Temporal Dynamics of Depressive Symptoms, Apathy, Daily Activities, and Cognitive Decline in Older People From the General Population: A Network Analysis.

Background: The prevalence of depressive symptoms, apathy, and cognitive decline increases with age. Understanding the temporal dynamics of these symptoms could provide valuable insights into the early stages of cognitive decline, allowing for more timely and effective treatment and management.

Methods: Participants from the Prevention of Dementia by Intensive Vascular Care (preDIVA) trial cohort with baseline and ≥3 follow-up measurements were included, with a median of 7.8 (0.68) years of follow-up. Dynamic Time Warping (DTW) analysis was used to model temporal dynamics of cognition using the Mini Mental State Exam (MMSE), activities of daily living (ADL) using the Amsterdam Linear Disability Scale (ALDS), and apathy and depressive symptoms using the 15-item Geriatric Depression Scale (GDS-15) at the individual and group level.

Results: The 1,537 participants were aged 74 (2.0) years at baseline, 56.5% were female, and 19.9% had finished higher education. A decline in ADL and increase in apathy tended to precede most indicators of cognitive decline, with all apathy items (i.e. being 'dropped activities/interests', 'not feeling energetic' and 'not doing new things') and ADL showing significant outstrength (all p's < 0.001). Many mood-related symptoms other than apathy, and the MMSE items 'immediate memory', 'verbal comprehension' and 'naming objects' tended to be the last to deteriorate, showing significant instrength (all p's < 0.001).

Conclusion: An increase apathy and a decline in ADL tended to precede mood-related symptoms and cognitive impairment in older adults from the general population. These changes may thus serve as potential early warning signs of both depression and dementia, and may allow for timely intervention.