Mechanisms underlying loneliness in Parkinson’s disease: the mediating role of illness acceptance and the moderating effect of community self-efficacy

Patients with Parkinson’s disease (PD) are prone to social isolation and loneliness, and these issues worsen as the disease progresses. Although studies have reported links between social isolation and loneliness, the specific pathways underlying these associations remain unclear. It is unknown whether illness acceptance mediates the relationship between objective social isolation and loneliness, or whether community self-efficacy moderates this mediating pathway. This study aims to examine the statistical association between objective social isolation and loneliness among patients with PD and investigate whether illness acceptance mediates this association and whether community self-efficacy moderates the mediating pathway. A cross-sectional study design was adopted. A convenience sample of 294 patients with PD was recruited from a tertiary care hospital in Henan Province, China, between November 2021 and October 2023. We measured objective social isolation using the Lubben Social Network Scale–6 (LSNS‑6), the Chinese version of the 20‑item UCLA Loneliness Scale (version 3), illness acceptance using the Acceptance of Illness Scale, and community self‑efficacy using the Community Self‑efficacy Scale. The moderated mediation model was tested by Hayes’ PROCESS (version 3.4) Macro Model 14, which is applicable to the scenario that the moderator only affects the mediating path (independent variable → mediator → dependent variable), without regulating the direct path. Illness acceptance mediated the association between objective social isolation and loneliness, and community self-efficacy moderated this mediation. Illness acceptance statistically mediated the association between objective social isolation and loneliness. The total effect was significant (β = − 0.352, p = 0.005). The indirect effect through illness acceptance was also significant (β = − 0.152, 95% bootstrap CI: [–0.286, − 0.039], p = 0.018), whereas the direct effect was non-significant (β = − 0.200, p = 0.092). Community self-efficacy significantly moderated the relationship between illness acceptance and loneliness (β = 0.040, p < 0.001). The conditional indirect effects indicated that the mediating role of illness acceptance was significant at low (M – 1SD: β = − 0.135, 95% CI: [–0.280, − 0.029]) and average (β = − 0.083, 95% CI: [–0.186, − 0.014]) levels of community self-efficacy, but not at high levels (M + 1SD: β = − 0.032, 95% CI: [–0.101, 0.020]). Among patients with PD, illness acceptance functions as a psychological statistical mediator between objective social isolation and loneliness. Community self-efficacy moderates this indirect pathway: Patients with higher community self-efficacy rely less on illness acceptance to mitigate loneliness. Stratified interventions should be implemented in clinical nursing. For patients with low community self-efficacy, health education should be prioritized to improve illness acceptance. For patients with high community self-efficacy, interventions should emphasize maintaining social and community networks during disease fluctuations rather than encouraging resource utilization. Loneliness is highly prevalent among patients with PD. Objective social isolation is associated with greater loneliness; however, the integrated pathway involving social isolation, illness acceptance, and community self-efficacy has not been studied. Illness acceptance fully mediated the statistical association between objective social isolation and loneliness in patients with PD, and this mediating pathway was moderated by community self-efficacy, such that the indirect effect disappeared at high efficacy levels. It provides a theory‑driven empirical basis for stratified psychosocial nursing for patients with PD.