Does risperidone improve verbal working memory in treatment-resistant schizophrenia?

Knowledge domain and trends in treatment-resistant schizophrenia (TRS) research based on CiteSpace bibliometrics analysis

Background

Although the number of studies on treatment-resistant schizophrenia (TRS) has been increasing, the global research hotspots and future research trends have not yet been established.

Objective

This study identify the hotspots of TRS research and predict future research trends using a bibliometric analysis.

Methods

The Web of Science Core Collection was searched using the keyword "TRS", econometric and co-occurrence analyses were conducted using CiteSpace and VOSviewer software, and the results were visualised. PRISMA reporting guidelines were used for this study.

Results

In total, 912 publications were included in the analysis. The number of publications on TRS has shown an increasing trend over the past 20 years. The United States and University of London were the countries and institutions with the highest total number of publications, respectively. Schizophrenia Research was the journal with the highest number of articles. American Journal of Psychiatry was the most cited journal. Based on the results of this analysis, cognitive impairment, clozapine-resistant schizophrenia, early-onset schizophrenia, and early recognition of TRS will be hotspots for future research in this field.

Conclusion

There has been an upward trend in the number of publications on TRS each year. However, issues such as how to use antipsychotics more efficiently to treat TRS and how to predict the emergence of TRS as early as possible are still in urgent need of research and are current challenges for clinicians. The results of this study not only predict and analyse future research hotspots but also help researchers identify appropriate research directions and partners.

The magnitude and variability of neurocognitive performance in first-episode psychosis: a systematic review and meta-analysis of longitudinal studies

Neurocognitive deficits are a core feature of psychotic disorders, but it is unclear whether they affect all individuals uniformly. The aim of this systematic review and meta-analysis was to synthesize the evidence on the magnitude, progression, and variability of neurocognitive functioning in individuals with first-episode psychosis (FEP). A multistep literature search was conducted in several databases up to November 1, 2022. Original studies reporting on neurocognitive functioning in FEP were included. The researchers extracted the data and clustered the neurocognitive tasks according to the seven Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) domains and six additional domains. Random-effect model meta-analyses, assessment of publication biases and study quality, and meta-regressions were conducted. The primary effect size reported was Hedges g of (1) neurocognitive functioning in individuals at FEP measuring differences with healthy control (HC) individuals or (2) evolution of neurocognitive impairment across study follow-up intervals. Of 30,384 studies screened, 54 were included, comprising 3,925 FEP individuals and 1,285 HC individuals. Variability analyses indicated greater variability in FEP compared to HC at baseline and follow-up. We found better neurocognitive performance in the HC group at baseline and follow-up but no differences in longitudinal neurocognitive changes between groups. Across the 13 domains, individuals with FEP showed improvement from baseline in all studied domains, except for visual memory. Metaregressions showed some differences in several of the studied domains. The findings suggest that individuals with FEP have marked cognitive impairment, but there is greater variability in cognitive functioning in patients than in HC. This suggests that subgroups of individuals suffer severe disease-related cognitive impairments, whereas others may be much less affected. While these impairments seem stable in the medium term, certain indicators may suggest potential further decline in the long term for a specific subgroup of individuals, although more research is needed to clarify this. Overall, this study highlights the need for tailored neurocognitive interventions for individuals with FEP based on their specific deficits and progression.

Consideration of the adaptive randomization allocation ratio in the presence of treatment group heteroscedasticity in clinical trials

For randomized clinical trials, subjects' variance structures may vary over time among treatment groups, resulting in the heteroscedasticity of residuals in a regression analysis. Commonly used methods that assume equal variance among all treatment groups may not be able to control for a type I error. When the variances are indeed the same across treatment groups, an equal randomization allocation ratio will yield the greatest study power. However, out of ethical concern or urgent need for rare disease clinical trials, more patients may have to be allocated to the study drug arm. In these situations, an unequal randomization ratio should be considered. We propose a group variance-covariance and structures-based method to adapt the randomization ratio after interim analysis. We use simulations to compare commonly used statistical methods for continuous endpoints in assessing the impact of heteroscedasticity in equal and unequal randomization ratios and examine the extent to which the findings are affected by missing data.

Correlation between telomere length and efficacy of oral and long-acting injectable antipsychotics on severity and cognitive impairment of schizophrenia

OBJECTIVE

To study the correlation between telomere length (TL) and long-acting injectable (LAI) and oral atypical antipsychotic (OAA) efficacy on schizophrenia (SCZ) severity and cognitive impairment.

METHODS

Sixty Schizophrenia patients of 18-50 years and of either sex were included in a 12-week study. Thirty patients were recruited in each group, LAI and OAA. Positive and Negative Syndrome Scale (PANSS) and National Institute of Mental Health and Neuro-Sciences (NIMHANS) neuropsychological battery tests were evaluated at baseline and 12 weeks. TL was estimated at baseline.

RESULTS

Both groups showed a significant improvement in PANSS and NIMHANS battery test scores after treatment (p < 0.001) within the group, though not between the groups. Mean TL at baseline was 407.58 ± 143.93 and 443.40 ± 178.46 in LAI and OAA groups respectively. A significant negative correlation (r = -0.28, p = 0.03) of TL was seen with the mean change in negative PANSS score after treatment.

CONCLUSIONS

LAI antipsychotics are similar to OAA in decreasing the disorder severity and improving the cognitive impairment in schizophrenia. Also, patients who have shorter TL show greater improvement in the negative PANSS score. Hence, TL holds the potential of predicting antipsychotic drug response in schizophrenia patients.KEY POINTSLong-acting injectable antipsychotic was comparable to oral atypical antipsychotics in bringing out improvement in disorder severity, cognitive functions over 12 weeks.Shorter telomere length has been found to be associated with a greater response in negative symptoms of schizophrenia.

The effect of antipsychotics on the cognitive performance of individuals with psychotic disorders: Network meta-analyses of randomized controlled trials

Cognitive deficits are a core aspect of psychotic disorders; however, it is not clear to which extent different pharmacological treatments could distinctly impact these outcomes. Hence, we conducted a systematic review and ten network meta-analyses of randomized controlled trials to compare the effect of antipsychotics on cognitive performance of individuals with psychotic disorders. Fifty-four trials were included in the analyses, enrolling 5866 patients. Compared to other antipsychotics, amisulpride performed better on verbal learning; quetiapine on composite score, attention and verbal learning; lurasidone on composite score; olanzapine on composite score and most cognitive domains; perphenazine on composite score, executive function, working memory, and verbal learning; risperidone on executive function and verbal learning; sertindole on processing speed; and ziprasidone on composite score, working memory, and verbal learning. Oppositely, haloperidol performed poorer on all cognitive domains, occupying the last positions in all rankings; and clozapine performed poorer on composite score, executive function, verbal learning, and visuoconstruction. We hope that these results should be taken into account when assessing and treating individuals with psychosis.

