Cognitive deficits and its relation with psychopathology and global functioning in first episode schizophrenia

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

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

The relationship between cognitive functioning, age and employment in people with severe mental illnesses in an urban area in India: A longitudinal study

Although there is substantial evidence of the association between cognitive impairment and work in people with severe mental illnesses (SMI) in developed countries, less is known about this relationship in developing countries such as India. Studies showing higher rates of employment in people with SMI in developing countries than developed ones raise the question of whether cognitive functioning is related to work status and characteristics of work (e.g., wages earned). We conducted a one-year follow-up study to investigate the relationship between employment and cognitive functioning, assessed with the Montreal Cognitive Assessment (MoCA), in 150 participants with SMI (92% schizophrenia) living in an urban area and receiving psychiatric outpatient treatment at a public hospital in India. The MoCA had good internal reliability and test-retest reliability over the one-year period. Better cognitive functioning was associated with younger age, shorter duration of illness, higher education, and male gender. Both younger and older participants with higher cognitive functioning at baseline were more likely to be employed at baseline and one year later. Work status at baseline and one year follow-up was consistently related to executive functions among younger participants, and to attention among older participants, suggesting changes over the course of illness in the importance of specific cognitive domains for achieving satisfactory work performance. The findings suggest that cognitive functioning is associated with employment in people with SMI in India. Attention to impaired cognitive functioning may be critical to improving employment outcomes in this population.

From Memories of Past Experiences to Present Motivation? A Meta-analysis on the Association Between Episodic Memory and Negative Symptoms in People With Psychosis

Based on findings from cognitive science, it has been theorized that the reductions in motivation and goal-directed behavior in people with psychosis could stem from impaired episodic memory. In the current meta-analysis, we investigated this putative functional link between episodic memory deficits and negative symptoms. We hypothesized that episodic memory deficits in psychosis would be related to negative symptoms in general but would be more strongly related to amotivation than to reduced expressivity. We included 103 eligible studies (13,622 participants) in the analyses. Results revealed significant, moderate negative associations of episodic memory with negative symptoms in general (k = 103; r = -.23; z = -13.40; P ≤ .001; 95% CI [-.26; -.20]), with amotivation (k = 16; r = -.18; z = -6.6; P ≤ .001; 95% CI [-.23; -.13]) and with reduced expressivity (k = 15; r = -.18; z = -3.30; P ≤.001; 95% CI[-.29; -.07]). These associations were not moderated by sociodemographic characteristics, positive symptoms, depression, antipsychotic medication or type of negative symptom scale. Although these findings provide sound evidence for the association between episodic memory deficits and amotivation, the rather small magnitude and the unspecific pattern of this relationship also indicate that episodic memory deficits are unlikely to be the only factor relevant to amotivation. This implicates that future research should investigate episodic memory in conjunction with other factors that could account for the association of episodic memory deficits and amotivation in psychosis.

Neurocognitive functioning and impulsivity in first-episode psychosis with suicidal ideation and behavior: A systematic review

BACKGROUND

The prevalence of suicidal ideation (SI) and behavior (SB) among people suffering from psychotic disorders is a public health issue. Most suicide attempts (SAs) occur before or during the early phases of first-episode psychosis (FEP). Improving knowledge about the suicide risk in the early stages is essential to develop therapeutic and prevention strategies. We conducted a systematic review to investigate an association between neurocognitive impairments or a history of impulsive behavior and SI or SB among patients with FEP.

METHOD

PRISMA guidelines were followed. Ten databases were searched using MeSH terms or key-words related to FEP, impulsivity or cognitive functioning measures and SI or SB, without restrictions for study design or length of follow-up. Included studies evaluated at least one cognitive function with neuropsychological tests or validated questionnaires, or provided records of impulsive behavior.

