Rumination interacts with life stress to predict depressive symptoms: An ecological momentary assessment study.

Rumination is a well-established vulnerability factor for depression that may exert deleterious effects both independently and in interaction with stress. The current study examined momentary ruminative self-focus (MRS) and stress-reactive rumination (SRR) as predictors of depressive symptoms utilizing a smartphone ecological momentary assessment (EMA) design. 121 undergraduates responded to four text message alerts per day for one week in which they indicated the occurrence of life stress, rumination, and depressed mood. SRR, but not MRS, independently predicted increases in depressive symptoms. MRS interacted with depressive symptoms to predict increases in symptoms at the subsequent timepoint, supporting the deleterious effects of depressive rumination on future mood state. Interactions emerged between stress and both MRS and SRR, such that experiencing higher levels of stressors and rumination at an observation predicted greater increases in depressive symptoms. To our knowledge, this study is the first to demonstrate that state rumination moderates the effect of stress in predicting depressive symptoms using EMA methodology. Results suggest that rumination levels in response to stress vary within individuals and can have an important effect on depressed mood. Findings may have important clinical implications, as lessening individuals' tendency to engage in rumination following stress may help to alleviate depressive symptoms.