Effects of Varenicline on Brain Activity During Nicotine Abstinence

Thirty treatment seeking smokers will be recruited to complete a 40-day within-subject (cross-over), double-blind study that will assess effects of varenicline on brain activation while performing certain tasks. Prior to beginning the study, participants will complete an health and physical screening to determine final eligibility. Following a medication run-up and a 3.5 day abstinence period, participants will complete study period 1 (an fMRI scan while performing attention, working memory and emotion tasks). After a 14 to 21-day washout period the study procedures will be repeated with placebo (order of study medication counterbalanced). After completion of both study periods, all participants will be offered a 13-week quit smoking program with varenicline.