Validation of the Chinese version of the Schizophrenia Quality of Life Scale Revision 4 (SQLS-R4) in Taiwanese patients with schizophrenia

We tested the reliability, sensitivity, and validity of a Chinese translation of the Schizophrenia Quality of Life Scale Revision 4 (SQLS-R4). One hundred Taiwanese individuals with schizophrenia were recruited. The internal consistency reliability was satisfactory for both the psychosocial and vitality domains (Cronbach's alpha = 0.92, 0.84). The test-retest reliability was also high (psychosocial: ICC = 0.84, vitality: ICC = 0.84) for those individuals whose psychological conditions remained stable between the two-week interval. However, the responsiveness coefficient for those with considerable changes in psychological conditions ranged from very small to moderate, suggesting either low responsiveness for the vitality domain or a complex relationship between the change of psychological conditions and quality of life, and the need to estimate responsiveness more conclusively in a future intervention study. The convergent validity was supported by moderate-to-large correlations between domains measuring related constructs of the SQLS-R4 and SF-36 (r = -0.65 to -0.67). Overall, the results of this study provide preliminary evidence for the reliability and validity of the SQLS-R4 used in Taiwanese individuals with schizophrenia. This study provides a common ground for international researchers to understand quality of life in Taiwanese patients with schizophrenia.