, 2007). Therefore, we predicted that both the FTND and the TTFC item would predict time to the first lapse within the abstinence incentive test. Furthermore, we predicted that smokers experiencing greater craving nothing and withdrawal upon initiating abstinence would lapse sooner within the model. Methods Participants Participants were smokers recruited from the community who participated in one of two different studies involving the ability to abstain from smoking when given an incentive to do so. Smokers qualified for participation if they were 18�C65 years of age, self-reported smoking at least 5 cigarettes/day (CPD) for the past year, exhaled an expired-air carbon monoxide (CO) level of at least 8 ppm at the initial screening visit, and reported no intention to quit smoking in the next month.

Exclusion criteria included self-reported significant medical or psychiatric illness in the past year, drug or alcohol dependence, use of nicotine replacement therapy, pharmacotherapy for smoking cessation, use of other tobacco products within the past 30 days, current use of any psychotropic medication, or pregnancy/lactation. Study assignment was based primarily on the timing of participant contact, given that the first study was nearly completed before the second study began. However, given that the second study required completion of a functional magnetic resonance imaging (fMRI) scan (described below), a few additional participants were routed into the first study when they had contraindications for completing the scan but were otherwise eligible for participation.

All participants provided informed consent in accordance with approved protocol and guidelines of the University of Pittsburgh Institutional Review Board. Fifty-eight participants were consented and participated in the abstinence incentive test; two were subsequently excluded due to procedural errors. The remaining 56 participants (55.4% female; mean age, 38.8 years �� 11.0 SD) were included in analyses. Of these, 46.4% were Caucasian, 48.2% were Black, and 5.4% identified with more than one race or preferred not to answer. Study Design All participants first completed an in-person screening and baseline assessment of several self-report and behavioral measures. Subsequent procedures differed according to which study participants were enrolled in: Twenty-seven were included Brefeldin_A in Study 1, during which ad libitum smoking behavior was assessed for 1 week; the remaining 29 participated in Study 2 and completed an fMRI session assessing blood oxygenation level dependent response to monetary reward following a period of overnight abstinence. Overnight abstinence was not explicitly reinforced with a monetary incentive but was required for continuation in the study.