Cochrane review of 9 trials, 537 adults: medical cannabis showed little effect on insomnia
A systematic review of nine randomized trials found little to no clinically meaningful effect of medical cannabis on sleep quality and duration versus placebo; the evidence is very uncertain.
A systematic review in The Cochrane database of systematic reviews assessed the benefits and harms of medical cannabis in adults with insomnia. The authors searched CENTRAL, MEDLINE, Embase, Global Index Medicus and two trial registers; the latest search was on 5 April 2025. They included nine randomized trials with 537 participants aged 18 to 76 years. wiley.com
The Cochrane database of systematic reviewswiley.comOpen source ↗
Most participants were women (72.66%). Most studies focused on primary insomnia, and one dealt with insomnia associated with comorbidities. Three studies enrolled patients with acute insomnia and six enrolled patients with chronic insomnia.
Eight studies compared medical cannabis with placebo, and one compared it with the antidepressant amitriptyline. Two studies used licensed medications (one plant-based cannabinoid, one synthetic cannabinoid); the other seven used magistral preparations.
Effects on sleep and quality of life
Compared with placebo, medical cannabis may have little to no clinically meaningful effect on sleep quality or satisfaction with sleep (SMD -0.49, 95% CI -1.06 to 0.08; 7 studies, 374 participants). The same applies to total sleep time (mean difference 7.68 minutes, 95% CI -23.04 to 38.39; 6 studies, 194 participants) and daytime functioning (SMD -0.34, 95% CI -0.83 to 0.16; 5 studies, 144 participants). The certainty of evidence for all three outcomes was very low. wiley.com
The Cochrane database of systematic reviewswiley.comOpen source ↗
For quality of life, the authors report a possible improvement (SMD 0.84, 95% CI -0.61 to 2.29; 3 studies, 95 participants), but the evidence is very uncertain.
Adverse events and limits of the evidence
In three studies with 98 participants, medical cannabis may have caused a slight increase in adverse events (OR 11.25, 95% CI 4.46 to 28.35). Adverse events occurred only during the cannabis period in 37 participants, only during the placebo period in none, in both periods in 14, and in neither period in 47. The certainty of this evidence was low.
The main reasons for downgrading the evidence were high risk of bias, serious inconsistency and imprecision. The authors call for adequately powered, well-designed randomized trials with longer follow-up, standardized outcomes and detailed reporting of efficacy and safety, including long-term harms. They also recommend enrolling more diverse populations and reporting data separately by sex, age and other characteristics. wiley.com
The Cochrane database of systematic reviewswiley.comOpen source ↗
