F-18 Altanserin PET Study of Patients Receiving Clozapine

Inclusion Criteria: * Overtly healthy males as determined by medical history and physical examination * Age from 19 to 45 years * Weight ≥ 45 kg and within ± 20% of IBW * Clinical laboratory test results within normal reference range for the National Cancer Center, Hospital or results with minor deviations which are judged to be not clinically significant by the investigator * Normal blood pressure and heart rate (supine and standing) as determined by the investigator * Are reliable and willing to make themselves available for the duration of the study, and who will abide by the study restrictions * Have given written informed consent Exclusion Criteria: * Evidence of significant active hematologic disease * History or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, neurological disorders capable of altering the absorption, metabolism or elimination of drugs, or of constituting a risk factor when taking the study medication * An episode of febrile disease or infectious disease within the past 2 weeks * Evidence of significant active neuropsychiatric disease * Regular use of drugs or abuse * History of drug hypersensitivity or clinically significant allergic reactions of any origin * Participation in a study involving administration of an investigational compound within the past 30 days * Use of any current medication * Smoking history for recent 3 months