Promoting psychological well-being in older adults through volunteering: A randomized controlled trial study in Hong...

As Hong Kong faces rapid population aging, promoting psychological well-being among older adults has become a public health priority. Volunteering, as a form of prosocial behavior, may enhance well-being, yet evidence from non-Western contexts is limited. This study examined the long-term effects of a Health Action Process Approach-based volunteering intervention on psychological well-being, exploring the mediating roles of self-efficacy and meaning in life. The study recruited 198 community-dwelling adults aged 55+ years in Hong Kong, randomized into intervention, active control, or passive control groups. The intervention group participated in a 2-week preparatory training followed by an 8-week structured volunteering program. Standardized measures of prosocial behavior (Prosocialness Scale for Adults), psychological well-being (World Health Organization-Five Well-Being Index), self-efficacy (General Self-Efficacy Scale), meaning in life (Meaning in Life Questionnaire), and loneliness (six-item UCLA Loneliness Scale) were administered at baseline and at 3-, 6-, and 9-month follow-ups. Repeated-measures analysis of variance and mediation analyses were conducted. The intervention group showed significantly greater improvements across all outcomes compared with both control group, with benefits sustained to 9 months. Mediation analyses indicated that self-efficacy fully mediated the effect of volunteering on psychological well-being, while a significant chain mediation pathway via meaning in life and then self-efficacy was also observed. A theory-driven volunteering intervention significantly enhances psychological well-being among older adults in Hong Kong, with self-efficacy as a central mechanism. These findings highlight the value of Health Action Process Approach-guided programs for active aging in collectivist societies. Policymakers should integrate structured volunteering into community health initiatives to promote mental health and social integration. (PsycInfo Database Record (c) 2026 APA, all rights reserved).