Study procedures were approved by the Institutional Review Board at the University of California, Los Angeles and all participants provided written informed consent after receiving a full explanation of the study. Following telephone screening, participants completed a 1-hour in-person assessment visit. Prior to assessment completion, participants had to produce a BrAC of 0.000 g/dl on a breathalyzer, a negative urine toxicology screen (except for marijuana), and a negative pregnancy test (if female). Current smoking status was also verified by a cotinine test (≥ 100ng/ml of cotinine) and participant’s expired carbon monoxide (CO) reading level was recorded at baseline. All participants completed a number of interviews and questionnaires assessing cigarette smoking, nicotine dependence (Fagerstrom Test for Nicotine Dependence (FTND): Heatherton, Kozlowski, Frecker, & Fagerstrom, 1991), alcohol, and drug use. Eligible participants were enrolled in the EMA portion of the study described below.
