SM-1 vs. an Active Comparator in A Model of Transient Insomnia

Inclusion Criteria: 1. Age 25 and 55 years 2. Body mass index (BMI) between 19 and 32 kg/m2 3. Report previous history of occasional difficulty falling asleep or staying asleep, but not currently having difficulty sleeping; 4. Regular, habitual bedtime between 21:00 and 24:00, routinely spend at least 7.5 and no more than 9.0 hours in bed nightly and a bedtime that does not vary by more than 2 hours over the course of the week. 5. Good general health 6. Females of childbearing potential must be using an acceptable method of contraception, have a negative serum pregnancy test at screening and have a negative urine pregnancy test before randomization and prior to each Treatment Period. 7. Female subjects who have been surgically sterilized are eligible if they have a negative serum pregnancy test at screening and negative urine pregnancy test at check-in or are post-menopausal or have had a complete hysterectomy; 8. Male subjects must use an acceptable method of contraception during the course of the study and for the 90 days following the last dose of study medication. 9. Obtain signed informed consent 10. Able to stay in the clinical research unit for 1 overnight stay during each treatment period 11. No alcohol on check-in days 12. Refrain from the use of alcohol and from napping on site check-in days 13. A recent history of napping of no more than once per week. Exclusion Criteria: 1. Clinically significant, acute illness within 14 days prior to screening 2. Clinically significant, unstable medical illness; 3. Evidence or history of clinically significant allergic hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic or neurological disease; 4. History of cancer or diabetes; 5. A sitting blood pressure \> 140/90 millimeters mercury (mm/Hg) at screening; 6. Heart rate \> 100 beats per minute (BPM) at screening; 7. Clinically significant psychiatric illness, including chronic psychiatric illness or the history or presence of any Axis I condition; 8. Subject has homicidal ideation/intent, per the investigator's clinical judgment, or has suicidal ideation with some intent to act within 6 months prior to the start of the screening phase, per the investigator's clinical judgment or based on the C-SSRS 9. History or presence of chronic pain; 10. Lifetime history of seizure disorder or serious head injury; 11. Clinically significant sleep disorder, including chronic insomnia, sleep apnea, narcolepsy, parasomnia, restless leg syndrome or circadian rhythm disorder; 12. Slept in a sleep laboratory at any time prior to Screening. 13. STOP-BANG sleep apnea questionnaire \>/= to 3 at Screening; 14. Epworth Sleepiness Scale (ESS) score \>10 at screening; 15. Any condition that may affect drug absorption; 16. Travel across more than three time zones or shift worker 17. Any clinically significant abnormal finding on physical examination, vital signs or clinical laboratory tests, 18. History of allergies, or known sensitivity, hypersensitivity, or adverse reaction to any drug similar to diphenhydramine, zolpidem or lorazepam; 19. Pregnant or lactating females; 20. Positive serum or urine pregnancy test 21. Positive urine drug screen 22. Recent history or current evidence of alcohol or drug abuse 23. Regular consumption of "large amounts" of xanthine-containing substances (i.e., \[equivalent to approximately 2 - 3 cups of regular coffee\] or equivalent amounts of xanthine-containing substances); 24. Usual consumption of more than 14 units of alcohol per week. 25. Use of more than 10 cigarettes or equivalent per day of any product containing nicotine or routinely smokes during sleep period. 26. Stopped smoking or in a smoking cessation program within 90 days of screening; 27. Use of restricted concomitant medications, any prescription drug, OTC medication, grapefruit, grapefruit juice, herbal preparation or food supplement, excluding vitamins, acetaminophen or hormonal contraceptives 29\. Exposure to any investigational drug or to diphenhydramine, zolpidem or lorazepam or other drugs of the same pharmaceutical classes within 30 days of screening 30. Positive alcohol or drug test