Effect of a Hypocretin/Orexin Antagonist on Neurocognitive Performance

Up to 216 healthy volunteers will be enrolled to participate in the 10 day study. After screening procedures have been completed (at SFVAMC), Days 1 - 7 will take place in subjects' homes, where their sleep/wake activity will be monitored. Days 8 - 10 will take place at Moffitt Hospital. On Day 10, subjects will take one dose of either almorexant 100mg, almorexant 200mg, zolpidem 10mg, or placebo. Cognitive tests will be administered to subjects throughout Day 10. Subjects will return for follow-up safety labs within 5 - 12 days of dosing with study medication. Based on animal studies, it is anticipated that subjects who take almorexant will be less cognitively impaired than those who take zolpidem.