The early development of tolerance symptoms in novice adolescent smokers may at least partially relate to the shortening of latencies between smoking one��s most recent selleck inhibitor cigarette and the onset of withdrawal symptoms, a process that has been well-characterized in dependent smokers (DiFranza et al., 2011). Specifically, the shortening of the latency-to-withdrawal that accompanies each additional cigarette may explain the need for increased amounts of smoking, in that youth find themselves having to smoke more in order to relieve or prevent withdrawal symptoms (DiFranza et al., 2011). Confirming this literature on latency-to-withdrawal, the current findings also demonstrate that nicotine dependence symptoms, and tolerance in particular, can occur in novice smokers and at less-than-daily patterns of smoking.

Although previous studies have demonstrated that the development of symptoms of nicotine dependence in many cases occurs before the onset of more established smoking patterns (Gervais et al., 2006; O��Loughlin et al., 2009), none have previously described the natural course of nicotine dependence specifically among adolescent smokers who had not yet consumed 100 cigarettes. We found, for example, that 20% of adolescents smoking fewer than 100 cigarettes reported ��smoking to relieve restlessness and irritability�� and ��smoking a lot more now to be satisfied.�� Although this study closely resembles a previous report by Gervais et al. (2006) with respect to both study design and the objective to describe the natural course of nicotine dependence in novice adolescent smokers, there are also notable differences.

Gervais used different criteria for assessing nicotine dependence (six symptoms based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and International Classification of Diseases, 10th Revision, rather than the adolescent version of the NDSS). Additionally, the analysis performed by Gervais et al. pooled more established adolescent smokers (smoked 100 cigarettes) with more novice smokers who had not yet smoked 100 cigarettes and did not stratify by this criterion. Thus, the current findings may be more generalizable to novice adolescent smokers. These differences in measurement and smoking populations may explain the difference between the results of the current study and those of Gervais�� study regarding the relative order of tolerance development compared with other dependence symptoms.

Most notably, the current study extends beyond examining the natural course of nicotine dependence symptoms in evaluating the predictive validity of each of these symptoms for future smoking behavior. The plausibility of the presence of symptoms at these very low levels of smoking exposure has been previously discussed by DiFranza et al. AV-951 (DiFranza et al., 2000; DiFranza, Savageau, Rigotti, et al., 2002).