Study Evaluating the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of SAM-531 in Healthy Subjects

Inclusion criteria 1. Men or women of nonchildbearing potential aged 18 to 45 years 2. Elderly men or women aged 65 years and above as of study day 1. 3. Body mass index in the range of 18 to 30 kg/m2 and body weight ≥50 kg. Body weight for elderly subjects must be ≥45 kg. Exclusion criteria 1. Any significant cardiovascular, hepatic, renal, respiratory, gastrointestinal, endocrine, immunologic, dermatologic, hematologic, neurologic, or psychiatric disease 2. Any clinically important deviation from normal limits in physical examination, vital signs, digital 12-lead ECGs, or clinical laboratory test results. 3. Tobacco use or the consumption of any caffeine-containing products (e.g., coffee, tea, chocolate, or soda) or alcoholic beverages within 48 hours before study day 1, or grapefruit or grapefruit-containing products 72 hours before study day 1, and until the end of the inpatient confinement period.