Does Marijuana Affect REM Sleep? Here’s How Cannabis Impacts Slumber

Interest in cannabis as a medicinal and therapeutic tool is at an all-time high. Pun intended. There’s a multi-billion-dollar cannabis market that is growing fast, filled with tinctures, vaping options, edibles, creams, oils and other cannabis products.

It all can be pretty confusing and more than a little overwhelming.

I’ve had a lot of interest from patients and readers about cannabis’ potential to help improve sleep and the science around the benefits of cannabis for sleep. But I’d like to do more to respond to all this interest. With that in mind, let’s get into what we know today about how cannabis affects sleep, where the research is headed, what the uses, benefits, and risks look like.

The cannabis-sleep relationship is complex, from its promise as a treatment for sleep disorders, including insomnia and sleep apnea, to issues and concerns around heavy use and withdrawal, to the question of whether cannabis offers a more natural alternative pharmaceutical sleep aids.

We’re starting with a pretty common question: how does cannabis affect sleep architecture, the cycles and stages of sleep we experience every single night? There isn’t a simple answer to that question, in large part because there are several factors that come into play, including:

• Dosing
• How cannabis is consumed or used
• The strain of cannabis being used

That said, there is scientific research that broadly addresses how cannabis affects sleep stages and sleep cycles, and how the major chemical compounds found in cannabis influence sleep architecture. That’s what we’ll look at today.

First, let’s begin thinking about different strains of cannabis in relation to sleep. When we talk about cannabis and its role in sleep, cannabinoids come right to the top of the list of important chemical compounds. There more than 400 chemical compounds in cannabis, and dozens of cannabinoids. 

Cannabinoids have attracted a lot of interest for their potential benefits for sleep and other health conditions, including depression and anxiety, Alzheimer’s and Parkinson’s, seizure disorders, different forms of cancer, and chronic pain.

Three of the best-known and most-studied cannabinoids all have effects on sleep.

THC

Tetrahydrocannabinol, or THC, is the main psychoactive cannabinoid in cannabis. THC is what gives the high that’s associated with cannabis use. THC has been shown to have a range of therapeutic benefits, including pain relief. THC has sedative effects. Really interesting emerging evidence indicates that THC may improve breathing during sleep, which makes THC a potential therapy in the treatment of obstructive sleep apnea

THC appears to play the most active role in altering sleep architecture, and time spent in specific stages of sleep. Over the decades of research on cannabis and sleep, many studies have found THC is most closely linked to reductions in REM sleep and increases to deep, slow-wave sleep and the lighter stages of non-REM sleep. While THC has clear sedative effects, a too-heavy concentration of THC can lead to next-day grogginess.

CBD

Cannabidiol, or CBD, is a non-mind-altering cannabinoid that promotes relaxation. CBD has no psychoactive effects—that means there’s no “high” associated with this compound. Scientists think instead that CBD works to balance or counteract the high that’s delivered from the cannabinoid, THC. There’s a compelling body of research showing CBD’s ability to reduce anxiety, relieve pain, promote mental focus and clarity. CBD also may to reduce daytime sleepiness and promote alertness.

It’s less clear what specific effects CBD has specifically on the cycles and stages of sleep. Some research has demonstrated that CBD delivers little to no effect on sleep architecture, but it’s important we see more research before drawing any firm conclusion. CBD has been shown as a promising therapy for REM behavior disorder. At different doses, CBD can be either stimulating or sedating. Low doses of CBD tend to provide stimulation, while higher doses deliver sedative, or sleep-inducing effects. Today, it appears that CBD’s most potent role in facilitating sleep comes through relief from its ability to relieve anxiety and pain.

CBN

Cannabinol, or CBN, is a less well-known cannabinoid than CBD. It appears to have powerful sedative effects, which may be enhanced when it’s combined with THC. CBN also has pain-relieving, anti-inflammatory properties. 

Terpenes for Sleep

Beyond cannabinoids, there’s another whole set of molecules that affect how cannabis acts in the body and specifically affects sleep. Terpenes are tiny, aromatic molecules in cannabis that create its smell and taste. Terpenes aren’t only found in cannabis—they’re abundant in the natural world, numbering in the thousands, and found in most natural plants, fruits and flowers.

