This is an open label pre-post study of the effects of clinical treatment with varenicline on 1) decreasing smoking in schizophrenic patients, 2) improving selected cognitive measures in schizophrenic patients, and 3)psychopathology.in schizophrenic patients,. Patients are assessed on subjective and objective measures of smoking , selected cognitive measures, and special chemical measures, during baseline testing and during 8 weeks of treatment with varenicline ( 1-2 mg/day).