Effects of socioeconomic status in cognition of people with schizophrenia: results from a Latin American collaboration network with 1175 subjects.

BACKGROUND: Cognition heavily relies on social determinants and genetic background. Latin America comprises approximately 8% of the global population and faces unique challenges, many derived from specific demographic and socioeconomic variables, such as violence and inequality. While such factors have been described to influence mental health outcomes, no large-scale studies with Latin American population have been carried out. Therefore, we aim to describe the cognitive performance of a representative sample of Latin American individuals with schizophrenia and its relationship to clinical factors. Additionally, we aim to investigate how socioeconomic status (SES) relates to cognitive performance in patients and controls. METHODS: We included 1175 participants from five Latin American countries (Argentina, Brazil, Chile, Colombia, and Mexico): 864 individuals with schizophrenia and 311 unaffected subjects. All participants were part of projects that included cognitive evaluation with MATRICS Consensus Cognitive Battery and clinical assessments. RESULTS: Patients showed worse cognitive performance than controls across all domains. Age and diagnosis were independent predictors, indicating similar trajectories of cognitive aging for both patients and controls. The SES factors of education, parental education, and income were more related to cognition in patients than in controls. Cognition was also influenced by symptomatology. CONCLUSIONS: Patients did not show evidence of accelerated cognitive aging; however, they were most impacted by a lower SES suggestive of deprived environment than controls. These findings highlight the vulnerability of cognitive capacity in individuals with psychosis in face of demographic and socioeconomic factors in low- and middle-income countries.

Working memory assessment in schizophrenia and its correlation with executive functions ability.

OBJECTIVE: Working memory impairment is common in schizophrenia and is possibly a cause of multiple features of the disorder. However few studies have replicated such findings of impairment patterns in Brazilian samples. The main target of this study was to assess auditory and visual working memory in patients with schizophrenia, to assess if they work as separate systems, and to correlate working memory deficits with executive functions. METHOD: Twenty subjects with schizophrenia and twenty healthy subjects matched by gender, age, and schooling have participated. The abilities assessed were auditory and visual working memory, selective attention, inhibitory control, cognitive flexibility, and planning. RESULTS: Patients showed declines in all measures evaluated, except for a measure reaction time of inhibitory control. Auditory working memory was correlated to selective attention, inhibition, flexibility and planning while Visual working memory to planning and flexibility. CONCLUSION: The present study suggests that working memory and executive functions deficits are present in patients with schizophrenia in the Brazilian sample evaluated. Alterations in executive functions may lead to incapacity of operation of processes of working memory. These findings may contribute to delineate and develop new strategies of schizophrenia treatment in the Brazilian population.

Component mechanisms of executive function in schizophrenia and their contribution to functional outcomes.

OBJECTIVE: In schizophrenia, scores reflecting deficits in different cognitive processes are strongly correlated, making it difficult to establish a solid relationship between different cognitive mechanisms and other features of this disorder. The objective of this study was to explore whether three frequently postulated executive functions (updating, shifting, and inhibition) could be compared between groups and considered independently in terms of their respective roles in functional outcome. METHODS: This study relied on confirmatory factor analysis of schizophrenia patients (n=141) and healthy controls (n=119). The main analyses examined the degree to which three executive functions (updating, set-shifting, and inhibition) could be separated in schizophrenia and compared this model among groups. Structural equation modeling analysis was also performed to examine the extent to which executive function components contribute to functional outcome in schizophrenia. RESULTS: Multiple-group confirmatory factor analysis with unconstrained model parameters indicated that the full three-factor model may fit the data in both groups (χ2 = 61.48, degrees of freedom = 34, p < 0.001, comparative fit index = 0.95; standardized root mean square residual = 0.037; root mean square error of approximation = 0.04; Akaike's information criteria = 169.49; normed fit index = 0.90), although there was also a good data fit for the patient group with a two-factor model. In the patient group, structural equation modeling suggested that shifting and (principally) updating were associated with the general measure of functional outcome (regression path coefficients: 0.34, p < 0.005; 0.39, p < 0.005, respectively), although when combined the mechanisms fail to contribute. CONCLUSION: This data suggests that the factor structure may be similar but not identical between groups, and both updating and shifting may play an important role in functional outcome in schizophrenia.

