The reward positivity mediates the association between adverse childhood experiences and anhedonia in young adults with drug-naïve major depressive disorder.

Background: Current clinical studies have indicated that major depressive disorder (MDD) with adverse childhood experiences (ACEs) is associated with greater anhedonia. However, little is known about whether the change in reward sensitivity among young MDD individuals with ACEs are related to anhedonia.

Methods: We evaluated anhedonia and ACEs of each patient. Then, we performed Iowa gambling task during EEG to measure the reward positivity (RewP) and its difference (ΔRewP) in 86 MDD patients (31 with no or one ACE and 55 with two or more ACEs) and 44 healthy controls (HCs). Furthermore, we constructed a mediation model to assessed whether aberrant ΔRewP could mediate the relationship between ACEs and anhedonia.

Results: Compared with healthy controls and MDD patients with no or one ACE, MDD patients with two or more ACEs had the most severe symptoms of anhedonia and impaired decision-making, and showed significantly reduced reward sensitivity (most blunted ΔRewP). More importantly, ΔRewP mediated relationship between ACEs and anhedonia in MDD.

Conclusions: We found that the ΔRewP partially mediates the association between ACEs and anhedonia in MDD patients, which provides evidence for the neurobiological basis of abnormal changes in the reward system in MDD individuals with early adverse experiences.