- Researchers say cannabis use can cause people to get too much or too little sleep.
- In a recent study, cannabis users said they had difficulties sleeping, with some even talking with their doctor about the issue.
- Experts say the frequency of cannabis use and the dose can be factors in sleep disruption.
The image of a smiling cannabis user getting mellow and drifting off to a light-hearted slumber, only to awake the next day feeling ready to meet another day, may be just that: an image.
In a recent study, researchers say the link between cannabis and sleep may be more complicated than that.
Researchers looked at data from 22,000 people in the 2005 to 2018 U.S. National Health and Nutrition Examination Survey who answered questions about sleep duration and sleep issues.
Researchers say cannabis use was linked to both getting too much sleep and not getting enough sleep.
“I think [the results] were somewhat surprising because, in our mind, anecdotally cannabis seems to help with sleep, but… the evidence to support that notion is just not there yet,” Dr. Karim Ladha, a senior study author, told U.S. News and World Report.
Ladha is an anesthesiologist and scientist in University of Toronto’s department of anesthesia and pain medicine.
The study by the numbers
Roughly 14 percent of the study’s participants used cannabis during the previous 30 days.
The researchers reported the cannabis users were 56 percent more likely to report getting too much sleep and 34 percent more likely to say they didn’t get enough sleep.
The cannabis users were also 31 percent more likely to experience difficulties falling asleep, staying asleep, or sleeping too much the previous 2 weeks.
They were 29 percent more likely to have spoken with their doctor about having sleep trouble.
Those using cannabis at least 20 of the previous 30 days were 64 percent more likely to not get enough sleep and 76 percent more likely to get too much sleep, the researchers reported.
Those using cannabis fewer than 20 of the previous 30 days were 47 percent more likely to sleep too much.
Researchers suggested users responded to a particular dose, although they also said the study didn’t prove cannabis actually causes sleep problems.
“Cannabis is variable, even when reported to come from a reliable source, so components and dose are not reliable,” Dr. Carl W. Bazil, a professor of neurology at Columbia University Irving Medical Center in New York City, told Healthline. “So even when one type seems to help, the next dose may not.”
The effects of cannabis on sleep
Bazil said the effects cannabis has on sleep depend heavily on the user.
“Cannabis is not a sleeping drug,” he said. “However, if you have difficulty shutting off thoughts at night, or anxiety about getting to sleep, finding what works is very individual. For some people, cannabis is relaxing and therefore could help.”
Bazil said it’s “difficult to say” which components of cannabis contribute to either too much or too little sleep.
“Tetrahydrocannabinol (THC) is generally considered the more active component, and this can make some people relax, but for others it can be activating,” Bazil said.
“Cannabidiol (CBD) has been reported to improve many conditions, but neither that nor THC reliably induces sleep when carefully studied. Cannabis also has many other components that are active in the brain and could contribute, making results variable,” he added.
The science of sleep
Dr. Eric Dorninger, the director of research and development for Blue Sky CBD, told Healthline that, without a control group of “healthy” sleepers, it’s difficult to reach conclusions about the study.
“In our clinic, we address the underlying causes of unresolved chronic illness and sleep disorders that are flagrant in the chronically ill,” Dorninger said.
“One of the major concerns for sleep issues is blood sugar dysregulation. We have all heard of ‘the munchies.’ [THC] does have effects on blood sugar and can lead to low blood sugar events. The two most important ingredients for a good night sleep are steady blood sugar… and steady oxygen,” he continued.
Nicolas Schlienz, the research director at cannabinoid research non-profit Realm of Caring, told Healthline two of the primary psychoactive compounds in cannabis — THC and CBD — “affect our endogenous cannabinoid system, which, in turn, is thought to influence the sleep-wake cycle”
“Still, the precise mechanisms through which major and minor cannabinoids promote relaxation and sleep remain unclear,” he said.
“Cannabis dose-response studies have found that consumption of cannabis containing higher levels of THC can be associated with greater ratings for drug effects that include unpleasant feelings, heart palpitations, feeling anxious or nervous, or feeling sick,” Schlienz said. “As a result, these effects may have a detrimental effect on promoting sleep.”
Bazil said good sleep usually comes down to the individual.
“Of course, no medication can force sleep, whether prescription or not,” he said. “It is much more important to pay attention to good sleep habits and learn what helps your own brain to turn off.”