These studies also found that childhood psychopathology whether externalizing or internalizing is associated with lower P300 amplitude (Hill et al., 1999) with any childhood psychopathology associated with greater likelihood of being in the low amplitude trajectory class (Hill and Shen 2002). Interestingly, children with internalizing disorder had lower P300 amplitude, and those with both internalizing and externalizing disorders had the lowest P300 amplitude (Hill et al.,1999). Similarly, Van Der Stelt (1999) found both internalizing and externalizing disorders moderated the effect of family history on P300 amplitude.
