Cognition in schizophrenia: impairments, determinants, and functional importance

Recovery from schizophrenia: a four-year study of an inner city cohort

Converging evidence support the establishment of integrative approaches combining pharmacotherapy and psychosocial interventions for the treatment of patients with schizophrenia. Nonetheless, most studies have been limited with regard to treatment duration and their external validty has been questioned. The present study aimed at evaluating the effectiveness of the routine use of a continued integrative treatment approach in promoting clinical and social recovery from schizophrenia over 4 years. At a community mental health centre in Athens, 60 consecutive cases with a DSM-IV diagnosis of schizophrenic spectrum disorders were included into the study. Indepedent raters assessed the patients' level of functioning, cognitive impairment, disability, distress and caregivers' stress at baseline and annually for 4 years. The results of the study showed a stable linear pattern of improvement in all outcome measures with moderate to small effect sizes; while competitive employment and independent living emerged as the areas which benefited the least from the treatment program. Overall, the study supports the application of evidence-based integrative strategies to routine services, as long as they are provided in a timely and continued manner.

The importance of measuring psychosocial functioning in schizophrenia

BACKGROUND

Schizophrenia is among the most disabling of mental illnesses and frequently causes impaired functioning. We explore issues of definition and terminology, and the relationship between social functioning, cognition, and psychopathology considering relevant research findings.

METHODS

The present article describes measures of social functioning and outlines their psychometric properties. It considers their usefulness in research and clinical settings. Treatment aims and objectives are explored in the context of cognitive and social functioning. Finally, we identify areas for developing research and refining the measurement of social functioning.

RESULTS

The definition and measurement of social functioning in schizophrenia remains a complex and disputed area. The relationships between symptoms, cognitive functioning and social functioning are complex but we are beginning to understand them better. Scales for measuring functioning in clinical practice must be brief and sensitive to change and the Personal and Social Performance (PSP) scale may offer several advantages in these regards. Brief cognitive assessments focusing upon the domains most commonly affected in schizophrenia, such as verbal memory and executive functions, should be coadministered with measures of functioning.

CONCLUSIONS

The use of validated scales for schizophrenia that are sensitive to change over the course of the illness and its treatment, should allow for a better understanding of patients' functional disabilities, enabling better and more comprehensive monitoring and evaluation of both pharmacological and non-pharmacological treatment strategies.

Patterns of association between performance in a natural environment and measures of executive function in people with schizophrenia

This study examined the relationships between a set of real-world performance measures and a set of executive function measures with a sample of community based individuals with schizophrenia (N=80). Participants were given a battery of cognitive tests and were evaluated with a real-world performance measure, the Test of Grocery Shopping Skills (TOGSS). Using canonical correlation analysis, executive functions of planning, problem solving, working memory, and task persistence were significantly related to grocery shopping efficiency and accuracy. Two canonical variates with moderate correlations (0.547 and 0.519) explain that 30% of the variance in the executive function and grocery shopping measures was shared. These results identify patterns of association between executive function performance and the independent living skill of grocery shopping indicating the Test of Grocery Shopping Skills may be considered a sensitive measure of executive function performance in a real-world setting.

Can small molecules provide truly effective enhancement of cognition? Current achievements and future directions

INTRODUCTION

The prevalence of age-related diseases that implicate a deterioration of cognitive abilities is increasing. Moreover, cognitive decline occurs in numerous CNS disorders affecting patients at younger ages as well, resulting in reduced functional ability and quality of life. Despite the existence of few medications treating cognition, the need for efficacious treatment options to alleviate, halt or even prevent cognitive decline is generally unmet to date. Consequently, extensive research efforts are undertaken to identify medications that can effectively enhance cognition.

AREAS COVERED

This review covers ongoing clinical trials for cognition and reflects on efforts undertaken to increase the success rates of procognitive drug treatment. The review discusses ways to optimize the drug development process for cognition enhancing agents at the preclinical to clinical interface and provides concrete examples.

EXPERT OPINION

The existing efficacy readouts addressing cognition in preclinical research offer little translational validity to the clinical situation. In order to identify truly efficacious drug candidates, biomarkers need to be developed that directly address conserved mechanisms underlying cognitive performances. To this end, technologies such as neuroimaging or electroencephalography constitute promising entry points for identifying both the cognitive domain and the patient population most responsive to drug treatment.

Reduction in perseverative errors with adjunctive ethyl-eicosapentaenoic acid in patients with schizophrenia: Preliminary study

INTRODUCTION

Patients with schizophrenia have significant cognitive deficits, generally resistant to conventional treatment. This preliminary study examined the effects of ethyl-eicosapentanoate (EPA) on an executive function in early course patients.

PATIENTS AND METHODS

Patients with schizophrenia were given, after an informed consent, 2 g of an EPA daily for 24 weeks, in an open-label study. The Wisconsin Card Sort Test (WCST) was administered at baseline, weeks 4, 12 and 24.

RESULTS

The 27 patients, with a mean duration of illness of 4.2 years, were all receiving atypical antipsychotics; treatment remained unchanged for the study. Perseverative errors - the key measure derived from WCST - were significantly reduced from the baseline mean of 28.2 to 18.4 errors at week 24. Positive symptoms also improved significantly. There were no correlations between EPA levels and any clinical or other neuropsychological measures.

CONCLUSION

These findings suggest that an EPA has procognitive effects for patients with schizophrenia, but controlled trials are required.

Neuropsychologische Modelle von Autismus-Spektrum-Störungen

Fragestellung: Der Artikel gibt einen Überblick über die Modelle der Theory of Mind (ToM), Exekutivfunktionen (EF) und Zentralen Kohärenz (ZK), welche die neuropsychologischen Auffälligkeiten bei Menschen mit Autismus-Spektrum Störungen (ASS) treffend zu beschreiben vermögen. Methodik: In einem selektiven Review werden Ergebnisse behavioraler und funktionell-bildgebender Arbeiten zu den sozial-kognitiven, emotionalen und exekutiven Funktionen sowie der lokal-orientierten Wahrnehmung bei ASS berichtet. Ergebnisse: Beeinträchtigungen in ToM und EF sowie Besonderheiten in ZK sind vielfach replizierte Phänomene bei ASS. Vor allem soziale Wahrnehmungsprobleme und ToM haben einen hohen Erklärungswert für die klinische Symptomatik von ASS. Cerebrale Aktivierungsmuster unterscheiden sich bei Menschen mit und ohne ASS für ToM, EF und ZK. Als übergeordnetes neurales Erklärungsmodell scheint sich verringerte Konnektivität rekrutierter kortikaler Netzwerke gegen das Konzept einzelner betroffener Gehirnareale durchzusetzen. Schlussfolgerungen: Für ein besseres Verständnis der komplexen Zusammenhänge bei ASS ist eine zukünftige Integration klinischer, neuropsychologischer, funktionell-bildgebender und molekulargenetischer Befunde essenziell. Schwächen bei ToM und EF sowie Stärken in den Bereichen detail-orientierte Wahrnehmung sollten bei der individuellen Interventionsplanung verstärkt Eingang finden.

