Does Weed Help You Sleep? A New Study Casts Doubt

A new study opens up questions about the relationship between a good night’s sleep and weed.

by Ethan Freedman
Originally Published: 
Collage of a man sleeping on his stomach with a teddy bear, on top of a marijuana leaf.
Ariela Basson/Fatherly; Getty Images, Shutterstock

Can’t fall asleep? Maybe you reach for some herbal tea, maybe you start up the soothing nature sounds playlist, melatonin might be on your list of sleep aids, or maybe you reach for a hit of some weed. Not so fast on that last option. Because when it comes to the question of “Does weed help you sleep?” the answer is a little skunky. According to a new study, marijuana use might disrupt sleep in a way that is far from helpful, giving people both shorter and longer nights of sleep — but not exactly that perfect restful night.

To determine whether marijuana use was associated with restful sleep habits, researchers looked at survey results from more than 20,000 adults, with questions about both marijuana use and reported sleep duration and difficulties.

The study, published in the journal Regional Anesthesia & Pain Medicine, defined an optimal night of sleep as getting somewhere between six and nine hours — and the vast majority of people got some amount of sleep in that range. But in an analysis that accounted for other variables such as age, hours worked per week, and some other drug use, the researchers found that people who had smoked weed in the past 30 days were more likely to get either too little or too much sleep.

Regular marijuana users were 34% more likely to get less than six hours of sleep compared to non-users and 56% more likely to get more than nine hours of sleep, according to their analysis.

Heavy users, which they defined as having gotten high more than 20 times in the past 30 days, were 64% more likely to get less sleep and 76% more likely to get more sleep than non-smokers.

People who smoked less than 20 days out of the last 30 days were 47% more likely to get more than nine hours of sleep a night compared to non-users, but there was no significant difference when it came to less than six hours of sleep.

In addition, recent users were 31% more likely than non-users to report trouble falling or staying asleep, as well as more likely to report sleeping too much in the past couple weeks. They were also 29% more likely to have “ever told a physician about having trouble with sleep,” according to the study. The researchers found no significant differences in reported daytime sleepiness.

“Anecdotally, when we talk to patients, many patients use cannabis for sleep and do self-report benefits,” says Dr. Karim Ladha, an anesthesiologist at the University of Toronto and one of the study authors. Because of that, he says they expected to find a positive relationship between weed use and sleep.

Ladha notes that this could be an instance of correlation not equaling causation. “One possibility with our results is that it could be that patients who have poor sleep are just more likely to use cannabis,” Ladha says.

That being said, although this study didn’t look at whether weed might be causing people to sleep more or less, Ladha adds that cannabis is a nervous system depressant, which could lead to increased sleep — but THC has also been found to cause “hyper-excitability” in some people.

Don’t necessarily take this as proof that weed is harmful to sleep — that kind of information would come in future studies.

“More and more people are using cannabis,” says Dr. Calvin Diep, an anesthesiology resident at the University of Toronto and another author on the study. “And the reason that a lot of people say that they have started to use cannabis is to help with their sleep.”

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