To achieve these goals, the effects of quitting smoking with or without the help of TNP and BUP will be assessed intensively across 66 days of abstinence. Dependent measures will be mood, vigilance, attentional bias to smoking and emotional stimuli, and related physiological measures (resting EEG activation and activation asymmetry indices of affective states and traits, and event-related potential activity elicited by emotional and smoking stimuli). Smokers will be randomly assigned to one of three immediate-quit groups (N = 60 per group): (1) bupropion + placebo patch, (2) placebo pill + nicotine patch, and (3) placebo patch + placebo pill; or to a fourth (control) group (N = 40) that will quit after the final experimental session (after the other subjects have completed their 66-day* abstinence period). Subjects in the 3 treatment groups and the control group will have the same set of biobehavioral measures assessed during the experimental sessions at the same points in time. It is hypothesized that BUP and TNP will have both common and unique mechanisms by which they reduce withdrawal symptoms and that gender and personality traits will moderate the effects of these treatments. (Note.* To avoid final-session mood and arousal effects subjects will actually quit for 67 days, but biobehavioral measures will be collected on the 66th day of abstinence.)