Researchers in Argentina and Canada have jointly warned that there is not enough proof that marijuana should be used to treat insomnia.
Based at Universidad Hospital Italiano de Buenos Aires and University of Manitoba, the team found the "existing evidence” to be "too uncertain” to recommend that marijuana be prescribed to patients with chronic sleep disorders.
In a paper published in the medical journal Cochrane Database of Systematic Reviews in October, the researchers said they could not confirm that medical cannabis either "improves sleep” or leads to better "daytime functioning.”
"The evidence is too weak and uncertain to draw firm conclusions about the use of medical cannabis for insomnia,” says Luis Garegnani, a doctor at the Buenos Aires hospital.
The team reviewed results of nine tests involving over 500 patients who in most cases were administered cannabis and a placebo, though in one case an antidepressant was given as well.
"Medical cannabis showed little to no clinically meaningful improvement in sleep quality and satisfaction, total sleep time, or daytime functioning compared with placebo,” Cochrane stated in a press release.
Compared to patients who took a placebo, those given medical cannabis "were substantially more likely to experience mild adverse events, such as a dry mouth and dizziness,” the researchers warned.
Around 50 countries have permitted medical cannabis for use against pain, depression and inflammatory bowel conditions.
However, some researchers have warned of clear links to mental health disorders such as psychosis, while others have questioned its medical efficacy.
In January, scientists led by Winfried Häuser of the Technical University of Munich said that cannabis-based medications failed to reduce neuropathic pain in tests pitting the treatments against a placebo.
However, in August 2025, researchers at Imperial College London released findings showing cannabis-infused meds helping people with sleep disorders to get "a good night’s rest.”
Published in the journal PLOS Mental Health, the study detailed improved sleep among 124 patients who tried cannabis-based treatments. – dpa
