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

This trial is studying whether varenicline (a prescription quit-smoking pill) can help people with schizophrenia or schizoaffective disorder stop smoking, and whether it affects certain involuntary movement symptoms sometimes caused by antipsychotic medications. **You may be eligible if...** - You have been diagnosed with schizophrenia or schizoaffective disorder and your condition is currently stable - You smoke at least 5 cigarettes a day and have done so for at least the past month - You are willing to try to quit smoking about 4 weeks after the study begins - Your mental health provider agrees to the treatment, or a clinician can consult with one **You may NOT be eligible if...** - You have untreated or unstable physical or mental health problems - You have a history of seizures or sleepwalking - You have a degenerative neurological condition like Parkinson's disease - You have used substances (including marijuana) heavily in the past 3 months - You are currently taking clozapine or certain memory medications - Your antipsychotic medication dose or type was recently changed - You have had suicidal thoughts or attempts in the past 12 months - You are pregnant or not using a reliable form of birth control - You are currently using other quit-smoking aids like nicotine patches or bupropion - You have a known allergy to varenicline Talk to your doctor to see if this trial is right for you.