Memory Impairments and Psychosis Prediction: A Scoping Review and Theoretical Overview

Impairments in memory functions are among the most robust correlates of schizophrenia and of poor functional outcomes in individuals with psychotic disorders. Prospective, longitudinal studies are crucial to determining the meaning of these deficits in relation to mechanisms associated with the onset and course of these disorders.The objective of this review is to examine the literature concerning premorbid memory impairments during the prodromal phase of psychosis to address three primary questions 1) are memory impairments present among individuals with a clinical high risk syndrome? 2) are memory deficits in clinical high risk cases predictive of future conversion to psychosis? and 3) what are the underlying neural correlates of memory impairment in clinical high risk individuals and are they also predictive of future conversion?PubMed and Google Scholar databases were systematically searched. The primary inclusion criteria were to select studies that 1) were original research articles published in a peer-reviewed journal in the past 25 years, 2) studied subjects at clinical high risk for psychosis or in the prodromal phase of illness, and 3) included examinations into verbal memory performance in those at clinical high risk for psychosis.64 articles were identified and screened for eligibility. The review included 34 studies investigating verbal memory impairment in clinical high risk individuals compared to controls. The average effect size of verbal learning total recall was .58, indicating a moderate level of impairment in verbal learning among individuals at clinical high risk for psychosis as compared to healthy controls. Of studies that predicted time to conversion, indices of memory, particularly declarative and verbal working memory, were especially predictive of future conversion. Finally, when examining investigations of the neural correlates of memory dysfunction in the clinical high risk state, findings suggest altered activation and functional connectivity among medial temporal lobe regions may underlie differences in memory performance between clinical high risk individuals and healthy controls.Findings to date strongly indicate that memory impairments are present during the premorbid phase of psychosis and that verbal memory impairment in particular is predictive of future conversion to psychosis. Evidence from fMRI studies is fairly consistent in showing greater activation of memory-related regions during retrieval among clinical high risk cases who convert, with less consistent evidence of altered functional connectivity in the encoding phase. These findings support the use of verbal learning and memory measures in the psychosis prediction and prevention field.

Emerging 5-HT receptor antagonists for the treatment of Schizophrenia

INTRODUCTION

While antipsychotics have been generally successful in treating psychosis in schizophrenia, there is a major treatment gap for negative symptoms and cognitive deficits. Given that these aspects of the disease contribute to poor functional outcomes independently of positive symptoms, treatments would have profound implications for quality of life. The 5-HT_2A- receptor has been considered a potential target for interventions aimed at negative and cognitive symptoms and multiple antagonists and inverse agonists of this receptor have been tested.

AREAS COVERED

Ritanserin and volinanserin, are historically important compounds in this area, while pimavanserin, roluperidone, and lumateperone are either newly approved, in late stages of development, or currently being tested for efficacy in schizophrenia-related features. The focus will be on their efficacy in the treatment of negative symptoms, with a limited secondary discussion of cognition.

EXPERT OPINION

In addition to their efficacy in treating negative symptoms and cognition, these compounds may also have a role in modulating antipsychotic-induced dopamine super-sensitivity and preventing relapse. They may also show efficacy in treating patients with milder symptoms such as patients with schizotypal personality disorder and attenuated psychosis syndrome. Their utility may also expand outside the spectrum of schizophrenia to encompass Parkinson's Disease psychosis, major depression, bipolar depression, and dementia-associated apathy.

[Problems in assessment of the effectiveness of psychosocial rehabilitation and treatment: area of psychosocial interventions, tools and evaluation criteria]

The literature review addresses the problems arising in assessing the effectiveness of psychosocial rehabilitation, selection of evaluation criteria and methodical tools most often used for this purpose. It is shown that for an objective assessment of the results of rehabilitation it is necessary to take into account the hierarchical structure of both the problems of evaluation and the information to be processed. This information includes both quantitative indicators (age, duration of disease, frequency of hospitalizations, results of biological study) and non-numerical (rank) indicators (severity of psychopathological symptoms, characteristics of compliance, social behavior and patient's environment). The proposed approach to assessing the results of rehabilitation of mental patients involves the development of specific criteria for the effectiveness of rehabilitation based on a multidimensional, hierarchical consideration of mental pathology with the inclusion of clinical and psychopathological, socio-environmental and personal indicators of patients in setting goals and objectives of rehabilitation.

Early Identification and Intervention of Schizophrenia: Insight From Hypotheses of Glutamate Dysfunction and Oxidative Stress

Schizophrenia is a severe mental disorder which leads to functional deterioration. Early detection and intervention are vital for better prognosis. However, the diagnosis of schizophrenia still depends on clinical observation to date. Without reliable biomarkers, schizophrenia is difficult to detect in its early phase. Further, there is no approved medication for prodromal schizophrenia because current antipsychotics fail to show satisfactory efficacy and safety. Therefore, to develop an effective early diagnostic and therapeutic approach for schizophrenia, especially in its prodromal phase, is crucial. Glutamate signaling dysfunction and dysregulation of oxidative stress have been considered to play important roles in schizophrenic prodrome. The N-methyl-D-aspartate receptor (NMDAR) is one of three types of ionotropic glutamate receptors. In this article, we reviewed literature regarding NMDAR hypofunction, oxidative stress, and the linkage between both in prodromal schizophrenia. The efficacy of NMDAR enhancers such as D-amino acid oxidase inhibitor was addressed. Finally, we highlighted potential biomarkers related to NMDAR and oxidative stress regulation, and therefore suggested the strategies of early detection and intervention of prodromal schizophrenia. Future larger-scale studies combining biomarkers and novel drug development for early psychosis are warranted.

The past and future of novel, non-dopamine-2 receptor therapeutics for schizophrenia: A critical and comprehensive review

Since the discovery of chlorpromazine in the 1950's, antipsychotic drugs have been the cornerstone of treatment of schizophrenia, and all attenuate dopamine transmission at the dopamine-2 receptor. Drug development for schizophrenia since that time has led to improvements in side effects and tolerability, and limited improvements in efficacy, with the exception of clozapine. However, the reasons for clozapine's greater efficacy remain unclear, despite the great efforts and resources invested therewith. We performed a comprehensive review of the literature to determine the fate of previously tested, non-dopamine-2 receptor experimental treatments. Overall we included 250 studies in the review from the period 1970 to 2017 including treatments with glutamatergic, serotonergic, cholinergic, neuropeptidergic, hormone-based, dopaminergic, metabolic, vitamin/naturopathic, histaminergic, infection/inflammation-based, and miscellaneous mechanisms. Despite there being several promising targets, such as allosteric modulation of the NMDA and α7 nicotinic receptors, we cannot confidently state that any of the mechanistically novel experimental treatments covered in this review are definitely effective for the treatment of schizophrenia and ready for clinical use. We discuss potential reasons for the relative lack of progress in developing non-dopamine-2 receptor treatments for schizophrenia and provide recommendations for future efforts pursuing novel drug development for schizophrenia.

First-episode schizophrenia: review of cognitive deficits and cognitive remediation

The presence of cognitive deficits in schizophrenic illness has been extensively documented, and deficits in memory and executive functioning may be related to poor prognosis. Targeting these deficits during the early phase has potential benefits. The neural basis for cognitive deficits in schizophrenia is not well understood, and hence pharmacological interventions alone are insufficient. Future strategies should focus on pharmacological interventions combined with psychological techniques such as cognitive remediation. This review summarises recent findings relating to first-episode schizophrenia.