The assessment of neuropsychological functioning in schizophrenia

Overwhelming evidence suggests that compromised neuropsychological function is frequently observed in schizophrenia. The neuropsychological profile is typically characterized by prominent specific deficits in memory and learning, working memory, executive functions, attention, and processing speed, which are evident on a background of a generalized cognitive deficit This paper provides a review of studies of neuropsychological functioning in schizophrenia. The main cognitive ability areas affected in schizophrenia are described, and the degree of impairment in each ability area as found in studies of schizophrenia patients is summarized, based on meta-analytic findings. Recent studies that have compared neuropsychological functioning across psychotic disorders are presented, and finally, neuropsychological assessment batteries specifically developed for schizophrenia are introduced.

Language in schizophrenia Part 1: an Introduction

This is the first of two articles that discuss higher-order language and semantic processing in schizophrenia. This article reviews clinical characterizations of language output and the phenomenon of positive thought disorder, as well as more principled characterizations of language output in schizophrenia. It also gives an overview of evidence for the predominant theory of language dysfunction in schizophrenia: that it arises from abnormalities in (a) semantic memory and/or (b) working memory and executive function. The companion article (Part 2) focuses on the study of language in schizophrenia using online psycholinguistic methods and considers how the study of schizophrenia may inform our understanding of normal language processing.

Adolescent brain maturation, the endogenous cannabinoid system and the neurobiology of cannabis-induced schizophrenia

Cannabis use during adolescence increases the risk of developing psychotic disorders later in life. However, the neurobiological processes underlying this relationship are unknown. This review reports the results of a literature search comprising various neurobiological disciplines, ultimately converging into a model that might explain the neurobiology of cannabis-induced schizophrenia. The article briefly reviews current insights into brain development during adolescence. In particular, the role of the excitatory neurotransmitter glutamate in experience-dependent maturation of specific cortical circuitries is examined. The review also covers recent hypotheses regarding disturbances in strengthening and pruning of synaptic connections in the prefrontal cortex, and the link with latent psychotic disorders. In the present model, cannabis-induced schizophrenia is considered to be a distortion of normal late postnatal brain maturation. Distortion of glutamatergic transmission during critical periods may disturb prefrontal neurocircuitry in specific brain areas. Our model postulates that adolescent exposure to Δ9-tetrahydrocannabinol (THC), the primary psychoactive substance in cannabis, transiently disturbs physiological control of the endogenous cannabinoid system over glutamate and GABA release. As a result, THC may adversely affect adolescent experience-dependent maturation of neural circuitries within prefrontal cortical areas. Depending on dose, exact time window and duration of exposure, this may ultimately lead to the development of psychosis or schizophrenia. The proposed model provides testable hypotheses which can be addressed in future studies, including animal experiments, reanalysis of existing epidemiological data, and prospective epidemiological studies in which the role of the dose-time-effect relationship should be central.

Cognition and disability in bipolar disorder: lessons from schizophrenia research

BACKGROUND

Cognitive and functional impairments occur in patients diagnosed with bipolar disorder (BPD), although they are usually less severe and far less studied than in schizophrenia. There may be value in applying approaches developed in schizophrenia research to study cognitive functioning among BPD patients in areas including performance-based disability assessment, cognitive remediation treatments, enhancement of the accuracy of real-world functioning, and studying cognition and disability in relatives.

METHODS

We reviewed current research on cognitive and functional disability in BPD, noted areas of similarity and discrepancy to research on schizophrenia, and highlighted methods and approaches used to study schizophrenia that can be applied to study unmet needs of BPD patients.

RESULTS

Research in schizophrenia increasingly separates potential functional capacity from real-world outcome status, and has assessed contributions of cognitive impairment and other illness factors to functional outcomes. For schizophrenia, various behavioral and pharmacological treatments aimed at cognitive enhancement have been attempted, with moderate success, compared to rare studies of treatment effects on cognitive impairment in BPD. Very little research has been performed in the occurrence of cognitive impairments in first-degree relatives of people with BPD, despite evidence that cognitive impairments may be stable traits across symptomatic status in people with BPD.

CONCLUSIONS

Research and treatment approaches developed for schizophrenia can productively be applied to the study and treatment of patients diagnosed with BPD, notably including studies of the characteristics of and treatments for functional impairment related to cognitive deficits.

Pergolide treatment of cognitive deficits associated with schizotypal personality disorder: continued evidence of the importance of the dopamine system in the schizophrenia spectrum

Cognitive deficits observed in schizophrenia are also frequently found in individuals with other schizophrenia spectrum disorders, such as schizotypal personality disorder (SPD). Dopamine appears to be a particularly important modulator of cognitive processes such as those impaired in schizophrenia spectrum disorders. In a double-blind, placebo-controlled clinical trial, we administered pergolide, a dopamine agonist targeting D(1) and D(2) receptors, to 25 participants with SPD and assessed the effect of pergolide treatment, as compared with placebo, on neuropsychological performance. We found that the pergolide group showed improvements in visual-spatial working memory, executive functioning, and verbal learning and memory. These results suggest that dopamine agonists may provide benefit for the cognitive abnormalities of schizophrenia spectrum disorders.

Neurocognitive function in schizophrenia with comorbid posttraumatic stress disorder

Individuals with schizophrenia are at a greater risk for experiencing trauma and developing posttraumatic stress disorder (PTSD) than the general population. Despite an increased incidence of neurocognitive dysfunction in both schizophrenia and PTSD, there are few studies that have examined the potential compounding effects of these diagnoses when they co-occur. The current study examined this issue by administering comprehensive diagnostic, symptom, and neurocognitive evaluations to four groups including normal controls (C), as well as individuals with PTSD (PTSD), schizophrenia (SZ), or both schizophrenia and PTSD (SZP). Results indicated that when compared to the SZ group, the SZP group exhibited higher rates of positive symptoms, general psychopathology, and PTSD symptoms, as well as lower rates of negative symptoms. Regarding neurocognitive test performance, both schizophrenia groups performed significantly worse than the C and PTSD groups across all neurocognitive domains. However, differences were not significant between the SZP and SZ groups, although a differential pattern of performance between the groups was indicated. Results of this study do not support the idea that the presence of comorbid PTSD in SZ results in a substantial increase in cognitive impairment.

