Associations Between Rumination and the Incidence of First-Episode Major Depressive Disorder in a Sample of Chinese University Students: From a 1-Year Longitudinal Study.

Background: As a core risk factor for major depressive disorder (MDD), rumination has been confirmed to predict the onset of MDD in adolescents significantly. However, its pathogenic effect on first-episode MDD in university freshmen has not been systematically evaluated. This study aims to investigate the impact of rumination on the incidence of first-episode MDD among university freshmen. Methods: In this longitudinal cohort study, 6985 participants without MDD at baseline completed a follow-up survey 1 year later. The Chinese version of the Composite International Diagnostic Interview 3.0 (CIDI-3.0) was used to assess MDD. Rumination was measured by the Ruminative Responses Scale. Results: The incidence of first-episode MDD among Chinese freshmen was 2.26%. Symptomatic rumination was significantly associated with a 1-year incidence of MDD (OR = 1.72, 95% CI: 1.33-2.23), controlling for the effects of baseline depressive symptoms and stressful life events. Limitations: All the information collected in this survey was from the participants' recall and selection, making recall and reporting biases possible. Conclusions: Rumination increases the likelihood of first-episode MDD among Chinese university freshmen. Therefore, mitigating or even avoiding rumination could be beneficial in reducing the risk of MDD among university freshmen.