RESULTS

Twenty one research papers were included from databases, bibliographic references or expert opinions. Among patients with FEP, seven studies showed more pronounced neuropsychological impairments, especially regarding attention, processing speed, executive functioning and theory of mind in patients that had attempted suicide. No association was found between cognitive impairments on neuropsychological tests and SI. Previous non-suicidal impulsive behaviors were associated with SAs and suicide.

CONCLUSION

Our review suggests an association between neurocognitive impairments and SAs among patients with FEP. Records of impulsive behavior are also associated with SB in that population. Further research on the neuropsychology of FEP is necessary to identify how these impairments facilitate SB and evaluate their potential utility as therapeutic targets.

Effect of clozapine on psychological outcomes of caregivers of patients with treatment resistant schizophrenia

BACKGROUND

There is limited information on caregiver outcomes of patients with treatment-resistant schizophrenia (TRS).

AIM

This study aimed to evaluate the impact of short-term treatment with clozapine (i.e. 3 months) on caregiver burden, expressed emotions, caregiver abuse, and psychological morbidity among the caregivers in patients with TRS. 52 caregivers of patients with TRS were evaluated on the Family Burden Interview Schedule, Perceived Criticism Measure, Caregiver Abuse Screening Questionnaire, and General Health Questionnaire-12.

RESULTS

Maximum caregiver burden was seen in the domain of disruption of routine family activities, and this was followed by the domains of disruption of family leisure, disruption of family interaction, and the effect on mental health on others. At the baseline assessment, three-fourth of the caregivers scored ≥12 on the objective burden. With 3 months of clozapine therapy, there was a significant reduction in the caregiver burden in all the domains of objective burden, subjective burden, and the global objective burden as per the clinician rating, in the expressed emotions as per both patients and the caregivers, caregiver abuse, and psychological morbidity among the caregivers.

CONCLUSION

To conclude, this study suggests that caregivers of patients with TRS, experience significantly higher caregiver burden, and a large proportion of them suffer from psychological morbidity and indulge in expressed emotions and abuse of the patient. Treatment with clozapine for 3 months leads to a reduction in the caregiver burden, expressed emotions, caregiver abuse, and psychological morbidity among the caregivers.

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.

Serum Eicosapentaenoic and Arachidonic Acids Concentration and Cognitive Function in Patients With Coronary Artery Disease

Introduction:

Recent studies have shown that Polyunsaturated Fatty Acids (PUFAs), including Eicosapentaenoic Acid (EPA), and Arachidonic Acid (AA), are associated with cognitive functions in patients with Coronary Artery Disease (CAD). Nevertheless, controversial results have been reported, too. The current study aimed to clarify the association of serum EPA and AA levels with cognitive decline in an Iranian sample with CAD.

Methods:

We evaluated cognitive function with the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA), in relation to serum levels of EPA and AA, in 179 CAD patients. The associations between the MMSE and MoCA scores and the other demographic parameters were evaluated.

Results:

Patients with CAD generally had mild cognitive impairment. But we could not find any significant correlation between PUFAs and cognitive function. However, BMI was associated with EPA/MoCA; age was associated with MMSE/MoCA and BMI. Finally, the correlation between sex and MMSE/MoCA was significant.

Conclusion:

Subjects generally had mild cognitive impairment, but we could not find any significant correlation between serum EPA and AA levels with cognitive function.

Effect of music listening on P300 event-related potential in patients with schizophrenia: A pilot study

