Although very common, insomnia can be very annoying. Around 16 million people suffer from sleepless nights or insomnia in the United Kingdom[1], and nearly 70 million Americans[2] have a sleep disorder.

Insomnia can be recognised very easily. People find it hard to go to sleep, wake up several times during the night, feel tired when you wake up and struggle to nap during the day even though you feel tired.

Not all insomnia is the same. People can experience it in different ways, as there are many potential causes of insomnia, including stress, irregular sleep, jet lag, shift work, lifestyle, and mental disorders.

Sometimes, insomnia can also become chronic and increase the risk of accidents and mental health disorders, including depression and anxiety.

Since ancient times, people have been using cannabis to treat insomnia as it has a beneficial effect on our sleep.

But as cannabis has gone mainstream in recent years, more and more people are using cannabis to relieve sleep disorders. Furthermore, the sales of CBD-based products have boosted the awareness of cannabinoid benefits of sleeping.

Enthusiasts claim cannabis helps them relax and sleep better. But what does science say about such a claim? Do people relieve insomnia following cannabis use?

In recent years, researchers have tried to answer this question. The growing interest in cannabis has generated the need to understand better the harms and benefits of acute and long-term cannabis use for therapeutic purposes.

But before going through some studies that showed the beneficial effects, it is essential to understand the impact of cannabis on insomnia.

Several studies have shown that our circadian rhythm interacts with our endocannabinoid system.

Circadian rhythm is the natural, internal process that regulates the sleep-wake cycle and repeats every 24 hours.

The endocannabinoid system is a complex cell-signalling system that involves a combination of endocannabinoids, enzymes, and cannabinoid receptors that help regulate several functions in the human body.

As cannabis strongly interacts with the endocannabinoid system through CB1 and CB2 receptors, its use facilitates our sleeping, according to several studies.[3]

In particular, while cannabis decreases the latency period for falling asleep, it increases the non-REM (rapid eye movement) sleep. During our REM phase, our brain activity is very intense, and THC decreases REM sleep.

Although researchers still don’t know how cannabis influences our circadian rhythm through the endocannabinoid system, they believe THC leads to drowsiness as it reduces the amount of REM sleep. More recent studies have shown that also high doses of CBD may support sleep.

A 2021 study published in the Journal of Medical Internet Research by a group of researchers from Canada[4] has found that medical cannabis patients improve their sleep when using cannabis.

But most importantly, researchers suggest a possible advantage in treating insomnia by using predominant-Indica strains, which are more effective when compared with predominant-Sativa strains.

As indica strains contain a high level of CBD, researchers have noted that predominant-Indica and Indica-Hybrid strains were the most commonly used strains for insomnia. Predominant-Sativa and Sativa-Hybrid strains were used least for the management of insomnia symptoms.

An article published in Medicines, an international, peer-reviewed, open-access journal by researchers from the University of New Mexico (United States) in 2018[5], has highlighted how the effectiveness of cannabis in treating insomnia also depends on the device used to consume cannabis.

Researchers have found that using pipes and vaping devices has greater symptom relief when compared to the use of joints. Furthermore, vaporisation was also associated with lower negative effects.

In this study, researchers have noted that CBD had a higher statistically significant symptom relief than THC, but the cannabinoid levels generally were not associated with differential side effects. Furthermore, researchers have found that the use of Sativa-strain products was associated with lower symptom relief and more negative side effects when compared with the use of Indica-strain products.

By reviewing several studies about the relationship between cannabis and insomnia, we can’t find congruous results. This pattern may be probably due to the different experimental approaches used. Although researchers state that the endocannabinoid system promotes sleep, the effects of cannabis on insomnia are not yet fully understood.

Researchers have found that THC has a sedative effect, whose mechanisms of action overlap with psychotropic ones. It facilitates falling asleep and probably increases the non-REM sleep phase and decreases the REM sleep phase.

CBD seems to have different behaviour depending on its dosage. Low doses of CBD stimulate wakefulness and decrease daytime sleepiness. High doses of CBD promote sleep and stabilise the sleep-wake cycle.

But interestingly, some studies[6] say that the interaction of these two cannabinoids may trigger the sleeping in a person through the entourage effect. In this context, cannabinoids don’t work singularly, but interact together to help people fall asleep.

Such a harmonised interaction between THC and CBD seems to carry over to sleep. CBD may just be reducing symptoms like anxiety. This effect would allow a person to relax so that natural sleep mechanisms can take over. Meanwhile, the sedative effect of THC and its other properties may be helpful to sleep.

However, since the data in the literature are sometimes conflicting, further studies are needed, especially on patients and on a large scale, to define cannabis consumption as sleep therapy.

[1] https://www.aviva.com/newsroom/news-releases/2017/10/Sleepless-cities-revealed-as-one-in-three-adults-suffer-from-insomnia/

[2] https://www.therecoveryvillage.com/mental-health/insomnia/insomnia-statistics/

[3] https://www.frontiersin.org/articles/10.3389/fnmol.2020.00125/full

[4] https://www.jmir.org/2021/10/e25730

[5] https://www.mdpi.com/2305-6320/5/3/75/htm

[6] https://pubmed.ncbi.nlm.nih.gov/15118485/