Blunted P300 prospectively bridges cognitive reappraisal and depressive symptoms

Cognitive reappraisal is a crucial modulator of depression. Scant research has examined how usage of cognitive reappraisal could prospectively influence depressive symptoms through its modulation effect on P300. Moreover, there is limited knowledge about how the social-environmental context, such as stressful societal disruption, could moderate this prospective process. Adopting a 6-month longitudinal design that recorded both behavioral and electroencephalogram data among 55 young adults (61.8% female) during the COVID-19 pandemic, this study examined the prospective associations from participants' Wave 1 [W1] usage of cognitive reappraisal strategy to W3 depressive symptoms through W2 P300 amplitude during an oddball task, and investigated the potential moderation effect of COVID-19 stress on this mediation path. Cognitive reappraisal was prospectively and indirectly linked to depressive symptoms through reduced P300 amplitude, which was suppressed by COVID-19 stress. Participants with more frequent use of cognitive reappraisal showed blunted P300 amplitude only when COVID-19 stress was low, which was subsequently linked to elevated depressive symptoms. Current findings highlight the central role of reduced P300 as a mediator between cognitive reappraisal and exacerbation of vulnerability for depressive symptoms. Moreover, current findings emphasize the interactive influence between the social-environmental context and cognitive strategy on psychiatric symptoms on a long-term timescale.