Trajectories of major depression in middle-aged and older adults: A population-based study.

OBJECTIVES: This study aimed to examine depression trajectories and correlates in a nationally representative sample of middle-aged and older adults in the United States.

METHODS: The study sample consisted of 15 661 participants aged over 50 years from the US Health and Retirement Study. Major depression was assessed using the Composite International Diagnostic Interview (CIDI-SF). Depression trajectories were identified using a group-based trajectory modeling enhanced to account for nonrandom attrition. Multinomial logistic regression was conducted to investigate predictors of depression trajectories.

RESULTS: Four depression trajectory groups were identified: "never" (85.8%), "increasing" (6.3%), "decreasing" (3.2%), and "persistently moderate/high" (4.7%). Baseline depressive symptom severity was a strong predictor of depression trajectories. Older age, male sex, and non-Hispanic African American race were associated with a lower risk of the three trajectories with small to high depression burden, whereas chronic disease count was associated with a higher risk of these trajectories. The risk of being on the increasing trajectory increased with mobility difficulties. Difficulties in household activities predicted membership in the persistently moderate/high group.

CONCLUSIONS: A small but nonignorable proportion of middle-aged and older adults have chronic major depression. Initial symptom severity and chronic disease burden are consistent risk factors for unfavorable depression trajectories and potential targets for screening and intervention.