Executive Dysfunction In Schizophrenia Research Articles

Transnosographic analysis of executive dysfunction – clinical, psychometric and therapeutic dimensions

The analysis of executive dysfunction in patients with mental disorders presents clinical and therapeutic importance, based on research that supports the involvement of this component in shaping the symptomatic picture and in determining the recovery prognosis. Although therapeutic approaches that specifically target cognitive impairments (in schizophrenia, vascular depression, ADHD etc.) are not yet used on a large scale, they can be considered augmentation strategies with the potential to improve the patients’ recovery and quality of life. A structured assessment of the executive functioning in clinical setting, using validated psychometric methods, is recommended in order to monitor as completely as possible the patients’ mental status and the adaptive difficulties generated by these cognitive problems. The current analysis will include aspects related to the correlations between executive dysfunction and specific psychiatric symptoms, on the one hand, as well as psychosocial functioning, on the other hand. The study of endophenotypes, which occupy an intermediate position between genotypes and clinical manifestations (phenotypes), can help reduce the heterogeneity of some nosographic categories and can motivate early therapeutic intervention strategies. Another dimension of the present analysis refers to the impact of specific therapies, pharmacological, psychosocial or neurostimulation, on executive dysfunction. This first part of the review presents data on executive dysfunction in schizophrenia, major depressive disorder, vascular depression, bipolar disorder, neurocognitive disorders and eating disorders.

Executive Dysfunctions in Schizophrenia: A Critical Review of Traditional, Ecological, and Virtual Reality Assessments.

In recent years, interest has grown in measuring executive function in schizophrenia with ecological and virtual reality (VR) tools. However, there is a lack of critical analysis comparing those tools with traditional ones. This paper aims to characterize executive dysfunction in schizophrenia by comparing ecological and virtual reality assessments with traditional tools, and to describe the neurobiological and psychopathological correlates. The analysis revealed that ecological and VR tests have higher levels of verisimilitude and similar levels of veridicality compared to traditional tools. Both negative symptoms and disorganization correlate significantly with executive dysfunction as measured by traditional tools, but their relationships with measures based on ecological and VR methods are still unclear. Although there is much research on brain correlates of executive impairments in schizophrenia with traditional tools, it is uncertain if these results will be confirmed with the use of ecological and VR tools. In the diagnosis of executive dysfunction, it is important to use a variety of neuropsychological methods—especially those with confirmed ecological validity—to properly recognize the underlying characteristics of the observed deficits and to implement effective forms of therapy.

Executive dysfunction in schizophrenia: Predictors of the discrepancy between subjective and objective measures

This study aimed to investigate what characterizes individuals with schizophrenia who experience more or less subjective executive dysfunction in everyday life compared to objective executive performance on neuropsychological tests.Sixty-six participants with broad schizophrenia spectrum disorders completed a comprehensive assessment of executive function. Discrepancies between performance on neuropsychological tests (objective) and an extensive self-report questionnaire (subjective) of central executive functions (inhibition, shifting and working memory) were calculated. Higher level of self-efficacy was the best predictor of experiencing fewer subjective cognitive complaints compared to objective performance, followed by higher levels of disorganized symptoms. Depressive symptoms did not predict discrepancy between subjective and objective executive function. Higher estimated IQ predicted greater subjective working memory difficulties in everyday life despite better objective performance.Results may aid clinicians in the assessment and remediation of cognitive impairment. Low self-efficacy may identify individuals who are not able to utilize their potential executive functions in daily life. Interventions aimed at fostering self-efficacy ought to be included in cognitive remediation for these individuals. Disorganized symptoms could prove useful in identifying individuals who are in need of cognitive remediation for executive dysfunction, despite that they overestimate their skills. These individuals may benefit from efforts to increase insight into cognitive dysfunction.

Examination and Comparison of Cognitive and Executive Functions in Clinically Stable Schizophrenia Disorder, Bipolar Disorder, and Major Depressive Disorder.

