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

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.