Part A: The purpose of this study is to evaluate the safety and tolerability of single oral
doses of E2006 administered in the morning to healthy male and female subjects.
Part B: The purpose of this study is to evaluate selected pharmacodynamic (PD) parameters
(e.g., polysomnographically defined sleep measures) with regard to dose response in subjects
with primary insomnia following single oral dosing of E2006 in the evening approximately 30
minutes prior to the sleep period, compared with 10 mg zolpidem and placebo.