Background Schizophrenia (SC), bipolar disorder (BD), and major depressive disorder (MDD) are associated with various cognitive and executive dysfunctions. The aim of the present study was to evaluate and compare cognitive and executive dysfunctions in schizophrenia, bipolar disorder, and major depressive disorder. Materials and Methods Sixty-four schizophrenia patients, 68 bipolar patients, 62 patients with major depressive disorder, and 75 healthy individuals participated in the present study. All participants were assessed with the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I), Young Mania Rating Scale (YMRS), Positive and Negative Syndrome Scale (PANSS), Beck Depression Inventory (BDI-II), Trial Making Test (TMT), Four-Choice Reaction Time Task, Ruler Drop Method (RDM), Tower of London (TOL) task, and the Wisconsin Card Sorting Task (WCST). Data were analyzed by chi-square, Kolmogorov-Smirnov, and independent t-tests; ANOVA; and MANOVA. Results In the cognitive function, the scores of SC, BD, and MDD patients were lower than those of healthy individuals. Also, the scores of MDD patients were lower than those of other patients, and the scores of BD patients were lower than those of SC patients. In the executive function, the scores of SC, BD, and MDD patients were lower than those of healthy individuals. Moreover, the scores of the MDD group were higher than those of the BD and SC groups, and the scores of the SC group were higher than those of the BD group. Conclusion Patients with SC, BD, and MDD have poorer cognitive and executive functions than healthy individuals, even when these patients are in a stable state. Assessment of cognitive and executive functions in SC, BD, and MDD patients can help in understanding the pathology of these disorders.

Thought Disorder on Object Sorting Test Is Associated with Executive Dysfunction in Schizophrenia.

Background:Thought disorder is considered to be central to the core disturbances in schizophrenia and was described by Goldstein as aberrant “concept formation.” Executive dysfunction is another core deficit in schizophrenia. With a greater emphasis on psychopathology in nosological systems, the classical thought disorder receives less prominence. The present study aimed to understand the association between classical thought disorder (aberrant concept formation and concrete abstraction) and executive dysfunction.Methods:Thirty patients with schizophrenia and thirty healthy subjects, matched on age, gender, education, and socioeconomic status, were screened using MINI 5.0, following which they were assessed on object sorting test (OST) and selected tests for executive functions (EFs).Results:Individuals with schizophrenia were found to have significantly decreased performance on all domains of EFs and OST. Total peculiar scores on OST were significantly associated with mental speed, focused attention, and divided attention. Total impoverished scores on OST was significantly associated with focused attention, sustained attention, planning, set shifting, perseveration, and concept formation.Conclusion:Several correlations, among performance on OST and neuropsychological tests, suggest that patterns of responses on OST can point to underlying executive dysfunction. Both thought disorder and executive dysfunction mirror similar constructs. This similarity represents a conceptual bridge between the classical and contemporary descriptions of the core deficits in schizophrenia.

Nature and Correlates of Executive Dysfunction in Schizophrenia: An Exploratory Study.

Background:Executive function (EF) impairment has been demonstrated in patients with schizophrenia. This study attempted to examine the clinical and demographic correlates associated with the different components of EF in these patients using a comprehensive battery of neuropsychological tests.Materials and Methods:Consecutive inpatients with schizophrenia in remission were recruited. The following instruments were administered: (a) Positive and Negative Syndrome Scale (PANSS), (b)World Health Organization Disability Assessment Schedule 2.0, (c) Tower of London, (d) Stroop Test, (e) Controlled Oral Word Association Test, (f) Animal Names Test, and (g) Verbal N-Back Test. Sociodemographic and clinical details were also recorded. Data was analyzed using standard bivariate and multivariate statistics.Results:A total of 50 patients were recruited. The mean age of the population was 30 years (standard deviation [SD]: 7.74). The majority were male, literate, single, from a rural background, from a middle socioeconomic background, and unemployed. The mean dose of antipsychotic medication was 618.57 mg (SD: 282.08) of chlorpromazine equivalents per day. Impairment was found in the different sub-components of EF. On multivariate analysis, factors significantly associated with executive dysfunction were lower education, unemployment, lower income, positive PANSS score, higher antipsychotic dose, and history of treatment with electroconvulsive therapy.Conclusion:EFs encompass a wide range of cognitive processes that influence an individual’s ability to adapt and function in the society. These are often impaired in patients with schizophrenia. Clinicians need to be aware of these deficits and factors associated with them, to plan appropriate and effective remedial measures.

