Walsh JH, Maddison KJ, Rankin T, Murray K, McArdle N, Ree MJ, Hillman DR, Eastwood PR. Treating insomnia symptoms with medicinal cannabis: a randomized, crossover trial of the efficacy of a cannabinoid medicine compared with placebo. Sleep. 2021 Nov 12;44(11):zsab149. doi: 10.1093/sleep/zsab149. PMID: 34115851; PMCID: PMC8598183.
Rationale: Good sleep is critical for overall health, cognitive functioning, and well-being. Some people report that cannabis helps with sleep, but evidence has been lacking.
Method: The study evaluated the effects of ZTL-101, compared to placebo, on sleep quality in 23 adults with chronic insomnia. ZTL-101 contains mostly THC (20 mg/mL), but also CBN (2 mg/mL) and CBD (1 mg/mL). Participants were assessed in a randomized crossover design by both self report and polysomnography to measure physical correlates of sleep including brain waves, muscle activity, oxygen levels and breathing.
Results: Participants reported that they fell asleep faster and had a longer and better sleep with ZTL-101, however, objective measures did not corroborate these self reports. There were no differences in any measure of sleep quality between drug and placebo groups.
Meaning: These findings indicate that ZTL-101, containing mostly THC, does not improve sleep quality. Results of the study also highlight the importance of experimental studies to dissociate effects of cannabis from placebo-driven expectations.