Using multilevel modeling to examine blunted neural responses to reward in major depression

Abstract Background Major depressive disorder (MDD) is a pernicious disorder characterized by deficits in reward processing. A better understanding of these deficits may help to elucidate the underlying pathophysiology and guide treatment development. Methods The present study assessed the reward positivity (RewP) and feedback negativity (FN) event-related potentials (ERPs) and their difference score (ΔRewP) elicited in response to monetary gains and losses among 100 young adults (52 MDD). Multilevel modeling (MLM) was used to assess individual and trial-level change in neural responses over time. Results Trial-level analyses indicated that a diagnosis of MDD and depressive symptom severity significantly moderated the trajectory of RewP, with individuals with higher symptoms of depression demonstrating less sensitivity to rewards over time. Conclusions These results provide further support for reward dysfunction in MDD and highlight important individual differences in the trajectory of neural responses to reward. Future studies are warranted to investigate reward sensitivity over time to elucidate important individual- and trial-level differences in reward processing.