Medical cannabis for insomnia? Evidence remains uncertain

Clinical takeaway: When patients ask about cannabis for insomnia, explain that meaningful sleep benefits and long-term safety remain unproven. Offer cognitive behavioral therapy for insomnia (CBT-I) as first-line treatment for chronic insomnia. For patients already using cannabis, review the product and dose, assess daytime functioning, and ask about adverse effects.

Patients seeking alternatives to conventional insomnia treatments may turn to medical cannabis, but reported sleep improvements do not necessarily establish a treatment benefit. A new Cochrane review finds that randomized evidence remains too uncertain to support recommending medical cannabis for insomnia.

The review’s contribution is its focus specifically on adults with insomnia, rather than broader populations reporting sleep problems. Earlier observational studies have described subjective improvements, but the randomized trials reviewed here did not establish reliable, clinically meaningful gains in sleep quality, sleep duration, or daytime functioning.

Researchers included nine randomized trials involving 537 adults aged 18–76 years. Most participants had insomnia without an associated medical condition. Approximately 73% were women. Eight trials compared cannabis with placebo, and one compared it with amitriptyline in patients with fibromyalgia.

Across six placebo-controlled trials involving 194 participants, cannabis increased total sleep time by an average of about eight minutes. However, the confidence interval ranged from 23 minutes less sleep to 38 minutes more, leaving both the size and direction of any benefit uncertain.

Analyses of sleep quality and daytime functioning likewise did not establish a clear benefit. A possible quality-of-life improvement was also highly uncertain.

Adverse effects were more common with cannabis. In three crossover trials involving 98 participants, 37 reported adverse effects only during cannabis treatment, none only during placebo, and 14 during both periods. Reported effects included dry mouth and dizziness. These small, short studies could not reliably assess rare or serious harms.

The trials tested different cannabinoid formulations and doses, so the findings do not identify a preferred THC/CBD product or regimen. Follow-up extended no longer than 12 weeks, leaving sustained benefit, tolerance, withdrawal, and long-term safety unresolved. Older adults and patients with comorbidities were underrepresented.

Cognitive behavioral therapy for insomnia (CBT-I) remains the recommended initial treatment for chronic insomnia. The review does not provide evidence that cannabis should replace it or established medication options. Larger, longer trials using standardized products and clinically meaningful outcomes are needed to clarify cannabis’s role.

“The main message is that the research currently available is not sufficient to reliably answer whether medical cannabis helps people with insomnia,” says Lucia Varela, MD, lead author of the study from the University of Manitoba. “This does not mean that medical cannabis is ineffective. It means that, based on the evidence we have, we cannot draw reliable conclusions about its effectiveness for insomnia in the general population.”

Source: Varela LB, et al. (2026 Oct 12) Cochrane Database Syst Rev. Medical cannabis for the treatment of insomnia