Improvement in cognitive functioning in patients with first-episode psychosis during treatment with quetiapine: An interim analysis

Background

The efficacies of second-generation antipsychotic medications in reducing symptoms are reasonably well-documented, but their effects on cognition are less clearly understood.

Aims

To undertake an interim analysis of an open label, 2-year study examining the effects of quetiapine on cognition in patients with a first episode of schizophrenia and related disorders.

Method

Cognitive testing was performed before quetiapine was initiated and repeated after 3, 6 and 12 months of treatment. To date, 13 patients have been fully assessed (mean dose 517.9 mg/day; s.d.=225.8).

Results

Statistically significant improvement was noted on measures of attention (Continuous Performance Test; CPT), verbal productivity (Verbal Fluency Test) and executive function (Object Alternation Test) after 6 and 12 months of treatment. For the CPT, improvement was also noted after 3 months of treatment.

Conclusions

During treatment for 1 year with quetiapine, cognitive performance was improved in young patients with psychosis. Continued controlled investigations of the effects of quetiapine on cognition are desirable.

Cognitive impairment in schizophrenia

“My whole mental power has disappeared, I have sunk intellectually below the level of a beast”(a patient with schizophrenia, quoted by Kraepelin, 1919, p. 25).

Insight into illness and its relationship to illness severity, cognition and estimated antipsychotic dopamine receptor occupancy in schizophrenia: An antipsychotic dose reduction study

Little is known about the influence of D₂ receptor occupancy on impaired insight into illness (III)-a core feature of schizophrenia. III is associated with illness severity and cognitive dysfunction. Comparably, supratherapeutic D₂ receptor occupancy can impair cognition. However, it is unclear how illness severity, cognition, and D₂ receptor occupancy interact to influence III in schizophrenia. The aim of this study was to explore the influence of antipsychotic dose reduction on the relationships of illness severity and cognition to III. III was assessed at baseline and 28 weeks post-antipsychotic dose reduction in 16 participants with schizophrenia and plasma antipsychotic concentrations. III was assessed primarily with the Schedule for the Assessment of Insight-Japanese version, and secondarily with the Positive and Negative Syndrome Scale item G12. Correlation and regression analyses were performed to explore III's relationship to illness severity, cognition, and estimated D₂ receptor occupancy (Est.D₂). Cognition and Est.D₂ predicted III at baseline. At 28 weeks post-reduction, illness severity and Est.D₂ predicted III. Our findings suggest a complex relationship may exist among III, illness severity, cognition and Est.D₂. At higher D₂ receptor occupancies, III is influenced by cognitive dysfunction, whereas, at lower occupancies, illness severity has a stronger effect on III.

Novel Dopamine Therapeutics for Cognitive Deficits in Schizophrenia

Schizophrenia is characterized by profound cognitive deficits that are not alleviated by currently available medications. Many of these cognitive deficits involve dysfunction of the newly evolved, dorsolateral prefrontal cortex (dlPFC). The brains of patients with schizophrenia show evidence of dlPFC pyramidal cell dendritic atrophy, likely reductions in cortical dopamine, and possible changes in dopamine D1 receptors (D1R). It has been appreciated for decades that optimal levels of dopamine are essential for dlPFC working memory function, with many beneficial actions arising from D1R stimulation. D1R are concentrated on dendritic spines in the primate dlPFC, where their stimulation produces an inverted-U dose response on dlPFC neuronal firing and cognitive performance during working memory tasks. Research in both academia and the pharmaceutical industry has led to the development of selective D1 agonists, e.g., the first full D1 agonist, dihydrexidine, which at low doses improved working memory in monkeys. Dihydrexidine has begun to be tested in patients with schizophrenia or schizotypal disorder. Initial results are encouraging, but studies are limited by the pharmacokinetics of the drug. These data, however, have spurred efforts toward the discovery and development of improved or novel new compounds, including D1 agonists with better pharmacokinetics, functionally selective D1 ligands, and D1R positive allosteric modulators. One or several of these approaches should allow optimization of the beneficial effects of D1R stimulation in the dlPFC that can be translated into clinical practice.

Development and Psychometric Properties of the Taiwan Odd-Even Number Sequencing Test: A Nonalphabetic Measure of Working Memory

Alphabetic working memory (WM) tests, such as the Wechsler Adult Intelligence Scale-III and IV Letter Number Sequencing, are not appropriate for nonalphabetic cultures. This study examined the psychometric properties of the Taiwan Odd-Even Number Sequencing Test (TOENST) and identified representative norms. The TOENST and other mental screening tasks were administered to 300 randomly selected healthy participants, 32 purposive sampling patients with schizophrenia, and 32 quota sampling controls. To investigate reliability and validity, a subset of the 300 healthy participants was randomly selected to receive a second TOENST ( n = 30) or conventional WM tests ( n = 42). The split-half reliability of the TOENST ranged from 0.69 to 0.95, and its test-retest reliability was 0.75. Criterion validity was demonstrated by significant correlations with conventional WM measures (all p < .05, except semantic verbal fluency), and construct validity was demonstrated by significant correlations with aging (main effect, F_10,259 = 10.99, p < .001). Normative data were established, and performance was significantly associated with age and education. TOENST scores of patients with schizophrenia were significantly lower and correlated with frontal lobe tests, but not demographical or clinical characteristics. The TOENST has adequate psychometric properties and clinical utility and is as a viable alternative WM task for nonalphabetic cultures.

An investigation into aripiprazole's partial D₂ agonist effects within the dorsolateral prefrontal cortex during working memory in healthy volunteers

RATIONALE

Working memory impairments in schizophrenia have been attributed to dysfunction of the dorsolateral prefrontal cortex (DLPFC) which in turn may be due to low DLPFC dopamine innervation. Conventional antipsychotic drugs block DLPFC D2 receptors, and this may lead to further dysfunction and working memory impairments. Aripiprazole is a D2 receptor partial agonist hypothesised to enhance PFC dopamine functioning, possibly improving working memory.

OBJECTIVES

We probed the implications of the partial D2 receptor agonist actions of aripiprazole within the DLPFC during working memory. Investigations were carried out in healthy volunteers to eliminate confounds of illness or medication status. Aripiprazole's prefrontal actions were compared with the D2/5-HT2A blocker risperidone to separate aripiprazole's unique prefrontal D2 agonist actions from its serotinergic and striatal D2 actions that it shares with risperidone.

METHOD

A double-blind, placebo-controlled, parallel design was implemented. Participants received a single dose of either 5 mg aripiprazole, 1 mg risperidone or placebo before performing the n-back task whilst undergoing fMRI scanning.

