale-Brown Scale), schizophrenia symptoms (Positive and Negative Syndrome Scale), SF (Strauss-Carpenter Scale) and cognition. 51 patients had one obsessive-compulsive symptom or more, whereas 59 patients had no obsessive compulsive-symptom, according to the Yale-Brown Scale. We mainly investigated: a) the predictive effect of OCSs on SF, controlling for cognition, illness duration and symptoms' severity and b) the moderating effect of cognition on the OCSs-SF relationship.

RESULTS

The mean score of OCSs for patients having at least one symptom was 13.43 (SD=8.32). Higher OCSs predicted increased SF (B=0.98, t=2.41, df=88, p=0.018). This relationship was driven by the association of compulsions with job functioning (B=0.074, t=2.029, df=88, p=0.046). Patients without OCSs demonstrated worse functioning compared with those having at least one obsessive-compulsive symptom (mean difference=2.496, t=3.732, df=88, p<0.001). We failed to find evidence that cognition moderates the effect of OCSs on SF.

CONCLUSION

There may be a beneficial effect of OCSs on SF in patients with schizophrenia which is independent of their cognitive performance.

Supervised multimodal fusion and its application in searching joint neuromarkers of working memory deficits in schizophrenia

Multimodal fusion is an effective approach to better understand brain disease. To date, most current fusion approaches are unsupervised; there is need for a multivariate method that can adopt prior information to guide multimodal fusion. Here we proposed a novel supervised fusion model, called "MCCAR+jICA", which enables both identification of multimodal co-alterations and linking the covarying brain regions with a specific reference signal, e.g., cognitive scores. The proposed method has been validated on both simulated and real human brain data. Features from 3 modalities (fMRI, sMRI, dMRI) obtained from 147 schizophrenia patients and 147 age-matched healthy controls were included as fusion input, who participated in the Function Biomedical Informatics Research Network (FBIRN) Phase III study. Our aim was to investigate the group co-alterations seen in three types of MRI data that are also correlated with working memory performance. One joint IC was found both significantly group-discriminating (p=7.4E-06, 0.001, 7.0E-09) and highly correlated with working memory scores(r=0.296, 0.241, 0.301) and PANSS negative scores (r=-0.229, -0.276, -0.240) for fMRI, dMRI and sMRI, respectively. Given the simulation and FBIRN results, MCCAR+jICA is shown to be an effective multivariate approach to extract accurate and stable multimodal components associated with a particular measure of interest, and promises a wide application in identifying potential neuromarkers for mental disorders.

Memantine augmentation in clozapine-refractory schizophrenia: a randomized, double-blind, placebo-controlled crossover study

BACKGROUND

Dysfunction of neuroplasticity due to N-methyl-d-aspartate (NMDA) receptor hypofunction may be a causal factor for memory and executive dysfunctioning in schizophrenia. Deregulation of NMDA transmission in the prefrontal cortex may also explain negative and positive symptoms. Clozapine augmentation with memantine targets altered NMDA receptor-mediated neurotransmission in schizophrenia and showed substantial beneficial effects on several symptom domains in a small proof-of-concept study. We evaluate effects of memantine add-on treatment to clozapine for memory and executive function, and negative and positive symptoms in schizophrenia.

METHOD

Clozapine-treated patients with refractory schizophrenia were randomly assigned to 12 weeks of double-blind adjunctive treatment with memantine (n = 26) or placebo (n = 26). Crossover occurred after a 2-week placebo wash-out period. Primary endpoints were change from baseline to 12 weeks treatment and 14 weeks to 26 weeks treatment on memory and executive function using the Cambridge Neuropsychological Test Automated Battery (CANTAB), Positive and Negative Syndrome Scale (PANSS), and Clinical Global Impression Severity Scale (CGI-S). Side effects were assessed using the Liverpool University Neuroleptic Side-Effect Rating Scale.

RESULTS

When compared with placebo, memantine improved a composite memory score comprising verbal recognition memory and paired associates learning task scores on the CANTAB (effect size = 0.30) and PANSS negative subscale score (effect size = 0.29). Side effects were mild and transient.

CONCLUSIONS

In patients with clozapine-treated refractory schizophrenia, memantine addition significantly improved verbal and visual memory and negative symptoms without serious adverse effects. These results justify further investigations on long-term memantine augmentation to clozapine in treatment-resistant schizophrenia.

Association of Cognitive Abilities and Brain Lateralization among Primary School Children in Kuwait

Background. Many studies have explored the cognitive variation between left- and right-handed individuals; however, the differences remain poorly understood. Aim of the Work. To assess the association between brain lateralization indicated by handedness and cognitive abilities. Material and Methods. A total of 217 students aged between 7 and 10 years of both genders were identified for the study. Males and females were equally distributed. All left-handed students were chosen. An equal group with right-handed students was randomly selected. Handedness was assessed using traditional writing hand approach as well as the WatHand Cabient Test and the Grooved Pegboard Test. Cognition was measured using Cambridge University's CANTAB eclipse cognitive battery. Pearson Correlation Coefficient Test “r” was calculated to measure the strength of association between quantitative data. Results. Right-handed children had superior visuospatial abilities (p = 0.011, r = 0.253), visual memory (p = 0.034, r = 0.205), and better scores in reaction time tests which incorporated elements of visual memory (p = 0.004, r = −0.271). Left-handed children proved to have better simple reaction times (p = 0.036, r = 0.201). Conclusion. Right-handed children had superior visuospatial abilities and left-handed children have better simple reaction times.