Reduced amplitude and increased latency of P300 auditory event-related potential (ERP) in patients with schizophrenia (SZ) indicate impairment in attention. Overall arousal level can determine the amount of processing capacity required for attention allocation. Music evokes strong emotions and regulates arousability. Music has been used to modulate P300, especially in normals. This exploratory study examined the effect of music listening on the amplitude and latency of P300 in SZ patients. EEG/ERP was recorded (32-channels) while SZ patients (n = 20; 18-45 years) performed an auditory oddball P300 task after the eyes-closed rest condition (Condition-A) and ten-minute music listening condition (Condition-B) as per the complete counterbalancing design (AB-BA). Patients listened to the researcher chosen, instrumental presentation of raag-Bhoopali in the North-Indian-Classical-Music, for ten-minutes. All patients rated the music excerpt as a relaxing and positively valenced. A significant increase in accuracy score and reaction time during the oddball task after music listening was noted. There was an increase in amplitude at TP7. A trend of increased amplitude was noted across all electrodes in the music condition compared to the rest condition. Mean amplitude in an apriori defined time window of interest (250 to 750 ms) showed significant changes in the frontal and central electrode sites. Power spectral analysis indicated a slight increase in frontal and central alpha and theta activity during music listening. However, this was not statistically significant. Findings add further impetus to examine the effect of music in chronic psychiatric conditions. Need for systematic studies on a larger cohort is underscored.

Caregiver assisted home-based cognitive remediation for individuals diagnosed with schizophrenia: A pilot study

Cognitive deficits in individuals diagnosed with schizophrenia are ubiquitous and, therefore, cognitive remediation is considered one of the prime targets of a comprehensive intervention program for schizophrenia. However, cognitive remediation is a resource consuming intervention and in lower and middle-income countries (LAMIC) such interventions are often neglected due to the resource constraints of the mental health services set-ups. Therefore, it is imperative to develop cognitive remediation programs that are less resource consuming for the mental health service delivery system. Keeping this in view, in the present pilot study, we tested the feasibility of a caregiver assisted home-based cognitive remediation program and compared its efficacy with a clinic-based cognitive remediation program. Findings show that it is feasible to conduct cognitive remediation program with the help of caregivers in patients' home settings and that the home-based cognitive remediation is as effective as the clinic-based cognitive remediation. The results of the study have been further discussed in the light of the practical implications, limitations and future research.

Diverse definitions of the early course of schizophrenia-a targeted literature review

Schizophrenia is a debilitating psychiatric disorder and patients experience significant comorbidity, especially cognitive and psychosocial deficits, already at the onset of disease. Previous research suggests that treatment during the earlier stages of disease reduces disease burden, and that a longer time of untreated psychosis has a negative impact on treatment outcomes. A targeted literature review was conducted to gain insight into the definitions currently used to describe patients with a recent diagnosis of schizophrenia in the early course of disease ('early' schizophrenia). A total of 483 relevant English-language publications of clinical guidelines and studies were identified for inclusion after searches of MEDLINE, MEDLINE In-Process, relevant clinical trial databases and Google for records published between January 2005 and October 2015. The extracted data revealed a wide variety of terminology and definitions used to describe patients with 'early' or 'recent-onset' schizophrenia, with no apparent consensus. The most commonly used criteria to define patients with early schizophrenia included experience of their first episode of schizophrenia or disease duration of less than 1, 2 or 5 years. These varied definitions likely result in substantial disparities of patient populations between studies and variable population heterogeneity. Better agreement on the definition of early schizophrenia could aid interpretation and comparison of studies in this patient population and consensus on definitions should allow for better identification and management of schizophrenia patients in the early course of their disease.

Executive function in patients with schizophrenia based on socio-occupational impairment: A cross-sectional study

BACKGROUND

Executive dysfunction deficit is the functionally most important cognitive deficit noted in schizophrenia. There is a dearth of Indian literature on the subject. The current study aimed at studying these executive functions in patients with schizophrenia in remission.

METHODOLOGY

Sixty outpatients with a diagnosis of schizophrenia as per international classification of diseases-10 criteria; in remission as measured by Positive and Negative Syndrome Scale scores were divided into two groups using the personal and social performance scale. The patients with and without socio-occupational impairment formed the two groups. All patients were administered the Wisconsin Card Sorting Test (WCST), Stroop test, Color Trails Test 1 and 2, Phonemic Fluency (Controlled Oral Word Association Test), and category fluency (animal names test) tests and the tower of London test to ascertain deficits in executive functions. The data obtained were subjected to statistical analysis.