RESULTS

Compared with placebo, the aripiprazole group demonstrated enhanced DLPFC activation associated with a trend for improved discriminability (d') and speeded reaction times. In contrast to aripiprazole's neural effects, the risperidone group demonstrated a trend for reduced DLPFC recruitment. Unexpectedly, the risperidone group demonstrated similar effects to aripiprazole on d' and additionally had reduced errors of commission compared with placebo.

CONCLUSION

Aripiprazole has unique DLPFC actions attributed to its prefrontal D2 agonist action. Risperidone's serotinergic action that results in prefrontal dopamine release may have protected against any impairing effects of its prefrontal D2 blockade.

Second-generation antipsychotic effect on cognition in patients with schizophrenia--a meta-analysis of randomized clinical trials

OBJECTIVE

To investigate the effect of second-generation antipsychotics on cognitive function in patients diagnosed with schizophrenia or schizoaffective disorder.

METHOD

Multiple-treatments meta-analysis model.

RESULTS

On cognitive composite score, sertindole was superior to clozapine, effect size (ES) 0.87; 95% CI: 0.12-1.63, quetiapine, ES 0.75; 95% CI: 0.00-1.49, and first-generation antipsychotics (FGAs), ES 0.89; 95% CI: 0.14-1.64. Analyses on each cognitive domain showed clozapine, ES 0.37; 95% CI: 0.00-0.74, olanzapine, ES 0.31; 95%CI: 0.02-0.59, quetiapine, ES 0.34; 95% CI: 0.03-0.64, and FGAs, ES 0.51; 95% CI: 0.18-0.83 performing poorer on verbal working memory than ziprasidone, as well as FGAs performing poorer than risperidone, ES 0.31; 95% CI: 0.04-0.58. On executive function, sertindole performed better than clozapine, ES 0.82; 95% CI: 0.06-1.58, olanzapine, ES 0.81; 95% CI: 0.07-1.55, quetiapine, ES 0.76; 95% CI: 0.02-1.51, ziprasidone, ES 0.90; 95% CI: 0.14-1.67, and FGAs, ES 0.83; 95% CI: 0.08-1.58. On processing speed, FGAs performed poorer than sertindole, ES 0.97; 95% CI: 0.02-1.91, and quetiapine, ES 0.36; 95% CI: 0.01-0.72. On long-term verbal working memory, clozapine performed poorer than olanzapine, ES 0.41; 95% CI: 0.06-0.76. On verbal fluency, FGAs performed poorer than olanzapine, ES 0.26; 95% CI: 0.01-0.50, and clozapine, ES 0.44; 95% CI: 0.06-0.81. Lastly, FGAs, ES 0.41; 95% CI: 0.04-0.78, and clozapine, ES 0.44; 95% CI: 0.05-0.83, performed poorer on visuospatial skill compared to olanzapine.

CONCLUSION

The meta-analysis was able to detect some trends in the data analyzed, but did not show any drug having a uniform positive cognitive profile.

WORKING MEMORY IMPAIRMENT AS AN ENDOPHENOTYPIC MARKER OF A SCHIZOPHRENIA DIATHESIS

This chapter focuses on the viability of working memory impairment as an endophenotypic marker of a schizophrenia diathesis. It begins with an introduction of the construct of working memory. It follows with a review of the operational criteria for defining an endophenotype. Research findings regarding the working memory performance of schizophrenia and schizophrenia-spectrum patients, first-degree relatives of schizophrenia patients and healthy controls, are reviewed in terms of the criteria for being considered an endophenotypic marker. Special attention is paid to specific components of the working memory deficit (namely, encoding, maintenance, and manipulation), in terms of which aspects are likely to be the best candidates for endophenotypes. We consider the extant literature regarding working memory performance in bipolar disorder and major depression in order to address the issue of relative specificity to schizophrenia. Despite some unresolved issues, it appears that working memory impairment is a very promising candidate for an endophenotypic marker of a schizophrenia diathesis but not for mood disorders. Throughout this chapter, we identify future directions for research in this exciting and dynamic area of research and evaluate the contribution of working memory research to our understanding of schizophrenia.

The cytokine model of schizophrenia: emerging therapeutic strategies

We discuss the rationale for a trial of a novel biological immunotherapy in schizophrenia (SCZ). Available antipsychotic treatments for SCZ are often limited by partial effectiveness and significant side effects. The search for novel medications is of high priority. All current antipsychotics function primarily by blocking D2-type dopamine receptors. An emerging theory of SCZ postulates disturbances of cytokines and inflammatory mediators (i.e., the cytokine model), possibly originating in part from infectious exposures. Cytokines are one of the most important components of the immune system that orchestrate the response to infectious and other exogenous insults. Preclinical models of SCZ support a convergence between a role for certain cytokines in the pathophysiology of SCZ and major neurochemical postulates of the disorder, including the dopamine and glutamate hypotheses. Several cytokines are elevated in plasma in SCZ, and positron emission tomography studies have shown active inflammation in the brains of patients with psychosis. Treatment studies of anti-inflammatory agents, such as celecoxib and aspirin, in patients with SCZ have provided further support for neuroinflammation in this disorder. The development of approved biological therapies for autoimmune diseases provides new opportunities to target cytokine signaling directly as a novel treatment strategy in SCZ. In addition, advances in imaging, immunology, and psychopharmacology have paved the way for using measures of target engagement of neuroimmune components that would facilitate the identification of patient subgroups who are most likely to benefit from cytokine modulation.

Possible dose-side effect relationship of antipsychotic drugs: relevance to cognitive function in schizophrenia

Management of adverse events is a major concern of clinicians who use antipsychotic drugs. The incidence of motor side effects is dose dependent. Atypical antipsychotic drugs are less likely to induce neurologic side effects compared with typical (conventional) antipsychotics, such as haloperidol. Some recent, large-scale studies have shown that the incidence of metabolic side effects often associated with atypical agents does not differ among typical and atypical antipsychotics. Cognitive function, such as verbal learning memory, working memory, executive function, verbal fluency and attention/information processing, is the most influential determinant of outcome in patients with schizophrenia. Atypical antipsychotic drugs have been shown to be more efficacious in treating cognitive disturbances of schizophrenia compared with typical antipsychotic drugs. Serotonin (5-hydroxytryptamine [5-HT]) receptor subtypes, such as the 5-HT1A receptor, are considered to mediate the ability of antipsychotic drugs to enhance cognition. On the other hand, treatment with some atypical agents, such as risperidone, may deteriorate working memory in some people with early-stage schizophrenia. The paradoxical side effects of these antipsychotic drugs in terms of cognition may be attributable to dose, duration of treatment and type of cognitive domain. Further research will add to the worldwide endeavor to develop more effective psychotropic drugs accompanied with minimal side effects, for the improvement of cognition, adherence and long-term outcome in patients with schizophrenia or other major psychiatric illnesses.

Efficacy of amisulpride and olanzapine for negative symptoms and cognitive impairments: An open-label clinical study

BACKGROUND

Negative symptoms and diminished cognitive ability are also considered as core features of schizophrenia. There are many studies in which negative symptoms and cognitive impairments are individually treated with atypical antipsychotic in comparison with either a placebo or a typical antipsychotic. There is paucity of studies comparing the efficacy of olanzapine and amisulpride on improvement of negative symptoms and cognitive impairments.

