20-year trajectories of depressive symptoms and subsequent functional limitation among middle-aged and elderly population: an analysis of longitudinal cohort.

BACKGROUND: Although depressive symptoms and late-life functional limitations were known to be interconnected, the heterogeneity of long-term depression courses and their respective impacts on physical functioning remained unclear.

METHODS: 5819 participants aged ≥45 years with at least three assessments of the 8-item version of the Center for Epidemiologic Studies Depression (CES-D) taken between 1996 and 2014 were selected from the Health and Retirement Study (HRS). Latent Class Growth Mixture Modelling (LCGMM) was used to identify depressive symptoms trajectories and linear mixed models were used to examine the association between different depressive symptoms trajectories and functional limitations.

RESULTS: The study identified four depressive symptoms trajectories: "Low-stable", "Moderate-stable", "Remitting" and "High-late-increasing". Compared with the "Low-stable" trajectory group, participants with all three other trajectories had significantly higher levels of 6-year-late functional limitations ratings (P < 0.001). In addition, having a "High-late-increasing" trajectory was associated with the highest score of 0.90 points (95% CI, 0.66-1.14) in ADL limitation, 0.48 points (95% CI, 0.34-0.62) in BADL limitation, and 0.42 points (95% CI, 0.30-0.55) in IADL limitation at the final interview, respectively.

CONCLUSION: The findings provide practising psychiatrists with insights into the functional consequences of specific patterns of depressive symptoms and thus efficiently facilitating to targeted prevention of functional limitations in high-risk individuals.