Individualized identification of euthymic bipolar disorder using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and machine learning

BACKGROUND

Previous studies have reported that patients with bipolar disorder (BD) present with cognitive impairments during mood episodes as well as euthymic phase. However, it is still unknown whether reported neurocognitive abnormalities can objectively identify individual BD patients from healthy controls (HC).

METHODS

A total of 21 euthymic BD patients and 21 demographically matched HC were included in the current study. Participants performed the computerized Cambridge Neurocognitive Test Automated Battery (CANTAB) to assess cognitive performance. The least absolute shrinkage selection operator (LASSO) machine learning algorithm was implemented to identify neurocognitive signatures to distinguish individual BD patients from HC.

RESULTS

The LASSO machine learning algorithm identified individual BD patients from HC with an accuracy of 71%, area under receiver operating characteristic curve of 0.7143 and significant at p=0.0053. The LASSO algorithm assigned individual subjects with a probability score (0-healthy, 1-patient). Patients with rapid cycling (RC) were assigned increased probability scores as compared to patients without RC. A multivariate pattern of neurocognitive abnormalities comprising of affective Go/No-go and the Cambridge gambling task was relevant in distinguishing individual patients from HC.

LIMITATIONS

Our study sample was small as we only considered euthymic BD patients and demographically matched HC.

CONCLUSION

Neurocognitive abnormalities can distinguish individual euthymic BD patients from HC with relatively high accuracy. In addition, patients with RC had more cognitive impairments compared to patients without RC. The predictive neurocognitive signature identified in the current study can potentially be used to provide individualized clinical inferences on BD patients.

[Subjective cognition in schizophrenia]

OBJECTIVES

Given the extent, magnitude and functional significance of the neurocognitive deficits of schizophrenia, growing attention has been paid recently to patients' self-awareness of their own deficits. Thus far, the literature has shown either that patients fail to recognize their cognitive deficits or that the association between subjective and objective cognition is weak in schizophrenia. The reasons for this lack of consistency remain unexplained but may have to do, among others, with the influence of potential confounding clinical variables and the choice of the scale used to measure self-awareness of cognitive deficits. In the current study, we sought to examine the relationships between subjective and objective cognitive performance in schizophrenia, while controlling for the influence of sociodemographic and psychiatric variables.

METHODS

Eighty-two patients with a schizophrenia-spectrum disorder (DSM-IV criteria) were recruited. Patients' subjective cognitive complaints were evaluated with the Subjective Scale to Investigate Cognition in Schizophrenia (SSTICS), the most frequently used scale to measure self-awareness of cognitive deficits in schizophrenia. Neurocognition was evaluated with working memory, planning and visual learning tasks taken from Cambridge Neuropsychological Tests Automated Battery. The Stroop Color-Word test was also administered. Psychiatric symptoms were evaluated with the Positive and Negative Syndrome Scale and the Calgary Depression Scale for Schizophrenia. The relationships between subjective and objective cognition were evaluated with multivariate hierarchic linear regression analyses, taking into consideration potential confounders such as sociodemographic and psychiatric variables. Finally, a factor analysis of the SSTICS was performed.

RESULTS

For the SSTICS total score, the regression analysis produced a model including two predictors, namely visual learning and Stoop interference performance, explaining a moderate portion of the variance. Visual learning performance was the most consistent predictor of most SSTICS subscores (e.g. episodic memory, attention, executive functioning, language and praxis). Modest associations were found between the PANSS cognitive factor and objective cognition (e.g. Stroop interference, visual learning, and working memory). Finally, the factor analysis revealed a 6-factor solution that echoes the classification of the items of the SSTICS based on the neuropsychological literature.

CONCLUSIONS

Using a scale having good internal validity, as shown by the factor analysis, the current study highlighted modest associations between subjective and objective cognitive performance, which suggests that schizophrenia patients are only partially aware of their own cognitive deficits. The results also showed a lack of correspondence between the impaired cognitive domain and the domain of cognitive awareness. It should be noted that clinicians were not better than patients at evaluating their cognitive deficits. Future research will need to determine if the observations reported here are schizophrenia-specific or not.

Cognitive Translation Using the Rodent Touchscreen Testing Approach

The development of novel therapeutic avenues for the treatment of cognitive deficits in psychiatric and neurodegenerative disease is of high importance, yet progress in this field has been slow. One reason for this lack of success may lie in discrepancies between how cognitive functions are assessed in experimental animals and humans. In an attempt to bridge this translational gap, the rodent touchscreen testing platform is suggested as a translational tool. Specific examples of successful cross-species translation are discussed focusing on paired associate learning (PAL), the 5-choice serial reaction time task (5-CSRTT), the rodent continuous performance task (rCPT) and reversal learning. With ongoing research assessing the neurocognitive validity of tasks, the touchscreen approach is likely to become increasingly prevalent in translational cognitive research.

