A recent article published in Sleep Medicine Reviews evaluated 12 clinical studies and 14 preclinical studies investigating the use of cannabinoids in the management of sleep disorders.
They concluded that while the existing data are insufficient to support the routine clinical use of cannabinoids for this purpose, preliminary “evidence provides the rationale for future [randomized] controlled trials of cannabinoid therapies in individuals with sleep apnea, insomnia, post-traumatic stress disorder-related nightmares, restless legs syndrome, rapid eye movement sleep [behavior] disorder, and narcolepsy.”
The impact of cannabinoids on insomnia (and certain other conditions such as PTSD), which may stem at least partly from their anxiolytic effects, appears to be dose-dependent. Some findings show decreased sleep latency after midrange doses of CBD and increased sleep latency after higher doses.
An earlier study of patients with fibromyalgia demonstrated the superiority of synthetic THC (nabilone) compared to amitriptyline on sleep in patients with fibromyalgia, although it is unknown whether this was attributable to the effect of nabilone on sleep quality or pain control.
Several randomized controlled trials are currently exploring the effects of cannabinoid products in patients with chronic insomnia, including the proof-of-concept CANSLEEP (cannabidiol and Δ9-tetrahydrocannabinol for chronic insomnia disorder) trial investigating the safety and efficacy of a combined THC-CBD product in this population.