Many people have difficulty sleeping, and there is no shortage of treatments that are supposed to help us get some sleep back. Unfortunately for the many people who use cannabis to combat insomnia, a comprehensive study released this week found little solid evidence of its effectiveness.
In a new Cochrane Library review, scientists conducted an in-depth analysis of randomized clinical trials of medical-grade cannabis for insomnia. There was not enough evidence supporting the idea that cannabis could reliably relieve insomnia, they concluded. While it’s still possible that the drug is a useful sleep aid, better studies are needed to know for sure, researchers say.
“I would not interpret these results as proof that medical cannabis does not work. Rather, they show that the available research is too limited and uncertain to give patients and clinicians a clear answer,” lead author Lucia Varela, a neurologist and fellow at the University of Manitoba in Canada, told Gizmodo.
Uncertain treatment
Cochrane is a well-respected organization that regularly publishes reviews from independent research teams analyzing the clinical trial literature on important health topics, including insomnia. Scientists from the Cochrane Associated Center at the Italian University Hospital of Buenos Aires in Argentina and the University of Manitoba in Canada led this particular study, which was published on Monday.
Varela and his team looked at nine studies that collectively included 537 people aged 18 to 76 treated for insomnia. Most people in these studies were treated for primary insomnia, that is, insomnia not related to another health problem. All but one study compared medical cannabis to a placebo, while the other used the antidepressant amitriptyline as a comparison. Overall, there were no measures indicating that cannabis appeared clearly superior to control treatments.
“In our review, we did not find reliable evidence of clinically meaningful improvements in key sleep outcomes, such as sleep quality, total sleep time, or daytime functioning,” Varela said. Adverse events were also more common among people taking medical cannabis, although they tended to be mild, such as dry mouth and dizziness, and overall evidence on its safety was also limited, she noted.
Better data is needed
A glaring trend in the team’s review is the low quality of the studies analyzed. Many of them faced problems such as small sample sizes and high risk of bias, for example. These studies also used different types of cannabis and often only followed people’s results over short periods of time (the longest had a 12-week follow-up).
Nothing is to say that cannabis cannot be an effective treatment for insomnia, and Varela believes that it is possible to conduct studies that can definitively resolve this question.
“More than just additional studies, we need larger, more consistent studies. So far, most trials have been small and short, making it difficult to draw definitive conclusions,” she said. “It would be helpful if future trials used well-defined products and doses, measured sleep comparably, and reported their methods clearly. This way, results can be compared, combined, and applied more easily in practice. Another valuable direction would be to compare medical cannabis with already commonly used treatments for insomnia to understand how it fits among existing options.”
She would also like to see studies focus specifically on groups of people particularly vulnerable to insomnia, such as older adults and people with chronic pain, and for those studies to include much longer follow-up periods to track people’s sleep habits.
We definitely need better data on this topic. Other research has found that about 18% of American adults under the age of 30 have recently used cannabis to help them sleep. And while it’s not a given that cannabis is worthless for people trying to get more sleep, they should talk to their doctor, the authors say.
“I think patients should be aware of this uncertainty and discuss the potential benefits and harms with their healthcare professional rather than assuming that because these products are widely used for sleep that their effectiveness has already been established, or using commercially available cannabis products without medical supervision,” Varela said.
Gn Health
