Is Marijuana Really a Sleep Aid? A New Study Casts Doubt

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

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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 or sleep aids, or maybe you reach for a hit of some weed. Not so fast on that last option. According to a new study, marijuana use might could 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, the researchers looked at survey results from over 20,000 adults, with questions about both marijuana use and reported sleep duration or 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, they 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. That healthy range of sleep between 6 to 9 hours appeared to be just out of reach.

People who smoked less than 20 days out of the last 30 days were 47% more likely to get over nine hours a night compared to non-users, but had 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 around 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. They 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 researchers. Because of that, he says that they expected to find a positive relationship between weed use and sleep – and 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, while this study didn’t look at why weed might be causing people to sleep more or less, Ladha notes that cannabis is a nervous system depressant, which could lead to increased sleep — and adds that 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. And this question of whether weed is good or bad for sleep isn’t likely to go away, either.

“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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