If you agree to participate in this study, we will then meet for a "screening visit" to see if you are eligible for participation in the study. You will have an interview where you will be asked about your history of psychiatric illness. We will also ask about your previous history with smoking and use of other drugs and about your current medications. We will ask you to sign an authorization form so that we can look at your medical record. We will review your medical record for medical and psychiatric diagnoses and treatment. We will check your heart rate and blood pressure. We will take a saliva (spit) sample to check for use of street drugs such as alcohol, cocaine, amphetamines, opiates, and marijuana. If you test positive for the presence of any of these substances, you will not be allowed to participate in the study. Information about drug use will not become a part of your medical record, but this information will become a part of your research record.