Diagnostic accuracy of a new instrument for detecting cognitive dysfunction in an emergent psychiatric population: the Brief Cognitive Screen

OBJECTIVES

In certain clinical contexts, the sensitivity of the Mini-Mental State Examination (MMSE) is limited. The authors developed a new cognitive screening instrument, the Brief Cognitive Screen (BCS), with the aim of improving diagnostic accuracy for cognitive dysfunction in the psychiatric emergency department (ED) in a quick and convenient format.

METHODS

The BCS, consisting of the Oral Trail Making Test (OTMT), animal fluency, the Clock Drawing Test (CDT), and the MMSE, was administered to 32 patients presenting with emergent psychiatric conditions. Comprehensive neuropsychological evaluation served as the criterion standard for determining cognitive dysfunction. Diagnostic accuracy of the MMSE was determined using the traditional clinical cutoff and receiver operating characteristic (ROC) curve analyses. Diagnostic accuracy of individual BCS components and BCS Summary Scores was determined by ROC analyses.

RESULTS

At the traditional clinical cutoff, MMSE sensitivity (46.4%) and total diagnostic accuracy (53.1%) were inadequate. Under ROC analyses, the diagnostic accuracy of the full BCS Summary Score (area under the curve [AUC]=0.857) was comparable to the MMSE (AUC=0.828). However, a reduced BCS Summary Score consisting of OTMT Part B (OTMT-B), animal fluency, and the CDT yielded classification accuracy (AUC=0.946) that was superior to the MMSE.

CONCLUSIONS

Preliminary findings suggest the BCS is an effective, convenient alternative cognitive screening instrument for use in emergent psychiatric populations.

Resting state and task-induced deactivation: A methodological comparison in patients with schizophrenia and healthy controls

Changes in the default mode network (DMN) have been linked to multiple neurological disorders including schizophrenia. The anticorrelated relationship the DMN shares with task-related networks permits the quantification of this network both during task (task-induced deactivations: TID) and during periods of passive mental activity (extended rest). However, the effects of different methodologies (TID vs. extended rest) for quantifying the DMN in the same clinical population are currently not well understood. Moreover, several different analytic techniques, including independent component analyses (ICA) and seed-based correlation analyses, exist for examining functional connectivity during extended resting states. The current study compared both methodologies and analytic techniques in a group of patients with schizophrenia (SP) and matched healthy controls. Results indicated that TID analyses, ICA, and seed-based correlation all consistently identified the midline (anterior and posterior cingulate gyrus) and lateral parietal cortex as core regions of the DMN, as well as more variable involvement of temporal lobe structures. In addition, SP exhibited increased deactivation during task, as well as decreased functional connectivity with frontal regions and increased connectivity with posterior and subcortical areas during periods of extended rest. The increased posterior and reduced anterior connectivity may partially explain some of the cognitive dysfunction and clinical symptoms that are frequently associated with schizophrenia.

Glutamatergic deficits and parvalbumin-containing inhibitory neurons in the prefrontal cortex in schizophrenia

BACKGROUND

We have previously reported that the expression of the messenger ribonucleic acid (mRNA) for the NR2A subunit of the N-methyl-D-aspartate (NMDA) class of glutamate receptor was decreased in a subset of inhibitory interneurons in the cerebral cortex in schizophrenia. In this study, we sought to determine whether a deficit in the expression of NR2A mRNA was present in the subset of interneurons that contain the calcium buffer parvalbumin (PV) and whether this deficit was associated with a reduction in glutamatergic inputs in the prefrontal cortex (PFC) in schizophrenia.

METHODS

We examined the expression of NR2A mRNA, labeled with a 35S-tagged riboprobe, in neurons that expressed PV mRNA, visualized with a digoxigenin-labeled riboprobe via an immunoperoxidase reaction, in twenty schizophrenia and twenty matched normal control subjects. We also immunohistochemically labeled the glutamatergic axon terminals with an antibody against vGluT1.

RESULTS

The density of the PV neurons that expressed NR2A mRNA was significantly decreased by 48-50% in layers 3 and 4 in the subjects with schizophrenia, but the cellular expression of NR2A mRNA in the PV neurons that exhibited a detectable level of this transcript was unchanged. In addition, the density of vGluT1-immunoreactive boutons was significantly decreased by 79% in layer 3, but was unchanged in layer 5 of the PFC in schizophrenia.

CONCLUSION

These findings suggest that glutamatergic neurotransmission via NR2A-containing NMDA receptors on PV neurons in the PFC may be deficient in schizophrenia. This may disinhibit the postsynaptic excitatory circuits, contributing to neuronal injury, aberrant information flow and PFC functional deficits in schizophrenia.

Neuropsychological performance as endophenotypes in extended schizophrenia families from the Central Valley of Costa Rica

OBJECTIVE

The understanding of complex heritable psychiatric disorders such as schizophrenia could be clarified by examining endophenotypes within genetically isolated populations, such as the one found in the Central Valley of Costa Rica. The reduction of familial variability within a sample could allow the relationship between the cognitive and symptomatic manifestations of the illness and the genetic underpinnings to become more observable. This study investigates the neuropsychological test performances of 41 family members from four extended multiplex families within the Spanish origin population of the Central Valley of Costa Rica as potential endophenotypes for genetic studies.

METHODS

Individuals with a diagnosis of schizophrenia or schizoaffective disorder were compared with unaffected relatives and 15 unrelated controls with no family history of schizophrenia.

RESULTS

Although the sample size is small, the results confirm previous reports in the literature of deficits in working memory, executive function, processing speed, and verbal fluency in individuals with schizophrenia compared with controls and intermediate performance in nonpsychotic family members compared with controls. We also found several suggestive quantitative cognitive trait loci with log of the odds greater than 1.75.

CONCLUSION

These findings suggest that the cognitive deficits in schizophrenia are consistent aspects of the illness, although their usefulness as endophenotypes for genetic studies remains unclear.

Absence of established sex differences in patients with schizophrenia on a two-dimensional object array task

Sex differences are pervasive in schizophrenia, ranging from differences in the age of onset and symptoms of the illness to structural brain differences. Yet, there has been very little research on the interaction of these differences with established cognitive sex differences that exist in healthy populations. We tested 25 patients with schizophrenia and 17 healthy controls on a two-dimensional task of object location memory. It has been previously shown that healthy females outperform healthy males on this task, a result that was upheld in this experiment. However, the female advantage is completely absent in patients with schizophrenia. This finding has important implications for the interpretation of clinical and physiological sex differences present in schizophrenia.