The Brazilian standardization of the MATRICS consensus cognitive battery (MCCB): Psychometric study.

OBJECTIVE: Translate, adapt, and validate the MATRICS Consensus Cognitive Battery (MCCB) in Brazil. METHOD: The present study followed three steps: 1) translation to Portuguese, cultural adaptation, and back translation to English; 2) completion of a pilot study (N=30) conducted with the purpose of assessing whether the general comprehension of the items was clear and all participants adequately responded to the battery; 3) completion of a Reliability and Validation Study of the Brazilian version of the MCCB with 99 individuals with schizophrenia and 99 healthy subjects. All participants were administered the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) and patients were also rated on the Global Assessment of Functioning (GAF) Scale and the Positive and Negative Symptoms Scale (PANSS). RESULTS: The results showed adequate to high levels of baseline and 4-week retest reliability, except the MSCEIT-ME; adequate internal consistency for the MSCEIT-ME for the total sample and patients group, and moderate Alpha for the health control sample; as well as evidence of convergent validity and sensitivity to differentiate performance between the groups. All the 10 MCCB measures showed the lowest learning effects. CONCLUSION: Overall the Brazilian version of the MCCB showed similar results to the original North American version. Our findings provides reassurance that the MCCB is a reliable and valid measure of cognition across different countries and cultures, which is especially important to the ongoing work in attempting to discover cognition-enhancing drugs and the effects of cognitive interventions for the treatment of schizophrenia.

Catechol-O-methyltransferase (COMT) polymorphisms modulate working memory in individuals with schizophrenia and healthy controls.

OBJECTIVE: Cognitive impairment is a core feature of schizophrenia, related to dopaminergic dysfunction in the prefrontal cortex (PFC). It is hypothesized that functional single nucleotide polymorphism (SNP) rs4680 of the catechol-O-methyltransferase (COMT) gene could mediate the relationship between cognition and dopamine activity in the PFC. Other COMT SNPs could also play a role. METHODS: We evaluated the role of three COMT SNPs (rs737865, rs165599, and rs4680) in schizophrenia and their impact on three working memory tasks. For genetic association analyses, 212 individuals with schizophrenia and 257 healthy controls (HCs) were selected. The Visual Working Memory (VWM) Task, Keep Track Task, and Letter Memory Task were administered to 133 schizophrenics and 93 HCs. RESULTS: We found a significant association of rs737865, with the GG genotype exerting a protective effect and the GA haplotype (rs4680/rs165599) exerting a risk effect for schizophrenia. COMT rs4680 AA carriers and rs737865 AA carriers scored lowest on the Keep Track Task. When the genotype*group interaction effect was evaluated, rs165599 exerted opposite effects for VWM and Keep Track task performance in patients and controls, with AA carriers scoring lowest on both tests among controls, but highest among patients. CONCLUSION: These data support the hypothesis that COMT polymorphisms may be associated with schizophrenia and modulate cognition in patients and controls.

Neuropsychological correlates of remission in chronic schizophrenia subjects: The role of general and task-specific executive processes.

BACKGROUND: Although cognitive deficits have consistently been characterized as core features of schizophrenia, they have not been incorporated into definitions of remission. Furthermore, just a few studies have examined the relationship between cognitive deficits and symptomatic remission. The main aim of the present study is to evaluate the executive functioning of nonremitted schizophrenia patients. METHODS: 72 remitted and 42 nonremitted schizophrenia patients, and 119 healthy controls were examined. Subjects were tested with a comprehensive battery of cognitive tests, including a measure to assess the general components of executive functioning and individual tasks to tap the three specific executive dimensions assessed in the present study, namely updating, shifting and inhibition. RESULTS: Schizophrenia subjects performed poorly on general executive functioning and shifting tasks in comparison to healthy controls. Remitted subjects performed better than nonremitted on inhibition and updating tasks. Whereas being a male and showing decreases in updating increase the chances of being in the nonremitted schizophrenia subjects group, increases in shifting and updating enhance the odds of being in the healthy control group. CONCLUSION: The present findings suggest that executive function deficits are present in chronic schizophrenic patients. In addition, specific executive processes might be associated to symptom remission. Future studies examining prospectively first-episode, drug naive patients diagnosed with schizophrenia may be especially elucidative.

