By Ian Hamilton, Associate Professor of Addiction, University of York
Problems with sleep are common. In recent research, 48% of UK adults said sleeping badly had a negative effect on their mental health. For teenagers, this proportion was significantly higher – 66%.
The large number of people experiencing sleep problems makes for an attractive market. Some companies have seized the opportunity to provide remedies, including several manufacturers of cannabis products.
Changes to the way cannabis is regulated in many countries, including the UK, have helped the boom in cannabis products, with more people able to access these types of offerings – even if the cannabis compounds that can be used in sleep products in some countries are more limited than in others. In the US, where cannabis is fully legal in many states, California-based Ganja Goddess reported more than a sevenfold increase in revenue for its cannabis sleep products during the first year of the COVID pandemic.
But what is the evidence that cannabis products can help people get a better night’s sleep?
Cannabis and sleep
Sleep disturbance is a common feature of withdrawal from cannabis use, indicating there may well be a relationship between cannabis use and sleep. But we still don’t have a clear understanding of the mechanisms in the brain involved in this relationship.
The effects of cannabis are due to a group of chemicals in the drug called cannabinoids. These include cannabidiol (CBD), cannabinol (CBN) and tetrahydrocannabinol (THC). THC is the psychoactive substance in cannabis. CBN and CBD don’t cause you to get high in the same way.
In the UK, CBD products are available legally, providing they don’t contain more than 0.2% THC. Retailers and suppliers make all kinds of assertions about the benefits of CBD products, including how CBD can improve sleep. There is some evidence to support these claims, but this is mainly based on animal and human observational studies rather than randomized control trials, where comparisons can be made between CBD and a placebo.
Although not legal in the UK, CBN is one of the main compounds contained in commercial cannabis sleep products, with more and more CBN formulations coming onto the market. A recent review sought to find out whether CBN really does improve sleep.
The review included studies going back as far as the 1940s. These mainly involved administering CBN to people and comparing the self-reported quality of their sleep with participants in a control group who had not received the drug.
However, the author of the review, Jamie Corroon, noted several problems with the research to date, including the fact that participants tended to be male and white. This male-centric perspective is not unique to research on cannabis; it’s known to be a problem more broadly in research.
Corroon was also critical of the lack of structured, evidence-based questionnaires used to assess sleep in the studies. He concluded there is insufficient published evidence to support any assertions that these products improve sleep, noting: “Individuals seeking cannabis-derived sleep aids should be skeptical of manufacturers’ claims of sleep-promoting effects.”
Other factors to consider
The review concentrated primarily on sleep outcomes associated with pure medical-grade CBN. This doesn’t necessarily reflect the way most people use cannabis or cannabis products. Most will either smoke a joint, or ingest a liquid or pill if they’re using a commercially supplied product.
The type of commercial product, the way it’s administered and the dose are all known to affect sleep. Notably, the dose of CBN in many commercial products is lower than what was tested in the majority of the studies in the review.
While most commercial cannabis sleep products contain less than 1% THC (if any), a cannabis joint will contain hundreds of compounds, including THC. And combining THC with CBN is thought to be a sedative. Pure CBN would therefore not have the same effect it has in real life when consumed with THC.
Although the review found a lack of evidence to support the sedative properties of CBN, scientists have found that medicinal cannabis containing THC and CBD can improve sleep for people with chronic pain. This benefit decreases, however, for people using these products regularly, as their tolerance to medicinal cannabis builds.
Further, while it’s useful to have a review that focuses on sleep and cannabis, it doesn’t capture the varied reasons many people use cannabis or products containing cannabis. Many people use cannabis to manage physical problems such as muscle and joint pain, or psychological issues like anxiety or stress, rather than as a sleep aid. It’s logical that alleviating these symptoms will improve sleep.
One example is people experiencing vivid nightmares as a result of post-traumatic stress disorder (PTSD). Nabilone, a synthetic cannabinoid, has proved to be beneficial in suppressing these types of nightmares, which could improve the quality of sleep for this group of people suffering from PTSD. So you can see why it’s difficult to untangle the effects of cannabis on sleep.
We need better research
As with many issues in research, there isn’t a neat answer to how effective cannabis is in improving sleep. How the drug is prepared, the way it’s taken and the person’s expectations are just some important factors that may influence the outcome.
And, as with all health products, there is a risk of side-effects. A recent review of medicinal cannabis products used for sleep found a substantial increase in the risk of developing dizziness, for example.
What is clear is when millions of people have a problem with sleep, there will be a commercial incentive to make money by offering remedies. We need more rigorous research to investigate any associations between cannabis and sleep, and whether these products work.