Cousens, K. & DiMascio, A. Psychopharmacologia (1973) 33: 355. doi:10.1007/BF00437513
(−)δ9 THC was found to significantly decrease the time it takes to fall asleep in physically healthy insomniacs. Once asleep, interruptions of sleep were not significantly altered over the whole night. The (−)δ9 THC tended to be associated with some decrease in awakenings in the first half of the night.
The primary side effect experienced by the subjects at all dose levels in the Pre-Sleep phase was temporal disorganization and mood alterations. There was an increase in intensity of side effects and number of subjects affected with increasing dosage.
The most significant side effect, however, was a “hangover” phenomenon, or continued “high” the next day, with some residual of temporal disorganization. It increased in intensity and duration with increase in dosage. This “hangover” seems severe enough to eliminate the consideration of the 30 mg dose range of (−)δ9 THC for clinical use as an hypnotic.