Participants were eligible if they were 18–75 years of age, smoked 10 or more cigarettes per day, and had < 3 months of abstinence in the past year (Gonzales et al., 2006; Jorenby et al., 2006). This trial was conducted at 19 centers in the US and the IRB at each site approved this trial. All subjects provided written informed consent including genetic analyses. Participants (N=790) were randomly assigned to either placebo (n = 376) or varenicline (n = 414) for 12 weeks. An additional study arm not included in this analysis was bupropion (n = 345). All participants received individual counseling.
