Many people struggle with their sleep, and there’s no shortage of treatments out there that can purportedly help us regain some dozing time. Unfortunately for the many people who reach for cannabis to fight insomnia, a comprehensive review published this week found little solid evidence that it helps.
In a new Cochrane Library review, scientists conducted a sweeping analysis of randomized clinical trials looking at medical-grade cannabis for insomnia. There was insufficient evidence supporting the idea that cannabis could reliably relieve insomnia, they concluded. Though it’s still possible the drug can be a useful sleep aid, better studies are needed to know for sure, the researchers say.
“I would not interpret these findings 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.
An 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, insomnia included. Scientists with The Cochrane Associate Center at the Universidad Hospital Italiano de Buenos Aires in Argentina and the University of Manitoba in Canada led this particular review, which was published Monday.
Varela and her team looked at nine studies that collectively involved 537 people between the ages of 18 and 76 being treated for insomnia. Most people in these studies were treated for primary insomnia, meaning insomnia not linked to another health condition. All but one study compared medical cannabis to a placebo, while the other used the antidepressant amitriptyline as a comparison. Across the board, there was no metric where cannabis appeared to be clearly superior to the control treatments.
“In our review, we did not find reliable evidence of clinically meaningful improvements in the main sleep outcomes, such as sleep quality, total sleep time, or daytime functioning,” Varela said. Adverse events were also more common among people who took medical cannabis, though these tended to be mild, like dry mouth and dizziness, and the overall evidence on its safety was limited as well, she noted.
Better data needed
A glaring pattern in the team’s review is the low quality of the studies analyzed. Many had problems like small sample sizes and a high risk of bias, for instance. These studies also used different types of cannabis and often only followed people’s outcomes for short lengths of time (the longest had a follow-up of 12 weeks).
None is to say that cannabis can’t be an effective treatment for insomnia, and Varela does think it’s possible to conduct studies that can definitively resolve this question.
“More than simply more studies, we need larger and more consistent ones. Most trials so far have been small and short, which makes it hard to draw firm conclusions,” she said. “It would help if future trials used well-defined products and doses, measured sleep in comparable ways, and reported their methods clearly. That way, results can be compared, combined, and applied more easily in practice. Another valuable direction would be comparing medical cannabis with treatments already commonly used for insomnia to understand how it fits among existing options.”
She would also like to see studies specifically focusing on groups of people especially vulnerable to insomnia, such as older people and people living with chronic pain, and that these studies include much longer follow-up periods to track people’s sleep habits.
We definitely need better data on this subject. Other research has shown that roughly 18% of American adults under 30 have recently used cannabis to help them sleep. And though it’s not a given that cannabis is worthless for people trying to get more sleep, it should be something that they bring up with their doctors, the authors say.
“I think patients should be aware of this uncertainty and discuss the potential benefits and harms with their healthcare provider rather than assuming that, because these products are widely used for sleep, their effectiveness has already been established, or using commercially available cannabis products without medical supervision,” Varela said.