Neuropsychological profile in adult schizophrenia measured with the CMINDS

Schizophrenia neurocognitive domain profiles are predominantly based on paper-and-pencil batteries. This study presents the first schizophrenia domain profile based on the Computerized Multiphasic Interactive Neurocognitive System (CMINDS(®)). Neurocognitive domain z-scores were computed from computerized neuropsychological tests, similar to those in the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB), administered to 175 patients with schizophrenia and 169 demographically similar healthy volunteers. The schizophrenia domain profile order by effect size was Speed of Processing (d=-1.14), Attention/Vigilance (d=-1.04), Working Memory (d=-1.03), Verbal Learning (d=-1.02), Visual Learning (d=-0.91), and Reasoning/Problem Solving (d=-0.67). There were no significant group by sex interactions, but overall women, compared to men, showed advantages on Attention/Vigilance, Verbal Learning, and Visual Learning compared to Reasoning/Problem Solving on which men showed an advantage over women. The CMINDS can readily be employed in the assessment of cognitive deficits in neuropsychiatric disorders; particularly in large-scale studies that may benefit most from electronic data capture.

Cognitive endophenotypes, gene-environment interactions and experience-dependent plasticity in animal models of schizophrenia

Schizophrenia is a devastating brain disorder caused by a complex and heterogeneous combination of genetic and environmental factors. In order to develop effective new strategies to prevent and treat schizophrenia, valid animal models are required which accurately model the disorder, and ideally provide construct, face and predictive validity. The cognitive deficits in schizophrenia represent some of the most debilitating symptoms and are also currently the most poorly treated. Therefore it is crucial that animal models are able to capture the cognitive dysfunction that characterizes schizophrenia, as well as the negative and psychotic symptoms. The genomes of mice have, prior to the recent gene-editing revolution, proven the most easily manipulable of mammalian laboratory species, and hence most genetic targeting has been performed using mouse models. Importantly, when key environmental factors of relevance to schizophrenia are experimentally manipulated, dramatic changes in the phenotypes of these animal models are often observed. We will review recent studies in rodent models which provide insight into gene-environment interactions in schizophrenia. We will focus specifically on environmental factors which modulate levels of experience-dependent plasticity, including environmental enrichment, cognitive stimulation, physical activity and stress. The insights provided by this research will not only help refine the establishment of optimally valid animal models which facilitate development of novel therapeutics, but will also provide insight into the pathogenesis of schizophrenia, thus identifying molecular and cellular targets for future preclinical and clinical investigations.

Modafinil for cognitive neuroenhancement in healthy non-sleep-deprived subjects: A systematic review

Modafinil is an FDA-approved eugeroic that directly increases cortical catecholamine levels, indirectly upregulates cerebral serotonin, glutamate, orexin, and histamine levels, and indirectly decreases cerebral gamma-amino-butrytic acid levels. In addition to its approved use treating excessive somnolence, modafinil is thought to be used widely off-prescription for cognitive enhancement. However, despite this popularity, there has been little consensus on the extent and nature of the cognitive effects of modafinil in healthy, non-sleep-deprived humans. This problem is compounded by methodological discrepancies within the literature, and reliance on psychometric tests designed to detect cognitive effects in ill rather than healthy populations. In order to provide an up-to-date systematic evaluation that addresses these concerns, we searched MEDLINE with the terms "modafinil" and "cognitive", and reviewed all resultant primary studies in English from January 1990 until December 2014 investigating the cognitive actions of modafinil in healthy non-sleep-deprived humans. We found that whilst most studies employing basic testing paradigms show that modafinil intake enhances executive function, only half show improvements in attention and learning and memory, and a few even report impairments in divergent creative thinking. In contrast, when more complex assessments are used, modafinil appears to consistently engender enhancement of attention, executive functions, and learning. Importantly, we did not observe any preponderances for side effects or mood changes. Finally, in light of the methodological discrepancies encountered within this literature, we conclude with a series of recommendations on how to optimally detect valid, robust, and consistent effects in healthy populations that should aid future assessment of neuroenhancement.

The NEWMEDS rodent touchscreen test battery for cognition relevant to schizophrenia

RATIONALE

The NEWMEDS initiative (Novel Methods leading to New Medications in Depression and Schizophrenia, http://www.newmeds-europe.com ) is a large industrial-academic collaborative project aimed at developing new methods for drug discovery for schizophrenia. As part of this project, Work package 2 (WP02) has developed and validated a comprehensive battery of novel touchscreen tasks for rats and mice for assessing cognitive domains relevant to schizophrenia.

OBJECTIVES

This article provides a review of the touchscreen battery of tasks for rats and mice for assessing cognitive domains relevant to schizophrenia and highlights validation data presented in several primary articles in this issue and elsewhere.

METHODS

The battery consists of the five-choice serial reaction time task and a novel rodent continuous performance task for measuring attention, a three-stimulus visual reversal and the serial visual reversal task for measuring cognitive flexibility, novel non-matching to sample-based tasks for measuring spatial working memory and paired-associates learning for measuring long-term memory.

RESULTS

The rodent (i.e. both rats and mice) touchscreen operant chamber and battery has high translational value across species due to its emphasis on construct as well as face validity. In addition, it offers cognitive profiling of models of diseases with cognitive symptoms (not limited to schizophrenia) through a battery approach, whereby multiple cognitive constructs can be measured using the same apparatus, enabling comparisons of performance across tasks.

