The primary objective of the data analysis will be to measure the rate of smoking cessation in the two treatment groups. Smoking cessation will be measured weekly through a composite measure of self-reported abstinence, end expired carbon monoxide (CO) of less than C10 ppm and urine cotinine dipstick measure of < 30 ng/ml. The primary endpoint will be point prevalence at 12 weeks. The four week continuous abstinence rate for the last four weeks of the treatment phase will also be evaluated. The point prevalence abstinence rates will also be obtained. The secondary objective is to determine whether smoking cessation is associated with a worsening of cognition and psychiatric symptomology. We hypothesize that subjects who achieve abstinence in the varenicline group will not show worsening on neurocognitive and symptom measures compared to abstinence subjects in the placebo group. Lastly, we will attempt to identify any clinical or topographic markers which predict cessation.