Cognitive functioning and negative symptoms in first episode schizophrenia: different patterns of correlates

Negative symptoms of schizophrenia have been related to disturbances of executive functions, memory, attention and motor functioning. The executive functions dimension comprises a variety of cognitive subprocesses, including speed of processing, flexibility and working memory. We independently analysed the relationship between different cognitive tasks and clinical symptoms (negative, positive and disorganized) in a sample of 126 first-episode patients with schizophrenia spectrum disorders. Negative symptoms were significantly associated with performance on executive-functions and motor coordination tasks. Within the executive functions domain only those tests that required speeded performance showed a significant association with the negative dimension. The widely described relationship between negative symptoms and executive impairments in schizophrenia appears to be mediated by likely dysfunctions in the speed of processing instead of by working memory impairment.

Relative contribution of antipsychotics, negative symptoms and executive functions to social functioning in stable schizophrenia

The purpose of this study was to examine the relative contributions of antipsychotic medication, negative symptoms and executive functions to impairment in social functioning in a sample of outpatients with stable schizophrenia. One-hundred and sixty-eight consecutive outpatients with stable schizophrenia were enrolled in a cross-sectional study. We performed a path analysis using multiple regression technique in order to assess the specific effect of antipsychotic type (first-generation antipsychotics versus second-generation antipsychotics) on social functioning and the possible mediating role of executive functions and negative symptoms. Our findings suggested that (i) second generation antipsychotics (SGAs) use predicted better social functioning (Beta=.24, p=.003) and better executive functions (Beta=.25, p=.003); conversely SGAs use was not associated with lesser negative symptoms (Beta=.00, p=.981); (ii) impaired executive functions and severity of negative symptoms were associated with worse social functioning (Beta=.19, p=.016; Beta=.28, p=.001); (iii) when we inserted in the model Positive and Negative Syndrome Scale - Negative Symptom subscale (PANSS-N) and Wisconsin Card Sorting Test - number of achieved sorting categories (WCST-cat), the former failed to show a mediation effect, while the latter seemed to mediate partially the effect of SGAs on social functioning. Taken together, the present results suggest that it is critical to examine individually executive functions and negative symptoms because they seem to relate to social functioning in different and independent ways and thus might represent separable treatment targets. Furthermore, social functioning appears a complex outcome multiply determined with no single predictor variable explaining a sufficient amount of variance.

Neuropsychological status of bipolar I disorder: impact of psychosis

BACKGROUND

The presence of schizotypal personality traits in some people with bipolar disorder, together with reports of greater cognitive dysfunction in patients with a history of psychotic features compared with patients without such a history, raises questions about the nosological relationship between bipolar disorder with psychotic features and bipolar disorder without psychotic features.

AIMS

To test the impact of a history of DSM-IV-defined psychosis on the neuropsychological status of participants with bipolar disorder while statistically controlling for confounding factors such as mood, medication, alcohol misuse/dependence and childhood abuse, and to evaluate the impact of schizotypal personality traits (and thus potential vulnerability to psychotic illness) on the cognitive performance of people with bipolar disorder and their healthy relatives.

METHOD

Neuropsychological data were obtained for 25 participants with type I bipolar disorder and a history of psychosis, 24 with type I bipolar disorder but no history of psychosis and 61 unaffected relatives. Schizotypal traits were measured with the Schizotypal Personality Scale (STA). Childhood trauma was measured with the Childhood Trauma Questionnaire.

RESULTS

The group with a history of psychosis performed significantly worse than the healthy relatives on measures of verbal working memory, cognitive flexibility and declarative memory. Nevertheless, the two bipolar disorder groups did not differ significantly from each other on any cognitive measure. Scores on the STA were negatively associated with verbal working and declarative memory, but positively associated with visual recall memory.

CONCLUSIONS

'Psychotic' and 'non-psychotic' subtypes of bipolar disorder may lie on a nosological continuum that is most clearly defined by verbal memory impairment.

Added ondansetron for stable schizophrenia: a double blind, placebo controlled trial

It is well documented that 5-hydroxytryptamine3 (5-HT3) receptors are involved in the pathogenesis of schizophrenia and cognitive impairment. The purpose of this study was to assess the efficacy of ondansetron, a 5-HT3 receptor antagonist as an adjuvant agent in the treatment of chronic schizophrenia in particular for cognitive impairments. This investigation was a 12-week, double blind study of parallel groups of patients with stable chronic schizophrenia. Thirty patients were recruited from inpatient and outpatient departments. All participants met Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision (DSM-IV-TR) criteria for schizophrenia. To be eligible, patients were required to have been treated with a stable dose of risperidone as their primary antipsychotic treatment for a minimum period of 8 weeks. The subjects were randomized to receive ondansetron (8 mg/day) or the placebo in addition to risperidone. Clinical psychopathology was assessed with Positive and Negative Syndrome Scale (PANSS). Cognition was measured by a cognitive battery. Patients were assessed at baseline and after 8, and 12 weeks after the medication started. The PANSS scores and cognitive performance were used as the outcome measures. The ondansetron group had significantly greater improvement in the negative symptoms, general psychopathological symptoms and PANSS total scores over the trial. Administration of ondansetron significantly improved visual memory based on improvement on visual reproduction, visual paired associate and figural memory sub tests of Wechsler Memory Scale--Revised. The present study indicates ondansetron as potential adjunctive treatment strategy for chronic schizophrenia particularly for negative symptoms and cognitive impairments.

Schizophrenia with obsessive-compulsive disorder and obsessive-compulsive disorder with poor insight: a neuropsychological comparison

Schizophrenia patients with obsessive-compulsive disorder (OCD) may be a subgroup of schizophrenia, and OCD patients with poor insight may show psychotic-like symptoms. The aim of this work is to compare the neuropsychological performance of those patients with schizophrenic patients who do not have OCD symptoms and with OCD patients who have good insight. The sample consisted of 89 patients (16 OCD-schizophrenic patients, 30 non-OCD schizophrenic patients, 30 OCD patients with good insight, 13 OCD patients with poor insight). Neuropsychological evaluation included executive functions, verbal and visual memory and attention tasks. While schizophrenic patients with OCD did not differ from the non-OCD schizophrenia and OCD with poor insight groups on long-term visual and verbal memory performance, they showed poorer performance than the OCD group on long-term visual and verbal memory tests. Considering executive function, the OCD group with poor insight performed significantly worse than their counterparts with good insight, and the latter group performed better than the schizophrenia patients. The results of this study suggest that the neuropsychological performance of schizophrenia patients with OCD did not differ from that of non-OCD schizophrenic patients, and that OCD patients with poor insight were more likely to share similar cognitive characteristics with the schizophrenia groups. Our results also provide neuropsychological support for the hypothesis that OCD and schizophrenia may be a spectrum disorders.

