Validity of the Functioning Assessment Short Tests (FAST), in patients with schizophrenia.

INTRODUCTION: Functional impairment in schizophrenia is one of the main features of the disorder and implies a great impact on the patient's quality of life. The Brief Functioning Assessment Scale (FAST), originally validated in bipolar disorder, has also been validated for its application in other mental disorders. However, we only found one study on the reliability and validity of the Brazilian version in schizophrenia. The purpose of this study was to analyze the psychometric properties of the Spanish version of the FAST in patients diagnosed with schizophrenia. MATERIAL AND METHODS: A total of 226 patients with a diagnosis of schizophrenia were evaluated by mean the FAST, the GAF and the self-care requirements scale (ERA). Scale properties were analyzed in terms of internal consistency, inter-observer agreement and test-retest reliability. Convergent validity with the GAF and ERA scales was also analyzed, as well as construct validity by means of a Confirmatory Factor Analysis (CFA). RESULTS: For the total scale, the results showed high internal consistency (Cronbach's Alpha of, 87), as well as good inter-observer (ICC=,86) and test-retest (ICC=,77) agreement. Concurrent validity with the GAF scale was discrete (r=-,32; P<,001) and with the ERA scale was moderate (r=,50; P<,001). CFA showed an internal structure that matched the six factors proposed by the original scale, with a good level of item saturation for each factor. CONCLUSIONS: The FAST scale showed good psychometric properties in terms of reliability and validity in its Spanish version for its application in patients with schizophrenia. It can be considered as a good tool to assess different areas of functional impairment in clinical practice and research.

Validación de la versión española de la Escala de funcionamiento breve (FAST) en pacientes diagnosticados de esquizofrenia / Validity of the Functioning Assessment Short Tests (FAST), in patients with schizophrenia

Introducción: El deterioro funcional es una de las principales características del curso de la esquizofrenia e implica un gran impacto en la calidad de vida del paciente. La Escala de funcionamiento breve (FAST), validada originalmente en trastorno bipolar, también ha sido validada para su aplicación en otros trastornos mentales, aunque solo encontramos un estudio sobre la fiabilidad y validez de la versión brasileña en esquizofrenia. El propósito de este estudio fue analizar las propiedades psicométricas de la versión española de la FAST en pacientes diagnosticados de esquizofrenia.Material y métodos: Un total de 226 pacientes con diagnóstico de esquizofrenia fueron evaluados, cumplimentando la FAST, la GAF y la Escala de requisitos de autocuidado (ERA). Se analizaron las propiedades de la escala en términos de consistencia interna, concordancia interobservador y fiabilidad test-retest. Se analizó también la validez convergente con las escalas GAF y ERA, y la validez de constructo mediante un análisis factorial confirmatorio.Resultados:Para el total del cuestionario los resultados mostraron una elevada consistencia interna (Cronbach's Alpha de 0,87), así como una buena concordancia interobservador (CCI=0,86) y test-retest (CCI=0,77). La validez concurrente con la escala GAF fue discreta (r=–0,32; p<0,001) y con la escala ERA moderada (r=0,50; p<0,001). El análisis factorial confirmatorio mostró una estructura interna que se ajustaba a los 6 factores de la escala original, con un buen nivel de saturación de los ítems para cada factor.Conclusiones: La escala FAST mostró buenas propiedades psicométricas en términos de fiabilidad y validez en su versión española para su aplicación en pacientes con esquizofrenia. Se puede considerar una buena herramienta para evaluar diferentes áreas del deterioro funcional en la práctica clínica y en investigación. (AU)

Introduction: Functional impairment in schizophrenia is one of the main features of the disorder and implies a great impact on the patient's quality of life. The brief functioning assessment scale (FAST), originally validated in bipolar disorder, has also been validated for its application in other mental disorders. However, we only found one study on the reliability and validity of the Brazilian version in schizophrenia. The purpose of this study was to analyze the psychometric properties of the Spanish version of the FAST in patients diagnosed with schizophrenia.Material and methods: A total of 226 patients with a diagnosis of schizophrenia were evaluated by mean the FAST, the GAF and the self-care requirements scale (ERA). Scale properties were analyzed in terms of internal consistency, inter-observer agreement and test–retest reliability. Convergent validity with the GAF and ERA scales was also analyzed, as well as construct validity by means of a Confirmatory Factor Analysis (CFA).Results: For the total scale, the results showed high internal consistency (Cronbach's Alpha of .87), as well as good inter-observer (ICC=.86) and test–retest (ICC=.77) agreement. Concurrent validity with the GAF scale was discrete (r=−.32; P<.001) and with the ERA scale was moderate (r=.50; P<.001). CFA showed an internal structure that matched the six factors proposed by the original scale, with a good level of item saturation for each factor.Conclusions: The FAST scale showed good psychometric properties in terms of reliability and validity in its Spanish version for its application in patients with schizophrenia. It can be considered as a good tool to assess different areas of functional impairment in clinical practice and research. (AU)