Background and Objectives: D9‐tetrahydrocannabinol (THC) promotes sleep in animals; clinical use of THC is associated with somnolence. Human laboratory studies of oral THC have not shown consistent effects on sleep. We prospectively evaluated self‐reported sleep parameters during controlled oral THC administration to research volunteers. Methods: Thirteen male chronic daily cannabis smokers (mean SD age 24.6 +/- 3.7 years, self‐reported smoking frequency of 5.5 +/- 5.9 (range 1–24) joint‐equivalents daily at study entry) were administered oral THC doses (20 mg) around‐the‐clock for 7 days (40–120 mg daily) starting the afternoon after admission. The St. Mary’s Hospital Sleep Questionnaire was completed every morning. Plasma THC and...
