• This is not a treatment study, but you will be asked to take medication and to make a practice quit attempt during the study.
• You will be randomly assigned to active or placebo medication. If assigned to the medication condition, doses currently recommended for healthy adults will be given.
• The in-person screening interview takes about two hours. Participation in the study lasts for five weeks, and requires 11 visits to the Johns Hopkins Bayview medical center. Most of the visits are short (about 20 minutes), but two of these visits will require a stay of four hours each, and one visit will last for about 9 hours.
• You will be compensated for your time and effort.