The cannabis plant contains about 200 terpenes, including several with benefits for sleep. The terpenes found in cannabis and other plants don’t all have the same effects. Individual terpenes have distinct impacts on sleep, mood, and cognition. Some are stimulating, others are sedating. 

Sleep architecture refers to the nightly structure of sleep, as it moves through repeated cycles and individual stages. Every full cycle of sleep contains two main types of sleep: NREM and REM sleep. Within NREM, there are four different sleep stages, moving from light sleep to deep sleep. REM sleep is a distinct stage from the 4 stages of Non-REM. All the stages of sleep appear to be affected by cannabis, to a degree.

Light Sleep: Stages 1 and 2

These light non-REM sleep stages tend to be increased by use of cannabis. Within the body, activation of the endocannabinoid system has been shown to lengthen non-REM sleep phases. The sedative properties of cannabis, most closely associated with the cannabinoid THC as well as with several different terpenes found in cannabis, help shorten sleep latency—meaning, it helps you fall asleep more quickly, and perhaps lengthens the early phases of these lighter stages of non-REM sleep.

Light sleep might sound like a throwaway sleep—inconsequential, or lacking in substance. It’s not. Throughout a night of sleep, light sleep paves the way for the cyclical stages of deep sleep and REM sleep, with changes to brain waves, nervous system activity, and hormones. Dreaming can occur during light sleep, and important elements of cognitive processing—including the emergence of sleep spindles in Stage 2, which help the brain transfer memories and newly acquired information, and also elevate the soundness (aka quality) of sleep—take place during these sleep stages. Sleep architecture is a finely-calibrated balance of stages, each serving important purposes. That’s true for light sleep as it is for slow-wave sleep and REM.

Deep Sleep: Stages 3 and 4

While the full spectrum of research to date is somewhat mixed, with some individual studies showing no changes to slow wave sleep or decreases to slow wave sleep via cannabis, a persuasive body of research has demonstrated that cannabis is likely to increases deep, non-REM, slow-wave sleep. This sleep phase, composed of Stages 3 and 4, is when the body engages in its most powerfully restorative work to the body, repairing cells and tissue, strengthening immune function, and makes important contributions to memory processing. One open question about the effects of cannabis on slow wave sleep is, for how long might these deep-sleep boosting effects last? Some research indicates that the increase of slow wave sleep from using cannabis may not be a long-term, durable phenomenon. We don’t know enough yet to have a clear answer to that question.

REM Sleep

There’s been a fair amount of attention paid to the effects of cannabis on REM sleep. Cannabis, especially THC-rich strains, are likely to reduce levels of REM sleep. This is the stage of sleep when we do our most active dreaming, and when the brain does a lot of memory processing and consolidation of acquired information, as well as the processing of emotional experiences. REM sleep can be thought of as a kind of wiping the slate clean in the brain each night, helping prepare the brain for all the activity, including cognitive and emotional activity, that it powers during every moment of waking life.

Too much suppression of REM sleep is not healthy—that’s true for all sleep stages. But it’s also possible to experience too much REM sleep. Cannabis is now increasingly recognized as a promising therapeutic tool for sleep disorders associated with abnormal REM sleep and disruptive dreaming, including REM Sleep Behavior Disorder and PTSD.

The most common cannabis strains are Indica and Sativa. There are also hybrid strains that combine the two. Indica is generally considered to be relaxing and sleep promoting. Sativa is generally regarded as more energizing and invigorating.

However, these broad generalizations of Indica and Sativa can be just that: too broad. A more specific way to target strains of cannabis to meet specific sleep and health goals is to go beyond the indica-sativa distinction, and focus on different strains specific compositions of cannabinoids and terpenes. When it comes to sleep, generally that means identifying a strain that contains relaxing terpenes, and a balance of CBD and a not-too-high concentration of THC.

What Happens to Sleep Architecture When You Stop Using Cannabis?

Studies have observed alterations to sleep architecture from stopping the use of cannabis, particularly after long-term and/or heavy use. Research of long-term, heavy cannabis users has found that stopping was linked to reductions in slow wave sleep, changes to REM sleep, increased sleep disruption, and a lengthening of the time it takes to fall asleep. These changes align with the anecdotal reports of heavy cannabis users who often describe increased difficulty sleeping after stopping. But there’s a lot we don’t yet understand about the changes to sleep that are associated with stopping regular cannabis use.