AIM

To examine the effectiveness of amisulpride and olanzapine in treatment of negative symptoms and cognitive impairments in schizophrenia.

MATERIALS AND METHODS

Total 40 adult inpatients diagnosed as schizophrenia fulfilling inclusion/exclusion criteria were included in the study with their informed consent. These patients were recruited consecutively to one of the two drug regimen group, i.e. tab Amisulpride (100-300 mg/day) and tab Olanzapine (10-20 mg). Patients were evaluated on day 0 and day 60 with various rating scales like Scale for the Assessment of Negative Symptoms (SANS), Scale for the Assessment of Positive Symptoms (SAPS), Schizophrenia Cognition Rating Scale (SCoRS), Brief Psychiatric Rating Scale (BPRS), Calgary Depression Scale for Schizophrenia (CDSS), and three different scales to measure drug side effects.

RESULTS

The mean SANS score in amisulpride and olanzapine group at day 0 and day 60 were 83.89 (±12.67) and 21.00 (±11.82) and 84.40 (±13.22) and 26.75 (±12.41), respectively. The mean rank of SCoRS global in amisulpride and olanzapine group at day 0 and day 60 were 4.78 (±1.13) and 2.78 (±0.63) and 4.85 (±1.18) and 3.30 (±1.12), respectively. The percentage improvement in SANS, SAPS, SCoRS interviewer, and SCoRS global in amisulpride group are 74.96%, 13.36%, 54.14%, and 42.00%, respectively. Similarly in olanzapine group percentage improvement in SANS, SAPS, SCoRS interviewer, and SCoRS global are 68.30%, 30.28%, 35.22%, and 31.95%, respectively. There is significant improvement in SANS, SCoRS, SAS, BPRS, and PANSS (Insight) in both amisulpride and olanzapine groups at the two time points. However, there is no significant difference between amisulpride and olanzapine group of patients.

CONCLUSION

Both amisulpride and olanzapine group patients showed significant improvement in negative and cognitive symptoms from baseline to endpoint, but there was no significant difference between amisulpride and olanzapine group of patients.

Conceptualization of the liability for schizophrenia: clinical implications

Historically, the Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnostic criteria for schizophrenia have emphasized several features, including symptoms of psychosis, a dissociation of symptoms from their etiology, a reliance on clinical symptoms, and a categorical approach to classifying the disorder. Although these emphases are quite useful, they have limitations. We review these here, and stress the importance of incorporating recent data on the genetic /biological and neurodevelopmental origins of schizophrenia into current conceptions of the disorder. We also review “schizotaxia, ” which is a concept thai embodies this point of view, occurs before the onset of psychosis, and is hypothesized to represent the liability for schizophrenia. If our hypothesis on this point is correct, the identification of schizotaxic individuals will eventually facilitate the development of prevention strategies by identifying a premorbid (but clinically significant) condition for schizophrenia. Moreover, the identification of biological or neuropsychological components of schizotaxia will provide more specific bases for developing novel treatment interventions. Our initial attempts to develop protocols for the assessment and treatment of schizotaxia are encouraging, and will be reviewed.

World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Schizophrenia, part 1: update 2012 on the acute treatment of schizophrenia and the management of treatment resistance

These updated guidelines are based on a first edition of the World Federation of Societies of Biological Psychiatry Guidelines for Biological Treatment of Schizophrenia published in 2005. For this 2012 revision, all available publications pertaining to the biological treatment of schizophrenia were reviewed systematically to allow for an evidence-based update. These guidelines provide evidence-based practice recommendations that are clinically and scientifically meaningful and these guidelines are intended to be used by all physicians diagnosing and treating people suffering from schizophrenia. Based on the first version of these guidelines, a systematic review of the MEDLINE/PUBMED database and the Cochrane Library, in addition to data extraction from national treatment guidelines, has been performed for this update. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into six levels of evidence (A-F; Bandelow et al. 2008b, World J Biol Psychiatry 9:242). This first part of the updated guidelines covers the general descriptions of antipsychotics and their side effects, the biological treatment of acute schizophrenia and the management of treatment-resistant schizophrenia.

Increased prefrontal cortical D₁ receptors in drug naive patients with schizophrenia: a PET study with [¹¹C]NNC112

D₁ receptors are the main mediators of dopamine transmission in the cortex and subserve cognitive functions that are affected in patients with schizophrenia. Prior imaging studies have suggested abnormalities in the expression of these receptors in schizophrenia, but no conclusive picture has emerged yet. One source of discrepancy may have been prior antipsychotic exposure. We used positron emission tomography (PET) and a D1 radiotracer, [¹¹C]NNC112, in drug naïve (DN, n = 12) and drug free (DF, n = 13) patients with schizophrenia and 40 healthy control subjects (HC, n = 40 total, n = 24 per comparison group) matched for age, gender, ethnicity, parental socioeconomic status and cigarette smoking. We measured the binding potential BPP, corrected for partial volume effects. The outcome measure was obtained in cortical and striatal subregions outlined on coregistered individual MRIs. Partial volume effect corrected BPP measures were significantly higher in DN vs controls in cortical regions. No such increases were found in the DF versus controls comparison. Furthermore, in the DF group, DF interval correlated positively with cortical BPP. We conclude that upregulation of D1 receptors in schizophrenia is related to the illness itself and may be corrected and normalized by chronic antipsychotic treatment.

Characteristics and clinical correlates of prospective memory performance in first-episode schizophrenia

OBJECTIVE

The aim of this study was to examine prospective memory (PM) and its socio-demographic, clinical, and neurocognitive correlates in first episode schizophrenia (FES).

METHODS

Fifty-one FES patients and 42 healthy controls formed the study sample. Time- and event-based PM (TBPM and EBPM) performance were measured with the Chinese version of the Cambridge Prospective Memory Test (C-CAMPROMPT). A battery of neuropsychological tests was also administered. Patients' clinical symptoms were evaluated with the Positive and Negative Symptom Scale (PANSS).

RESULTS

Patients performed significantly worse in both TBPM (8.7 ± 5.3 vs. 14.8 ± 3.5) and EBPM (11.3 ± 4.7 vs. 15.7 ± 2.7) than the controls. After controlling for age, gender, education level and neurocognitive test score, the difference in performance on the two types of PM tasks between patients and controls was no longer present. In multiple linear regression analyses, longer duration of untreated psychosis (DUP), lower scores of the Hopkins Verbal Learning Test-Revised (HVLT-R) and the categories completed of the Wisconsin Card Sorting Test (WCST-CC) and higher score of the Color Trails Test-2 (CTT-2) contributed to poorer TBPM performance, while lower score of HVLT-R, higher score of the perseverative errors of the Wisconsin Card Sorting Test (WCST-PE) and longer DUP contributed to worse performance on EBPM.

CONCLUSIONS

Both subtypes of PM are impaired in first-episode schizophrenia suggesting that PM deficits are an integral part of the cognitive dysfunction in the disease process.