Working memory impairments in first-episode psychosis and chronic schizophrenia

Working memory (WM) impairments are core cognitive deficits in patients with schizophrenia linked to prefrontal cortical dysfunctions. Determining the differences between early phases of illness allows a better understanding of its course and constitutes an important guide for treatment. The present cross-sectional study examined differences of working memory functions between 33 first-episode and 29 chronic schizophrenic patients, as well as 64 healthy controls. On the basis of a two-back visual-verbal computerized working memory task, reaction time was slower and accuracy was worse in both patient groups than in controls. Test variables, however, were not significantly different between the patient groups, suggesting stability of the deficits over time. Effect size accuracy variables nevertheless showed larger deficits in chronic patients.

A 12-week, double-blind, placebo-controlled trial of donepezil adjunctive treatment to risperidone in chronic and stable schizophrenia

There is considerable incentive to develop new treatment strategies that effectively target cognitive deficits in schizophrenia. One of the theoretically promising novel treatment candidates is acetylcholinesterase inhibitors that increase the synaptic levels of cholinergic, nicotinic, and muscarinic receptor activity. The purpose of this study was to assess the efficacy of donepezil as an adjuvant agent in the treatment of chronic schizophrenia in particular for cognitive impairments. This investigation was a 12-week, double-blind study of parallel groups of patients with stable chronic schizophrenia. Thirty patients were recruited from inpatient and outpatient departments, age ranging from 22 to 44 years. All participants met DSM-IV-TR. diagnostic criteria for schizophrenia. To be eligible, patients were required to have been treated with a stable dose of risperidone as their primary antipsychotic treatment for a minimum period of 8 weeks. The subjects were randomized to receive donepezil (10 mg/day) or placebo, in addition to risperidone (4-6 mg/day). Clinical psychopathology was assessed with Positive and Negative Syndrome Scale (PANSS). Cognition was measured by a cognitive battery. Patients were assessed by a psychiatrist at baseline and after 8, and 12 weeks after the medication started. The PANSS scores and cognitive performance were used as the outcome measures. The donepezil group had significantly greater improvement in the negative symptoms over the 12-week trial. There were no differences between the donepezil and placebo groups on any neurocognitive assessments at endpoint (week 12). The present study indicates donepezil as a potential adjunctive treatment strategy for negative symptoms of chronic schizophrenia.

Distinct conflict resolution deficits related to different facets of Schizophrenia

An important issue in understanding the nature of conflict processing is whether it is a unitary or multidimensional construct. One way to examine this is to study whether people with impaired conflict processing exhibit a general pattern of deficits or whether they exhibit impairments in distinct aspects of conflict processing. One group who might exhibit conflict deficits are people with schizophrenia. Schizophrenia is a heterogeneous disorder, with one way to break down the heterogeneity of schizophrenia is to examine specific symptoms. Previous research has found that specific symptoms of schizophrenia are associated with specific deficits in conflict processing. In particular, disorganization is associated with increased response conflict, alogia is associated with increased retrieval conflict, and anhedonia is associated with increased emotional conflict. Moreover, there is evidence that different types of conflict processing are unassociated with each other. This evidence suggests that conflict processing is a multidimensional construct and that different aspects of schizophrenia are associated with impairments in processing different types of conflict.

The dual-state theory of prefrontal cortex dopamine function with relevance to catechol-o-methyltransferase genotypes and schizophrenia

There is now general consensus that at least some of the cognitive deficits in schizophrenia are related to dysfunctions in the prefrontal cortex (PFC) dopamine (DA) system. At the cellular and synaptic level, the effects of DA in PFC via D1- and D2-class receptors are highly complex, often apparently opposing, and hence difficult to understand with regard to their functional implications. Biophysically realistic computational models have provided valuable insights into how the effects of DA on PFC neurons and synaptic currents as measured in vitro link up to the neural network and cognitive levels. They suggest the existence of two discrete dynamical regimes, a D1-dominated state characterized by a high energy barrier among different network patterns that favors robust online maintenance of information and a D2-dominated state characterized by a low energy barrier that is beneficial for flexible and fast switching among representational states. These predictions are consistent with a variety of electrophysiological, neuroimaging, and behavioral results in humans and nonhuman species. Moreover, these biophysically based models predict that imbalanced D1:D2 receptor activation causing extremely low or extremely high energy barriers among activity states could lead to the emergence of cognitive, positive, and negative symptoms observed in schizophrenia. Thus, combined experimental and computational approaches hold the promise of allowing a detailed mechanistic understanding of how DA alters information processing in normal and pathological conditions, thereby potentially providing new routes for the development of pharmacological treatments for schizophrenia.

A review of repetitive transcranial magnetic stimulation use in the treatment of schizophrenia

Patients with schizophrenia often fail to respond to standard antipsychotic medications or have a partial treatment response. Few treatment options are available for these patients. Repetitive transcranial magnetic stimulation (rTMS) was developed and investigated over the last 10 years as a potential treatment option for various psychiatric conditions. Increasingly, studies are focusing on potential applications of rTMS in schizophrenia. To date, most of these studies were symptom-specific rather than focused on the treatment of the disorder in general. The most extensive literature focuses on the use of low-frequency stimulation to attempt to disrupt or reduce the intensity of persistent refractory auditory hallucinations. This research tends to suggest that rTMS could have a role in this subset of patients. There is also preliminary but limited evidence that rTMS could have a role in reducing the negative symptoms of schizophrenia and perhaps in augmenting cognitive function. These findings also highlight the pressing need for further research including multisite studies to confirm the value of these options.

Context processing in schizotypal personality disorder: evidence of specificity of impairment to the schizophrenia spectrum

Working memory abnormalities, which are particularly pronounced on context processing tasks, appear relatively specific to schizophrenia spectrum illnesses compared with other psychotic disorders. However, the specificity of context processing deficits to schizotypal personality disorder (SPD), a prototype of schizophrenia, has not been studied. The authors administered 3 versions of the modified AX Continuous Performance Test and an N-back working memory test to 63 individuals with SPD and 25 with other personality disorders, as well as 42 healthy controls. For the AX Continuous Performance Test standard and degraded versions, there was a significant Trial Type x Delay x Group interaction, as SPDs made significantly more errors reflecting poor maintenance of context and fewer errors reflecting good maintenance of context. SPDs also demonstrated poor performance on the N-back, especially at the 2-back condition. Context processing errors and N-back accuracy scores were related to disorganization symptoms. These findings, which are quite similar to those previously reported in patients with schizophrenia, suggest that context processing deficits are specific to the schizophrenia spectrum and are not a reflection of overall psychopathology.

