# High-Frequency Functional Trajectories Predict Depressive Worsening in Singapore’s Community-Dwelling Older Adults

## TL;DR

Older adults in Singapore with worsening functional abilities are at higher risk of developing depression, suggesting early intervention could help prevent mental health decline.

## Contribution

This study identifies functional difficulty trajectories as predictors of depressive worsening using high-frequency longitudinal data in older adults.

## Key findings

- Three functional trajectories (stable, medium increase, high increase) were linked to depression risk in older adults.
- Older adults with high functional difficulty trajectories had a 2.37 hazard ratio for worsening depression compared to stable groups.
- Early functional decline was associated with socioeconomic disadvantage and worse baseline health outcomes.

## Abstract

What is the main finding?
Using a data-driven longitudinal clustering approach, this study found that older Singaporeans with greater functional difficulty trajectories faced a significantly higher risk of worsening depression within a one to two-year period.

Using a data-driven longitudinal clustering approach, this study found that older Singaporeans with greater functional difficulty trajectories faced a significantly higher risk of worsening depression within a one to two-year period.

What is the implications of the main finding?
The findings emphasise the importance of early rehabilitation and supportive services for older adults experiencing rapid functional difficulty as an effective approach to lower late-life depression rates.

The findings emphasise the importance of early rehabilitation and supportive services for older adults experiencing rapid functional difficulty as an effective approach to lower late-life depression rates.

Background/Objectives: Functional difficulty and depression often coexist in older adults, yet local Singapore-based research often lacks detailed temporal resolution due to heterogeneity in ageing. This study employs non-parametric, data-driven longitudinal clustering to analyse functional trajectories and their association with depression, using high-frequency data to pinpoint key intervention periods. Methods: Data were drawn from 4273 community-dwelling older adults from Singapore Life Panel® (2020–2024). Participants completed quarterly self-reported assessments of ADL, IADL and depressive symptoms (8-item CES-D). We employed k-means longitudinal clustering (kml) to identify functional trajectory groups and Cox regression to evaluate the hazard of increased depression (≥5-point increase in CES-D). Results: Three distinct trajectories emerged for both ADL and IADL (Stable, Medium increase in difficulty, High increase in difficulty). In fully adjusted Cox models, Medium and High clusters had higher hazard ratios for increased depression than Stable (ADL: HR 1.71 and 2.37; IADL: HR 1.60 and 2.20). Median time-to-event was not reached in the Stable group and occurred earlier in Medium/High clusters (ADL: 3.25 years and 1.75 years; IADL: 4.0 years and 2.1 years). The High cluster, comprising older and socioeconomically disadvantaged individuals, exhibited worse baseline health and psychosocial factor scores. Depression scores escalated in the Medium and High groups. Conclusions: Rapid functional difficulty acts as a precursor to worsening depressive symptoms. Routine monitoring of functional trajectories offers a strategic window for proactive mental health interventions in at-risk older adults.