Antipsychotic drug treatment for elderly people with late-onset schizophrenia

BACKGROUND

Schizophrenia is usually considered an illness of young adulthood. However, onset after the age of 40 years is reported in 23% of patients hospitalised with schizophrenia. At least 0.1% of the world's elderly population have a diagnosis of late-onset schizophrenia which seems to differ from earlier onset schizophrenia on a variety of counts including response to antipsychotic drugs.

OBJECTIVES

To assess the effects of antipsychotic drugs for elderly people with late-onset schizophrenia.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group Trials Register (January 2010) which is based on regular searches of CINAHL, EMBASE, MEDLINE and PsycINFO. We inspected references of all identified studies for further trials. We contacted relevant authors of trials for additional information.

SELECTION CRITERIA

All relevant randomised controlled trials that compared antipsychotic drugs with other treatments for elderly people (at least 80% older than 65 years) with a recent (within five years) diagnosis of schizophrenia or schizophrenia like illnesses.

DATA COLLECTION AND ANALYSIS

For the 2010 search, two new review authors (AE, AG) inspected all citations to ensure reliable selection. We assessed methodological quality of trials using the criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions. AE and AG also independently extracted data. For homogenous dichotomous data, we planned to calculate the relative risk (RR) and 95% confidence interval (CI).

MAIN RESULTS

There were no included studies in the original version of this review (2002 search). The 2010 search for the current update produced 211 references, among which we identified 88 studies. Only one study met the inclusion criteria and was of acceptable quality. This was an eight-week randomised trial of risperidone and olanzapine in 44 inpatients with late-onset schizophrenia. All participants completed the eight-week trial, indicating that both drugs were well tolerated. Unfortunately, this study provided little usable data. We excluded a total of 81 studies, 77 studies because they either studied interventions other than antipsychotic medication or because they involved elderly people with chronic - not late-onset - schizophrenia. We excluded a further four trials of antipsychotics in late-onset schizophrenia because of flawed design. Five studies are still awaiting classification, and one is on-going.

AUTHORS' CONCLUSIONS

There is no trial-based evidence upon which to base guidelines for the treatment of late-onset schizophrenia. There is a need for good quality-controlled clinical trials into the effects of antipsychotics for this group. Such trials are possible. Until they are undertaken, people with late-onset schizophrenia will be treated by doctors using clinical judgement and habit to guide prescribing.

Associations of serum brain-derived neurotrophic factor with cognitive impairments and negative symptoms in schizophrenia

Brain-derived neurotrophic factor (BDNF) may be involved in the pathophysiology of schizophrenia. The aim of this study was to examine the associations of serum BDNF levels with the cognition and clinical characteristics in patients with schizophrenia. Sixty-three patients with schizophrenia and 52 age- and sex-matched healthy controls were examined with neuropsychological tests. Serum BDNF levels were determined by enzyme-linked immunosorbent assay (ELISA). There were no significant differences in serum BDNF levels between normal controls and patients with schizophrenia. Serum BDNF levels of normal controls showed negative correlations with verbal working memory, but this was not the case with schizophrenic patients. Meanwhile, serum BDNF levels of schizophrenic patients showed positive correlations with the scores of the Scale for the Assessment of Negative Symptoms (SANS) and the Information subtest scores of Wechsler Adult Intelligence Scale Revised (WAIS-R). Serum BDNF levels are related with the impairment of verbal working memory and negative symptoms in patients with schizophrenia.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: recommendations from the British Association for Psychopharmacology

These guidelines from the British Association for Psychopharmacology address the scope and targets of pharmacological treatment for schizophrenia. A consensus meeting, involving experts in schizophrenia and its treatment, reviewed key areas and considered the strength of evidence and clinical implications. The guidelines were drawn up after extensive feedback from the participants and interested parties, and cover the pharmacological management and treatment of schizophrenia across the various stages of the illness, including first-episode, relapse prevention, and illness that has proved refractory to standard treatment. The practice recommendations presented are based on the available evidence to date, and seek to clarify which interventions are of proven benefit. It is hoped that the recommendations will help to inform clinical decision making for practitioners, and perhaps also serve as a source of information for patients and carers. They are accompanied by a more detailed qualitative review of the available evidence. The strength of supporting evidence for each recommendation is rated.

Glutamate signaling in the pathophysiology and therapy of schizophrenia

Glutamatergic neurotransmission, particularly through the N-methyl-d-aspartate (NMDA) receptor, has drawn attention for its role in the pathophysiology of schizophrenia. This paper reviews the neurodevelopmental origin and genetic susceptibility of schizophrenia relevant to NMDA neurotransmission, and discusses the relationship between NMDA hypofunction and different domains of symptom in schizophrenia as well as putative treatment modality for the disorder. A series of clinical trials and a meta-analysis which compared currently available NMDA-enhancing agents suggests that glycine, d-serine, and sarcosine are more efficacious than d-cycloserine in improving the overall psychopathology of schizophrenia without side effect or safety concern. In addition, enhancing glutamatergic neurotransmission via activating the AMPA receptor, metabotropic glutamate receptor or inhibition of d-amino acid oxidase (DAO) is also reviewed. More studies are needed to determine the NMDA vulnerability in schizophrenia and to confirm the long-term efficacy, functional outcome, and safety of these NMDA-enhancing agents in schizophrenic patients, particularly those with refractory negative and cognitive symptoms, or serious adverse effects while taking the existing antipsychotic agents.

An event-related FMRI study of phonological verbal working memory in schizophrenia

Background

While much is known about the role of prefrontal cortex (PFC) in working memory (WM) deficits of schizophrenia, the nature of the relationship between cognitive components of WM and brain activation patterns remains unclear. We aimed to elucidate the neural correlates of the maintenance component of verbal WM by examining correct and error trials with event-related fMRI.

Methodology/Findings

Twelve schizophrenia patients (SZ) and thirteen healthy control participants (CO) performed a phonological delayed-matching-to-sample-task in which a memory set of three nonsense words was presented, followed by a 6-seconds delay after which a probe nonsense word appeared. Participants decided whether the probe matched one of the targets, and rated the confidence of their decision. Blood-oxygen-level-dependent (BOLD) activity during WM maintenance was analyzed in relation to performance (correct/error) and confidence ratings. Frontal and parietal regions exhibited increased activation on correct trials for both groups. Correct and error trials were further segregated into true memory, false memory, guess, and true error trials. True memory trials were associated with increased bilateral activation of frontal and parietal regions in both groups but only CO showed deactivation in PFC. There was very little maintenance-related cortical activity during guess trials. False memory was associated with increased left frontal and parietal activation in both groups.

Conclusion

These findings suggest that a wider network of frontal and parietal regions support WM maintenance in correct trials compared with error trials in both groups. Furthermore, a more extensive and dynamic pattern of recruitment of the frontal and parietal networks for true memory was observed in healthy controls compared with schizophrenia patients. These results underscore the value of parsing the sources of memory errors in fMRI studies because of the non-linear nature of the brain-behavior relationship, and suggest that group comparisons need to be interpreted in more specific behavioral contexts.