Emotion word use in the conversational speech of schizophrenia patients

INTRODUCTION

Many recent studies have found that, although schizophrenia patients tend to display diminished facial expressions of emotion, they report levels of emotional experiences that are similar to those of controls. Although these findings are very informative, it is unknown whether such dissociation exits for other modalities such as verbal expression of emotion. The purpose of this study was to investigate the association between the use of emotion words during a free speech task and subjective experience of emotion in schizophrenia patients and controls.

METHODS

Speech samples of 48 schizophrenia patients and 48 nonpsychiatric control individuals were compared on the type and amount of emotional words used, as well as on the level of self-reported stress experienced while providing descriptions of themselves.

RESULTS

Groups did not differ in the amount or type of emotion words uttered during the free speech task. Patients, however, found the task more stressful than controls. Emotion word use and subjective emotional experience were not related in either group.

CONCLUSIONS

Results do not fully support prior findings, but are consistent with the notion of a lack of correspondence between the expression and experience of emotion.

Differentiating cortical patterns of cognitive dysfunction in schizophrenia and posttraumatic stress disorder

Comparative studies are needed to determine whether the cognitive impairments found in various psychiatric disorders are specific to those disorders, or are a more universal consequence of mental illness. This study compares the patterns of cognitive dysfunction in two conditions characterized by working memory dysfunction, schizophrenia and posttraumatic stress disorder (PTSD). Three matched groups (Schizophrenia, PTSD, Control) of 16 subjects had event related potentials recorded, using a 27 electrode array, while they performed a working memory auditory target detection task. Both disorders were associated with impaired task performance, with greater impairment in schizophrenia. Reduction in N1 amplitude was found only in schizophrenia, and an increase in target N2 amplitude and latency was found only in PTSD. Both patient groups showed a reduction in the amplitude of the non-target and target P3, but the groups were distinguished by a reduction in non-target parietal P3 amplitude in the schizophrenia group and a reduction in target P3 amplitude over the left posterior parietal region in the PTSD Group. This study demonstrates that there are specific patterns of cognitive dysfunction associated with schizophrenia and with PTSD.

Working memory and multi-tasking in paranoid schizophrenia with and without comorbid substance use disorder

AIMS

Addiction is a frequent comorbid disorder in schizophrenia and associated with poor outcome. The present study sought to determine whether addicted and non-addicted schizophrenic patients are impaired differentially on the executive abilities of working memory and multi-tasking which are relevant for maintaining abstinence.

DESIGN

Comparisons of executive performance in clinical and control groups.

SETTING

In-patient setting.

PARTICIPANTS

The cognitive profile of schizophrenic patients with and without comorbid substance abuse disorder was compared with that of patients suffering from major depression or alcoholism and healthy participants.

MEASUREMENTS

A range of cognitive tasks was used to assess: (i) the ability to update continuously context information in working memory and to use it for action selection; and (ii) the capacity to divide attention between different sensory input channels and to coordinate verbal and manual responses.

FINDINGS

Single-diagnosis schizophrenic patients showed pronounced impairments on measures of online maintenance and use of context information. Their ability to coordinate different sensory input channels (divided attention) was also impaired. Addicted schizophrenics showed evidence of impaired sensory input management and of reduced context sensitivity, when age differences were controlled.

CONCLUSIONS

The present study indicates severe working memory and multi-tasking deficits in schizophrenia which are, however, not exacerbated by comorbid addiction.

Disease-specific alterations in glutamatergic neurotransmission on inhibitory interneurons in the prefrontal cortex in schizophrenia

Glutamatergic modulation of inhibitory interneurons plays a crucial role in shaping the flow of information in the cerebral cortex. In a cohort of postmortem human brains from schizophrenia (n=20), bipolar disorder (n=20) and normal control (n=20) subjects, we colocalized the mRNA for the N-methyl-d-aspartate (NMDA) receptor NR2A subunit, labeled with [35S], and the mRNA for the gamma-aminobutyric acid (GABA) synthesizing enzyme glutamic acid decarboxylase (GAD)67, labeled with digoxigenin. We found that the density of GAD67+ neurons in layers 2-5 of the prefrontal cortex was decreased by 27-36% in both schizophrenia and bipolar disorder. In addition, the density of the GAD67+/NR2A+ neurons was decreased by 57% and 49% in layers 3 and 4, respectively, in schizophrenia, but it was unchanged in bipolar disorder. These findings raise the possibility that glutamatergic innervation of inhibitory interneurons via the NMDA receptor in the prefrontal cortex may be selectively altered in schizophrenia.

Processing speed mediates the relationship between verbal memory, verbal fluency, and functional outcome in chronic schizophrenia

Verbal fluency and verbal memory have been reported to be diminished in patients with schizophrenia. These deficits could partially predict functional disability in this pathology. However, processing speed often mediates the relationship among cognitive processes in the disorder. Our goal was to analyse the influence of processing speed as mediator of the relation between verbal fluency-verbal memory and functional disability in chronic schizophrenia. We examined 90 hospitalized patients and 30 healthy controls (matched for gender, age and years of education). The neuropsychological battery included tests for verbal fluency, verbal memory, motor speed and processing speed. Outcome measures included Disability Assessment Schedule (DAS-WHO) and number of hospitalizations (NH). Results confirmed chronicity on clinical symptoms (PANSS total X=48.94+14.97 PANSS negative X=27.81+10.18, PANSS positive X=23.51+10.81) and impairment on functional disability (DAS-WHO X=13.62+4.28). As expected, verbal fluency was severely impaired in patients and significantly predicted functional outcome. Immediate and Delayed Verbal Memory were also severely impaired and predicted functional outcome. However, when processing speed was entered in the regression analyses the significance of verbal fluency and verbal memory decreased significantly. Sobel's equation was significant, suggesting full mediation. Our findings suggest that processing speed may be a central factor in the relation between cognitive symptoms and functional outcome in chronic schizophrenia.

Subtle cognitive dysfunction in nonaffected siblings of individuals affected by nonpsychotic disorders

BACKGROUND

Previous studies have reported that as a group, individuals affected by psychotic and nonpsychotic disorders perform below norms on cognitive tests. Other studies have indicated that unaffected siblings of individuals affected by psychotic disorders also perform below norms on the same tests. We investigated cognitive performance on a large, population-based sample of individuals, affected at the time of testing by nonpsychotic disorders, and their unaffected siblings.

METHODS

Subjects were taken from a population-based cohort of 523,375, 16- to 17-year-old male adolescents who had been assessed by the Israeli Draft Board. Cognitive test scores were examined in sib-pairs discordant for nonpsychotic (n = 19,489) and psychotic (n = 888) disorders and compared with 224,082 individuals from sibships with no evidence of mental illness.

