Emotion differentiation moderates the effects of rumination on depression: A longitudinal study

Elevated trait rumination is associated with and predicts onset of major depressive disorder, but not all people with elevated trait rumination develop major depressive disorder. We hypothesize that certain emotional processes weaken the rumination-depression link, protecting against increases in depression. In this prospective longitudinal study, we examined one such process, emotion differentiation-the ability to discern specific emotions. Because higher negative emotion differentiation (NED) facilitates down-regulating negative emotions and the content of rumination tends to be negative, we predicted that NED, but not positive emotion differentiation (PED), would moderate the rumination-depression association, such that rumination would only predict increases in depression when negative emotions are less, not more, differentiated. Over 1 week of experience sampling, 65 community-dwelling adults (M = 38.4 years) repeatedly reported their emotions, from which we computed NED and PED. Participants completed self-report measures of rumination and depression at baseline and a measure of depression 6 months later. Regression analyses suggested that the combination of NED and PED, but not a unique contribution of either NED or PED, interacted with rumination to predict significant changes in depression, after controlling for mean emotion. Specifically, rumination predicted significant increases in depression when emotion differentiation was lower, but not higher. Findings demonstrate longitudinal benefits of emotion differentiation in adults and suggest emotion differentiation as a promising avenue for studying major depressive disorder.