London, United Kingdom: Patients diagnosed with insomnia experience sleep-related improvements following their use of medical cannabis preparations, according to long-term observational data published in the journal PLoS Mental Health.
British investigators assessed the adjunctive use of cannabis-based medicinal products (CBMPs) in a cohort of 124 patients enrolled in the UK Medical Cannabis Registry. (British healthcare providers may prescribe cannabis-based medicinal products to patients unresponsive to conventional medications.) Patients’ outcomes were assessed at baseline and at 1, 3, 6, 12, and 18 months. Study participants consumed either herbal cannabis or oil extracts containing standardized concentrations of THC and CBD.
Consistent with other studies, participants reported improvements in their sleep quality, anxiety, depression, and health-related quality of life. Fewer than 1 in 10 participants reported an adverse event, most of which were categorized as mild or moderate (e.g., fatigue, dry mouth).
“These findings indicate a promising association between cannabis-based medicinal product treatment and improvements in sleep-specific outcomes and general HRQoL [health-related quality of life] measures,” the study’s authors concluded. They cautioned, however, that the magnitude of participants’ improvements declined over time – suggesting that some patients may become tolerant to the sleep-inducing effects of cannabis. Therefore, there remains “a need for high quality RCTs [randomized clinical trials] to assess the long-term efficacy and safety of cannabis-based medicinal products for primary insomnia.”
Placebo-controlled clinical trial data have previously documented the short-term efficacy of plant-derived cannabis extracts in patients suffering from chronic insomnia. A 2025 observational study reported sustained improvements in subjective sleep scores among state-registered medical cannabis patients over one year.
Other observational studies assessing the use of cannabis products among patients enrolled in the UK Medical Cannabis Registry have reported them to be beneficial for those diagnosed with treatment-resistant epilepsy, cancer-related pain, anxiety, endometriosis, inflammatory bowel disease, hypermobility disorders, migraine, multiple sclerosis, osteoarthritis, substance use disorders, and inflammatory arthritis, among other conditions.
Full text of the study, “UK Medical Cannabis Registry: A clinical outcomes analysis for insomnia,” appears in PLoS Mental Health. Additional information on cannabis and insomnia is available from NORML’s publication, Clinical Applications for Cannabis & Cannabinoids.