The relationship between cingulum bundle integrity and different aspects of executive functions in chronic schizophrenia

BackgroundEvidence suggests that disruption in the cingulum bundle (CB) may influence executive dysfunctions in schizophrenia, but findings are still inconsistent. Using diffusion tensor imaging tractography, we investigated the differences in fiber integrity between schizophrenia patients and healthy controls together with the association between fiber integrity and executive functions. MethodsThirty-two patients with chronic schizophrenia and 24 healthy controls took part in the study. Both groups were matched for age, sex, and years of education. Assessment of cognitive functions was performed using the Berg Card Sorting Test (BCST), the Color Trail Test (CTT), and the Stroop Color-Word Test (SCWT). ResultsResults showed group differences, bilaterally (left and right) in fractional anisotropy (FA) of the CB, where patients showed less anisotropy than controls. Moreover, normal asymmetry (left FA > right FA) in the CB in schizophrenia was found. There were no group differences in mean diffusivity (MD). Patients had a similar but reduced profile of executive functions compared to healthy controls. However, when premorbid IQ was controlled for, the differences were no longer statistically significant. In schizophrenia patients, a negative correlation was found between FA of the left CB and perseverative errors in the BCST. ConclusionsThese findings provide evidence that CB disruption appears in schizophrenia patients and might account for impairments of executive processes, including concept formation.

The efficacy of computer-based cognitive training for executive dysfunction in schizophrenia

The purpose of this study was to assess the effect of computer-based cognitive training on executive dysfunction in patients with schizophrenia. Sixty-five patients with schizophrenia were randomly assigned to a training group (n = 33) or a non-training group (n = 32), and compared in terms of executive performance to a healthy control group (n = 33). Executive function was assessed using the Trail Making Test, the Stroop Color and Word Test, and the Wisconsin Card Sorting Test (computer version). Cognitive training was performed using RehaCom software over a course of 16 individual sessions. Primary outcomes were training (performance at three different timepoints) and neuropsychological components (flexibility and cognitive inhibition, high executive processing, and processing speed). In both clinical groups, all aspects of executive function were found to be deficient. In the patient training group, the use of computer-based training alongside pharmacological treatment was more effective in terms of cognitive improvement than pharmacological treatment alone. However, there was no significant effect of cognitive training on processing speed. Cognitive training in schizophrenia patients was effective at improving several aspects of executive function, but did not improve processing speed.

Practical value of Stroop task of symptomatic words and identity-related words for screening executive dysfunction in schizophrenia

Objective To explore the practical value of Stroop task of symptomatic words and identity-related words for screening executive dysfunction in schizophrenia. Methods Sixty-five patients with schizophrenia in clinical remission and sixty-two healthy controls were recruited in this trial.Patients and controls completed the Stroop task of symptomatic words and identity-related words.Analyze and compare the difference of reaction time between the two groups on the two stroop paradigms and further analyze the degree of discrimination of the two stroop paradigme. Results The reaction time of schizophrenic patients was longer than that of healthy controls in both symptom-word Stroop task ((1 206.65±476.39)ms vs (916.01±395.85)ms, t=6.46, P<0.001), and identity-word Stroop task((1 256.22±630.18)ms vs (927.85±419.98)ms, t=6.01, P<0.01). The sensitivity and specificity were obtained by Receiver Operating Characteristic curves in symptom-word Stroop task (89% and 57%, respectively) and identity-word Stroop task (81% and 66%, respectively). Conclusion Symptom-word Stroop task and identity-word Stroop task showed moderate diagnostic value for the identification executive dysfunction in patients with schizophrenia. Key words: Schizophrenia; Stroop task; Executive function; Screening test

Aberrant cerebellar neural activity and cerebro-cerebellar functional connectivity involving executive dysfunction in schizophrenia with primary negative symptoms.

