This is a proof of concept study to determine the safety and efficacy of dronabinol for the treatment of obstructive sleep apnea syndrome (OSA).

Inclusion Criteria:

• Adult 21 to 64 years of age;
• 15≤AHI ≤ 50 on screening polysomnogram (PSG)
• ESS score ≥ 7
• Able to understand and complete informed consent and all study assessments and forms, presented in an English-speaking format;
• Women of child-bearing potential (WCBP) must have a negative urine pregnancy test. In addition sexually active WCBP must agree to use adequate contraceptive methods (oral, injectable or implantable hormonal contraceptive; tubal ligation; intra-uterine devices; barrier contraceptive with spermicide; or vasectomized partner).

Exclusion Criteria:

• Arterial oxygen saturation < 75% for > 5% of sleep period time on screening PSG;
• Occupation or life situation that may impart risk by study participation (e.g. commercial driver, pilot, police officer, fireman);
• Motor vehicle accident or "near-miss" related to sleepiness (self-report) within 2 years of the first dose of study drug (Day 8);
• Body mass index > 45 kg/m2
• Severe obstructive sleep apnea syndrome (OSAS) that, based on the clinical judgment of the Investigator, precludes delaying positive airway pressure treatment;
• History of shift work or rotating shifts within the month prior to the first dose of study drug (Day 8);
• Prior upper airway surgery for snoring or OSAS as an adult (≥ 18 years of age);
• Prior non-invasive treatment for OSAS within 6 months prior to the first dose of study drug (Day 8);
• Major surgery within 6 months prior to the first dose of study drug (Day 8);
• Bariatric surgery within 2 years prior to the first dose of study drug (Day 8). If post-bariatric surgery, weight must be stable ±5% (self-report) for at least 6 months prior to first dose of study drug (Day 8).
• Any form of medically managed weight loss program within 6 months prior to the first dose of study drug (Day 8);
• Significant defect in nasal patency due to anatomical abnormalities or uncontrolled or recurrent episodes of rhinitis;
• Any clinically significant unstable or progressive medical condition;
• Any primary sleep disorder other than OSAS as determined by history, physical examination, or Visit 2 PSG (after 7-day screening run-in period);
• Clinically significant or uncontrolled: chronic obstructive pulmonary disease (COPD), cardiovascular disease, gastrointestinal, respiratory, pancreatic, hepatic, renal, hematologic, endocrine [including insulin-dependent diabetes mellitus (IDDM)], neurological, urogenital, connective tissue, dermatological, thyroid, or other medical disorder;
• Any clinically significant psychiatric disorder;
• History of seizure disorder;
• Treatment with any prescription antidepressant medication within 1 month prior to the first dose of study drug (Day 8);
• Treatment with sedatives, hypnotics or other psychoactive drugs within 30 days prior to the first dose of study drug (Day 8);
• Any complete blood count (CBC) or liver function test (LFT) laboratory value outside the normal range which, in the clinical judgment of the Investigator renders a subject inappropriate for randomization to treatment;
• Pregnancy [as demonstrated by positive urine human chorionic gonadotropin (hCG) test] or lactation;
• Allergic to cannabinoids or sesame oil;
• History of substance abuse (including alcohol abuse or dependence) or laboratory evidence of drug abuse on the Visit 1 drug-screening panel;
• Use of dietary supplements which in the judgment of the Investigator may impact sleep or breathing behaviors;
• Average daily caffeine consumption > 500 mg/day (~5 cups of coffee);
• Average weekly alcohol consumption > 10 units;
• Unwillingness to abstain from caffeine and alcohol on all days when overnight or daytime testing will be performed;
• Participation in any other investigational protocol within the 30 days prior to the first dose of study drug (Day 8);
• Any condition which, in the opinion of the Investigator, places the patient at unacceptable risk if he or she were to participate in the study.

Baseline analysis population includes all participants who were randomized to treatment.