Treating Schizophrenic Smokers: Effects on Craving, Cues and Withdrawal

Inclusion Criteria: Eligible participants for this study: * Are between the ages 18-65 years of age * Are daily cigarette smokers * Have smoked a minimum of 10 cigarettes per day for at least one year * Are confirmed smokers as verified by CO * Have a psychiatric diagnosis of schizophrenia or schizoaffective disorder (any subtype) as determined by the SCID-IV. Participants must have received a stable dose of antipsychotic medication for at least 2 weeks prior to beginning the study. Patients receiving clozapine at 500 mg/day or more must also be receiving anti-seizure prophylaxis. Patients must be determined to be psychiatrically stable at baseline as established by standardized interview and medical review by psychiatrist. Exclusion Criteria: Individuals who are not eligible to participate in this study include individuals with: * Any serious or unstable medical problem in the last 6 months * Severe renal impairment * A history of clinically significant allergic reactions to nicotine agonist medications * Current primary use of tobacco products other than cigarettes * Breath alcohol level \> 0.005 g/l at screening * Current substance abuse or dependence (besides nicotine) * Current attempts to quit smoking using any method * Designation as legally incompetent to sign the informed consent (i.e., have a guardian or have delegated power of attorney to another). Other exclusions are: * Current use of medications that might affect the behavioral response to cigarette smoking, including transdermal nicotine or nicotine gum and bupropion - Inability to participate in the screening session due to severe psychosis, severe depression or suicidality, current mania, or an organic mental disorder such as dementia or delirium * Presence of unstable psychiatric symptoms or clinical deterioration (i.e., unstable psychosis, homicidality, or suicidality) within the last month. * Females of childbearing potential are eligible if not pregnant or nursing and if they practice effective contraception (oral, injectable, or implantable contraceptives; intrauterine device; or barrier method with spermicide). * There currently are no known contraindications to the use of varenicline and no identified drug-drug interactions. However, reduced dosage of varenicline is recommended for individuals with severe renal impairment.