impulsivity scores suggests that individuals with lower P3 amplitudes have higher impulsivity, lending further support to the notion that P3 abnormalities are intrinsically related to impulsivity traits (Justus et al., 2001; McGue et al., 2001; Moeller et al., 2004; Potts et al., 2006; Chen et al., 2007; Kamarajan et al., 2009) as well as to externalizing conditions (Justus et al., 2001; McGue et al., 2001; Moeller et al., 2004; Chen et al., 2007; Kamarajan et al., 2010). It is possible that P3 deficits and high impulsivity may have common underlying brain mechanisms. Recent fMRI studies have found differences between high and low impulsive individuals in terms of engagement and activation patterns of frontal lobe structures (Sripada et al., 2011; Diekhof et al., 2012; Davis et al., 2013). Frontal lobe structures have also been implicated in several disorders involving impulsivity and externalizing traits (Vollm et al., 2004; Lee et al., 2005; Vollm et al., 2007; Wolf et al., 2011; Costa Dias et al., 2013; Cyders et al., 2014). Taken together, these findings add support to the view that P3 amplitude, impulsivity, and externalizing disorders are etiologically related (Iacono et al., 2003; Iacono and McGue, 2006; Chen et al., 2007; Carlson et
