Rumination Mediates the Effects of Childhood Maltreatment and Trait Anxiety on Depression in Non-Clinical Adult Volunteers

Background: Several psychological studies have shown that depressive rumination is associated with the onset and severity of depression. However, it is unclear how rumination interacts with other predisposing factors to cause depression. In this study, we hypothesized that rumination mediates the association between depression and two predisposing factors of depression, ie, childhood maltreatment and trait anxiety. Subjects and Methods: Between 2017 and 2018, 473 adult volunteers were surveyed using self-report questionnaires regarding the following: demographic information, rumina-tion (Ruminative Responses Scale), trait anxiety (State-Trait Anxiety Inventory-Y), and the experience of childhood maltreatment (Child Abuse and Trauma Scale). The effects of these factors on depression (Patient Health Questionnaire-9) were analyzed by multiple regression and path analysis to analyze the mediating effects of rumination. This study was conducted with approval from the relevant ethics committee. Results: Multiple regression analysis using depression as a dependent variable demonstrated that trait anxiety, rumination, childhood maltreatment, and living alone were significantly associated with depression. Path analysis showed that childhood maltreatment had a positive effect on trait anxiety, rumination, and depression; trait anxiety had a positive effect on rumination and depression; and rumination had a positive effect on depression. Regarding indirect effects, the experience of childhood maltreatment increased rumination and depres-sion indirectly via trait anxiety. Furthermore, the experience of childhood maltreatment increased depression indirectly via rumination, and trait anxiety significantly increased depression via rumination. In other words, rumination mediated the indirect effects of abusive experiences and trait anxiety on depression. This model accounted for 50% of the variance in depression in adult volunteers. Conclusion: Our results suggest that rumination mediates the association between child-hood maltreatment, trait anxiety, and depression in adulthood.