Is semantic verbal fluency impairment explained by executive function deficits in schizophrenia?

OBJECTIVE: To investigate if verbal fluency impairment in schizophrenia reflects executive function deficits or results from degraded semantic store or inefficient search and retrieval strategies. METHOD: Two groups were compared: 141 individuals with schizophrenia and 119 healthy age and education-matched controls. Both groups performed semantic and phonetic verbal fluency tasks. Performance was evaluated using three scores, based on 1) number of words generated; 2) number of clustered/related words; and 3) switching score. A fourth performance score based on the number of clusters was also measured. RESULTS: SZ individuals produced fewer words than controls. After controlling for the total number of words produced, a difference was observed between the groups in the number of cluster-related words generated in the semantic task. In both groups, the number of words generated in the semantic task was higher than that generated in the phonemic task, although a significant group vs. fluency type interaction showed that subjects with schizophrenia had disproportionate semantic fluency impairment. Working memory was positively associated with increased production of words within clusters and inversely correlated with switching. CONCLUSION: Semantic fluency impairment may be attributed to an inability (resulting from reduced cognitive control) to distinguish target signal from competing noise and to maintain cues for production of memory probes.

Factor structure of the Positive and Negative Syndrome Scale (PANSS) in Brazil: convergent validation of the Brazilian version.

OBJECTIVES: The Positive and Negative Syndrome Scale (PANSS) was developed to assess the symptoms of schizophrenia dimensionally. Although it is widely used in clinical trials in Brazil, it is not fully validated. The aim of this study is to assess the factor structure of the Brazilian PANSS and generate validation data for its current version. METHODS: A total of 292 patients diagnosed with schizophrenia were enrolled. RESULTS: Principal component analysis suggested a forced five-factor final model that accounted for 58.44% of the total variance, composed of negative, disorganization/cognition, excitement, positive, and depression/anxiety. CONCLUSION: The Brazilian PANSS has a similar factor structure and internal consistency compared to versions in several other languages.

Component mechanisms of executive function in schizophrenia and their contribution to functional outcomes

Objective: In schizophrenia, scores reflecting deficits in different cognitive processes are strongly correlated, making it difficult to establish a solid relationship between different cognitive mechanisms and other features of this disorder. The objective of this study was to explore whether three frequently postulated executive functions (updating, shifting, and inhibition) could be compared between groups and considered independently in terms of their respective roles in functional outcome. Methods: This study relied on confirmatory factor analysis of schizophrenia patients (n=141) and healthy controls (n=119). The main analyses examined the degree to which three executive functions (updating, set-shifting, and inhibition) could be separated in schizophrenia and compared this model among groups. Structural equation modeling analysis was also performed to examine the extent to which executive function components contribute to functional outcome in schizophrenia. Results: Multiple-group confirmatory factor analysis with unconstrained model parameters indicated that the full three-factor model may fit the data in both groups (χ2 = 61.48, degrees of freedom = 34, p < 0.001, comparative fit index = 0.95; standardized root mean square residual = 0.037; root mean square error of approximation = 0.04; Akaike's information criteria = 169.49; normed fit index = 0.90), although there was also a good data fit for the patient group with a two-factor model. In the patient group, structural equation modeling suggested that shifting and (principally) updating were associated with the general measure of functional outcome (regression path coefficients: 0.34, p < 0.005; 0.39, p < 0.005, respectively), although when combined the mechanisms fail to contribute. Conclusion: This data suggests that the factor structure may be similar but not identical between groups, and both updating and shifting may play an important role in functional outcome in schizophrenia.

Peripheral interleukin-2 level is associated with negative symptoms and cognitive performance in schizophrenia.

