Introduction
Late-life depression affects nearly one-fifth of older adults, while approximately 16% experience mild cognitive impairment. These conditions are reciprocally related: depression may signal prodromal dementia, while cognitive deficits can increase vulnerability to depression. Stressful life events, such as bereavement, represent additional risk factors for both outcomes. Network theory posits that depressive symptoms and related risk factors form interdependent systems, where their dynamic interactions may reveal pathways toward resilience or depression onset, highlighting potential prevention targets.


Purpose
This study investigated how interactions between depressive symptoms and cognitive functions evolve over time in older adults following bereavement. We compared individuals who developed depression with those who remained resilient, aiming to identify temporal patterns that distinguish flexible versus rigid symptom networks.


Method
Participants were 1,992 Danish adults aged >70 who met the following eligibility criteria: (1) recent bereavement, (2) no prior depression, (3) complete depressive symptoms and cognitive function data at baseline and two-year follow-up. At follow-up, 1,770 participants remained non-depressed, while 222 developed depression. Contemporaneous and cross-lagged panel networks (CLPNs) were estimated to examine cross-sectional and longitudinal associations between 15 depressive symptoms and five cognitive functions.


Results
Both groups showed an increase in depressive symptom severity over time, though the difference widened at follow-up. Resilient networks displayed significant structural change, indicating flexibility, while depression-onset networks remained rigid. In CLPN analyses, the resilient group exhibited few repeated temporal predictions, whereas the depression-onset group showed consistent bidirectional influences between cognition and depression. Depressive symptoms predicted later verbal fluency decline, while poorer baseline attention, working memory, and memory functions predicted greater depressive symptoms.


Conclusions
Following bereavement, resilient elders demonstrated flexible network restructuring, whereas those who developed depression showed rigid, self-perpetuating interactions. Lower baseline cognitive function within an inflexible network increased depression risk by activating later anhedonia and worthlessness. Preventive strategies should target sustaining attention and memory functions in older adults.