Direct and indirect effects of loneliness on depression in late life: Persistent loneliness as a primary longitudinal pathway.

Abstract

Objectives: Loneliness is a well-established longitudinal predictor of depression in later life, yet the mechanisms through which this association unfolds remain unclear. This study examined the direct and indirect effects of loneliness on subsequent depressive symptoms in late life, with particular emphasis on persistent loneliness over time.

Methods: Community-dwelling, older Israeli adults (N = 1216; M age = 81.1 years) completed annual assessments of loneliness and depressive symptoms over three years. Structural equation modelling was used to estimate autoregressive pathways, prospective effects of loneliness on subsequent depressive symptoms, and indirect effects operating through the persistent loneliness. Models were adjusted for age, sex, education, marital status, financial status, self-rated health, living arrangement, religiosity, and Holocaust survivor status.

Results: Loneliness and depressive symptoms both demonstrated substantial temporal stability over time. After adjusting for prior depressive symptoms and sociodemographic covariates, loneliness remained a significant prospective predictor of subsequent depressive symptoms. Decomposition of longitudinal effects, however, indicated that indirect pathways, transmitted through persistent loneliness, accounted for a greater proportion of the total longitudinal association than direct prospective effects. In fact, direct prospective effects were not statistically significant after accounting for indirect pathways. Baseline loneliness and depressive symptoms did not predict study attrition, supporting the robustness of the longitudinal findings.

Conclusions: The association between loneliness and subsequent depressive symptoms in later life appears to operate primarily through persistent loneliness rather than through direct prospective effects. These findings suggest that chronic loneliness functions as a longitudinal pathway sustaining depressive symptoms over time. Interventions that mitigate loneliness in late life may also reduce depression among older adults.