This study will be a single-center, multiple-dose, randomized, double-blind, placebo-controlled, parallel-group study in healthy male and female subjects. The study will consist of 2 parts: Part A (3 cohorts of healthy Japanese subjects dosed in the evening) and Part B (one cohort of healthy white subjects dosed in the evening). The cohorts will be conducted sequentially. Part A will be started first with the 2.5-mg dose cohort, followed by the 10-mg dose cohort and then the 25-mg dose cohort. Part B will be conducted in parallel with the 10-mg cohort of Part A, with the possibility of overlap.

Inclusion Criteria

Subjects have to meet all of the following criteria to be included into this study:

1. Non-smoking, male or female subjects age greater than or equal to 20 years and less than or equal to 55 years old at the time of informed consent.
2. Japanese subjects must have been born in Japan of Japanese parents and Japanese grandparents, must have lived no more than 5 years outside of Japan, and must not have changed their life style or habits, including diet, while living outside of Japan.
3. Who report habitual time in bed greater than 7 hours, with lights-out 21:00 to 24:00 hours and lights-on 06:00 to 09:00 hours.
4. Who report typical sleep latency of less than or equal to 30 minutes.
5. With typical total sleep time greater than or equal to 420 minutes.
6. Body mass index (BMI) greater than or equal to 18 and less than or equal to 28 kg/m2 at Screening.

Exclusion Criteria

Subjects who meet any of the following criteria will be excluded from this study:

1. Clinically significant illness that requires medical treatment within 8 weeks or a clinically significant infection that requires medical treatment within 4 weeks of dosing.
2. Any subject that has a known history of malaria or has traveled to a country with known malarial risk (ie, countries designated as 'high' or 'moderate' risk according to the list available at http://www.cdc.gov/malaria) within the last year.
3. Evidence of disease that may influence the outcome of the study within 4 weeks before dosing (eg, psychiatric disorders, disorders of the gastrointestinal tract, liver, kidney, respiratory system, endocrine system, hematological system, neurological system, or cardiovascular system, or subjects who have a congenital abnormality in metabolism).
4. Any history of abdominal surgery that may affect PK profiles of E2006 (eg, hepatectomy, nephrotomy, digestive organ resection).
5. Any clinically abnormal symptom or organ impairment found by medical history, physical examination, vital sign and, ECG assessments, or laboratory test results that requires medical treatment.
6. A QTcF interval greater than 450 ms demonstrated on a repeated ECGs (repeated if initial ECG indicates QT greater than 450 ms) at Screening or Baseline.
7. A history or a family history of congenital QT prolongation or with a history of risk factors for torsade de pointes (eg, heart failure, hypokalemia, family history of long QT Syndrome), or use of concomitant medications that prolong the QT/QTc interval.
8. Any suicidal ideation with intent with or without a plan at Baseline or within 6 months of Baseline (ie, answering "Yes" to questions 4 or 5 on the Suicidal Ideation Section of the C-SSRS).
9. Any lifetime suicidal behavior (per the Suicidal Behavior Section of the C-SSRS).
10. Known history of clinically significant drug allergy at screening.
11. Known history of food allergies or presently (at Screening or Baseline) experiencing significant seasonal or perennial allergy.
12. Active viral hepatitis (A, B or C) as demonstrated by positive serology at Screening. Subjects with HIV infection as confirmed verbally.
13. History of drug or alcohol dependency or abuse within the 2 years before Screening, or those who have a positive urine drug test or breath (or urine) alcohol test at Screening or Baseline.
14. Habitually consumes more than 400 mg caffeine per day. Caffeine consumption must be discontinued for at least 24 hours before Baseline check-in.
15. Intake of nutritional supplements, juice, and herbal preparations or other foods or beverages that may affect the various drug metabolizing enzymes and transporters (eg, alcohol, grapefruit, grapefruit juice, grapefruit-containing beverages, apple or orange juice, vegetables from the mustard green family [eg, kale, broccoli, watercress, collard greens, kohlrabi, brussel sprouts, mustard], charbroiled meats) within 1 week before dosing.
16. Intake of herbal preparations containing St. John's Wort within 4 weeks before dosing.
17. Use of prescription drugs within 4 weeks before dosing.
18. Intake of over-the-counter medications within 2 weeks before dosing.
19. Currently enrolled in another clinical study or used any investigational drug or device within 30 days preceding initial dose of study drug.
20. Receipt of blood products within 4 weeks, donation of blood within 8 weeks, or donation of plasma within 1 week of dosing.
21. Engagement in strenuous exercise within 2 weeks before Screening and check-in (eg, marathon running, weight lifting).
22. Diagnosis of a sleep disorder (eg, insomnia, obstructive sleep apnea, restless leg syndrome, Periodic Limb movements in Sleep, narcolepsy, circadian rhythm disorder).
23. Performed shift work within 2 weeks before Screening.
24. Had taken an airline flight across 3 or more time zones in the 7 days before Screening.