By Review Finds Little Evidence Cannabis Helps Insomnia
A major new scientific review has found that the available evidence is too weak to reliably determine whether medical cannabis improves sleep quality, sleep duration, or daytime functioning for people with insomnia. Researchers from The Cochrane Associate Centre at the Universidad Hospital Italiano de Buenos Aires and the University of Manitoba conducted the review.
The team examined nine clinical studies involving 537 adults between the ages of 18 and 76 who were receiving treatment for insomnia. Most participants had primary insomnia, meaning their sleep problems were not attributed to another medical condition.
Eight of the trials compared regulated medical cannabis with a placebo.
Across the placebo comparisons, medical cannabis produced little or no clinically meaningful improvement in sleep quality, satisfaction with sleep, total hours slept, or daytime functioning. Participants who received medical cannabis were substantially more likely to experience mild side effects, including dizziness and dry mouth, than those given a placebo.
There was some indication that medical cannabis might improve overall quality of life, but the evidence was highly uncertain. Combined results were consistent with outcomes ranging from a slight decline in quality of life to a substantial improvement.
Why the Evidence Falls Short
The reviewers rated their confidence in the available evidence as low or very low. They cited small study populations, conflicting findings, and potential bias in how the trials were conducted.
The studies tested different medical cannabis products, making it difficult to directly compare results or determine whether particular formulations might work better than others. The studies were also relatively short, with the longest following participants for just 12 weeks.
That leaves major unanswered questions about whether medical cannabis could provide lasting sleep benefits or produce additional effects with prolonged use. The participants also did not adequately represent the broader population of people living with insomnia.
Women accounted for nearly three-quarters of participants, at 72.66%, and the research was heavily weighted toward younger adults. It remains unclear whether the findings would apply equally to men, older individuals, or people whose insomnia occurs alongside other medical conditions.
Insomnia affects millions of people and can increase the likelihood of developing anxiety or depression.
Researchers Call for Larger Trials
“The main message is that the research currently available is not sufficient to reliably answer whether medical cannabis helps people with insomnia,” says Dr. Lucia Varela, lead author of the study from the University of Manitoba, Canada.
“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,” Varela adds.
The authors emphasize that larger, more rigorous clinical trials are needed before medical cannabis can be confidently recommended for improving sleep. The findings do not establish that medical cannabis is ineffective.
