Smoking Cessation With Varenicline in Schizophrenia: Antipsychotic-Induced Neurological Symptoms as Correlates

Who May Qualify: - DSM 5 criteria for schizophrenia or schizoaffective disorder and stable disease - Glazer-Morgenstern-Doucette criteria for TD - Smoking at least 5 cigarettes on average daily for at least 30 days prior to screening - An exhaled carbon monoxide concentration greater than 5 parts per million (ppm) at screening - Agree to stop smoking by the target date (four weeks after baseline - Concurrence for varenicline treatment from the patient's mental health provider if the patient is under mental health care; OR, if the patient is not under mental health care, the prescribing clinician should consult with a mental health provider to evaluate the patient for appropriateness to receive varenicline Who Should NOT Join This Trial: - Have untreated or unstable acute medical or psychiatric illnesses - Have a history of seizures - History of somnambulism - Have chronic degenerative neurological illnesses (e.g., Parkinson's disease) - Have a history of active substance abuse (including marijuana abuse) in the 3 months prior to screening or a positive toxicology screen - Are receiving clozapine or cholinesterase inhibitors - Had a change in dosing or medication type of antipsychotic or anti-muscarinic for one month prior to enrollment (two months for long-acting antipsychotics) - Are unable to remain on a stable dose of antipsychotic or anti-muscarinic during the study period - Have acute suicidal ideation, intent or behavior within 12 months or risk based assessed on the C-SSRS or depression/anxiety score ≥ 8 on the HADS. - Female subjects of childbearing age will have a negative pregnancy serum test at screening and are required to use approved methods of birth control - Use of an investigational drug within 30 days of screening - Use of other smoking cessation aids (bupropion, nicotine replacement products) - Use of other tobacco products - History of allergic reactions to varenicline - Lack capacity to provide willing to sign a consent form Always talk to your doctor about whether this trial is right for you.