Although several studies have pointed to a possible role of interleukin 2 (IL-2) in schizophrenia (SZ), association between IL-2 and the different groups of symptoms has not been explored. The objective of this study was to investigate a possible correlation of peripheral IL-2 levels with symptoms and cognitive performance in patients with SZ. In addition, we compared the plasma levels of IL-2 between patients with SZ and healthy controls. Twenty-nine chronically medicated outpatients with SZ according to DSM-IV were compared with twenty-six healthy controls. The patients were evaluated with the Positive and Negative Syndrome Scale (PANSS), the Calgary Depression Scale for Schizophrenia (CDSS), the Clinical Global Impression (CGI) and the Global Assessment of Functioning (GAF). All the participants had blood collected into EDTA tubes by venipuncture between 9:00 and 10:00AM. Plasma concentrations of IL-2 were determined by cytometric bead array. A computerized neuropsychological battery assessed verbal learning, verbal fluency, working memory, set shifting, executive function, inhibition and intelligence. Patients with SZ had lower levels of IL-2 than healthy controls (p<0.001). In the SZ group, IL-2 levels were positively correlated with scores in the digit span test (rho=0.416, P=0.025) and intelligence (rho=0.464, P=0.011). We also found a negative correlation between IL-2 and total score in the negative subscale of PANSS (rho=-0.447, p=0.015). Our findings suggest that IL-2 may be involved in the mechanisms related to cognitive deterioration and negative symptomatology in schizophrenia.

Recognition of bipolar disorder type I before the first manic episode: challenges and developments.

Bipolar disorder (BD) usually follows a neurobiological progression pathway, but a relatively long interval between the first symptoms of the disorder and the correct diagnosis and treatment takes place in most patients. Strategies used to recognize BD at an early stage and even prior to the first manic episode could help identify the risk and modifying factors that influence the onset and course of disease, and improve outcomes. Drawing on current research results, this article presents considerations on risk factors for the development of BD, including genetic/familial risk, endophenotypes and clinical characteristics. Taken together, this article provides a framework and tools for research on the BD prodrome, as well as for the early recognition and timely treatment of patients prior to and immediately after the emergence of BD.

Polymorphisms in schizophrenia candidate gene UFD1L may contribute to cognitive deficits.

We aimed to investigate UFD1L polymorphisms in schizophrenia and in relation to cognition. A total of 299 cases and 363 controls were genotyped, and 130 patients completed nine neuropsychological tests. We found that rs5992403 AA-genotype carriers showed lower scores on the set-shifting task. Therefore, UFD1L may participate in the core cognitive deficits observed in schizophrenia.

Impact of peripheral levels of chemokines, BDNF and oxidative markers on cognition in individuals with schizophrenia.

OBJECTIVE: To investigate possible differences in peripheral levels of chemokines, BDNF and oxidative markers between patients with Schizophrenia (SZ) and matched healthy controls, and investigate the correlation of these biomarkers with cognitive performance. METHODS: Thirty individuals with SZ and 27 healthy controls were included and the following plasmatic biomarkers' levels were determined according to manufacturers' instructions: BDNF, TBARS, protein carbonyl content (PCC) and the chemokines CXCL-10/IP-10, CXCL-8/IL-8, CCL-11, CCL-24/Eotaxin-2, CCL-2/MCP-1, CCL-3/MIP-1. Selected neuropsychological tasks were administered to assess verbal learning (Hopkins Verbal Learning Test), verbal fluency (FAS test), working memory (Visual Working Memory Task, Keep Track Task, Letter Memory Task), set shifting (Plus-minus task, Number-letter task), inhibition (Computerized Stroop Task, Semantic Generation Task) and complex executive function tasks (Tower of London and the shortened version of the WCST-64). RESULTS: Compared with the healthy control group, individuals with SZ presented significantly higher levels of BDNF and the chemokine CCL-11, and lower levels of TBARS and the chemokine CXCL-10/IP-10. When we examined only the SZ group, BDNF levels were positively correlated with semantic generation tasks. Working memory ability was negatively correlated with PCC. Regarding chemokines, CCL-11 was negatively correlated to performance in working memory test, and positively correlated with cognitive flexibility task. CXCL-8/IL-8 was positively correlated with verbal fluency. CCL-24/Eotaxin-2 was positively correlated with semantic generation ability and letter memory task. CONCLUSIONS: Our results indicate that cognitive performance in SZ is associated with mediators of neuroplasticity that can be measured peripherally.

