Abstract Deviations in P300 activity have been implicated in depression and anxiety; however, much of this research has been conducted in adult samples and has primarily examined the association between P300 amplitude and internalizing symptoms between participants . We sought to simultaneously examine the between- and within-subject associations between depression and anxiety symptoms with P300. Self-report and neural data from a flanker task were collected at three timepoints over the course of two years in a large sample of adolescents ( n = 490). Blunted P300 was robustly related to elevated between-subject depression. Conversely, elevations in within-subject anxiety were associated with larger P300. Results implicate the P300 as a reliable correlate of between-subjects level depression-related deficits in cognitive functions that is not susceptible to within-subject changes. Additionally, P300 also serves as a correlate of within-subject elevations in youth anxiety symptoms likely reflecting greater hyperarousal at the time of assessment.
Santopetro et al. (Tue,) studied this question.