Pathways to Depression and Anxiety: Characterizing the Roles of Life Stress and Emotion Inhibition
Individuals with depression and anxiety have difficulty inhibiting their response to emotional information. Depression has been related to more attentional bias to negative information as well as less attentional bias to positive information. Anxiety has been associated with more attentional bias to high arousal, negative (or threat-related) stimuli. Independent of depression and anxiety symptoms, stress across the lifespan has also been linked to alterations in emotion inhibition along with increased risk for the development of internalizing psychopathology in adulthood. Three studies were conducted in order to identify behavioral and neural correlates of a novel emotion inhibition task, and evaluate a potential mechanistic pathway linking stress exposure to psychopathology via alterations to emotion inhibition. To better characterize the role that distracting emotional contexts plays in disruption of inhibitory control, the Image-Color-Word Stroop (IMCWS) task was developed. Participants (N=133) completed the IMCWS as well as questionnaires assessing life stress, resilience, depression, and anxiety. EEG data were collected on a subset of participants (N = 72) during completion of the IMCWS task. The inclusion of emotionally valenced, high-arousal scenes resulted in longer reaction times during high-conflict conditions of the superimposed color-word Stroop, indicating that the IMCWS task successfully enhanced the automatic recruitment of emotion processing to be inhibited. Further, the IMCWS was found to alter event-related potential (ERP) components commonly associated with allocation of attention and emotion processing (e.g., N250, P300) and inhibitory control processes (N450), suggesting that emotion inhibition during the IMCWS involved increased early attentional allocation to emotional contexts followed by increased recruitment of inhibitory control mechanisms. Current life stress (CLS) was found to be predictive of anhedonic depression, and both were associated with alterations in emotion inhibition. Whereas CLS was associated with more biased attention and, therefore, reduced emotion inhibition during the presentation of negative-valence context images, anhedonic depression was found to be related to less biased attention (i.e., increased emotion inhibition) during the presentation of positive-valence context images. Emotion inhibition was not found to play a mechanistic role in the pathway from CLS to anhedonic depression. Rather, results suggest distinct, yet complementary impacts of CLS and anhedonic depression on emotion inhibition function. Given the comorbidity of CLS and depression, CLS should be considered in future studies of emotion regulation and cognitive control disruptions in depression.