CONCLUSION

This battery of tests constitutes an extensive tool package for both model characterisation and pre-clinical drug discovery.

Does the Cambridge Automated Neuropsychological Test Battery (CANTAB) Distinguish Between Cognitive Domains in Healthy Older Adults?

The Cambridge Neuropsychological Test Automated Battery (CANTAB) is a semiautomated computer interface for assessing cognitive function. We examined whether CANTAB tests measured specific cognitive functions, using established neuropsychological tests as a reference point. A sample of 500 healthy older (M = 60.28 years, SD = 6.75) participants in the Tasmanian Healthy Brain Project completed battery of CANTAB subtests and standard paper-based neuropsychological tests. Confirmatory factor analysis identified four factors: processing speed, verbal ability, episodic memory, and working memory. However, CANTAB tests did not consistently load onto the cognitive domain factors derived from traditional measures of the same function. These results indicate that five of the six CANTAB subtests examined did not load onto single cognitive functions. These CANTAB tests may lack the sensitivity to measure discrete cognitive functions in healthy populations or may measure other cognitive domains not included in the traditional neuropsychological battery.

Antipsychotic-induced parkinsonism is associated with working memory deficits in schizophrenia-spectrum disorders

In view of the significant cognitive deficits in schizophrenia and their impact on patients' social and occupational functioning, and considering that the influence potential influence of antipsychotic-induced extrapyramidal symptoms on cognition in schizophrenia remains poorly understood, the current study sought to identify the clinical, socio-demographic and neurologic predictors of the cognitive performance of schizophrenia patients. Eighty-two schizophrenia-spectrum (DSM-IV criteria) outpatients were recruited. Psychiatric symptoms were evaluated with the Positive And Negative Syndrome Scale and the Calgary Depression Scale for Schizophrenia. Extrapyramidal symptoms were evaluated with the Extrapyramidal Symptoms Rating Scale, while spatial working, planning abilities and visual paired associates learning were evaluated with the CAmbridge Neuropsychological Tests Automated Battery. The Stroop test was also administered. Multivariate hierarchic linear regression analyses were performed. We found that negative symptoms were associated with cognitive flexibility, planning, visual learning and working memory performance in schizophrenia. Age, sex, number of hospitalizations and antipsychotic type also emerged as significant predictors. More importantly, we found a significant association between antipsychotic-induced parkinsonism and working memory performance. The fact that negative symptoms and socio-demographic variables predicted cognitive performance in schizophrenia is consistent with the previous literature on the topic. The finding of an association between parkinsonism and working memory may have clinical implications, since working memory deficits are considered putative endophenotypes of schizophrenia and are known to impair patients' social and occupational functioning. Our results will need to be replicated in longitudinal studies involving larger samples of patients.

The FOCUS trial: cognitive remediation plus standard treatment versus standard treatment for patients at ultra-high risk for psychosis: study protocol for a randomised controlled trial

Background

Cognitive deficits are a distinct feature among people at ultra-high risk (UHR) for psychosis and pose a barrier to functional recovery. Insufficient evidence exists on how to ameliorate these cognitive deficits in patients at UHR for psychosis and hence improve daily living and quality of life. The aim of the trial is to investigate whether cognitive remediation can improve cognitive and psychosocial function in patients at UHR for psychosis.

Methods

The FOCUS trial (Function and Overall Cognition in Ultra-high risk States) is a randomised, parallel group, observer-blinded clinical trial enrolling 126 patients meeting the standardised criteria of being at UHR for psychosis. Patients are recruited from psychiatric in- and outpatient facilities in the Copenhagen catchment area. Patients are randomised to one of the two treatment arms: cognitive remediation plus standard treatment versus standard treatment. The cognitive remediation consists of 24 weekly group-based and manualised sessions targeting neurocognition and social cognition. In addition to the group sessions, the patients will be offered 12 individual sessions aiming at maximising the transfer of the effects of the cognitive training to their everyday lives. Follow-up assessments will be conducted at 6 and 12 months after randomisation. The primary outcome is the composite score on the Brief Assessment of Cognition in Schizophrenia at cessation of treatment after 6 months. Secondary outcomes are social and daily functioning, psychosis-like symptoms, negative symptomatology, and depressive symptomatology as measured with the Personal and Social Performance Scale, Brief Psychiatric Rating Scale-Expanded Version, Scale for the Assessment of Negative Symptoms, and the Montgomery-Åsberg Depression Rating Scale.

Discussion

This is the first trial to evaluate the effects of neurocognitive and social cognitive remediation in UHR patients. The FOCUS trial results will provide evidence on the effect of targeted and comprehensive cognitive rehabilitation on cognition, daily living, and symptomatology as well as long-term outcome in preventing transition to psychosis in UHR patients.

Trial registration

ClinicalTrials.gov NCT 02098408. Date of registration 18 March 2014.

A preliminary validity study of the cambridge neuropsychological test automated battery for the assessment of executive function in schizophrenia and bipolar disorder

OBJECTIVE

Although the executive function subtests of the Cambridge Neuropsychological Test Automated Battery (CANTAB) have been used to assess cognitive function in diverse psychiatric illnesses, few studies have verified the validity of this battery for Korean psychiatric patients. Therefore, this preliminary study evaluated the construct and concurrent validity of the executive function subtests of the CANTAB for Korean psychiatric patients by comparing it with subtests of the Computerized Neuropsychological Test (CNT).

