Medical cannabis looks like a dud for insomnia

Insomnia is one of the most common health complaints, and it carries a substantial burden for individuals and for society. The standard drug treatments bring their own problems: adverse effects and concerns about long-term use. Into that gap has stepped medical cannabis, which is increasingly used for sleep even though clinical guidelines offer no clear recommendation, because nobody has been sure whether it actually works or how safe it is. This review set out to weigh the benefits and harms of medical cannabis for adults with insomnia using the full body of randomised evidence.

The authors searched the major medical databases and trial registers up to 5 April 2025, checked references and contacted study authors. They included randomised controlled trials comparing medical cannabis with placebo or with established sleep and psychiatric medications in adults with any type of insomnia. Nine studies made the cut, covering 537 participants aged 18 to 76, with women making up 72.66% of the pooled sample. Eight of the nine trials compared cannabis against placebo and one against the antidepressant amitriptyline; two used licensed cannabinoid medications while seven used magistral preparations. Six trials enrolled people with chronic insomnia and three with acute insomnia.

Compared with placebo, medical cannabis may make little to no clinically meaningful difference to sleep quality or satisfaction with sleep. Total sleep time shifted by an average of just 7.68 minutes, with the uncertainty running from 23.04 minutes less to 38.39 minutes more, and daytime functioning showed no meaningful improvement either. Quality of life may improve, but the evidence behind that signal is very uncertain. Adverse events told a clearer story: 37 participants experienced them during cannabis periods against none during placebo-only periods, and the review concludes cannabis may cause a slight increase in harms. Certainty was rated very low for almost every outcome, mainly because of bias, inconsistency and imprecision in the trials.

Medical cannabis use for sleep has run well ahead of the evidence, and this updated synthesis confirms the gap has not closed. It does not prove cannabis useless for sleep; it shows the trials run so far are too small, too inconsistent and too short to demonstrate a benefit, while already registering more adverse events than placebo. That distinction matters, because the door remains open for better trials with longer follow-up, standardised outcomes and more diverse participants, which is exactly what the authors call for. Until those exist, guidelines are unlikely to change.

If cannabis products are being pitched to you as a sleep fix, this is the most rigorous accounting of the evidence available, and it does not back the pitch. The pooled trials found no clinically meaningful gain in sleep quality or sleep time, and more side effects than placebo. That is worth knowing before spending money, or before taking on the uncertainty of a product whose long-term harms have not been properly measured. None of this is medical advice about any prescription you may hold; it is a reading of where the evidence currently stands.