Deficit schizophrenia (DS) is a distinct subtype of schizophrenia characterized by primary and enduring negative symptoms. More severe executive dysfunctions were observed in DS patients, however, the associated neuroimaging characteristics, especially cerebellar functional anomalies in DS, remain largely unknown. We employed resting-state functional and structural MRI data of 106 male participants, including data from 29 DS patients, 39 non-deficit schizophrenia (NDS) patients and 38 healthy controls (HCs). Z-standardized fractional amplitude of low-frequency fluctuation (zfALFF) values were calculated in order to examine spontaneous regional brain activity. Cerebro-cerebellar functional connectivity and changes in the volume of gray matter in the cerebellum were also examined. Relative to the HCs, both DS and NDS patients exhibited decreased zfALFF in the bilateral cerebellar lobules VIII and IX. The zfALFF in the left Crus II was lower in DS patients compared to NDS patients. No significant difference was observed in the volume of cerebellar gray matter among the three groups. Compared with NDS patients, cerebro-cerebellar functional connectivity analysis revealed increased connectivity in the left orbital medial frontal cortex and right putamen regions in DS patients. Reduced zfALFF in the left Crus II in the DS group was significantly positively correlated with Stroop Color and Word scores, while negatively correlated with Trail-Making Test part B scores. The increased functional connectivity in the right putamen in DS patients was significantly positively correlated with Animal Naming Test and semantic Verbal Fluency Test scores. These results highlight cerebellar functional abnormality in DS patients and provide insight into the pathophysiological mechanism of executive dysfunction.

Pragmatic Ability Deficit in Schizophrenia and Associated Theory of Mind and Executive Function.

Deficits in pragmatic abilities have frequently been observed in patients with schizophrenia. The objective of the study was to investigate the relationship between pragmatic deficits, ToM deficits and executive dysfunctions in schizophrenia. A group of 42 schizophrenic patients and 42 healthy controls were assessed on irony task (one type of pragmatic language), two subcomponents of ToM (cognitive and affective), and three subcomponents of EF (inhibition, updating, and switching). The clinical symptoms in schizophrenia were assessed using the positive and negative symptoms of schizophrenia. The schizophrenia group exhibited significant impairments in all above tasks compared to the control group. Correlation results found that irony scores were correlated with the two subcomponents of ToM and two of the three subcomponents of EF (inhibition and updating). The regression analysis revealed that the cognitive ToM and inhibition predicted 9.2% and 29.9% of the variance of irony comprehension in the patient group, and inhibition was the best predictor for performance on irony task. Irony understanding was related to positive symptoms, but not to negative symptoms. The results suggest that the ability to interpret pragmatic language depends on schizophrenic patients’ ability to infer mental states and the ability of inhibition. It provides empirical evidence for a particular target of inhibition for rehabilitation and intervention programs developed for schizophrenic patients.

Executive dysfunction in schizophrenia and its association with mentalizing abilities

IntroductionPatients with schizophrenia have been found impaired in important aspects of their basic and social cognition. Our aim in this study is to explore the relationship between executive function (EF) and theory of mind (ToM) deficiencies in patients that suffer the illness. Materials and methodsTwenty-two Spanish-speaking inpatients and 22 healthy controls matched in age, sex, education, language dominance, and premorbid IQ were assessed in EF and ToM abilities. The former were assessed using 10 tasks that covered 5 cognitive dimensions and the latter using 3 different tasks. Correlation analyses were used to explore the level of association between executive and mentalizing abilities. A series of discriminant function analyses were carried out to examine the relative contribution of each executive and mentalizing task to discriminate between patients and controls. ResultsPatients showed impairments in both, executive and ToM abilities. The correlation analyses showed a virtual absence of association between EF and ToM abilities within the group of patients, and an almost opposite pattern within the healthy group. ToM performance was more accurate than executive performance to discriminate patients from controls. ConclusionsAlthough EFs and ToM deficits come into view together in schizophrenia, they appear to belong to different and relatively independent cognitive domains.

Neural correlates of executive dysfunction in schizophrenia: failure to modulate brain activity with task demands.

