The study was approved by the Research Ethics Committee (REC) at National Cheng Kung University (NCKU No. 109-419). All participants were given a full explanation about the study and signed an informed consent form agreeing to join the research. Each informed consent was obtained from all participants and this study has been performed in accordance with the Declaration of Helsinki. In addition, all participants were provided reimbursement for transportation. Data were anonymized and collected in confidentiality.
All participants were recruited via advertisements on posters and an online platform. Each participant was required to complete the following questionnaires: the Mandarin version of the Social Support Questionnaire (SSQ), the Satisfaction with Life Scale (SwLS), the Beck Depression Inventory-II (BDI-II), the Peace of Mind (PoM) scale, and the Connor–Davidson Resilience Scale (CD-RISC).
Depression tendency was assessed using the Chinese version of the Beck Depression Inventory-II (BDI-II). The original BD-II is a 21-item self-reported inventory to evaluate people’s feelings in the last 7 days, with severity from 0–3 for each item. A higher score indicates more severe depression (<10, normal; 10–18, mild; 19–29 moderate; 30–63, severe) 28. The Mandarin version of the BPI-II showed good reliability with Cronbach’s α of 0.87 29.
Connor-Davidson Resilience Scale (CD-RISC)
The original CD-RISC is a 25-item resilience instrument with five domains: personal competence (CD-RISC_pc), trust in one’s instincts (CD-RISC_tru), positive acceptance of change (CD-RISC_acc), control (CD-RISC_con), and spiritual influences (CD-RISC_spi); good psychometric and test–retest reliability are shown by Cronbach’s α of 0.89 and 0.87, respectively 30. Each item is rated on a 5-point Likert scale (0-4), with higher scores indicating greater resilience. It was later translated into Mandarin and modified, showing good reliability with Cronbach’s α of 0.953 and test–retest reliability of 0.798 31,32.
Social Support Questionnaire (SSQ)
The SSQ was originally developed with 27 items to evaluate an individual’s perception of social support and satisfaction with the support 33. The Mandarin version was translated by Wu (1985) 34, and then was shortened and modified to 20 items by Chang (1989) 35. The internal reliability of SSQ(N) was 0.91 and of SSQ(S) was 0.92. The 2-week retest reliability for SSQ(N) and SSQ(S) was 0.9269 and 0.9369, respectively.
Satisfaction with Life Scale (SwLS)
The Mandarin version of the Satisfaction with Life Scale (SwLS) is a 5-item questionnaire rated from 1, strongly disagree, to 7, strongly agree, measuring subjective perception of well-being 6. Cronbach’s alpha was 0.87, and two-month retest reliability was 0.82 36. Several studies have reported only one factor 36-38. The Chinese version of SwLS was defined and validated with a Cronbach’s alpha of 0.9639.
Peace of Mind (PoM) scale
The PoM scale was developed and defined according to an internal state of peacefulness and harmony. The construct was originally developed based on the description of well-being valuation in Chinese culture 17. The cross-cultural validation was conducted and showed cultural differences with a higher PoM score for Taiwanese individuals than Europeans or Americans.
Pearson’s r correlation analysis was conducted to explore the associations among variables. SPSS 22.0 (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. To further explore the mediating role of resilience in the association between life satisfaction and depression, the role of peace of mind between life satisfaction and depression, and the role of social support between peace of mind and resilience, bootstrap analysis was carried out. Structural equation modeling (SEM) was employed to empirically test the hypothesis that number of social support providers indirectly mediates the correlation between well-being and resilience, in which peace of mind plays a double mediating role between depression and social satisfaction. The fit index was computed to evaluate model fit, with RMSEA < 0.08 40,41.