METHODS

Three subtests of the CANTAB and three subtests of the CNT were administered to 36 patients diagnosed with either schizophrenia or bipolar disorder. Subtests of the CANTAB included the Intra/Extra-Dimensional Set Shift (IED), Stockings of Cambridge (SOC), and Spatial Working Memory (SWM). Differences between groups on each subtest as well as correlations between the subtests of the CANTAB and the CNT were assessed.

RESULTS

The schizophrenia group performed significantly more poorly on the IED and the Wisconsin Card Sorting Test (WCST) compared with the bipolar disorder group. Additionally, correlation analyses revealed a significant correlation between the IED and the WCST; a positive correlation between the SOC and the Trail Making Test, Part B and the Stroop test; and a significant correlation between the SWM and the Stroop test.

CONCLUSION

This study verified the construct and concurrent validity of the executive function subtests of the CANTAB for Korean psychiatric patients and suggests that the subtests of this battery would be useful and appropriate for assessing deficits in executive function in Korean clinical settings.

Daily Task Performance and Information Processing among People with Schizophrenia and Healthy Controls: A Comparative Study

Introduction:

Many individuals with schizophrenia have information processing difficulties. This study investigated the use of information processing skills during the performance of a daily task by participants with schizophrenia and compared it to that of participants without a psychiatric diagnosis. Studies comparing similar groups found differences in the number and types of errors. However, there is limited knowledge about the related problematic information processing skills. This information could help to better pinpoint the needs of this group of clients.

Method:

Participants were paired based on age and gender. Information processing skills were assessed with the Perceive, Recall, Plan, and Perform system of task analysis. Generalized linear mixed models were used to compare both groups.

Results:

Individuals with schizophrenia made more accuracy errors and had more difficulties when attending and gathering information and when planning was required during the task. They were also more cognitively impaired than the comparison group.

Conclusion:

The large number of accuracy errors may result from specific skills deficits that impact on other processing skills or from a general vulnerability affecting most processing skills. In future studies, the influence of employment and of the social environment of housing on task performance should be investigated.

Cognitive function in idiopathic intracranial hypertension: a prospective case-control study

OBJECTIVE

To explore the extent and nature of cognitive deficits in patients with idiopathic intracranial hypertension (IIH) at the time of diagnosis and after 3 months of treatment.

DESIGN

Prospective case-control study.

SETTING

Neurological department, ophthalmological department and a tertiary headache referral clinic at a Danish university hospital.

PARTICIPANTS

31 patients with definite IIH referred from June 2011 to February 2013 and included within 1 week of diagnostic intracranial pressure (ICP) measurement. 29 patients completed re-examination at the 3-month follow-up. At the time of testing, none of the patients took medication potentially affecting cognitive function. Controls were 31 healthy age-matched and sex-matched volunteers from the local community.

OUTCOME MEASURES

Executive function, working memory, visuospatial memory, processing speed, attention and reaction time assessed by a comprehensive neuropsychological test battery consisting of validated computerised (Cambridge neuropsychological test automated battery) and paper-and-pencil tests.

RESULTS

Patients with IIH performed significantly worse than controls in four of six cognitive domains (p≤0.02). Deficits were most pronounced in reaction time (1.45 SD below controls 95% CI 2.10 to 0.85) and processing speed (1.48 SD below controls 95% CI 2.08 to 0.81). Despite marked improvement in ICP and headache, re-examination showed persistent cognitive dysfunction 3 months after diagnosis and start of treatment.

CONCLUSIONS

We demonstrate for the first time in a well-defined cohort of patients that IIH may be associated with cognitive dysfunction. This could explain the functional disability of patients with IIH. A focused multidisciplinary approach including neuropsychological rehabilitation, therefore, might be relevant in the treatment of patients with IIH.

Sex differences in cognitive functioning in patients with bipolar disorder who recently recovered from a first episode of mania: data from the Systematic Treatment Optimization Program for Early Mania (STOP-EM)

BACKGROUND

Studies investigating bipolar disorder (BD) showed that healthy patterns of sex differences in cognitive functioning are altered within this population, but is it unknown whether these alterations are present in BD patients early in their course of illness.

METHODS

Patients with bipolar I disorder (36 males, 38 female), who had recently experienced their first manic or mixed episode were tested along with healthy controls (39 males, 59 females) similar in age, sex and premorbid IQ. Cognitive function was assessed through a comprehensive neuropsychological test battery.

RESULTS

Significant group effects were found in a majority of administered tests (p<0.05) with patients performing worse than healthy controls. Significant sex effects (p<0.05) were observed on tasks of spatial working memory and sustained attention, with males performing better than females. No significant group by sex interaction was found in any of the tasks administered.

LIMITATIONS

The cognitive battery employed in this study may not have been optimally sensitive in detecting sex differences.

CONCLUSIONS

The results suggest that unlike patients with long standing multi-episode BD or schizophrenia, healthy cognitive sex differences are maintained in patients with early BD, following recovery from a first-episode of mania. These findings highlight the progressive nature of the illness and provide justification for an early intervention.

