Reduced flanker P300 prospectively predicts increases in depression in female adolescents

Past research has found that P300 is smaller in depressed adults. Research examining P300 in relation to adolescent depression is more inconsistent; most studies fail to find P300 differences between currently depressed adolescents and controls. Previous studies have not examined the potential predictive utility of P300 in regard to adolescent depression. Therefore, the current study investigated the relationship between P300 amplitude and depression symptoms at baseline and two years later in a sample of 199 female adolescents. At baseline, participants completed measures of depression, followed by a speeded response task (flanker) while EEG was recorded. Two years later, participants completed the same depression measures. Reduced baseline P300 predicted increases in depression at two-year follow-up. Baseline P300 related particularly to two-year anhedonia and negative self-esteem symptoms. Our study suggest that reduced P300 amplitude can be utilized as a potential risk marker for adolescents at risk for developing increases in depressive symptoms.