This 10-week study consists of an unassisted (pretrial) acute tobacco withdrawal (AW) phase and a 7-week randomized double-blind placebo-controlled trial of bupropion (300 mg/day) for tobacco dependence. Neuropsychological examinations will be conducted at baseline, during acute withdrawal, and during treatment (incl. early withdrawal) with bupropion. We expect smoking cessation in approximately 25% of the active medication group and significant overall smoking reduction. We postulate that bupropion will also reduce the irritability, depressed mood and anxiety symptoms that typically occur during tobacco withdrawal. We expect to observe optimal cognitive performance, (i.e., attention, memory), and affective state during satiety, impairment during pre-treatment abstinence, and intermediate level cognitive performance in the abstinent active-treatment group. Because limited data are available on cognitive tasks in adolescent smokers, a non-smoking group will be included in order to establish the validity and appropriateness of our paradigm with a normative sample.