Marijuana may make sleep worse, especially for regular users, study finds

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Marijuana users tend to believe that marijuana will help them fall and stay asleep. Scientists are not so sure.

The study was not conducted by Wendy Troxel. She is a sleep specialist and senior behavioral scientist with Rand Corp.

Troxel said, "But we lack solid evidence to demonstrate whether cannabis is good for sleep or bad."

A study from December 2021 found that smoking weed can actually cause sleep problems. Researchers published their findings in the BMJ journal. They found that adults who used weed at least 20 days a month during the previous month were more likely than others to sleep for less than six or nine hours per night.

The US Centers for Disease Control and Prevention define optimal sleep for adults as seven to eight hour a night.

The study found that moderate consumption of marijuana -- less than 20 days in the last month -- did not cause sleep problems. However, people were more likely to sleep nine hours or more at night.

Why are short and long sleeps a problem for you?

"Large studies in the population show that short sleep is associated with increased risks of strokes and heart attacks, as well as long-term progression of atherosclerosis and diabetes, coronary arterial disease, and other major cardiovascular diseases," said Calvin Diep, the lead author of the study and resident of anesthesiology at the University of Toronto.

Diep explained that there is a 'Goldilocks' phenomenon with sleeping, where the amount of sleep (that's) "just right" can be found.

According to the CDC, one third of Americans do not get enough sleep. Sleep disorders, such as insomnia, sleep apnea and restless legs syndrome, affect 50 to 70 millions Americans.

The CDC describes this as a 'public-health problem', because disturbed sleep is linked to a greater risk of certain conditions such as high blood pressure and weakened immunity, increased weight, a loss of libido and mood swings. It can also lead to depression, diabetes, strokes, cardiovascular diseases, dementia, and some types of cancer.

There is no clear evidence in either direction

In December 2021, a study examined the use of marijuana to sleep by 21,729 adults aged between 20 and 59. Data was collected by the National Health and Nutrition Examination Survey and is representative of more than 146 million Americans.

Diep explained that in addition to sleep issues, those who had used marijuana within the past 30 days were more likely than others to have difficulty falling or staying asleep. They were also more likely, she said, to have spoken to a healthcare provider about their sleep problems.

He added, 'The problem is, we cannot say for certain that the cannabis was the cause of the insomnia. We can't tell if it was just that the individuals were experiencing sleep problems and used cannabis to help them or if the cannabis itself caused the insomnia.

Previous studies have found a link between CBD and THC in marijuana and poor sleep. CBD, or cannabidiol, is a key component of medical marijuana, while THC, or tetrahydrocannabinol, is the main psychoactive compound in cannabis that produces the high sensation.

In a 2018 double-blind placebo-controlled randomized study, the gold standard, CBD had no effect on healthy volunteers' sleep. In other studies, high rates of insomnia were also observed when marijuana was stopped at night.

'At the moment, there is no clear evidence that cannabis helps sleep,' stated Dr. Bhanu Prakash Kolla, sleep medicine specialist at the Mayo Clinic's Center for Sleep Medicine in Rochester, Minnesota. He was not involved with any of the studies.

Kolla stated that although there are immediate benefits to using cannabis, tolerance is quickly developed. There is currently no evidence that cannabis can improve sleep duration or quality.

Confounding factors

People still believe that marijuana helps them sleep. According to surveys of marijuana users, they do indeed depend on the drug to help them sleep.

Diep explained that the issue was that the anecdotal evidence of therapeutic benefits reported by people did not match the actual data.

Kolla suggested that withdrawal symptoms from cannabis can disrupt sleep when people stop smoking after a long period of regular use. This can lead people to think that cannabis is helping them sleep, when in reality they are experiencing withdrawal symptoms.

The potency of cannabis today is a factor that should be considered, according to Dr. Karim L. Ladha, anesthesiologist at the University of Toronto and clinician-scientist of pain medicine and anesthesiology.

Ladha explained that a lot of older cannabis data is based on much lower THC doses than the patients use today, and very little research has been done in relation to CBD.

He said: 'Studies give us information about what happens on a population-level, but the discussion at an individual level is more personal.' The studies only give us a possibility that (marijuana could) hurt your sleep. But it may help, and we don't know unless you try it.

He added that additional studies are needed.

Ladha stated that patients are currently spending time, money and resources in order to get cannabis to aid with sleep. I think that as a medical community, we should do all we can to ensure that our patients are able to make the right decisions about their health.