Melatonin Treatment for Induced Transient Insomnia

Inclusion Criteria: * Non-smoking for at least 6 months; * Healthy (no medical, psychiatric or sleep disorders); * No clinically significant deviations from normal in medical history, vital signs, physical examination, blood chemistry and hematology, and ECG; * Women of childbearing potential must agree to use an acceptable method of birth control, and must have a negative serum pregnancy test; * Body mass index of \> 18 or \< 30 kg/m2; * No drugs or medication likely to affect sleep or alertness, as determined by the investigators; Exclusion Criteria: * History of alcohol or substance abuse; * Positive result on drugs of abuse screening; * Current or past history of sleep disorders, including but not limited to obstructive sleep apnea, or any significant sleep complaint; * Psychiatric disorder, including a history of depression or dysthymia (characterized by depressed mood on the majority of days for at least two years); * Recent acute or chronic medical disorder, including but not limited to hepatic impairment and severe chronic obstructive pulmonary disease; * History of intolerance or hypersensitivity to melatonin or melatonin agonists; * Pregnancy or lactation; * Shift work in the last 3 years; * Transmeridian travel (2 or more time zones) in past 3 months; * Any other scientific or medical reason, as determined by the PI, such as non-compliance with protocol or intolerance to inpatient study conditions.