DronabinolAppetite StimulantsCannabinoid Receptor AgonistsMarijuana SmokingAnorexiaContinuous Positive Airway PressurePain PerceptionCannabisMarijuana AbusePsychotropic DrugsPlacebo EffectSleep Apnea, ObstructiveDouble-Blind MethodAnalgesics, Non-NarcoticSubstance Withdrawal SyndromeCross-Over StudiesSleepPositive-Pressure RespirationPolysomnographySleep Apnea SyndromesEatingTreatment OutcomeDrug Administration ScheduleMasksPatient ComplianceDose-Response Relationship, Drug