ABSTRACT
Objectives
Late-life depression is the most common mental disorder in older adults. As symptom progression and risk factors are not well understood, this study focuses on longitudinal symptom progression and time-varying risk factors.
Methods
Longitudinal data of adults aged 60+ were drawn from six waves (2008–2023) of the German Aging Survey (DEAS), with the largest analytic sample in 2014 (n = 6515). At each wave participants were classified as having “no” (0–9), “minor” (10–17) or “major” (18–45) depressive symptoms (DS) based on the German Center for Epidemiologic Studies Depression Scale (CES-D). Persistent DS were defined as PDS (at least minor DS) or majorPDS (major DS) across two consecutive waves. Weighted transition probabilities between DS stages were calculated across all person-years. Linear fixed effects regression with cluster-robust standard errors was used to identify time-varying determinants of DS.
Results
In 2014, the prevalence rate was 17.4% [16.6%–18.1%] for minor DS, 7.2% [6.6%–7.8%] for major DS, 12.2% [11.3%–13.1%] for PDS and 2.5% [2.0%–3.1%] for majorPDS. Estimates were similar across all six waves. Minor DS frequently persisted (37.3% [34.1%–40.6%]) or progressed to major DS (11.7% [9.6%–14.2%]). Major DS persisted in 38.6% [31.1%–46.7%] and remitted to minor DS in 31.8% [25.9%–38.3%] of cases. Transition to widowhood (β = 0.67, p < 0.05), worsening of physical functioning (β = −0.06, p < 0.01), increasing loneliness (β = 1.02, p < 0.01), worsening of sleep quality (β = 0.78–4.40, p < 0.01) and decreasing BMI (β = −0.08, p < 0.01) were associated with increases in DS.
Conclusions
DS are common in later life and are frequently persistent. Minor DS often persist or worsen, underscoring their role as a key risk factor. Major DS frequently remits only partly. Early, targeted interventions could be informed by modifiable determinants that may also help to allocate scarce mental health resources effectively.