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Cannabis Use Linked to Poorer Sleep and More Extreme Sleep Schedules, Study Finds

By Alexander Beadle

Published: Dec 16, 2021   
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Many think that cannabis can help them relax and drift off into better sleep. But new research is casting doubt over this belief.

Published in the BMJ’s Regional Anesthesia & Pain Medicine, a new study from researchers at the University of Toronto suggests that cannabis users are more likely to experience the extremes of sleep – either sleeping too little or too much – than non-users. Cannabis users are also more likely to report other sleeping problems, such as difficulties in getting to sleep, staying asleep, or sleeping too much.

The study design did not allow the researchers to suggest a reason why cannabis consumers appear to be more likely to have extreme sleep schedules. Instead, the researchers say their findings highlight the need for additional studies to characterize sleep health in regular cannabis consumers and suggest that further research should investigate whether this effect might be dose-dependent.

Regular cannabis users sleep worse than their peers

The researchers examined data taken from the National Health and Nutrition Examination Survey between 2005 to 2018. This survey asked respondents about their past 30-days of cannabis use, which was used to categorize respondents as being either cannabis users or non-users, as well as several questions relating to sleep health.

From a sample size of over 21,700 study respondents, the researchers found that 14.5 percent reported recent cannabis use. When comparing the sleep data from these two groups against each other, the researchers found that the cannabis users were 34 percent more likely to report short nightly sleep durations (<6 hours) and 56 percent more likely to report longer sleep durations (>9 hours), as compared to their peers who did not use cannabis.

The American Academy of Sleep Medicine (AASM) and Sleep Research Society (SRS) both advise that adults should sleep for between 7 and 9 hours every night to ensure optimal health. According to these two bodies, sleeping for more than 9 hours a night appears to only be beneficial for people suffering from illness, those recovering from a loss of sleep, or teenagers/young adults. Regularly sleeping for less than 7 hours is a more serious worry as it has been linked to an array of different health concerns, including impaired immune function, increased pain, heart disease, and diabetes.

The researchers also noted that this effect of cannabis on sleep appeared to have some element of dose-dependence, with the heavier cannabis users (those who reported using cannabis on more than 20 of the past 30 days) being even more likely to be at the extremes of nightly sleep duration.

Cannabis users were also around 30 percent more likely than non-users to report other sleep problems, such as difficulty falling asleep, staying asleep, sleeping too much in the past two weeks, or having ever spoken to a physician about their sleep troubles.

Sleep aid or sleep disturbance?

The literature describing cannabis’ effects on sleep paints a fairly mixed picture. In a recent survey of 1,000 recreational cannabis customers in Colorado, 84 percent of respondents felt that cannabis had been “very or extremely helpful” for their sleep, with many others saying that they had reduced their use of other sleep aids in favor of cannabis.

However, a 2017 literature review concluded that while CBD may improve insomnia and THC may decrease sleep latency, THC can impair sleep in the long-term. Additionally, they found that CBD could act as a stimulant in high enough doses, again raising the possibility that this could disturb sleep.

Published earlier this year, a study in the Journal of Psychosocial Oncology detailed the results of interviews with cancer patients who reported also using cannabis medicinally. Cancer patients are known to experience a disproportionately high level of sleeping problems as a demographic, and these problems can continue for many even once their cancer is in remission.

“Poor sleep is common among cancer patients. Some are choosing medical cannabis to treat their poor sleep and it appears that this has beneficial effects for their ability to fall asleep and to stay asleep,” lead author Eric Zhou, an assistant professor at Harvard Medical School and a staff psychologist at the Dana-Farber Cancer Institute, told Analytical Cannabis following the publication of the study.

Remarkably, every cancer patient interviewed felt that their cannabis use had been effective in addressing their poor sleep, with no side effects reported. Many also believed that their improved sleep had a knock-on effect in reducing anxiety and promoting a generally more positive emotional outlook.

“In some cases, the use of medical cannabis [also] reduced the use of prescription medication sleep aids,” Zhou added.

Beneficial effects for cannabis on sleep health have also been reported in people with chronic pain. However, these studies have also suggested that patients build up a tolerance to these effects over time. This tolerance can lessen the sleep-promoting effects of the drug, scientists say, and also lead to more problems with waking up at night or falling asleep readily.

“Increasing prevalence of both cannabis use and sleep deprivation in the population is a potential cause for concern,” the researchers behind the new Regional Anesthesia & Pain Medicine study said in a press release.

“Despite the current literature demonstrating mixed effects of cannabis and various cannabinoid formulations on sleep architecture and quality, these agents are being increasingly used as both prescribed and unprescribed experimental therapies for sleep disturbances.”

“Our findings highlight the need to further characterize the sleep health of regular cannabis users in the population,” they continued. “Sleep-wake physiology and regulation is complex and research about related endocannabinoid pathways is in its early stages.”


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