- A new study found some beneficial effects of medical cannabis on sleep in people with chronic pain, but frequent cannabis use may cause other sleep problems.
- Researchers found that people who used medical cannabis were slightly less likely to report waking up in the middle of the night compared to non-medical cannabis users.
- Researchers still aren’t sure how the mechanisms behind the possible sleep benefits of cannabis work.
Chronic pain and difficulty sleeping often go hand-in-hand. Which is why many people who use medical cannabis say they rely on it to help them sleep better.
Even people who buy recreational cannabis from adult-use dispensaries report that they do so to relieve pain and promote sleep.
So far, research on the sleep benefits of cannabis — or cannabis compounds like tetrahydrocannabinol (THC) and cannabidiol (CBD) — has been mixed.
Also, while some studies have shown positive effects, many of those have been poorly designed.
A new study published January 20 in the medical journal BMJ Supportive & Palliative Care adds to this ongoing scientific debate around cannabis and sleep.
Israeli researchers found that medical cannabis may help middle-aged and older adults with chronic pain sleep through the night. But they also found that regular users can develop a tolerance, at which point the sleep benefits diminish.
This study, though, may not clear things up that much.
Some experts point out that the study has some of the same shortcomings as earlier research.
Even the researchers write in the paper that given the limitations of the study, the results should be considered “preliminary.”
In the study, researchers looked at the sleep patterns of 128 people ages 50 and older with chronic pain.
Sixty-six of the people used medical cannabis. The other 62 didn’t have a medical cannabis license, although 12 percent of these people used recreational cannabis.
Most of medical cannabis users in the study used whole-plant based cannabis, also known as the cannabis flower.
Many other studies have focused on cannabis compounds like THC or CBD. However, these are just two of hundreds of compounds found in the cannabis flower.
“While THC and CBD are among the most well-known compounds, others are likely to have important effects as well,” write the authors.
Researchers found that people who used medical cannabis were less likely to report waking up in the middle of the night compared to non-medical cannabis users. However, this beneficial effect of cannabis on sleep was small.
There was no difference between the two groups when it came to falling asleep or waking too early.
“This suggests that [medical cannabis] may have a sleep-promoting characteristic in terms of minimizing awakenings during the night, but not in terms of other types of sleep problems,” write the authors.
The study also showed a potential downside of long-term cannabis use — poor sleep.
People who used medical cannabis frequently had a harder time falling asleep at bedtime and they woke up more often in the middle of the night.
“This may signal the development of tolerance after chronic administration of [medical cannabis] akin to what has been found in preclinical studies,” write the authors.
But the authors added that people who use medical cannabis frequently may also have more severe pain or other health problems such as depression or anxiety. These conditions can cause sleep problems.
Timothy A. Roehrs, PhD, director of research at the Sleep Disorders and Research Center of Henry Ford Health System in Detroit, pointed to the study’s limitations — many of which the authors also mentioned in their paper.
The study isn’t a randomized clinical trial, the “gold standard” of medical research. It also doesn’t follow patients long-term to see how their sleep patterns — or cannabis use — changes.
And because the study is observational, the authors can’t say whether cannabis use improves sleep — just that there’s some link between the two.
Roehrs had other concerns, such as patients using different strains and doses of medical cannabis, people reporting on their own sleep patterns rather than having them measured, and the fact that some non-medical cannabis users used recreational cannabis.
The mechanisms behind the possible sleep benefits of cannabis are also not clear — does cannabis improve sleep directly, or do people sleep better because cannabis relieves their pain?
The authors write that much more research is needed, including studies that take into account the short- and long-term sleep effects of different strains, doses, and modes of use of medical cannabis.
However, even with this new study, Roehrs said right now there’s not enough scientific evidence to be able to say whether cannabis can help with sleep problems.
But he said that in someone who’s new to cannabis use, cannabis probably has a “very mild sedative effect.”
Still, there’s the problem of tolerance — where the beneficial sleep effects can diminish as people use cannabis more frequently. This tolerance can also create other problems when people stop using cannabis.
“With any mild sedative, one has to be very cautious about using it continuously because tolerance can develop,” said Roehrs. “After that, when you don’t use the sedative, your sleep is much worse than when you do use it.”
Older research shows that regular cannabis users can have withdrawal symptoms such as anxiety, depressed mood, and insomnia. These can be severe enough that they discourage people from quitting.
Although many people seek out cannabis when they’re having trouble sleeping, Roehrs thinks they should also be talking to a doctor.
“There can be many problems around their difficulties sleeping,” said Roehrs. “A sleep specialist can help sort that out.”