Disruption of performance in the five-choice serial reaction time task induced by administration of N-methyl-D-aspartate receptor antagonists: relevance to cognitive dysfunction in schizophrenia

Schizophrenia patients suffer from cognitive impairments that are not satisfactorily treated by currently available medications. Cognitive dysfunction in schizophrenia encompasses deficits in several cognitive modalities that can be differentially responsive to different medications and are likely to be mediated by different neurobiological substrates. Translational animal models of cognitive deficits with relevance to schizophrenia are critical for gaining insights into the mechanisms underlying these impairments and developing more effective treatments. The five-choice serial reaction time task (5-CSRTT) is a cognitive task used in rodents that allows simultaneous assessment of several cognitive modalities, including attention, response inhibition, cognitive flexibility, and processing speed. Administration of N-methyl-D-aspartate (NMDA) glutamate receptor antagonists disrupts multiple 5-CSRTT performance measures in a way that mirrors various cognitive deficits exhibited by schizophrenia patients. Some of these disruptions are partially attenuated by antipsychotic medications that exhibit partial effectiveness on cognitive dysfunction in schizophrenia, suggesting that the model has predictive validity. Examination of the effects of pharmacological manipulations on 5-CSRTT performance disruptions induced by NMDA antagonists have implicated a range of brain regions, neurotransmitter systems, and specific receptor subtypes in schizophrenia-like impairment of different cognitive modalities. Thus, disruption of 5-CSRTT performance by NMDA antagonists represents a valuable tool for exploring the neurobiological bases of cognitive dysfunction in schizophrenia.

Genetics and intermediate phenotypes of the schizophrenia--bipolar disorder boundary

Categorization of psychotic illnesses into schizophrenic and affective psychoses remains an ongoing controversy. Although Kraepelinian subtyping of psychosis was historically beneficial, modern genetic and neurophysiological studies do not support dichotomous conceptualization of psychosis. Evidence suggests that schizophrenia and bipolar disorder rather present a clinical continuum with partially overlapping symptom dimensions, neurophysiology, genetics and treatment responses. Recent large scale genetic studies have produced inconsistent findings and exposed an urgent need for re-thinking phenomenology-based approach in psychiatric research. Epidemiological, linkage and molecular genetic studies, as well as studies in intermediate phenotypes (neurocognitive, neurophysiological and anatomical imaging) in schizophrenia and bipolar disorders are reviewed in order to support a dimensional conceptualization of psychosis. Overlapping and unique genetic and intermediate phenotypic signatures of the two psychoses are comprehensively recapitulated. Alternative strategies which may be implicated into genetic research are discussed.

Effect of second-generation antipsychotics on cognition: current issues and future challenges

Generalized cognitive impairments are stable deficits linked to schizophrenia and key factors associated with functional disability in the disorder. Preclinical data suggest that second-generation antipsychotics could potentially reduce cognitive impairments; however, recent large clinical trials indicate only modest cognitive benefits relative to first-generation antipsychotics. This might reflect a limited drug effect in humans, a differential drug effect due to brain alterations associated with schizophrenia, or limited sensitivity of the neuropsychological tests for evaluating cognitive outcomes. New adjunctive procognitive drugs may be needed to achieve robust cognitive and functional improvement. Drug discovery may benefit from greater utilization of translational neurocognitive biomarkers to bridge preclinical and clinical proof-of-concept studies, to optimize assay sensitivity, enhance cost efficiency, and speed progress in drug development.

Relationship of "prodromal" symptoms with severity and type of psychopathology in the active phase of schizophrenia

BACKGROUND

Both retrospective and prospective studies have identified a broad spectrum of "prodromal" symptoms, but their relationship to those of frank psychosis remains largely unexplored.

METHOD

In 73 successive hospitalized patients with schizophrenia in the first or second psychotic episode and with duration of illness 3 years or less from the onset of psychosis, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, Axis I diagnoses were made. In addition, within the first 5 days from the psychotic episode's onset, symptom severity was assessed with the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Stepwise regression analyses showed that 8 prodromal symptoms carried an increased risk for high total PANSS and the components of the PANSS scores, independently of sex; 1 symptom was associated with mild psychopathology. However, the categories of negative- and positive-disorganization prodromal symptoms were not associated with the corresponding PANSS components. Similar findings were observed in the nonparanoid patients, whereas in the paranoid, only 2 nonspecific symptoms were associated with high PANSS psychopathology. In addition, there were significant associations between number of prodromal symptoms and total PANSS and the subscales positive and general scores in the patients with the nonparanoid subtypes, but there were not such associations in those with the paranoid.

CONCLUSIONS

Several prodromal symptoms, as well as the number of symptoms, are associated with the severity of the psychopathology of frank psychosis. In the nonparanoid subtypes there is a continuance in the transition from the prepsychotic to the psychotic stage, whereas in the paranoid, the transition appears to be disrupted.

Weight gain related to treatment with atypical antipsychotics is due to activation of PKC-β

Atypical antipsychotics (APDs) are currently used in clinical practice for a variety of mental disorders such as schizophrenia, bipolar disorder and severe behavioral disturbances. A well-known disadvantage of using these compounds is a propensity for weight gain, resulting frequently in obesity. The mechanisms underlying pharmacologically induced weight gain are still controversial. The objective of this study was to evaluate in vitro the effects of different APDs on adipogenic events in cultured human pre-adipocytes and in rat muscle-derived stem cells (MDSCs), aiming to identify a common intracellular event contributable to these drugs. Culture behavior was evaluated in terms of cell proliferation, lipid accumulation, gene expression and morphological features. Results indicate that APDs influence adipogenic events through changes in the differentiation and proliferation of pre-adipocytes and MDSCs that are brought on by protein kinase C-β (PKC-β) activation. These data identify a signaling route that could be a potential target of pharmacological approaches for preventing the weight gain associated with APD treatment.

Specific metabolites in the medial prefrontal cortex are associated with the neurocognitive deficits in schizophrenia: a preliminary study

We measured brain metabolites in the medial prefrontal cortex of 19 schizophrenic patients and 18 healthy controls by 3 T proton magnetic resonance spectroscopy ((1)H MRS), and examined the relationship between prefrontal cortex-related neurocognitive functions and brain metabolites in the medial prefrontal cortex. The patients with schizophrenia exhibited deficits on the verbal fluency, Wisconsin card sorting test (WCST), trail making test, Stroop test and digit span distraction test (DSDT), but not on the Iowa gambling test. The patients showed statistical significant changes in the ratio of glutamine/glutamate, the ratio of N-acetyl-l-aspartate (NAA)/glycerophosphorylcholine plus phosphorylcholine (GPC+PC) and the levels of taurine in the medial prefrontal cortex compared with normal controls. Furthermore, we found significant correlations of the ratio of glutamine/glutamate with WCST and DSDT scores, the ratio of NAA/(GPC+PC) with verbal fluency and WCST scores, and the levels of taurine with scores on the Stroop test and Trail making test A among the participants. The ratios of NAA/(GPC+PC) and (GPC+PC)/(Cr+PCr) had significant relationships with the duration of untreated psychosis of the schizophrenic patients. The glutamine/glutamate ratio and levels of taurine were significantly related to the duration of illness of the patients. These data suggest that specific metabolites of the medial prefrontal cortex are associated with the neurocognitive deficits in schizophrenia.

