Abstract: Objective To understand the prevalence of depressive symptoms among college students,analyze the characteristics of life behaviors and their changing trends,explore the relationship between life behavioral characteristics and depressive symptoms,and provide clues for the early identification and targeted interventions of depressive symptoms among college students. Methods The continous cross-sectional survey design was adopted and stratified cluster sampling method was conducted to investigate 2 046 college students from a university in Tianjin from October 2020 to October 2023. Information on depression symptoms and life behavior factors among college students was collected and analyzed. Results The prevalence of depressive symptoms in 2 046 college students was 21.2%. From 2020 to 2022,there would be an upward trend（20.7%,20.7%,29.4%）,followed by a decrease in 2023（12.6%）. Except for sleep and alcohol consumption,the reporting of unhealthy lifestyle behaviors showed an increasing trend from 2020 to 2022 and a decreasing trend in healthy lifestyle behaviors,both of which were reversed in 2023. Intake of sugary drinks once a day or more,heavy alcohol consumption,internet addiction,and use of headphones at high volume were risk factors for the development of depressive symptoms,with OR of 1.471,2.435,3.534 and 1.638 times higher than those of the non-exposed group,respectively.Eating breakfast every day,being outdoors for at least 1 hour every day,and sleeping ≥7 hours per day were protective factors,with OR of 0.669,0.760 and 0.520 times that of the non-exposed group,respectively. Internet addiction was the primary lifestyle behavioral factor in the classification and regression tree（CART） model for the development of depressive symptoms. Internet addiction,sleeping for ≥7 hours per day,prolonged use of headphones,and eating breakfast every day interacted with each other to influence the development of depressive symptoms. In the latent class analysis（LCA） model,there were 3 potential categories based on the distributional characteristics of the behavioral factors：low-risk group,high-risk group,and intermediate group. The risk of developing depressive symptoms was highest in the high-risk group（OR=2.773,95%CI：1.925-3.995）,while lowest in the low-risk group（OR=0.616,95%CI：0.469-0.810）,with the intermediate group in the middle. Conclusion Depressive symptoms and unhealthy living behaviors increased and healthy living behaviors decreased among college students in 2020-2022. Healthy life behaviors were negatively associated with depressive symptoms,and unhealthy life behaviors were positively associated with depressive symptoms. Internet addiction was the primary lifestyle behavioral factor for the development of depressive symptoms,there were interactions between different behavioral factors that collectively influenced the development of depressive symptoms,and individuals with multiple exposures to unhealthy lifestyle behaviors were at the highest risk.

Key words: College students, Depressive symptoms, Life-behavioral factors