Validação da Recovery Assessment Scale (RAS) no Brasil para avaliar a capacidade de superação das pessoas com esquizofrenia / Validation of the Recovery Assessment Scale (RAS) in Brazil in people with schizophrenia

RESUMO Objetivo Adaptar para o Brasil e investigar a confiabilidade e validade da Recovery Assessment Scale (RAS) em pessoas com esquizofrenia. Métodos Etapa 1 – foi realizada tradução profissional para o português, adaptação e retrotradução da RAS. Etapa 2 – estudo-piloto em um grupo de 12 pessoas com esquizofrenia para garantir compreensão dos itens da escala. Etapa 3 – As pessoas com esquizofrenia (N = 104) foram submetidas à versão brasileira da RAS e a instrumentos de funcionalidade, qualidade de vida e sintomas para busca de evidências de validade. Resultados Os resultados revelaram bons índices de consistência interna e de precisão teste e reteste dos instrumentos. Foram estabelecidas evidências de validade convergente entre a RAS e medidas de qualidade de vida (r = 0,58; p < 0,001), funcionamento ocupacional (r = 0,40; p < 0,001), habilidades de vida independente (r = 0,24; p < 0,02), gravidade (CGI, r = -0,31; p < 0,003) sintomas da esquizofrenia: PANSS total (r = -0,21; p < 0,05), PANSS negativa (r = -0,28; p < 0.007), PANSS positiva (r = -0.08; p = 0,437)] e depressão [Calgary (r = -0,27; p < 0,01)]. A análise fatorial exploratória revelou seis fatores, sendo quatro destes similares a estudos prévios. Conclusão A partir deste estudo, considerou-se que a palavra “superação” reflete melhor o conceito de “recovery”. A versão brasileira da escala RAS é um instrumento válido e reprodutível para aferir a capacidade de “superação” das pessoas com esquizofrenia.

ABSTRACT Objective To adapt and investigate the validity reliability study of the Brazilian version of the Recovery Assessment Scale-RAS in people with schizophrenia. Methods Stage 1 – professional translation to Portuguese, adaptation, and back-translation of the RAS; Stage 2 – RAS was presented to 12 outpatients with schizophrenia to evaluate if they would be able to understand and respond to the instrument; Stage 3 – patients with schizophrenia (n = 104) were assessed with the Brazilian version of the RAS, functional outcomes measures, quality of life and symptoms scales. Results Results showed good internal consistency and retest reliability, and convergent validity between the RAS and quality of life measures (r = 0.58; p < 0.001), occupational functioning (r = 0.40; p < 0.001), independent living skills (r = 0.24; p < 0,02), functionality (CGI, r = -0.31; p < 0.003) and symptoms of schizophrenia, including PANSS total score total (r = -0.21; p < 0.05), PANSS negative (r = -0.28; p < 0.007), PANSS positive (r = -0.08; p = 0.48), and Calgary Depression Scale (r = -0.27; p < 0.01)]. Exploratory factor analysis yielded six factors, four of these very similar to previous studies. Conclusion This study suggests that the word “superação” (“overcome”) better reflects the concept of “recovery” in Brazilian Portuguese. The Brazilian version of RAS is a valid and reliable instrument to evaluate the process of recovery in people with schizophrenia.

