Cannabis and Sleep: What Research Says

## Preliminary Note

This article is for informational purposes only and does not constitute medical advice. Anyone suffering from sleep problems should consult a physician. The research on cannabis and sleep is still incomplete, and many findings come from observational studies or small samples.

## Cannabis as a Sleep Aid: A Common Phenomenon

Many cannabis users report that cannabis helps them fall asleep. In fact, improving sleep is one of the most commonly cited reasons for cannabis use. A survey by the National Sleep Foundation (USA, 2022) found that approximately 70% of surveyed cannabis users reported using cannabis to improve their sleep.

However, the relationship between cannabis and sleep is complex and by no means uniformly positive. The effect depends on numerous factors: the composition of the consumed strain (cannabinoid and terpene profile), dosage, frequency of use, individual physiology, and the underlying cause of sleep problems.

## THC and Sleep Stages

THC (tetrahydrocannabinol) shows a biphasic effect on sleep in studies. In low doses, it can shorten sleep onset time and slightly increase total sleep duration. In high doses or with chronic use, the picture changes.

Impact on sleep architecture: Several studies (including Babson et al., 2017; Kesner & Lovinger, 2020) show that THC reduces the proportion of REM sleep (Rapid Eye Movement). REM sleep is the stage in which most dreams occur and which is important for memory consolidation, emotional processing, and cognitive recovery. A reduction in REM sleep means less dream activity — which may be helpful short-term for individuals with PTSD-related nightmares but could impair cognitive recovery in the long run.

Deep sleep (Slow-Wave Sleep): Some studies suggest that THC can initially increase the proportion of deep sleep (Stage N3). Deep sleep is important for physical recovery, immune function, and growth hormone release. However, this effect appears to diminish with regular use.

## The Role of CBD

CBD (cannabidiol) has a different effect profile than THC. It does not bind directly to CB1 receptors and produces no intoxication. Research on CBD and sleep shows mixed results:

A 2019 study published in The Permanente Journal (Shannon et al.) examined 72 patients with anxiety disorders and sleep problems. In the first two months, sleep scores improved in 66.7% of participants — however, results fluctuated over the course of the study.

CBD appears to promote wakefulness at low doses (under 160 mg), while higher doses are associated with sedative effects. The anxiolytic (anxiety-reducing) properties of CBD could indirectly improve sleep by reducing the difficulty falling asleep caused by anxiety or rumination.

## Myrcene and Sleep

Myrcene is the most common terpene in most cannabis strains and is traditionally associated with sedative properties. In folk medicine, hop tea — rich in myrcene — has been used as a sleep aid for centuries.

Animal studies (do Vale et al., 2002) showed that myrcene prolonged sleep duration in mice and had muscle-relaxant effects. However, the transferability to humans is not established. The myrcene concentrations found in cannabis flowers are significantly below the doses used in animal studies.

Strains with high myrcene content (often marketed as "indica") are subjectively perceived as more calming — whether this is primarily due to myrcene or to the totality of the terpene profile and cannabinoid composition remains scientifically unclear.

## Tolerance Development and Rebound Effect

With regular cannabis use, tolerance develops to the sleep-promoting effects. This means that over time, higher doses are needed to achieve the same sleep-inducing effect — a mechanism that increases the risk of dependency development.

If use is abruptly discontinued after a period of regular consumption, many individuals report a so-called rebound effect: significantly intensified dreaming (as previously suppressed REM activity is compensated), difficulty falling asleep, and insomnia. These withdrawal symptoms can last 2 to 6 weeks and are one of the main reasons why affected individuals find it difficult to stop using.

## Dependency Risk

Cannabis Use Disorder (CUD) affects approximately 9% of regular users according to the DSM-5. Sleep disturbances are both a common symptom of existing CUD and a reason why affected individuals continue using — a kind of vicious cycle. Those who primarily use cannabis as a sleep aid should be aware that alternative, non-pharmacological approaches (Cognitive Behavioural Therapy for Insomnia / CBT-I, sleep hygiene, relaxation techniques) are evidence-based and effective without dependency risk.

## Summary

The relationship between cannabis and sleep is multifaceted. In the short term, cannabis — particularly THC — can reduce sleep onset time. At the same time, it alters sleep architecture, particularly by reducing REM sleep. CBD shows a more complex picture with dose-dependent effects. Tolerance development and rebound effects upon discontinuation are well documented. Research is still in an early stage, and controlled long-term clinical studies are largely lacking. Anyone suffering from chronic sleep problems should seek professional help rather than using cannabis as self-medication.