Associations of one-to-one peer support service and intervention outcomes among older adults with depressive symptoms: Evidence from a community-based stepped care programme for late-life depression in Hong Kong.

OBJECTIVE Evidence on the outcomes of peer support for late-life depression is limited. This study examined whether the presence of a peer supporter alongside intervention improves older adults' mental health outcomes and the differential impacts of different peer support types and contents. METHOD From January 2024 to July 2025, depressive symptoms (Patient Health Questionnaire-9), generalised anxiety symptoms (Generalised Anxiety Disorder-7), and loneliness (3-item UCLA Loneliness Scale) of service users in the community-based mental health programme were collected at pre- and post-intervention. Linear mixed models examined the interaction effects between time and the presence of a peer supporter, service type, content, year of peer support experience, adjusting for sociodemographic variables, on mental health outcomes. RESULT Among 1124 older adults, 591 received peer support. Those with peer support showed a greater reduction in depressive symptoms (b = -0.42, CI = -0.80 - -0.05) compared to those without. Home visits (b = -1.27, CI = -1.97 - -0.57) and sharing personal recovery stories and life experiences (b = -1.07, CI = -1.87 - -0.26) were associated with a greater reduction in depressive symptoms than those who did not receive any peer support service. Service users with a more experienced peer supporter had a greater reduction in anxiety symptoms (b = -0.29, CI = -0.47 - -0.11) and loneliness (b = -0.14, CI = -0.24 - -0.03) following treatment. CONCLUSION Employing older adults as peer supporters may be a promising approach to improve service outcomes and promote productive ageing.