Loneliness, Depression, and Subjective Memory Complaints in Middle-Aged and Older Adults: The Role of Meaning in Life

This study examined whether depressive symptoms mediate the association between loneliness and subjective memory complaints (SMCs), and whether meaning in life (MIL) moderates this pathway, among middle-aged and older Korean adults.

A cross-sectional survey was conducted with 580 adults aged 41-71 years (mean age=58.80; 54.8% males). Participants completed measures of loneliness, depression, SMCs, and MIL. Mediation (PROCESS Model 4) and moderated mediation (Model 7) analyses were performed using 5,000 bootstrap resamples while adjusting for demographic covariates. Supplementary analyses examined MLQ subscales (Presence and Search for Meaning) and age-stratified models.

Loneliness was significantly associated with depressive symptoms (β=0.523, p<0.001) and SMCs (β=0.131, p=0.008). Depression was also associated with SMCs (β=0.200, p<0.001) and partially mediated the loneliness-SMCs link (indirect effect=0.011; 95% confidence interval [CI] [0.006, 0.018]). The index of moderated mediation was significant (index=-0.0002, 95% CI [-0.0004, -0.0001]). MIL moderated the loneliness-depression association (interaction B=-0.005, p<0.001), with a stronger slope at low MIL (B=0.237) than at high MIL (B=0.148). Subscale analyses showed similar patterns for presence and search when tested separately, but neither showed a unique moderating effect when entered simultaneously. Age-stratified analyses showed depression mediated the loneliness-SMCs link only in older adults, whereas MIL attenuated the loneliness-depression association only in middle-aged adults.

Loneliness was associated with SMCs partly through depressive symptoms, and MIL may buffer this pathway. These mechanisms differed by life stage, with stronger evidence for depression as a mediator in later life than in midlife, suggesting age-tailored approaches targeting emotional distress and life purpose.