RESULTS

There appears to be a gradient in cognitive performance (worst to best) from individuals currently affected by psychotic illnesses (Cohen's d = -.82), followed by individuals currently affected by nonpsychotic illness (Cohen's d = -.58), unaffected siblings of individuals affected by psychotic illness (Cohen's d = -.37), unaffected siblings of individuals affected by nonpsychotic illness (Cohen's d = -.27), and members of sibships with no evidence of mental illness. Unaffected siblings of both psychotic and nonpsychotic individuals from multiple affected sibships (more then one affected sibling) had worse cognitive test scores compared with unaffected siblings from simplex sibships (only one affected sibling).

CONCLUSIONS

The results support, but do not prove, the notion that cognitive impairment in psychiatric disorders is familial and cuts across diagnostic entities.

Deficits in neurocognition, theory of mind, and social functioning in patients with schizophrenic disorders: are they related?

In schizophrenic disorders, impairments in social functioning, neurocognition, and theory of mind (ToM) are frequently reported but little is known about the relationships between them. The aim of this study is twofold: (a) to compare neurocognition, social-functioning, and ToM in patients and controls and (b) to investigate whether impairments in these domains are related to psychiatric symptoms. Participants were 16 outpatients with schizophrenic disorders (DSM-IV), and 16 healthy controls. We administered neuropsychological tests, ToM, social functioning, and psychopathology measures. Patients and controls differed on most neurocognitive variables (memory, attention, executive functions). We also found significant differences in 1 ToM factor and 2 social measures. The latter were the only 2 related to manic-hostility and negative symptoms subscores of Brief Psychiatric Rating Scale. Our findings suggest that there is no direct relation between neurocognitive impairments and social dysfunctions.

[Perturbed consciousness in schizophrenia: an evaluation of C.D. Frith's model]

INTRODUCTION

While many neurocognitive models of schizophrenia coexist, a lot of attention has been centered on C.D. Frith's model over the past few years, especially in regard to its parsimony.

BACKGROUND

The aim of this paper is to examine its validity. The model relies on the assumption that there are two main components: self-monitoring and monitoring. The first permits one to keep consciousness of personal goals and intentions with metarepresentations. Losing consciousness of personal goals would be the source of schizophrenics' avolition and losing consciousness of personal intentions would generate reference ideas. The second component refers to the so-called "theory of mind", which is the monitoring of others' mental content (knowledge and intentions). Disturbing monitoring would cause schizophrenics persecution disillusions, third order persecutions or speech content disorders.

LITERATURE FINDINGS

After reviewing the empirical and theoretical bases of Frith's model, strengths and weaknesses are highlighted, in particular by contrasting Hardy-Baylé's and Abu-Akel's theoretical proposals. For explaining the monitoring impairments of schizophrenics, Hardy-Baylé's model emphasizes the executive functioning defect, while Abu-Akel's model proposes a "hyper theory of mind" where too many hypotheses would lead to misattributions. In addition, several criticisms of Frith's model are examined, particularly those voiced by phenomenologists who underline its reductionism presupposition and argue that the underlying cognitive conception of the "theory of mind" neglects the fundamental intersubjectivity issue. In addition, Gallagher points out that monitoring is a tautological concept and that intention is not like thinking inherent to behaviour.

CONCLUSION

Frith's model validity is finally discussed at large in the light of these criticisms and competing models, and it is concluded that the self-monitoring part of the model needs to be redefined and that the measurement of the "theory of mind" has to be standardized.

Self-assessment of functional status in schizophrenia

With new treatments targeting features of schizophrenia associated with functional disability, there is a need to evaluate the validity of ratings of everyday outcomes. It is unknown whether patients can validly self-report on aspects of their functional status, which would be a potentially economical method for obtaining outcome data. In this study, 67 older schizophrenia outpatients provided self-ratings of everyday real-world functioning using the specific levels of functioning scale (SLOF). They were also administered assessments of neuropsychological performance, performance-based measures of functional capacity and social skills, clinical symptoms, and quality of life. Case managers, unaware of other ratings, also generated SLOF ratings. Based on discrepancy scores, participants were categorized as accurate raters (n=24), underestimators (n=16), or overestimators (n=27) of their functional status as compared to case managers' ratings. Patients' self-rated functional status was correlated with their subjective quality of life, but remarkably unassociated with case manager ratings of functional status or their own performance on functional capacity or social skills measures. Case manager ratings, however, were highly correlated with performance on functional capacity and social skills measures. Patients who underestimated their real world performance had better cognitive skills and greater self-rated depression than those who overestimated. Accurate raters demonstrated greater social skills than both overestimators and underestimators, while overestimators were most cognitively and functionally impaired. Accurate ratings of everyday outcomes in schizophrenia may require systematic observation of real world outcomes or performance-based measures, as self-reports were inconsistent with objective information.

A review of the effects of modafinil on cognition in schizophrenia

Modafinil, a wake-promoting agent believed to operate via the hypocretin/orexin system, has a similar clinical profile to that of conventional, dopaminergic stimulants but different biochemical and pharmacological properties. There is increasing interest in the use of modafinil to improve cognition in schizophrenia as well as in other disorders such as attention-deficit/hyperactivity disorder. Recent research has focused on enhancing cognition in patients with schizophrenia because of the association between cognitive performance and functional outcome. Initial findings indicate that modafinil may lead to better executive functioning and attentional performance in patients with schizophrenia. The results further suggest that patient characteristics such as overall current cognitive functioning levels, genetic polymorphisms, and medication status may be important mediators for the effectiveness of modafinil, allowing for future treatment to be targeted to those most likely to benefit. Currently, further research is required to address the potential benefits and risks of chronic administration of modafinil to patients with schizophrenia.

Physical illness and schizophrenia: a review of the literature

OBJECTIVE

The lifespan of people with schizophrenia is shortened compared to the general population. We reviewed the literature on comorbid physical diseases in schizophrenia to provide a basis for initiatives to fight this unacceptable situation.

METHOD

We searched MEDLINE (1966 - May 2006) combining the MeSH term of schizophrenia with the 23 MeSH terms of general physical disease categories to identify relevant epidemiological studies.

RESULTS

A total of 44 202 abstracts were screened. People with schizophrenia have higher prevalences of HIV infection and hepatitis, osteoporosis, altered pain sensitivity, sexual dysfunction, obstetric complications, cardiovascular diseases, overweight, diabetes, dental problems, and polydipsia than the general population. Rheumatoid arthritis and cancer may occur less frequently than in the general population. Eighty-six per cent of the studies came from industrialized countries limiting the generalizability of the findings.

