Psychometric properties of the Taiwanese version of the World Health Organization‐Five Well‐Being index

Psychological studies show that early detection in high-risk groups of mental illness is a critical public health issue (1), especially in depressive disorder, for such mental illness may negatively affect their well-being. Additionally, studies on mental health interventions have focused on ameliorating suffering, weakness, and anxiety rather than on increasing happiness and well-being. Chida and Steptoe indicated that positive psychological well-being has a favorable effect on survival in both healthy and diseased populations (2). A number of structured interviews and tests have been developed in Taiwan, all of which are extensive, time consuming, and focus on negative effect. The World Health Organization-Five Well-Being Index (WHO-5) is a self-administered five-item scale that provides a brief screening tool for detecting depression (3). We have examined the reliability and validity of the Taiwanese version of the WHO-5 (WHO-5TW), which is short and easy to use as a brief screening tool for well-being, and to development the first positive depression screening tool in Taiwan. The English version of the WHO-5 Well-Being Index was translated into traditional Chinese. Final adjustments were performed, including back translation, cross-cultural adaptation and field testing of the pre-final version. The WHO-5-TW was administered randomly to 242 community samples. Their mean age was 40.3 years, and 64% of them were female. Significant differences in the WHO-5-TW total scores were observed between the male and female subjects [male vs. female (mean SD), 15.93 4.62 vs. 13.50 5.30, t = 3.72, P < 0.001). The females experienced depression at roughly two or three times the rate of males. There were significant differences in the Chinese Health Questionnaire total scores between the male and female subjects [male vs. female (mean SD), 1.23 2.27 vs. 2.04 2.36, t = 2.60, P < 0.01]. The internal consistency of the WHO-5TW (alpha coefficient = 0.94) was excellent. The homogeneity and unidimensionality were also good, with a Loevinger coefficient of 0.80. The Loevinger coefficient is an analysis of unidimensionality that tests the extent to which an extra item fits into the structure established by other items of a scale (4). We determined the convergent validity of the WHO-5-TW in relation to the Chinese Health Questionnaire (CHQ) (5), which is scored in the opposite direction (r = 0.68; P < 0.001). The General Health Questionnaire has been shown to be a useful screening method to detect non-psychotic mental disorders in general clinical settings (5). Factor analysis identified only one factor that explained 80.8% of the variance. Among the limitations to be mentioned, first, the study was conducted exclusively in a community in Hualien County in the east of Taiwan. Second, discriminatory validity for the detection of depression disorders was not examined in the present study because we know that depression disorders may influence respondents’ subjective well-being. Finally, there was a possibility that our respondents underor over-reported their feelings, which may occur in any subjective study. The WHO-5-TW was found to be a reliable and valid selfassessment instrument to screen well-being and depression in a community population in Taiwan.