RESULTS

The two groups were well matched. The group with socio-occupational impairment showed a lesser number of categories completed (P = 0.001), more perseverative errors (P = 0.001), and greater percentage of the same (P = 0.001) on the WCST. Statistically significant differences between both groups were observed for scores on phonemic fluency (P = 0.012) and category fluency (P = 0.049) tests as well as the Tower of London test (P = 0.021). They also showed differences on the Stroop test and Color Trail tests, but this was not statistically significant.

CONCLUSIONS

Performance on executive function tests is significantly correlated with functional outcome. It is important that future studies explore the role of these tests as a marker of socio-occupational impairment in schizophrenia.

Neuropsychological Profile of Specific Executive Dysfunctions in Patients with Deficit and Non-deficit Schizophrenia

Objectives: Although it has been shown that there are more profound deficits present in deficit schizophrenia (DS) patients than in non-deficit schizophrenia (NDS) patients, there still remain some matters requiring further investigation. In this context, we formulated three research aims: (1) to compare executive functions between the investigated groups, (2) to determine the relationship between particular aspects of executive functions within the groups, and (3) to draw up a neuropsychological profile for executive functions.

Methods: The study involved 148 schizophrenia patients divided into two groups on the basis of the Schedule for the Deficit Syndrome: DS (n = 70) and NDS (n = 78). Patients were matched for sex, age, years of education, and overall cognitive functioning. For assessing executive functions we used the Wisconsin Card Sorting Test (WCST), the Trail Making Test (TMT), the Phonemic Verbal Fluency Test (VFT P), the Stroop Color and Word Test (SCWT), and the Go/No Go task (GNG).

Results: Deficit schizophrenia patients scored lower on the WCST and TMT (relative flexibility) than did the NDS patients. There were no inter-group differences in the VFT P, SCWT (relative inhibition), or GNG. There were significant correlations between WCST and TMT scores in both groups. The general neuropsychological profiles were similar in both groups.

Conclusion: Deficit schizophrenia patients exhibited slightly greater interference with concept formation and non-verbal cognitive flexibility. Therefore, such problems may be specific to this particular type of schizophrenia. These results may be useful for the development of neuropsychological diagnostic methods for patients with schizophrenia.

A review of Indian research on cognitive remediation for schizophrenia

Cognitive deficits play a central role in recovery from Schizophrenia (SZ). Cognitive remediation (CR) is increasingly being examined to improve cognitive functions in SZ. It is becoming an inevitable component of treatment for this debilitating illness. This review article presents the current status of research on CR for SZ in India. In contrast to the numerous studies reported from across the globe, there are only five studies on CR for SZ published from India. Of the five, only two are randomized controlled trials, two are non-randomized studies and one is a series of case reports. With different strategies used for CR and a variety of tools and measurements as outcome measures, combined analysis of the data was not feasible. Improvement in cognitive functions and sustenance of the improvement observed at follow-up period ranging from 2 to 6 months duration was underscored by all the four studies. Indigenous methods such as home-based CR techniques and Yoga therapy as an adjunct CR technique have been researched upon. Established method of CR such as the Integrated Psychological Therapy (IPT) has been used with modifications made to suit the cultural scenario. Other treatment methods such as family therapy have been added along with CR for chronic patients. The limited number of research studies has tried to encompass various dimensions. However, there is a dire need for studies with larger sample size with stringent research methods. Culturally feasible CR technique and multi-centric studies with larger sample size can be the next way forward.

Intact neural activity during a Go/No-go task is associated with high global functioning in schizophrenia

AIM

Go/No-go derived event-related potential (ERP) signals have been widely used in schizophrenia research to monitor self-control deficits in this disorder. However, no study to date has associated Go/No-go-related ERP with global functioning.

METHODS

Participants consisted of 21 patients with schizophrenia and 22 healthy controls. We used a visual Go/No-go paradigm to measure Go/No-go-related N2/P3 ERP components by means of a 64-electrode cap for electroencephalogram recording. We used the Global Assessment of Functioning to evaluate global functioning and analyzed the correlation between ERP indices and global functioning scores.