CONCLUSION

The increased frequency of physical diseases in schizophrenia might be on account of factors related to schizophrenia and its treatment, but undoubtedly also results from the unsatisfactory organization of health services, from the attitudes of medical doctors, and the social stigma ascribed to the schizophrenic patients.

The pipeline and future of drug development in schizophrenia

While the current antipsychotic medications have profoundly impacted the treatment of schizophrenia over the past 50 years, the newer atypical antipsychotics have not fulfilled initial expectations, and enormous challenges remain in long-term treatment of this debilitating disease. In particular, improved treatment of the negative symptoms and cognitive dysfunction in schizophrenia which greatly impact overall morbidity is needed. In this review we will briefly discuss the current pipeline of drugs for schizophrenia, outlining many of the strategies and targets currently under investigation for the development of new schizophrenia drugs. Many of these compounds have great potential as augmenting agents in the treatment of negative symptoms and cognition. In addition, we will highlight the importance of developing new paradigms for drug discovery in schizophrenia and call for an increased role of academic scientists in discovering and validating novel drug targets. Indeed, recent breakthroughs in genetic studies of schizophrenia are allowing for the development of hypothesis-driven approaches for discovering possible disease-modifying drugs for schizophrenia. Thus, this is an exciting and pivotal time for the development of truly novel approaches to drug development and treatment of complex disorders like schizophrenia.

Ziprasidone for schizophrenia and bipolar disorder: a review of the clinical trials

Ziprasidone is a newer "atypical" or "second-generation" antipsychotic. Oral ziprasidone (ziprasidone hydrochloride) is approved by the U.S. Food and Drug Administration (FDA) for the treatment of schizophrenia, and acute manic or mixed episodes associated with bipolar disorder (with or without psychotic features). Ziprasidone intramuscular (ziprasidone mesylate) is FDA-approved for acute agitation in patients with schizophrenia. Oral ziprasidone appears efficacious, and has been shown to have some limited clinical advantages over chlorpromazine and haloperidol in ameliorating negative symptoms of schizophrenia. In Phase 2 of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) for schizophrenia, ziprasidone did not match the clinical performance of olanzapine and risperidone, appearing closer in overall effectiveness to quetiapine. The rate of dose titration and the dose achieved may have an important bearing on ziprasidone's efficacy profile. In studies of usage for acute agitation in individuals with schizophrenia, intramuscular ziprasidone has been shown to be efficacious and relatively well tolerated. Regarding tolerability, ziprasidone, has important advantages in that it is not associated with clinically significant weight gain or adverse changes in cholesterol, triglycerides, or glycemic control, and patients may experience moderate improvement in these measures when switching to ziprasidone from a different antipsychotic agent. It also lacks significant persistent effects on prolactin levels, is not anticholinergic, and only infrequently causes extrapyramidal side effects or postural hypotension, although it can be associated with somnolence. This tolerability profile may be quite valuable in the treatment of some patients. Ziprasidone may prolong the electrocardiogram (ECG) QTc interval (QT interval corrected for heart rate by a standard algorithm), but after 5 years' clinical availability ziprasidone (by itself) does not appear to pose a substantial clinical problem in this regard. Therefore, ziprasidone may be considered a first-line drug option in the treatment of schizophrenia or manic episodes, but, in view of the differences among antipsychotic medications, drug selection should be guided by the patient's individual characteristics and situation.

Molecular targets for treating cognitive dysfunction in schizophrenia

Cognitive impairment is a core feature of schizophrenia as deficits are present in the majority of patients, frequently precede the onset of other positive symptoms, persist even with successful treatment of positive symptoms, and account for a significant portion of functional impairment in schizophrenia. While the atypical antipsychotics have produced incremental improvements in the cognitive function of patients with schizophrenia, overall treatment remains inadequate. In recent years, there has been an increased interest in developing novel strategies for treating the cognitive deficits in schizophrenia, focusing on ameliorating impairments in working memory, attention, and social cognition. Here we review various molecular targets that are actively being explored for potential drug discovery efforts in schizophrenia and cognition. These molecular targets include dopamine receptors in the prefrontal cortex, nicotinic and muscarinic acetylcholine receptors, the glutamatergic excitatory synapse, various serotonin receptors, and the gamma-aminobutyric acid (GABA) system.

Factors affecting outcome in schizophrenia and their relevance for psychopharmacological treatment

A major focus of current treatment research in schizophrenia is the determinants of long-term outcome, including functional outcome and general medical well being, rather than just specific domains of psychopathology such as positive and negative symptoms, mood symptoms, and cognitive impairment. This focus does not negate the importance of the latter issues but sees them as factors contributing to long-term outcome to variable extents. A long-term treatment focus facilitates a more clinically relevant assessment of benefits versus risks of available treatments. For instance, atypical antipsychotic drugs as a group have clear advantages for several important domains of efficacy that may influence long-term outcome, but are also more expensive over the long term. Use of some agents may also result in deleterious physical health consequences as well as large additional costs over the long term owing to metabolic adverse effects. The present paper focuses on several key issues in schizophrenia which are important determinants of long-term outcome in schizophrenia, or influence choice of antipsychotic drugs, or both, including: (i) duration of untreated psychosis; (ii) impact of relapse on long-term outcome; (iii) limited efficacy for specific domains of psychopathology of current treatments; (iv) mortality owing to suicide; and (v) mortality owing to other causes (e.g. cardiovascular disease).

Treating schizophrenia symptoms with an alpha7 nicotinic agonist, from mice to men

Current antipsychotic treatments fail to fully address the range of symptoms of schizophrenia, particularly with respect to social and occupational dysfunctions. Recent work has highlighted the role of nicotinie in both cognitive and attentional deficits as well as deficient processing of repetitive sensory information. The predilection for schizophrenia patients to be extremely heavy cigarette smokers may be related to their attempt to compensate for a reduction in hippocampal alpha7 nicotinic cholinergic receptors by delivering exogenous ligand to the remaining receptors. Studies in rodent models of both learning and memory deficits and deficits in sensory inhibition have confirmed a role for the alpha7 subtype of the nicotinic cholinergic receptor in these processes. Rodent studies also demonstrated the efficacy of a selective partial alpha7 nicotinic agonist, DMXBA, to improve these deficits. Subsequent human clinical trials demonstrated improved sensory inhibition in 12 schizophrenia patients and showed improvement in several subtests of the RBANS learning and memory assessment instrument. These data suggest that therapeutic agents selected for alpha7 nicotinic activity may have utility in treating certain symptoms of schizophrenia.