Rapid visual information processing as a cognitive endophenotype of attention deficit hyperactivity disorder

BACKGROUND

Deficits in sustained attention and reaction time are core features of attention deficit hyperactivity disorder (ADHD). However, little is known about attention performance in unaffected siblings. Hence, we examined sustained attention and reaction time in youths with ADHD, unaffected siblings and controls to test whether impaired performance in attention tasks can be a potential endophenotype of ADHD.

METHOD

We recruited 438 probands with clinical diagnosis of ADHD according to DSM-IV criteria, 180 unaffected siblings, and 173 healthy controls without lifetime ADHD. They were assessed using psychiatric interviews, Conners' Continuous Performance Test, and the tasks involving attention performance of the Cambridge Neuropsychological Test Automated Battery (CANTAB): Rapid Visual Information Processing (RVP), Reaction Time (RTI) and Match to Sample Visual Search (MTS). Multi-level models were used for data analysis.

RESULTS

Compared with the controls, probands with ADHD and unaffected siblings had significantly higher total misses, lower probability of hits in the RVP task and probands with ADHD performed worse in the RTI and MTS tasks after controlling for sex, age, co-morbidity, parental educational levels and IQ. The duration of methylphenidate use and IQ but not psychiatric co-morbidity or current use of methylphenidate were associated with deficits in sustained attention in probands with ADHD.

CONCLUSIONS

Our findings suggest that attention performance assessed by the RVP task, but not the RTI or MTS tasks, of the CANTAB may be a useful cognitive endophenotype for ADHD genetic studies.

Oscillatory underpinnings of mismatch negativity and their relationship with cognitive function in patients with schizophrenia

Background

Impairments in mismatch negativity (MMN) generation have been consistently reported in patients with schizophrenia. However, underlying oscillatory activity of MMN deficits in schizophrenia and the relationship with cognitive impairments have not been investigated in detail. Time-frequency power and phase analyses can provide more detailed measures of brain dynamics of MMN deficits in schizophrenia.

Method

21 patients with schizophrenia and 21 healthy controls were tested with a roving frequency paradigm to generate MMN. Time-frequency domain power and phase-locking (PL) analysis was performed on all trials using short-time Fourier transforms with Hanning window tapering. A comprehensive battery (CANTAB) was used to assess neurocognitive functioning.

Results

Mean MMN amplitude was significantly lower in patients with schizophrenia (95% CI 0.18 - 0.77). Patients showed significantly lower EEG power (95% CI -1.02 - -0.014) in the ~4-7 Hz frequency range (theta band) between 170 and 210 ms. Patients with schizophrenia showed cognitive impairment in multiple domains of CANTAB. However, MMN impairments in amplitude and power were not correlated with clinical measures, medication dose, social functioning or neurocognitive performance.

Conclusion

The findings from this study suggested that while MMN may be a useful marker to probe NMDA receptor mediated mechanisms and associated impairments in gain control and perceptual changes, it may not be a useful marker in association with clinical or cognitive changes. Trial-by-trial EEG power analysis can be used as a measure of brain dynamics underlying MMN deficits which also can have implications for the use of MMN as a biomarker for drug discovery.

Pharmacological Interventions for the MATRICS Cognitive Domains in Schizophrenia: What's the Evidence?

Schizophrenia is a disabling, chronic psychiatric disorder with a prevalence rate of 0.5-1% in the general population. Symptoms include positive (e.g., delusions, hallucinations), negative (e.g., blunted affect, social withdrawal), as well as cognitive symptoms (e.g., memory and attention problems). Although 75-85% of patients with schizophrenia report cognitive impairments, the underlying neuropharmacological mechanisms are not well understood and currently no effective treatment is available for these impairments. This has led to the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative, which established seven cognitive domains that are fundamentally impaired in schizophrenia. These domains include verbal learning and memory, visual learning and memory, working memory, attention and vigilance, processing speed, reasoning and problem solving, and social cognition. Recently, a growing number of studies have been conducted trying to identify the underlying neuropharmacological mechanisms of cognitive impairments in schizophrenia patients. Specific cognitive impairments seem to arise from different underlying neuropharmacological mechanisms. However, most review articles describe cognition in general and an overview of the mechanisms involved in these seven separate cognitive domains is currently lacking. Therefore, we reviewed the underlying neuropharmacological mechanisms focusing on the domains as established by the MATRICS initiative which are considered most crucial in schizophrenia.

Examination of spatial working memory performance in children and adolescents with attention deficit hyperactivity disorder, combined type (ADHD-CT) and anxiety

Spatial working memory (SWM) is known to be impaired in children with ADHD-CT, whether anxiety is present or not. Yet, it remains unclear whether anxiety disorders add to the SWM impairments evident in ADHD-CT and whether these findings extend into adolescents with ADHD-CT and anxiety. Further, it is not yet known whether children and adolescents with carefully defined anxiety disorders alone, demonstrate SWM deficits. This study explored the association of SWM and its strategy and spatial span components in carefully defined children and adolescents (age 6-16 years) with ADHD-CT alone (N = 163; 14 % female), ADHD-CT and anxiety (N = 243; 23 % female), anxiety disorders alone (N = 69; 25 % female) compared to age- and gender-matched healthy control participants (N = 116; 19 % female). The relationship between SWM and its strategy and span components and core ADHD-CT symptoms and anxiety symptoms were also examined. There was no evidence of an additive effect of ADHD and anxiety on SWM, strategy and spatial span deficits. But, anxiety disorders alone were associated with impaired SWM and span performance compared to healthy control participants. In contrast, strategy did not differ between children and adolescents with anxiety disorders alone and healthy control participants, suggesting that with anxiety span is the most affected component. Further, these findings were age-independent. This study concurs with and extends current influential models about the cognitive effects of anxiety on performance in the setting of ADHD-CT. Clinical implications and future research directions are discussed.

