BackgroundChildhood maltreatment (CM) has been shown to be related to a severe and/or chronic course of depression. This study investigated which psychological processes mediate this relationship.MethodA large sample of acute or recovered depressed individuals (N=340) participated in an online survey assessing characteristics of depression, trauma exposure, and potential mediators (emotion regulation difficulties, attributional style, and attachment).ResultsThe experience of CM was related to more severe depression and more depressive episodes. In multiple mediation models, emotion dysregulation, a depressogenic attributional style, and avoidance in close relationships conjointly mediated the relationship between CM and depression severity as well as number of depressive episodes. However, a significant direct path between CM and depression characteristics remained. Exploratory analyses suggested that posttraumatic stress disorder symptom severity was an important additional mediator in our sample.ConclusionsOur findings provide preliminary evidence for psychological mediators between CM and depression that may be promising targets for interventions tailored for the treatment of depression in this subgroup.Highlights of the article Childhood maltreatment (CM) is related to more severe depression. The study investigates how this relationship can be explained.CM was related to difficulties in emotion regulation, relationships and thinking style, and symptoms of posttraumatic stress disorder.Statistical analyses showed that these four variables were also able to (partly) explain how CM is related to more severe depression.Treatment for depression in individuals who have experienced CM may need to directly target these variables.