Another major correlate of risky behavior in adolescents is a set of relatively stable personality traits under the rubric of impulsivity (S. B. G. Eysenck & Eysenck, 1977, 1978; Patton, Stanford, & Barratt, 1995; Verdejo-Garcia, Lawrence, & Clark, 2008; Whiteside & Lynam, 2001; Zuckerman, 2006). These traits are regarded as under the control of both the prefrontal cortex (PFC) and the subcortical motivational systems to which it is linked (Chambers & Potenza, 2003; Chambers, Taylor, & Potenza, 2003; Cloninger, 1987, 1988; Zuckerman, 2006). Research in both humans and animals suggests that impulsivity is multidimensional (Evenden, 1999; Whiteside & Lynam, 2001) and that some of its manifestations grow in strength during adolescence (Casey, Getz, & Galvan, 2008; Chambers & Potenza, 2003; Chambers et al., 2003; Spear, 2000a). In particular, sensation seeking, the attraction to novel and exciting experiences peaks during adolescence (Romer & Hennessy, 2007; Zuckerman, 2006), likely reflecting enhanced dopamine release to the ventral striatum and prefrontal cortex (Chambers et al., 2003; Spear, 2000a, 2000b). Based on this increase, one would expect early risk takers to exhibit higher levels of sensation seeking, a pattern confirmed in one study of early drug use initiation (Crawford, Pentz, Chou, Li, & Dwyer, 2003).
