The present study extended previous findings of an association between P3-AR and externalizing psychopathology in a population-based sample of adolescents by employing a novel, data-driven time-frequency analysis method to decompose the averaged ERP data in a new way. The extracted time-frequency component measures accounted for almost all of the variance in the time-domain P3 measures, demonstrating that the relevant variance for measuring the P3-AR was well represented in the decomposition. Next, these P3-related TF components were shown to be associated with disinhibitory disorders in the externalizing spectrum. Further, delta activity in particular time ranges was associated with externalizing disorders above and beyond the association between these disorders and P3 amplitude, suggesting that these TF components may serve as more parsimonious endophenotypes for externalizing than P3-AR.
