Patient volunteers will be recruited from the MPRC Outpatient and Inpatient Programs and through NIDA. Control subjects will be recruited by MPRC and NIDA via newspaper advertisements from the Baltimore metropolitan area. We anticipate recruiting up to 110 schizophrenia patients for a total of 100 completers and up to 110 normal controls for a total of 100 completers. All participants will be 18-65 years old, will smoke cigarettes daily, and must not be interested in reducing or quitting tobacco use. Nicotine dependence appears to be about equally represented among ethnic and racial backgrounds and gender.