Recent advances in treating cognitive impairment in schizophrenia

INTRODUCTION

Schizophrenia is often associated with chronic disability and poor outcome. In addition to positive symptoms, such as hallucinations and delusions, and negative symptoms including poverty of speech and blunted affect, schizophrenia is also associated with deficits in cognitive function. It has been increasingly recognized that the severity of cognitive impairment is a major determinant of outcome. Therefore, interventions to improve cognitive function also have the capacity to improve quality of life and social and occupational outcomes. Whilst some of the antipsychotic drugs have shown some selective benefits, there is some controversy about the extent of these benefits.

OBJECTIVES

This article provides an overview of research into drugs that might enhance cognition in schizophrenia.

CONCLUSION

Drugs such as modafanil and galantamine are being evaluated, and a number of new drugs are currently in development. Standardized cognitive assessment measures are being developed so studies can be compared more easily. This field is advancing rapidly, but as yet, no widely applicable, evidence-based treatments are available to the clinician.

Changes in neuropsychological functioning following treatment with risperidone, olanzapine, and conventional antipsychotic medications

OBJECTIVE

To compare changes in neuropsychological functioning over time among adults with schizophrenia treated with atypical and conventional antipsychotics, controlling for phenomenological changes, medication dosage, concomitant use of anticholinergic medications, and practice effects.

METHODS

In a larger clinical trial, 108 patients diagnosed with schizophrenia or schizoaffective disorder were randomly assigned to medication groups (risperidone, olanzapine, or conventional medications), treated in an open-label design, and monitored prospectively for 12 months using standard neuropsychological and symptomatology instruments.

RESULTS

Significant differential effects were evident on the ability to maintain and rapidly shift mental set within a psychomotor task, with patients in the conventional medication group consistently making more errors over time until the 12-month follow-up, when the olanzapine group made significantly more errors. Significant differential effects were also evident on delayed memory, with patients receiving olanzapine improving more steadily over time until the 12-month follow-up, when patients in the conventional group were able to recall significantly more. Positive and negative symptomatology was a significant, inversely related covariate on most of the cognitive measures examined.

CONCLUSIONS

The atypical and conventional medications examined were not consistently differential enhancers of cognitive functioning on disparate cognitive functioning measures over time.

Associations of SNAP-25 polymorphisms with cognitive dysfunctions in Caucasian patients with schizophrenia during a brief trail of treatment with atypical antipsychotics

The synaptosomal-associated protein of 25 kDa (SNAP-25) is part of the soluble N-ethylmaleimide-sensitive fusion protein (NSF) attachment receptor (SNARE), which mediates synaptic neurotransmission. In earlier studies a possible involvement of this protein in schizophrenia has been shown. As neurocognitive impairment is a core feature in the pathology of schizophrenia and considered to be a putative endophenotype according to genetic studies we investigated the influences of different SNAP-25 polymorphisms on neuropsychological test results before and during treatment with atypical antipsychotics. A total of 104 schizophrenic patients treated with atypical antipsychotics were genotyped for three different polymorphisms of the SNAP-25 gene (MnlI, TaiI and DdeI in the 3'-UTR). Cognitive function was assessed at baseline, week 4 or 6 and week 8 or 12. Results of individual neuropsychological tests were assigned to six cognitive domains (reaction time and quality; executive function; working, verbal and visual memory) and a general cognitive index. The MnlI and TaiI polymorphisms showed no associations to deficits on neuropsychological test results. In contrast, we observed a significant relation between the DdeI polymorphism of the SNAP-25 gene and cognitive dysfunctions. Homozygote T/T allele carriers of the DdeI polymorphism showed significant better neuropsychological test results in cognitive domains verbal memory and executive functions than those with the combined T/C and C/C genotypes (P < 0.01) at all three time points, but no differences in response to treatment with atypical antipsychotics. Additionally, TT carriers exhibited significantly better results in a general cognitive index (P < 0.05). As we observed an association between the DdeI polymorphism of the SNAP-25 gene and cognitive dysfunctions of schizophrenic patients our finding suggests that the SNAP-25 gene could play a role in the pathophysiology of neurocognitive dysfunctions in schizophrenia but is not predictive for treatment response with atypical antipsychotics.

Longitudinal studies of cognition in schizophrenia: meta-analysis

BACKGROUND

A wide range of cognitive deficits have been demonstrated in schizophrenia, but their longitudinal course remains unclear.

AIMS

To bring together all the available information from longitudinal studies of cognitive performance in people with schizophrenia.

METHOD

We carried out a meta-analysis of 53 studies. Unlike previous reviewers, we included all studies (regardless of the type of medication), analysed each variable separately and compared results with data from controls.

RESULTS

Participants with schizophrenia showed a significant improvement in most cognitive tasks. The available data for controls showed, with one exception (the Stroop test), a similar or greater improvement. Performance in semantic verbal fluency remained stable in both individuals with schizophrenia and controls.

CONCLUSIONS

Participants with schizophrenia displayed improvement in most cognitive tasks, but practice was more likely than cognitive remediation to account for most of the improvements observed. Semantic verbal fluency may be the best candidate cognitive endophenotype.

Risperidone use in children with Down syndrome, severe intellectual disability, and comorbid autistic spectrum disorders: a naturalistic study

OBJECTIVE

We report on an open-label, naturalistic study using risperidone to treat disruptive behaviors and self-injury in children with Down syndrome, severe intellectual disability, and comorbid autism spectrum disorders (DS+ASDs). We hypothesized that hyperactivity and disruptive behaviors would improve in response to risperidone treatment consistent with previous studies of children with ASD.

METHODS

Subjects were children (mean age, 7.8 +/- 2.6 years), consisting of 20 males and three females identified through our outpatient Down Syndrome Clinic between 2000 and 2004.

RESULTS

Using the Aberrant Behavior Checklist as the primary outcome measure, all five subscales showed significant improvement following risperidone treatment. The mean duration of treatment was 95.8 +/- 16.8 days, and mean total daily dose was 0.66 +/- 0.28 mg/day. The Hyperactivity, Stereotypy, and Lethargy subscale scores showed the most significant reduction (p < .001), followed by Irritability (p < .02), and Inappropriate Speech (p < .04). Children with disruptive behavior and self-injury showed the greatest improvement. Sleep quality improved for 88% of subjects with preexisting sleep disturbance. Subjects for whom a follow-up weight was available showed a mean weight increase of 2.8 +/- 1.5 kg during the treatment period.

CONCLUSIONS

These findings support our clinical impression of improvement on important target behaviors such as aggression, disruptiveness, self-injury, stereotypy, and social withdrawal. Low-dose risperidone appears to be well tolerated in children with DS+ASD, although concerns about weight gain and metabolic alterations may limit its usefulness over the long term in some children.