Social reward responsiveness as a moderator of the association between perceived bonding with infants and depressive symptoms in postpartum women

There is a need to identify neurobiological and psychosocial risk processes for postpartum depression (PPD). Previous research links low reward responsiveness with lower reported affiliation or bond to one's infant and PPD symptoms, but the potential moderating role of reward processing in the relationship between bonding with infants and PPD has yet to be examined. The current study (n = 117) used a personally salient social reward task to examine whether neural reward responsiveness moderates the association between bonding difficulties and PPD symptoms. Postpartum women (n = 93) completed the Postpartum Bonding Questionnaire biweekly following childbirth until 8 weeks postpartum, with responses averaged across timepoints. At 8 weeks postpartum, participants completed an electroencephalogram (EEG) Social Incentive Delay task, which included social reward feedback indicating participants would see a personally salient social reward (i.e., cute photo of their infant) and neutral feedback indicating participants would see a neutral image while electroencephalogram data were collected. Participants also self-reported depressive symptoms. A larger social RewP was associated with greater perceived bonding difficulties, and social RewP and self-reported bonding interacted to predict PPD symptoms. The association between bonding difficulties and greater PPD symptoms was statistically significant only for women low in social reward responsiveness. RewP to personally salient infant social reward may be a relevant measure of brain function in the context of maternal perceived bonding and PPD risk.