Anxiety and Anhedonia in Major Depressive Disorder: The Contributing Roles of Neuroticism, Cognitive Control, and Reward Learning

Higher levels of anxiety and higher levels of anhedonia in Major Depressive Disorder (MDD) are two clinical presentations linked to poorer depression treatment outcomes. However, the mechanisms contributing to these symptom presentations remain unclear. Neuroticism, impaired cognitive control, and blunted reward learning have been suggested to be critical processes involved in MDD, and may help to explain symptoms of anxiety and anhedonia. Using baseline data from individuals with MDD (N=296) in the Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care (EMBARC) study, we conducted a path analysis using structural equation modeling to model hypothesized relationships between the constructs of neuroticism, cognitive control, and reward learning and symptom levels of anxiety and anhedonia. Post-hoc model modifications were performed and relative model fit was compared. Findings indicate that neuroticism was significantly and positively associated with both anhedonia (standardized coefficient = 0.26, p < .001) and anxiety (standardized coefficient = 0.40, p < .001), whereas cognitive control was significantly and negatively associated with only anxiety (standardized coefficient = -0.18, p < .05). Reward learning was not significantly associated with anxiety or anhedonia in the model. These findings suggest that neuroticism may be a potential predisposing factor to both anxiety and anhedonia in MDD, and that cognitive control may be a protective factor to anxiety in MDD. Reducing neuroticism and improving cognitive control through targeted interventions may improve treatment in MDD for those with anxiety and anhedonia.