Impulsivity may also play a role in the manifestation of various types of externalizing problems that have also been associated with drug use and other risky behaviors in childhood and adolescence. Indeed, sensation seeking and poor behavioral control are major characteristics of externalizing behaviors (Caspi et al., 1995; White et al., 1994). In addition, externalizing problems tend to correlate moderately with internalizing symptoms in children and adolescents (Achenbach, 1991; Krueger, Caspi, Moffitt, & Silva, 1998), perhaps reflecting overlapping genetic influences (Kendler, Aggen, Jacobson, & Neale, 2003). Given that both externalizing and internalizing problems in childhood foreshadow later drug use in adolescence (Zucker, Donovan, Masten, Mattson, & Moss, 2008; Zuckerman, 2006), we anticipate that impulsivity would be an important source of those symptoms. Nevertheless, externalizing problems may be related to risk taking apart from their relation to impulsivity as suggested by models such as Tarter’s neurobehavioral disinhibition approach.
