, 2000). Despite the success of these initiatives, national monitoring surveys have shown that decreases in smoking prevalence have slowed in recent years (Nelson et al., 2008). It is estimated that 21% of adults in the United States currently smoke and that of current smokers, 78% smoke Brefeldin A ATPase daily (CDC, 2010b). As the primary contributor to the establishment and maintenance of chronic smoking (Berrettini & Lerman, 2005; Hu, Davies, & Kandel, 2006), nicotine dependence has been characterized by both physiological adaptations (e.g., tolerance and withdrawal) and other accommodating behaviors (e.g., time spent in activities necessary to obtain/use nicotine and recover from its effects and the forfeiting or reduction of important social, occupational, or recreational activities).

Although traditional descriptions of the development of nicotine dependence have suggested the need for both heavy and long-term smoking, an emerging body of research based on separate cohorts of novice adolescent smokers has demonstrated that symptoms of nicotine dependence can occur soon after smoking initiation (DiFranza, Savageau, Rigotti, et al., 2002; Gervais, O��Loughlin, Meshefedjian, Bancej, & Tremblay, 2006; Kandel, Hu, Griesler, & Schaffran, 2007), at relatively low levels of smoking exposure (Caraballo, Novak, & Asman, 2009; Gervais et al., 2006; Scragg, Wellman, Laugesen, & DiFranza, 2008) and before the establishment of daily smoking habits (DiFranza et al., 2007; Gervais et al., 2006).

For example, in a cohort of seventh graders sampled from Montreal secondary schools, 30% and 20% developed mental and physical symptoms of dependence, respectively, within 3 months of reporting their first puff (Gervais et al., 2006). Similarly, based on a cohort of 6th to 10th graders drawn from Chicago public schools, 25% of new adolescent smokers were found to experience Batimastat symptoms of dependence within 5 months of smoking onset (Kandel et al., 2007). Furthermore, in the Montreal study, it took much less time to develop symptoms of nicotine dependence (e.g., mental addiction, physical addition, cravings, withdrawal symptoms, and tolerance) compared with reaching lifetime consumption of 100 cigarettes and daily smoking (Gervais et al., 2006), indicating that symptoms of nicotine dependence in adolescents can occur before the emergence of established smoking patterns.