The “Brightening” Effect: Reactions to Positive Events in the Daily Lives of Individuals With Major Depressive Disorder and Generalized Anxiety Disorder

Abstract Depressed individuals are less reactive than healthy individuals to positive stimuli in the laboratory, but accumulating evidence suggests that they are more emotionally reactive to positive events in their daily lives. The present study probed the boundaries of this curious “mood brightening” effect and investigated its specificity to major depressive disorder (MDD) vis-a-vis generalized anxiety disorder (GAD), its closest boundary condition. We used ecological momentary assessment to measure reactions to positive events over one week in individuals with MDD ( n = 38), GAD ( n = 36), comorbid MDD-GAD ( n = 38), and no psychopathology ( n = 33). Depressed individuals responded to positive events with larger changes in affect, cognition, reported withdrawal (but not approach) behavior, and symptoms than healthy controls. More severe depression assessed before the sampling week predicted greater brightening. Altered reactivity to positive events was relatively specific to MDD when compared with GAD, similar to patterns found for other positive emotional processes. The robustness, scope, and relative specificity of the brightening effect highlights the need to resolve conflicting findings across laboratory and non-laboratory studies to advance understanding of altered reactivity in emotional disorders.