Redevelopment of tertiary psychiatric services in British Columbia: a prospective study of clinical, social, and residential outcomes of former long-stay inpatients

OBJECTIVE

The objective of this study is to assess the clinical and social outcomes for a cohort of patients who were part of the redevelopment of psychiatric services in British Columbia.

METHOD

This study used a naturalistic, quasi-experimental design, to examine the outcomes of a cohort of 189 long-stay patients at Riverview Hospital (RVH), some of whom moved into Tertiary Psychiatric Residential Facilities (TPRFs), some into the community in less structured facilities, and some remained at RVH. Data was collected from clinical files at RVH and at each participating site, semi-structured interviews and self-report measures were completed with patients. In addition, semi-structured interviews were also conducted with staff members.

RESULTS

There was very minimal evidence of transinstitutionalization to prisons or homelessness; one participant resided in a correctional facility, one resided in a forensic facility, and one participant spent some time homeless. In addition, the majority of participants remained in residences that provided 24h care. Eighty percent of our population was diagnosed with a schizophrenia spectrum disorder. Psychiatric symptoms remained fairly stable; some embarrassing social behaviors increased; however, aggressive behaviors showed no increase; neuropsychological deficits did not deteriorate, there were even some improvements. Participants demonstrated increases in several independent living skills including: money management, food preparation and storage, job skills, and transportation skills. In addition, participants experienced a significant increase in their perceived quality of life.

CONCLUSIONS

This study builds on existing research demonstrating that well-planned and appropriately resourced hospital closures can lead to positive psycho-social outcomes for participants and can successfully avoid negative outcomes such as transinstitutionalization to the judiciary system and homelessness.

Predictors of community functioning in schizophrenia and substance use disorder patients

Community functioning is a broad term that encompasses various 'real world' measures of disability among schizophrenia patients. It includes outcomes such as independent living, social competence and behavioural problems-all of which are priorities for treatment among schizophrenia patients, mental health care providers, and family members. An important goal for rehabilitation programs is to identify predictors of community functioning which, in turn, could be used as targets for intervention. The present case-control study examined socio-demographic and substance use disorder (SUD) variables as well as psychiatric, extrapyramidal, and cognitive symptoms as predictors of community functioning in schizophrenia patients with (DD patients; n=31) and without comorbid SUDs (SCZ patients; n=31), and non-psychosis substance abusers (SUD patients; n=39). Psychiatric and extrapyramidal symptoms were evaluated with the Positive and Negative Syndrome Scale, the Calgary Depression Scale for Schizophrenia and the Extrapyramidal Symptoms Rating Scale. Cognition was evaluated using the Cambridge Neuropsychological Test Automated Battery (speed of processing, explicit and working memory). In SCZ patients, community functioning was predicted by explicit memory performance. In DD patients, community functioning was predicted by substance abuse, depression and speed of processing. In SUD patients, community functioning was predicted by substance abuse, positive symptoms and education. Our results suggest that cognition should be among the top treatment priorities in SCZ patients, whereas the key treatment targets in DD patients should be substance abuse and depression. Future studies will need to replicate the current findings, using prospective research designs.

First episode psychosis patients show impaired cognitive function--a study of a South Asian population in the UK

BACKGROUND

Cognitive deficits are a core symptom of schizophrenia, severely debilitating and untreated by current medication. However, to date there is limited research focusing on the precise nature of the cognitive disturbances at first episode in ethnic populations. Improved understanding of this will allow improved approaches to therapy. The aim of this study was to investigate cognitive function with a first episode of psychosis South Asian patients.

METHODS

Twenty South Asian first episode psychosis patients and 15 healthy South Asian matched controls were recruited. All were second generation South Asian people living in the UK. Subjects who took part in the study completed the Positive and Negative Syndrome Scale (patient group), the Wechsler Test of Adult Reading and a battery of neuropsychological assessments to assess specific domains of cognition of relevance to Measurement and Treatment Research to Improve Cognition in Schizophrenia using the Cambridge Neuropsychological Test Automated Battery (CANTAB) (all groups).

RESULTS

Results show that first episode patients performed significantly worse than controls across all cognitive domains tested using CANTAB. Significant impairments were found in tests of visual and spatial memory, executive function, working memory, spatial planning and attention. Importantly, a number of cognitive performance indices (visual memory, spatial memory, executive function) were positively correlated with the severity of negative symptoms.

CONCLUSION

We demonstrate that first episode South Asian patients display significant and specific cognitive deficits with evidence to support an association between negative symptoms and certain cognitive domains at first episode in this patient population.

