Sustained consummatory reward processing deficits in remitted melancholic depression.

BACKGROUND

Depression is believed to be associated with functional alterations in both the anticipation and the consumption phase of the reward processing. It may also manifest in depressed individuals during remission. Still, depression is a heterogeneous syndrome, and reward-related impairments could be more evident in those having melancholic depression. Therefore, the present study aimed to examine whether neural abnormalities are present in individuals with remitted melancholic depression during the reward anticipation and reward consumption phases.

METHODS

Thirty-one participants with melancholic depression (MD), thirty-two participants with remitted melancholic depression (rMD), and thirty-two healthy controls (HCs) completed the monetary incentive delay (MID) task with event-related potential (ERP) recording.

RESULTS

Behavioral results showed no significant difference in reaction time (RT) between the rMD and MD groups, whereas RT was marginally prolonged in the rMD group relative to the HCs group. During reward anticipation, cue-P3 showed no significant intergroup difference in amplitude. HCs exhibited no significant contingent negative variation (CNV) difference from rMD or MD groups, while rMD had significantly enhanced CNV amplitude relative to MD. During reward consumption, no significant difference in feedback-P3 (Fb-P3) was observed among the groups. However, reward positivity (RewP) magnitude was markedly diminished in the rMD and MD groups relative to the HCs during monetary feedback, with no significant difference between rMD and MD groups. Moreover, separate correlation analyses for the three groups revealed that the RewP elicited by monetary feedback was significantly positively correlated with behavioral activation and hedonic tone, and significantly negatively correlated with depressive symptoms.

CONCLUSIONS

These findings provide important evidence indicating that individuals with rMD exhibit persistent impairments in reward consumption. The attenuation of RewP may serve as a potential susceptibility marker for the recurrence of remitted melancholic depression.