The etiology of major depressive disorder is heterogeneous, and differing pathways leading to the development of depression are proposed to account for alternative variants of depressive illness and their distinct comorbidity patterns. The present study was undertaken as a step toward developing a model for conceptualizing and quantifying dispositional proneness to depression, marked by reduced neural sensitivity to rewarding events and more persistent occurrence of depressive symptomatology. Using data for college and community adult participants (N = 201), we sought to quantify variations in depression proneness by combining symptom indicators of persistent depressive conditions (dysthymic disorder, depressive personality) with a brain potential response that has been shown to index sensitivity to pleasurable events-the reward positivity (RewP; Proudfit, 2015). We first extended prior work on the RewP and depression by showing that the magnitude of RewP covaried negatively with symptoms of persistent depressive conditions (dysthymia, depressive personality) but not with current levels of depression. Persistent depressive symptoms and the RewP were then combined to form a composite neuroclinical index of depression proneness. Compared to persistent depressive symptoms alone, this composite dimensional index showed improved specificity of relations with diagnostic criterion measures, that is, similar-level associations with other indicators of depression proneness but significantly lower associations with fear disorder symptomatology. These findings provide evidence that a dimension of depression proneness can be quantified effectively by combining psychological indicators of persistent depression with a neurophysiological index of a core depression-related process (i.e., reward sensitivity).
Keywords: biomarker; depression; dysthymia; neuroclinical assessment; reward positivity; reward sensitivity.
© 2019 Society for Psychophysiological Research.