Catechol-O-methyltransferase (COMT) polymorphisms modulate working memory in individuals with schizophrenia and healthy controls

Objective: Cognitive impairment is a core feature of schizophrenia, related to dopaminergic dysfunction in the prefrontal cortex (PFC). It is hypothesized that functional single nucleotide polymorphism (SNP) rs4680 of the catechol-O-methyltransferase (COMT) gene could mediate the relationship between cognition and dopamine activity in the PFC. Other COMT SNPs could also play a role. Methods: We evaluated the role of three COMT SNPs (rs737865, rs165599, and rs4680) in schizophrenia and their impact on three working memory tasks. For genetic association analyses, 212 individuals with schizophrenia and 257 healthy controls (HCs) were selected. The Visual Working Memory (VWM) Task, Keep Track Task, and Letter Memory Task were administered to 133 schizophrenics and 93 HCs. Results: We found a significant association of rs737865, with the GG genotype exerting a protective effect and the GA haplotype (rs4680/rs165599) exerting a risk effect for schizophrenia. COMT rs4680 AA carriers and rs737865 AA carriers scored lowest on the Keep Track Task. When the genotype*group interaction effect was evaluated, rs165599 exerted opposite effects for VWM and Keep Track task performance in patients and controls, with AA carriers scoring lowest on both tests among controls, but highest among patients. Conclusion: These data support the hypothesis that COMT polymorphisms may be associated with schizophrenia and modulate cognition in patients and controls.

Is semantic verbal fluency impairment explained by executive function deficits in schizophrenia?

Objective: To investigate if verbal fluency impairment in schizophrenia reflects executive function deficits or results from degraded semantic store or inefficient search and retrieval strategies. Method: Two groups were compared: 141 individuals with schizophrenia and 119 healthy age and education-matched controls. Both groups performed semantic and phonetic verbal fluency tasks. Performance was evaluated using three scores, based on 1) number of words generated; 2) number of clustered/related words; and 3) switching score. A fourth performance score based on the number of clusters was also measured. Results: SZ individuals produced fewer words than controls. After controlling for the total number of words produced, a difference was observed between the groups in the number of cluster-related words generated in the semantic task. In both groups, the number of words generated in the semantic task was higher than that generated in the phonemic task, although a significant group vs. fluency type interaction showed that subjects with schizophrenia had disproportionate semantic fluency impairment. Working memory was positively associated with increased production of words within clusters and inversely correlated with switching. Conclusion: Semantic fluency impairment may be attributed to an inability (resulting from reduced cognitive control) to distinguish target signal from competing noise and to maintain cues for production of memory probes.

Investigation of cognition in schizophrenia: psychometric properties of instruments for assessing working memory updating / Investigação da cognição na esquizofrenia: propriedades psicométricas de instrumentos para avaliação de atualização da memória de trabalho

Objective This study describes the development of two updating measures of working memory (WM): Letter Updating Test (LUT) and Word Updating Test (WUT). Methods In stage 1, items were created and the instruments were assessed by experts and laymen. In stage 2, tests were given to 15 patients with schizophrenia and 15 paired controls. All were able to understand and respond to the instruments. In stage 3, 141 patients with schizophrenia and 119 healthy controls aged 18 to 60 took part; they were assessed on WM, processing speed (PS) and functional outcome. Results The results showed adequate rates of internal consistency for both measures developed, for both the total sample and each group separately, as well as evidence of convergent validity, discriminant validity and sensitivity to differentiate performance among the groups. Principal component analysis yielded two components, one for updating tests and other for PS measures, indicating factorial validity. Positive and significant, yet low, correlations were found with functionality measures. Conclusion These results provide adequate psychometric parameters for the measures developed, applicable to cognitive research settings in schizophrenia.

Objetivo O estudo descreve o desenvolvimento de duas medidas de atualização da memória de trabalho (MT): Teste de Atualização de Letras (TAL) e Teste de Atualização de Palavras (TAP). Métodos Na etapa 1 foram criados itens e os instrumentos foram analisados por experts e leigos. Na etapa 2, os testes foram aplicados em 15 pacientes com esquizofrenia e 15 controles pareados. Todos foram capazes de compreender e responder aos instrumentos. Na etapa 3, participaram 141 pacientes com esquizofrenia e 119 controles saudáveis com idades entre 18 e 60 anos, avaliados em MT, velocidade de processamento (VP) e funcionalidade. Resultados Os resultados revelaram bons índices de consistência interna para ambas as medidas desenvolvidas, tanto para a amostra total como para cada grupo separadamente, bem como evidências de validade convergente com medidas de MT, validade discriminante com medidas de VP e sensibilidade para discriminar o desempenho entre os grupos. Análise de componentes principais revelou que os testes de atualização apresentaram altas cargas e um fator separado das medidas de VP. Relações positivas, significativas, porém baixas, foram encontradas com medidas de funcionalidade. Conclusão Esses resultados fornecem bons parâmetros psicométricos para as medidas desenvolvidas, aplicáveis em contextos de pesquisa cognitiva da esquizofrenia.

