To identify and delineate the developmental trajectories of depressive symptoms in the middle-aged and elderly population in China, and to explore the risk factors for depressive symptom trajectories in China's middle-aged and elderly population.

According to our inclusion and exclusion criteria, 7 600 participants were subjected based on the data from the China Health and Aged Care Tracking Survey (CHARLS) published by Peking University. The data from 5 waves of the survey from 2011 to 2023 were collected and analyzed with latent growth curve model (LGCM), latent class growth model (LGCM) to identify the developmental trajectories of depressive symptoms in the participants. Multicategorical logistic regression analyses were conducted to analyze whether gender, marital status, educational level, urban/rural residence, annual income, self-rated health status, and childhood bullying experience were risk factors for different trajectories of depressive symptoms.

Two developmental trajectories of depressive symptoms were identified and classified in this study, that is, low-level stable (n=5 545, 72.96%) and high-level ascending (n=2 055, 27.04%). With the low-level stable group as a reference, multicategorical logistic regression analysis revealed that female (OR=1.373, 95CI%: 1.191~1.584, P<0.001), residence of rural area (OR=1.634, 95CI%: 1.410~1.895, P<0.001), and poor self-rated health status (OR=2.059, 95%CI: 1.890~2.243, P<0.001), and experience of childhood bullying (OR=1.76, 95%CI: 1.489~2.080, P<0.001) were associated with an increased risk of high-level ascending trajectory of depression.

There are 2 different trajectories of depressive mood in Chinese middle-aged and elderly population. And poor self-rated health status, history of childhood bullying, being female, and residence of rural area are risk factors for a high-level ascending trajectory of depressive symptoms.