Opposing Relations of Reward Positivity with Anhedonia and Threat Sensitivity: Implications for Differential Dimensional Diagnosis.

Given the substantial symptom overlap between anxiety and depressive disorders, researchers have sought to develop approaches for better differentiating these subdimensions of internalizing psychopathology. Neurophysiological indices of biobehavioral processes specific to either subdimension may provide a means for doing so. Here, we report evidence for opposing associations of a well-established neural indicator of reward responsiveness - the reward positivity (RewP) - with trait indices of depressive and phobic fear pathology. We show that these relationships were strengthened when controlling for their shared variance via regression modeling. Additionally, structural equation modeling revealed that broad negative affectivity (NA) constituted the shared variance between the two trait indices. Our findings point to the potential use of reduced RewP to improve differential diagnosis of depressive versus phobic fear conditions. They also indicate that variance shared between conditions of these types may operate to obscure their observed associations with neural indicators of core processes unique to each.