COMT and MTHFR polymorphisms interaction on cognition in schizophrenia: an exploratory study

The investigation of the catechol-O-methyltransferase (COMT-[rs4680]) and methylenetetrahydrofolate reductase (MTHFR-[rs1801133]) polymorphisms' interaction might shed light into the pathogenetic mechanisms of the cognitive dysfunction in schizophrenia. In an exploratory study, we hypothesized that the MTHFR 677T allele which has been related to a hypoactive MTHFR enzyme would augment the unfavorable effects of COMT Val158 homozygosity which has been associated with COMT enzyme hyperfunction. 90 schizophrenia patients and 55 healthy volunteers were assessed on psychomotor speed, pattern and spatial recognition memory (SRM), spatial working memory (SWM), attentional flexibility and planning (Stockings of Cambridge-SOC). IQ scores in a random subgroup of patients were also measured. A significant COMT×MTHFR interaction on SWM (p=0.048) and planning (p=0.026) was revealed in both groups. Among COMT-Val/Val participants, MTHFR-C/C made more SWM errors (p=0.033) and solved fewer SOC problems (p=0.025) than MTHFR-T carriers. In patients, there was a significant COMT×MTHFR interaction on full scale IQ (p=0.035): among COMT-Met carriers, MTHFR-T carriers performed significantly worse than MTHFR-C/C (p=0.021), which was driven by a COMT×MTHFR interaction involving performance IQ (p=0.047). In conclusion, COMT and MTHFR polymorphisms interacted on cognition, suggesting that the MTHFR enzyme activity might moderate the effects of the COMT enzyme. In contrast to our initial hypothesis, the MTHFR T-allele attenuated the cognitive effects of COMT Val homozygosity. In this preliminary study, we propose that dopaminergic and intracellular methylation mechanisms could interact on cognitive deficits in schizophrenia.

Executive functioning during full and partial remission (positive and negative symptomatic remission) of schizophrenia

BACKGROUND

Despite the upsurge of research regarding cognitive impairment in schizophrenia we still lack adequate understanding of the executive functioning of patients in symptomatic remission. Moreover, the cognitive functioning of patients in partial remission has not been studied previously although they comprise a significant proportion of schizophrenia patients. The current study therefore examined the executive functioning of patients in full symptomatic remission and for the first time assessed two sub-groups of patients in partial remission.

METHODS

Executive functioning of five groups was compared; symptomatic patients, patients in positive symptomatic remission, negative symptomatic remission, full symptomatic remission (SP, PSR, NSR, and FSR; N=101) and healthy controls (N=37).

RESULTS

A graded cognitive profile was evident between the groups. SP patients exhibited widespread executive dysfunction while the performance of FSR patients was comparable to that of the healthy controls. Both PSR and NSR patients had working memory deficits, with PSR patients showing additional deficits in cognitive planning.

CONCLUSIONS

The findings are encouraging, tentatively suggesting intact executive functioning among patients in full symptomatic remission. The graded cognitive profile of the patient groups strengthens earlier findings indicating the significant role of negative symptoms in determining executive dysfunction in schizophrenia. The findings point toward potential targets for therapeutic efforts and emphasize the need for further research of sub-groups of schizophrenia patients in partial remission.

Remission of positive symptoms according to the "remission in Schizophrenia Working Group" criteria: a longitudinal study of cognitive functioning

Schizophrenia patients in positive symptomatic remission (PSR; n=39) were assessed using a longitudinal research design. The patients were found to exhibit widespread cognitive impairments that were stable over the three-year follow-up period. The findings support a generalized and stable cognitive impairment profile among schizophrenia patients in partial symptomatic remission.

Examination of neurological subtle signs in ADHD as a clinical tool for the diagnosis and their relationship to spatial working memory

BACKGROUND

  Neurological subtle signs (NSS) are minor neurological abnormalities that have been shown to be increased in a number of neurodevelopmental conditions. For attention deficit/hyperactivity disorder (ADHD), it remains unclear whether NSS may aid the clinical diagnostic process.

METHODS

  This study explored the association of total and specific domains of NSS in 1,055 children and adolescents with ADHD compared to 130 age-matched typically developing participants; the relationship between NSS and Spatial Working Memory (SWM) as a cognitive process integrally involved in ADHD was also assessed. To determine the diagnostic and predictive efficiency of NSS, a receiver operating curve analysis was performed and the area under the curve (AUC) quantified. The best discriminant points for differentiating between ADHD and typically developing participants and the predictive power of NSS for SWM impairment in ADHD young people were also calculated.

RESULTS

  Area under the curves for total NSS, smoothness/accuracy, cerebellar signs and choreo-athetoid movements scores were considered good (.84, .79, .74 and .73 respectively), and the results remained after controlling for gender and IQ. A total score of 13 or over on the Scored Developmental Neurological Examination proved to be a good threshold point for differentiating between the ADHD and typically developing participants. For ADHD children, the AUC of total NSS to distinguish between those below 25th and above 75th percentile were .77 and .73 for Spatial Span and for Between Search Errors respectively (the two SWM-dependent measures examined).

CONCLUSIONS

  This study provides evidence suggesting that NSS may aid the clinical evaluation of a child or adolescent with ADHD. In children and adolescents with ADHD, NSS are associated with difficulties in SWM, specifically the Spatial Span and Between Search Error components.