Measuring Smoking Behaviors While Using Varenicline

Inclusion Criteria: * self report minimum 10 daily cigarettes * self report smoking every day past 5 years * between the ages 21-65 * self report intention to try to quit smoking in the next 6 months Exclusion Criteria: * self reported use of any nicotine-containing products other than non-menthol cigarettes * self reported history or current treatment of substance abuse (other than nicotine dependence) * self reported alcohol use greater than 25 standard drinks per week; * currently pregnant, planned pregnancy or lactating (females: negative urine pregnancy screen) * self reported history or current diagnosis of any Axis 1 disorders except past depression * self reported serious or unstable disease within past year * self reported history of epilepsy or seizure disorder; * self reported history or current diagnosis of COPD (chronic obstructive pulmonary disease), cardiovascular disease, heart attack, or uncontrolled hypertension * self reported kidney function impairment * any current or recent (30 day) use of: smoking cessation medications, anti-psychotics, anti-depressants, anti-anxiety, panic medications, stimulants or opiate-containing medications * less than 5 years of daily smoking * any medical condition or concomitant medication that could compromise participant safety or treatment * provide a baseline carbon monoxide (CO) reading \< 10 ppm * self reported use of non filtered cigarettes * inability to provide informed consent or complete any of the study tasks as determined by the Principal Investigator and/or Study Physician