Can CBD Improve REM and Deep Sleep? The Science Says It’s Complicated

---

Key Takeaways:

• The endocannabinoid system has a modulating role in sleep, and both cannabinoids and terpenes affect the sleep-wake cycle.
• THC is known to reduce REM sleep, which makes it beneficial for managing nightmares in PTSD patients.
• CBD may impact slow-wave (N3) sleep, but results in humans are currently inconsistent.  

---

The restorative properties of sleep really come down to a couple of key stages of the sleep cycle.

First off, you drift into stage one (N1), light sleep, then progress into stage 2 (N2) sleep within 5 minutes or so, where your body really starts to wind down with reductions in heart rate, relaxed muscles and slowed breathing.

The next stage, N3, is called deep sleep, where brain activity switches to a distinctive slow pattern, the body relaxes even further and you gain a lot of the restorative benefits of a good night’s rest.

Then finally, after around 90 minutes of sleep, you enter rapid eye movement (REM), where brain activity picks up to near-waking levels and your eyes dart around under your eyelids. This stage of sleep is most often associated with vivid dreams and is thought to bring the cognitive benefits of a good night’s sleep.

Put together, this four-stage cycle is at the heart of many sleep issues, whether it’s movement during REM sleep, nightmares from PTSD or the loss of sleep quality from a condition like restless legs syndrome or sleep apnea.

So if CBD can help with sleep conditions, finding out more about its impact on “sleep architecture” is absolutely vital.

---

The Endocannabinoid System and Sleep: Why Cannabinoids Might Help

The body’s cannabinoid system – called the endocannabinoid system (or ECS) – has a key role in modulating sleep, so researchers have long-suspected that taking cannabinoids could help treat sleep conditions.

We spoke to Dr. Ethan Russo, cannabis researcher and founder/CEO of CReDO Science, who explained that the role of the endocannabinoid system in regulating sleep is “complex,” but added, “It is clear that the ECS is a modulator of sleep, and antagonists of the CB1 receptor produce arousal.”

He pointed us to a paper he authored based on tests of a pharmaceutical cannabinoid medication, Sativex.

Russo and his co-authors note that the endocannabinoid anandamide mediates sleep induction, and that it inhibits the binding of serotonin (a crucial neurotransmitter for the sleep-wake cycle) to the 5-T receptors, and point out that CBD and some terpenes can have the same effect.

CBD also directly inhibits the uptake of anandamide, which effectively means it can induce the same functions as the endocannabinoid.

Sherri Mack, BSN, RN, Chief Nursing Officer at Holistic Caring & the Green Nurse and Bloom Hemp CBD, also noted that the medicinal effects of cannabinoids can also have a knock-on effect on sleep, “The endocannabinoid system (ECS) plays a key role in regulating sleep, with cannabinoids showing promise in improving sleep by alleviating issues such as anxiety and pain.”

CBD, Cannabinoids and Sleep Architecture: What We Know So Far

While the overall theory that cannabinoids will have some impact on sleep is well-established, the details of how different cannabinoids affect the stages of sleep are a little more complicated.

THC and Sleep Architecture

Short-term use of THC is known to reduce REM sleep and increase N3 sleep, but this latter effect is not persistent and there are contradictory results, according to a 2021 evidence review.

Over the long term, chronic use decreases N3 sleep, and studies show an increased time to REM and a decreased percentage of REM sleep.

Dr. Russo explained to us that,

THC does suppress REM sleep to a degree, and this is the reason that it is an essential component of PTSD treatment, as it is most effective at reducing intrusive dreams and nightmares. However, this effect is not total – we cannot function properly without some REM sleep.

CBD and Sleep Architecture

We know a little less about how CBD impacts sleep architecture, but the authors of the study cited above note that animal studies show “biphasic” effects on the time it takes to go into REM sleep, with low doses decreasing the time and higher doses increasing it.

One study on people with obstructive sleep apnea noted increased N3 sleep and decreased REM sleep in people who use cannabis (including both THC and CBD dominant products).

For CBD specifically, results from studies of humans are inconsistent, with some finding no difference whatsoever.

Other Cannabinoids and Sleep Architecture

Dr. Russo expects a reduction in N3 (deep/slow wave) sleep based on the increased alertness after CBD use, and points out that other cannabinoids could act similarly, “If CBD increases alertness, it would tend to reduce deep/slow wave sleep. As tetrahydrocannabivarin (THCV) acts as a neutral antagonist at the CB1 receptor, it is possible that it would act similarly, but I do not believe that this has been formally investigated.”

Cannabinoids Have an Impact, But Details Are Unclear

Theoretically, researchers have long-suspected notable impacts of cannabinoids on sleep architecture, but the evidence so far is often unclear.

The most robust result to date is that THC reduces REM sleep, which may not sound ideal, but actually has therapeutic applications for people with PTSD.

For CBD, the picture is much less clear, but it’s likely that other effects of CBD (such as reducing anxiety) will have positive impacts on sleep for those who suffer from some conditions.