An explanatory model of quality of life in schizophrenia: the role of processing speed and negative symptoms.

INTRODUCTION: Improving the quality of life of patients with schizophrenia is a major goal in managing this devastating disorder, but agreement is lacking about the factors that predict quality of life (QoL) over the course of the disorder. METHODS: We examined 165 hospitalized patients with schizophrenia in this study. We included measures for psychiatric (PANSS, insight and affective symptoms) and cognitive symptoms. Confirmatory factor analysis established a cognitive structure composed of the following six factors: attention, processing speed, verbal memory, fluency, working memory and executive functioning. Quality of life was assessed using the Heinrichs-Hanlon-Carpenter Scale. RESULTS: Age, duration of illness, presence of more severe negative symptoms and most cognitive factors correlated significantly with QoL indicators. Regression analysis showed that processing speed (PS) was by far the most important cognitive factor that predicted QoL. Moreover, the interaction between PS and negative symptoms, patient age and executive functions modified the effect of PS on QoL. Finally, positive symptoms and other socio-demographic data were not related to QoL in the current study. CONCLUSIONS: Our findings suggest that PS and negative symptoms predict QoL in schizophrenia.

Un modelo explicativo de la calidad de vida en la esquizofrenia: el papel de la velocidad de procesamiento y los síntomas negativos / An explanatory model of quality of life in schizophrenia: the role of processing speed and negative symptoms

Introducción. Mejorar la calidad de vida de los pacientes con esquizofrenia es un objetivo fundamental en una enfermedad que resulta devastadora, pero no hay acuerdo sobre qué factores predicen la calidad de vida (CV) en el curso de la enfermedad. Metodología. En el presente estudio se examinaron a165 pacientes hospitalizados con esquizofrenia. Se incluyeron medidas de síntomas psiquiátricos (PANSS, insight y síntomas afectivos) y cognitivas. Un análisis factorial confirmatorio estableció una estructura cognitiva compuesta de seis factores, que incluyen atención, velocidad de procesamiento, memoria verbal, fluidez, memoria de trabajo y funciones ejecutivas. La calidad de vida fue medida mediante la Escala de Calidad de Vida de Heinrichs-Hanlon-Carpenter. Resultados. La edad, tiempo de duración de la enfermedad, mayor gravedad de síntomas negativos y la mayoría de factores cognitivos correlacionaron significativamente con los indicadores de CV. Los análisis de regresión mostraron que, muy por encima de los demás factores cognitivos, la velocidad de procesamiento (VP) es un importante predictor de la CV. Además, la interacción de la VP con los síntomas negativos, la edad del paciente y el nivel de deterioro en funciones ejecutivas modificaron el efecto de la VP sobre la CV. Finalmente, los síntomas positivos y otros datos sociodemográficos no guardaron relación con la CV en nuestro estudio. Conclusiones. Nuestros hallazgos sugieren que la VP y los síntomas negativos predicen la CV en la esquizofrenia (AU)

Introduction. Improving the quality of life of patients with schizophrenia is a major goal in managing this devastating disorder, but agreement is lacking about the factors that predict quality of life (QoL) over the course of the disorder. Methods. We examined 165 hospitalized patients with schizophrenia in this study. We included measures for psychiatric (PANSS, insight and affective symptoms) and cognitive symptoms. Confirmatory factor analysis established a cognitive structure composed of the following six factors: attention, processing speed, verbal memory, fluency, working memory and executive functioning. Quality of life was assessed using the Heinrichs-Hanlon-Carpenter Scale. Results. Age, duration of illness, presence of more severe negative symptoms and most cognitive factors correlated significantly with QoL indicators. Regression analysis showed that processing speed (PS) was by far the most important cognitive factor that predicted QoL. Moreover, the interaction between PS and negative symptoms, patient age and executive functions modified the effect of PS on QoL. Finally, positive symptoms and other socio-demographic data were not related to QoL in the current study. Conclusions. Our findings suggest that PS and negative symptoms predict QoL in schizophrenia (AU)

Verbal fluency in schizophrenia: does cognitive performance reflect the same underlying mechanisms in patients and healthy controls?

Verbal fluency is impaired in patients with schizophrenia, but the association with other cognitive domains remains unclear. Forty-seven patients with schizophrenia (DSM-IV) and 47 controls matched by age, gender, years of education, and vocabulary (Wechsler Adult Intelligence Scale-III) were assessed in terms of sociodemographic, clinical, and cognitive variables. Healthy controls performed significantly better than patients with schizophrenia in all cognitive measures. However, the way these cognitive domains were related differed across groups. Semantic fluency (SF) and phonological fluency (PF) were predicted by working memory (WM) in patients with schizophrenia, whereas the predictor in the healthy controls was processing speed (PS). Moreover, after dividing the sample of patients according to their performance on fluency tests, we found that a worse performance on SF or PF was predicted by WM. However, for patients with a better performance on fluency, the pattern was similar to that of healthy controls. Cognition may show a different pattern of interaction in schizophrenia, with less impaired patients showing a closer pattern to healthy controls. Therefore, we suggest that, depending on the severity of cognitive deficits, performance on neuropsychological tests may not reflect the same underlying mechanisms.

[Attention deficits and response to drug therapy in patients with treatment-resistant schizophrenia: results through confirmatory factor analysis]. / Déficit atencionales y respuesta al tratamiento farmacológico en pacientes con esquizofrenia resistente al tratamiento: Resultados mediante análisis factorial confirmatorio.

INTRODUCTION: There are no experimental data that demonstrate whether patients with neuroleptic-resistant schizophrenia differ or not in their pattern of neuropsychological functioning from patients with adequate drug response. METHOD: Fifty-two patients with drug-resistant psychosis (DRP) and 42 patients with schizophrenia not resistant to treatment (NDRP) were recruited following the criteria of Kane et al (1988). A sample of 45 healthy controls matched by age, sex and educational level was also recruited. The clinical evaluations used were the Positive and Negative Symptom Scale (PANSS), functional disability (WHO-DAS) and the Clinical Global Impression (CGI) scale. RESULTS: Through the use of confirmatory factor analysis, we obtained a latent cognitive structure of six cognitive factors: attention, processing speed, verbal memory, working memory, verbal fluency and executive functions. As expected, the control group performed better than the two patient groups (both DRP and NDRP) in all neuropsychological domains. Additionally, the DRP group scored significantly worse in attention than the NDRP group even though no differences between these two groups were found in age of disease onset, number of hospitalizations or length of hospitalization. From a clinical point of view, the DRP group showed greater severity of positive symptoms (p<0.01) and higher global deterioration (p<0.01), which did not translate into greater functional disability. CONCLUSIONS: The results obtained do not allow us to conclude that there is a specific neuropsychological profile in neuroleptic-resistant patients. The only differential parameter was performance in the attentional domain. Our findings better fit the hypothesis of a «clinical continuum¼ and differ from the categoric classification of this mental disorder.