Interplay between Stress, Rumination, and Memory in Predicting Depression: An Ecological Momentary Assessment Study

Abstract

Rumination is a well-established vulnerability factor for major depressive disorder (MDD) that may exert deleterious effects both independently and in interaction with life stress, and may contribute to the negative memory biases associated with MDD. Chapter 1 examines the role of both momentary ruminative self-focus (MRS) and stress-reactive rumination (SRR) as predictors of increases in depressive symptoms utilizing a smartphone ecological momentary assessment (EMA) design. SRR, but not MRS, independently predicted increases in depressive symptoms. Interactions emerged between negative life events (NLEs) and both MRS and SRR, such that experiencing higher levels of NLEs and rumination at an observation predicted greater increases in depressive symptoms. The results suggest that rumination levels in response to stress vary within individuals and can have an important effect on depressed mood. Chapter 2 tests the hypotheses that 1) engaging in greater SRR relative to an individual’s mean would lead to deeper encoding and improved retrieval of stressors, and 2) this biased memory for negative autobiographical information would predict increases in depressive symptoms over time. NLEs followed by increased SRR relative to individuals’ means were significantly more likely to be recalled two weeks later. In addition, a significant interaction emerged between the number of NLEs experienced and proportional recall of those events, such that individuals who endorsed and recalled greater numbers of stressors during the EMA week displayed increased depressive symptoms at follow-up. These findings support the role of rumination and memory biases as vulnerability factors for depression, and suggest potential clinical benefits of modifying ruminative response styles to daily stressors.