DESCRIPTION: (Applicant's Description) Tobacco smoking by adolescents poses a major health threat, with 90% of adults having initiated smoking before the age of 18. Research with chronic adult smokers has demonstrated certain aversive effects of nicotine abstinence which have been implicated in maintenance of smoking among adults. Little is known about the characteristics, intensity, or relevance of nicotine withdrawal among adolescent smokers. The primary objective of this research is to measure the physiological and psychological characteristics of nicotine withdrawal among adolescent smokers and to assess the relevance of these measures in predicting subsequent difficulty quitting smoking. In the proposed study, adolescent smokers (ages 13-17) will be recruited from a primary care setting to participate in a 3-session experimental protocol designed to assess nicotine withdrawal under carefully controlled laboratory conditions. Measures will include: a cognitive performance computerized test battery, negative affect and reactive irritability, smoking cue reactivity, and caloric intake. During session I, baseline assessments will be completed with no deprivation from nicotine. During session 2, assessments will be repeated after overnight abstinence from nicotine. In session 3, assessments will be re-administered after participants have resumed smoking at their baseline level. Immediately following session 3, a brief smoking intervention will be delivered. Follow-up assessments will occur in person at 3 and 6 months later, to measure smoking outcome. Measures of nicotine withdrawal effects (changes from session 1 to 2) and withdrawal relief effects (changes from session 2 to 3) will be evaluated and validated against: (1) baseline measures of tobacco use history, current intake levels, nicotine dependence, and motivation to quit smoking; and (2) subsequent tobacco use and quit attempts at follow up. A pilot study is proposed for Year 1 of this application in order to determine the cognitive performance test battery components to use in the larger trial. This research will contribute the first: 1) assessment of withdrawal among adolescents that is not retrospective or subjective; 2) evaluation of objective withdrawal characteristics among abstaining adolescents under controlled conditions; and 3) prospective validation of withdrawal measures as they relate to subsequent smoking outcomes. Thus, it will provide a greater understanding of nicotine withdrawal as a maintaining factor of adolescent smoking, and thereby provide an empirical basis for enhancing smoking cessation approaches for youth.