Validity, reliability and factor analysis of Persian version of schizophrenia quality of life scale

Abstract

CONTEXT: Exact measurement of quality of life (QOL) in schizophrenia patients for evaluation of the patient's deterioration and also to assess the efficacy of therapeutic Interventions has become a daily task, which requires accurate assessment tools. AIMS: This study was aimed to assess the psychometric properties of a Persian version of schizophrenia QOL scale (SQLS) as a common transcultural instrument. SETTINGS AND DESIGN: One hundred and fifty schizophrenia patients who referred to Psychiatric Clinic in Noor Hospital (Isfahan, Iran) have been selected using simple sampling method. SUBJECTS AND METHODS: Aside with SQLS, short form-36 general health (SF-36) and World Health Organization QOL-brief-26 (WHOQOL-BREF-26). Questionnaires were completed by the cases for determination of correlation coefficients. STATISTICAL ANALYSIS USED: The data were analyzed using descriptive statistics, factor analysis, Cronbach's coefficient alpha, Pearson correlation coefficient by Statistical Package for Social Sciences software, version 18 (SPSS-18). RESULTS: Total reliability of the questionnaire was reported by using Cronbach's coefficient alpha 0.84, reliability of individual relationships subscales was 0.91, signs 0/87, symptoms 0/72 and motivation/energy 0/61. Correlation coefficients of SF-36 with a total scale of SQLS and correlation coefficient of WHOQOL-BREF-26 with a total scale of SQLS were acceptable. Exploratory factor analysis using varimax rotation identified four principle components (interpersonal relationship, symptoms, signs, motivation, and energy), which will determine QOL at 52.7 variance. CONCLUSIONS: Persian version of the SQLS can be used as a simple, reliable and valid tool in Iranian population.