RESULTS

N2 amplitudes were reduced in patients with schizophrenia, but not influenced by either of the Go/No-go conditions. P3 amplitudes were influenced by the Go/No-go conditions, but not reduced in patients with schizophrenia. Global functioning was correlated with the No-go P3 amplitudes, but not N2 amplitudes, in patients with schizophrenia.

CONCLUSION

These results indicate that global functioning is associated with intact neural activity rather than impaired neural activity during Go/No-go response inhibition tasks in patients with schizophrenia.

Neurocognitive Functioning in Schizophrenia, their Unaffected Siblings and Healthy Controls: A Comparison

AIM

Neurocognitive functions are considered to be reliable endophenotypes for schizophrenia. This study aimed to study the neurocognitive functioning of unaffected siblings of patients with schizophrenia and compare the same with a group of patients with schizophrenia and a group of healthy controls.

MATERIALS AND METHODS

Three study groups, that is, unaffected siblings of patients with schizophrenia, patients of schizophrenia and healthy controls, each group comprising of 20 participants were evaluated on Wisconsin Card Sorting Test, Brief Visuospatial Memory Test-Revised, Hopkins Verbal Learning Test-Revised, Wechsler Adult Intelligence Scale and Digit Symbol Test.

RESULTS

Compared to healthy controls, unaffected siblings of patients with schizophrenia performed poorly on the tests of short-term verbal learning and memory, but no significant differences were seen between the two groups for executive functions, visual learning and psychomotor speed, concentration and graphomotor abilities. However, when compared with patients with schizophrenia, unaffected siblings performed poorly on the tests of executive functions, visual memory, verbal memory, psychomotor speed, concentration and graphomotor abilities.

CONCLUSION

Cognitive markers like verbal memory deficits can distinguish unaffected siblings of schizophrenia from healthy controls and serve as an endophenotype for schizophrenia.

Comparing cognitive functions in medication adherent and non-adherent patients with schizophrenia

BACKGROUND

Medication non-adherence presents a considerable problem in patients with schizophrenia. Cognitive and executive functions can affect adherence. The association between medication non-adherence and cognitive impairment in schizophrenia is under investigated with limited and conflicting research data.

PURPOSE OF THE STUDY

To prospectively assess the rate of drug adherence among a sample of patients with schizophrenia and to compare the cognitive and executive functions between adherent and non-adherent patients.

SUBJECTS AND METHODS

109 patients with schizophrenia diagnosed according to the DSM-IV classification were initially assessed by the Wechsler Adult Intelligence Scale (WAIS), Wechsler Memory Scale-Revised (WMS-R) and Wisconsin Card Sorting Test (WCST) and six months later by the Brief Adherence Rating Scale (BARS).

RESULTS

68.8% were non-adherent to their antipsychotic medication. Adherent patients (31.2%) had significantly higher mean scores for the total, verbal and performance IQ. They had significantly higher mean scores in most of WMS subtests (orientation, information, verbal paired association, digit span, visual memory span), and higher mean scores for; total correct, conceptual level response, percentage and categories completed on the WSCT subscales (P < 0.0001). Whereas the non-adherent group had higher mean scores in; trials administered, total errors, perseverative responses, and perseverative errors (P < 0.0001). In a step regression analysis, digit span, conceptualization, total and percentage of errors were putative predictors of non-adherence.

CONCLUSION

Cognitive deficits, especially verbal memory and executive functions were the strongest patients' related factors associated with non adherence to medication. Psychiatrists ought to consider possible cognitive factors influencing adherence to enable offering proper interventions.