Factor structure of the Positive and Negative Syndrome Scale (PANSS) in Brazil: convergent validation of the Brazilian version

Objectives: The Positive and Negative Syndrome Scale (PANSS) was developed to assess the symptoms of schizophrenia dimensionally. Although it is widely used in clinical trials in Brazil, it is not fully validated. The aim of this study is to assess the factor structure of the Brazilian PANSS and generate validation data for its current version. Methods: A total of 292 patients diagnosed with schizophrenia were enrolled. Results: Principal component analysis suggested a forced five-factor final model that accounted for 58.44% of the total variance, composed of negative, disorganization/cognition, excitement, positive, and depression/anxiety. Conclusion: The Brazilian PANSS has a similar factor structure and internal consistency compared to its other country versions.

Working memory assessment in schizophrenia and its correlation with executive functions ability / Avaliação da memória de trabalho na esquizofrenia e sua correlação com habilidades de funções executivas

OBJECTIVE: Working memory impairment is common in schizophrenia and is possibly a cause of multiple features of the disorder. However few studies have replicated such findings of impairment patterns in Brazilian samples. The main target of this study was to assess auditory and visual working memory in patients with schizophrenia, to assess if they work as separate systems, and to correlate working memory deficits with executive functions. METHOD: Twenty subjects with schizophrenia and twenty healthy subjects matched by gender, age, and schooling have participated. The abilities assessed were auditory and visual working memory, selective attention, inhibitory control, cognitive flexibility, and planning. RESULTS: Patients showed declines in all measures evaluated, except for a measure reaction time of inhibitory control. Auditory working memory was correlated to selective attention, inhibition, flexibility and planning while Visual working memory to planning and flexibility. CONCLUSION: The present study suggests that working memory and executive functions deficits are present in patients with schizophrenia in the Brazilian sample evaluated. Alterations in executive functions may lead to incapacity of operation of processes of working memory. These findings may contribute to delineate and develop new strategies of schizophrenia treatment in the Brazilian population.

OBJETIVO: Prejuízos em memória de trabalho são comuns na esquizofrenia e possíveis causas de múltiplas características do transtorno. Entretanto, poucos estudos reproduziram achados de padrões específicos de déficits em amostras brasileiras de pacientes com esquizofrenia. O objetivo desta pesquisa foi avaliar a memória de trabalho auditiva e visual na esquizofrenia, verificar se estas habilidades operam como dois sistemas separados, e relacionar possíveis déficits de memória de trabalho com habilidades de funções executivas. MÉTODO: Foram incluídos 20 indivíduos com esquizofrenia e 20 indivíduos saudáveis pareados quanto a sexo, idade e escolaridade. As habilidades avaliadas foram memória de trabalho auditiva e visual, atenção seletiva, controle inibitório, flexibilidade cognitiva e planejamento. RESULTADOS: Os pacientes demonstraram prejuízos em todas as medidas dos testes, exceto em tempo de reação de controle inibitório. Pacientes apresentaram significante correlação entre MT auditiva com medidas de atenção seletiva, controle inibitório, flexibilidade e planejamento. Memória de trabalho visual apresentou correlações com planejamento e flexibilidade. CONCLUSÃO: Este estudo sugere que déficits em memória de trabalho e funções executivas estão presentes em pacientes esquizofrênicos na amostra brasileira avaliada. Alterações nas funções executivas podem levar a incapacidade de adequadas operações de memória de trabalho. Esses achados podem contribuir no delineamento de novos procedimentos de intervenção na esquizofrenia em populações brasileiras.