Subjects are physically healthy as determined by medical evaluation at the NIAAA outpatient clinic. In particular, subjects must demonstrate no cardiovascular or blood pressure abnormalities, such as a resting blood pressure of 140/90 or greater. All values of laboratory test must be within the NIH defined normal range and all radiological and cardiac evaluations must be considered normal by the NIH radiologist or cardiologist reading the scan or record. As is usual clinical practice, in the case of minor abnormalities a lab test may be repeated to ensure the validity of the initial report.