In schizophrenia, executive functions are impaired and are associated with altered activation of prefrontal areas. We used H2[15]O PET to examine patients with schizophrenia and matched controls on a random number generation (RNG) task and a control counting (COUNT) task. To assess the effects of increasing task demand, both tasks were performed at three different rates (intervals 1, 2 or 3 s). Both groups showed a significant increase in the nonrandomness of responses at faster rates of RNG. Despite similar performances, patients but not controls showed higher activation of the right dorsolateral prefrontal cortex (DLPFC) and atypically reduced activation of the right anterior cingulate gyrus and the right medial frontal gyrus in RNG compared with COUNT, whereas only for controls, activation of the left DLPFC was increased and activation of the right superior temporal gyrus and the right superior frontal gyrus was reduced in the same comparison. Whereas for the controls several cortical areas including the bilateral superior temporal gyrus and the bilateral DLPFC, together with the right cerebellum, showed significant changes in regional cerebral blood flow with faster or slower rates, patients with schizophrenia showed rate-dependent changes only in the left cerebellum. In conclusion, the patients' failure to modulate cortical activation with changing demands of rate, particularly in prefrontal areas and in the cerebellum, and even when performance is similar to that in healthy controls, is a characteristic of their abnormal pattern of executive processing.

Executive dysfunction in schizophrenia and its association with mentalizing abilities.

Patients with schizophrenia have been found impaired in important aspects of their basic and social cognition. Our aim in this study is to explore the relationship between executive function (EF) and theory of mind (ToM) deficiencies in patients that suffer the illness. Twenty-two Spanish-speaking inpatients and 22 healthy controls matched in age, sex, education, language dominance, and premorbid IQ were assessed in EF and ToM abilities. The former were assessed using 10 tasks that covered 5 cognitive dimensions and the latter using 3 different tasks. Correlation analyses were used to explore the level of association between executive and mentalizing abilities. A series of discriminant function analyses were carried out to examine the relative contribution of each executive and mentalizing task to discriminate between patients and controls. Patients showed impairments in both, executive and ToM abilities. The correlation analyses showed a virtual absence of association between EF and ToM abilities within the group of patients, and an almost opposite pattern within the healthy group. ToM performance was more accurate than executive performance to discriminate patients from controls. Although EFs and ToM deficits come into view together in schizophrenia, they appear to belong to different and relatively independent cognitive domains.

INECO frontal screening: an instrument to assess executive dysfunction in schizophrenia.

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

1474 – Executive functions in first episode remitted patients with schizophrenia

Introduction Literature suggests that schizophrenia (SCZ) could, early in the evolution, involve significant deficits in executive functioning. However, little is known about patients with recent onset first episode. Besides, only few studies focused on symptom-free intervals. Furthermore, most of them included patients on polymedication of antipsychotics including also add on psychotropics. Objectives We aimed to investigate executive dysfunction in first-episode schizophrenia remitted patients with recent onset of the disease, receiving a strict monotherapy of antipsychotics. Aims Enhance the existence of executive dysfunction early in SCZ limiting the impact of relapses, medication and symptoms. Methods 25 first episode outpatients with schizophrenia, having less than 3 years illness duration were included. All patients received a monotherapy of antipsychotic with no antidepressant, mood stabilizer, hypnotics or benzodiazepines. 25 healthy participants were matched one by one, according to age and educational level. For clinical evaluation, PANSS was applied. Executive functions were assessed with the Davidson et al. (2006) computerized battery designed to manipulate both inhibition and cognitive flexibility. It encompasses interrelated tasks that enabled us to independently vary demands on these abilities. Results Compared to controls, patients showed significant differences in the percentage of correct responses and in reaction time attesting difficulties in inhibition and in cognitive flexibility. Conclusions Our results emphasize the notion that executive dysfunction in schizophrenia stands for itself early in the disease, cannot be only explained by relapses, duration of the disease, impact of medication nor symptoms.

A Cross-Sectional Analysis of the Development of Response Inhibition in Children with Chromosome 22q11.2 Deletion Syndrome

Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a neurogenetic disorder that is associated with cognitive impairments and significantly elevated risk for developing schizophrenia. While impairments in response inhibition are central to executive dysfunction in schizophrenia, the nature and development of such impairments in children with 22q11.2DS, a group at high risk for the disorder, are not clear. Here we used a classic Go/No-Go paradigm to quantify proactive (anticipatory stopping) and reactive (actual stopping) response inhibition in 47 children with 22q11.2DS and 36 typically developing (TD) children, all ages 7–14. A cross-sectional design was used to examine age-related associations with response inhibition. When compared with TD individuals, children with 22q11.2DS demonstrated typical proactive response inhibition at all ages. By contrast, reactive response inhibition was impaired in children with 22q11.2DS relative to TD children. While older age predicted better reactive response inhibition in TD children, there was no age-related association with reactive response inhibition in children with 22q11.2DS. Closer examination of individual performance data revealed a wide range of performance abilities in older children with 22q11.2DS; some typical and others highly impaired. The results of this cross-sectional analysis suggest an impaired developmental trajectory of reactive response inhibition in some children with 22q11.2DS that might be related to atypical development of neuroanatomical systems underlying this cognitive process. As part of a larger study, this investigation might help identify risk factors for conversion to schizophrenia and lead to early diagnosis and preventive intervention.

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

BackgroundDespite the upsurge of research regarding cognitive impairment in schizophrenia we still lack adequate understanding of the executive functioning of patients in symptomatic remission. Moreover, the cognitive functioning of patients in partial remission has not been studied previously although they comprise a significant proportion of schizophrenia patients. The current study therefore examined the executive functioning of patients in full symptomatic remission and for the first time assessed two sub-groups of patients in partial remission. MethodsExecutive functioning of five groups was compared; symptomatic patients, patients in positive symptomatic remission, negative symptomatic remission, full symptomatic remission (SP, PSR, NSR, and FSR; N=101) and healthy controls (N=37). ResultsA graded cognitive profile was evident between the groups. SP patients exhibited widespread executive dysfunction while the performance of FSR patients was comparable to that of the healthy controls. Both PSR and NSR patients had working memory deficits, with PSR patients showing additional deficits in cognitive planning. ConclusionsThe findings are encouraging, tentatively suggesting intact executive functioning among patients in full symptomatic remission. The graded cognitive profile of the patient groups strengthens earlier findings indicating the significant role of negative symptoms in determining executive dysfunction in schizophrenia. The findings point toward potential targets for therapeutic efforts and emphasize the need for further research of sub-groups of schizophrenia patients in partial remission.

Brief Screening for Executive Dysfunction in Schizophrenia in a Rehabilitation Hospital

Few tools assessing neurocognitive dysfunction in schizophrenia are able to measure integrated executive functions in the context of the problem-solving demands of a patient's everyday world. The authors evaluated the BRIEF-A (Behavior Rating Inventory of Executive Function-Adult version) Informant Report in 112 inpatients with chronic schizophrenia in a rehabilitation hospital. Factor analysis yielded a three-factor solution (Emotional Regulation, Problem-Solving, Orderliness). The BRIEF-A is psychometrically robust in this population and, in the absence of patient participation, provides an estimate of executive functions in a population that may otherwise be beyond the reach of formal neurocognitive testing.

P-1320 - Executive functions in remitted patients with recent onset of first episode of schizophrenia under monotherapy

Research has suggested that schizophrenia involves significant deficits in executive functioning. Yet, the literature has little studied patients with a recent onset of first episode of schizophrenia. Besides, only few studies have focused on symptom-free intervals. Furthermore, previous studies have included patients under polymedication of antipsychotics without any restriction on other psychotropes. To investigate executive functions in remitted patients with recent onset of first episode of schizophrenia receiving only a monotherapy of antipsychotics. Executive dysfunction in schizophrenia is not a consequence of the long term course of the disease, of the relapses, of the symptoms or of the polymedication. 25 schizophrenic outpatients with less than 3 years of illness duration and only one psychotic episode were included. All patients received a monotherapy of antipsychotics and none had an antidepressant, mood stabilizer, hypnotics or benzodiazepines. 25 healthy participants were matched according to age and educational level. Patients were assessed by the Positive and Negative Syndrome Scale. Executive functions were assessed by the Davidson et al. computerized battery designed to manipulate inhibition and cognitive flexibility vary demands on these abilities. Compared to healthy controls, remitted schizophrenia patients have shown significant differences in the percentage of correct responses and in the reaction time. This indicates a disorder in inhibition and in cognitive flexibility. Our results reinforce the findings that the executive dysfunction in schizophrenia stands for itself and that it cannot be explained by relapses, duration of the disease and impact of medication or symptoms.