The Trouble With Pot, CBD and Sleep

People take different forms of cannabis to try to help them sleep. Products include edibles, oils or materials that are smoked. 

They often contain a combination of THC, or tetrahydrocannabinol, which is the main psychoactive component of marijuana and what causes the high, and cannabidiol, or CBD, another part of the cannabis plant that is not psychoactive. Many products contain both THC and CBD and can also include other compounds from the plant. 

Much of the research on sleep and cannabis has looked at sleep only indirectly, doctors and researchers say. For instance, people who use marijuana to alleviate pain or anxiety may note that their sleep has improved because their pain lessened. Or patients with chronic conditions, like multiple sclerosis, have reported better sleep when they take cannabis. 

But research hasn’t found enough evidence to prove that cannabis helps healthy adults sleep better. A review in 2020 that looked at studies on cannabis use to treat sleep disorders didn’t find enough evidence to support using it to treat insomnia, sleep apnea and other sleep conditions, says senior author Camilla Hoyos, a senior research fellow at the Center for Sleep and Chronobiology at the Woolcock Institute of Medical Research in Sydney.

Since then, Australian researchers have published two small randomized controlled studies comparing cannabis with placebo.In a 2021 study in the journal Sleep, 23 people with insomnia took an extract containing THC, CBD and CBN, which is mildly psychoactive and often associated with improved sleep, for two weeks. The researchers found that the extract improved sleep duration and quality, as well as insomnia symptoms. 

A study last year in the Journal of Sleep Research tested a medicinal cannabis oil containing THC and CBD in 29 people with insomnia and found it improved sleep quality and quantity. Levels of the sleep hormone melatonin increased by 30% and about 60% of participants were no longer considered to have insomnia at the end of a two-week period. 

The drawbacks

Studies have found downsides. People taking cannabis for sleep are more likely to report feeling sleepy the next day, says Nicole Bowles, assistant professor at the Oregon Institute of Occupational Health Sciences at Oregon Health & Science University. And people who use marijuana regularly can develop dependence, and often report trouble sleeping if they abruptly stop, says Bowles. 

Studies have also found that cannabis reduces rapid eye movement sleep, or REM, a phase in which the brain is active and when dreaming and memory consolidation take place.

A recent study looked at more than 230,000 people who take cannabis daily and found irregular sleep patterns. People tended to sleep either less than seven hours or more than nine. Healthy adults should get seven to nine hours of sleep, health guidelines recommend. Sleep that is too long or too short are both risk factors for certain chronic conditions, such as cardiovascular disease, says Bowles, who was senior author on the study. 

Staci Gruber, director of the Marijuana Investigations for Neuroscientific Discovery program at McLean Hospital in Belmont, Mass., and associate professor of psychiatry at Harvard Medical School, is following patients taking medical cannabis for up to three years. She says they report improvements in their sleep relatively quickly. 

However, all of these patients are taking cannabis for medical reasons. So better sleep may be at least partly related to improvements in other problems that often interfere with sleep, such as chronic pain or anxiety. 

“Medical patients are different from recreational consumers,” she says.

Potential to help

Using cannabis as a sleep aid needs to be weighed against the alternatives, which are typically prescription sleep medications that can have significant side effects, says Dr. Peter Grinspoon, a primary care physician and cannabis specialist at Massachusetts General Hospital. 

“The alternatives are not entirely benign,” says Grinspoon, who is a board member of Doctors for Cannabis Regulation. “Cannabis can be a safer alternative.”  

With his patients, he often recommends starting with a tincture, an extract that is mostly CBD with a little bit of THC and using one or two drops under the tongue. Limiting it to two to three times a week as needed is best, he says, because you don’t want to develop a dependence or build up a tolerance that makes the products less effective. 

The combination of ingredients in a cannabis product matters, says Dr. Benicio N. Frey, a professor in the department of psychiatry and behavioral neurosciences at McMaster University in Hamilton, Ontario. THC appears to have a stronger effect on sleep than CBD, but CBD helps counteract some of the side effects from THC, such as dizziness and grogginess, he says.

There are different strains of THC and retailers often market certain ones, such as indica, for sleep. Frey says his research has found people who take indica seem to report having a better night’s sleep than when taking other strains. The problem, he says, is that product labels aren’t always accurate. He says capsules and oil are more likely to be accurately labeled.