Neurocognitive Impairments in Deficit and Non-Deficit Schizophrenia and Their Relationships with Symptom Dimensions and Other Clinical Variables

Background

Deficit schizophrenia (DS) has been proposed as a pathophysiologically distinct subgroup within schizophrenia. Earlier studies focusing on neurocognitive function of DS patients have yielded inconsistent findings ranging from substantial deficits to no significant difference relative to non-deficit schizophrenia patients (NDS). The present study investigated the severity and characteristic patterns of neurocognitive impairments in DS and NDS patients and their relationships with clinical variables.

Methods

Attention, ideation fluency, cognitive flexibility and visuospatial memory function were assessed in 40 DS patients, 57 NDS patients, and 52 healthy controls by a comprehensive neuropsychological battery.

Results

Both schizophrenia subgroups had overall more severe cognitive impairments than controls while DS performed worse on every neuropsychological measure except the Stroop interference than the NDS patients with age and education as the covariates. Profile analysis found significantly different patterns of cognitive profiles between two patients group mainly due to their differences in attention and cognitive flexibility functions. Age, education, illness duration and negative symptoms were found to have the correlations with cognitive impairments in the NDS group, while only age and the negative symptoms were correlated with the cognitive impairments in the DS group. Multiple regression analyses revealed that sustained attention and cognitive flexibility were the core impaired cognitive domains mediating other cognitive functions in DS and NDS patients respectively.

Conclusions

DS patients exemplified worse in almost all cognitive domains than NDS patients. Sustained attention and cognitive flexibility might be the key impaired cognitive domains for DS and NDS patients respectively. The present study suggested the DS as a specific subgroup of schizophrenia.

Is duration of illness really influencing outcome in major psychoses?

BACKGROUND

An increasing number of studies identifies the duration of illness (DI) as an important predictor of outcome in patients affected by major psychoses (MP). The aim of the present paper was to revise medical literature about DI and its effects on MP, focusing in particular on the relationship between DI and outcome with particular reference to treatment response, suicidal risk, cognitive impairment and social functioning.

METHODS

A search in the main database sources has been performed to obtain a comprehensive overview. Studies with different methodologies (open and double-blinded) have been included, while papers considering other variables such as duration of untreated episode/illness were excluded. MP included the diagnoses of schizophrenia, bipolar disorder and major depressive disorder.

RESULTS

Available data show that DI influences treatment response, suicidal risk and loss of social functioning in schizophrenic patients, while results are more controversial with regard to cognitive impairment. In bipolar disorder, a long DI has been associated with less treatment response, more suicidal risk and cognitive impairment, but more data are needed to draw definitive conclusions. Finally, studies, regarding DI of illness and its predictive value of outcome in major depressive disorder show contradictory results.

CONCLUSIONS

DI appears a negative outcome factor particularly for schizophrenia, while with regard to mood disorders, more data are needed to draw definitive sound conclusions.

Cognitive control and schizophrenia: The greatest reliability of the Stroop task

Three components of cognitive inhibition were compared in patients with schizophrenia and healthy controls. Nineteen patients with schizophrenia were compared to 30 healthy controls, matched for age, sex, and educational level. Cognitive inhibition was examined by (i) access to relevant information (Reading with distraction task), (ii) suppression of no longer relevant information (Trail Making Test B), and (iii) restraint of cognitive resources to relevant information (Stroop Test, Hayling Sentence Completion Test, Go/No-Go Test). Beck Depression Inventory, and Positive and Negative Syndrome Scale were also used. Compared to healthy controls, patients with schizophrenia and stabilized for at least 6 months were slower in the inhibition condition at the Stroop task, read more distractors at the RWD, and made more perseverative errors at the TMT, even after controlling for age, Mini-Mental State Examination score, information speed processing, and accuracy. This difference remained significant after taking into account the level of depressive symptoms and the severity of psychotic symptoms. In multivariate analyses, only the Stroop interference index explained cognitive inhibition deficit in patients with schizophrenia. The abnormal cognitive inhibition process observed in patients with schizophrenia could therefore concerns the ability to restraint, rather than the access or the suppression processes.