Struggling to get a good night’s rest? Research shows that cannabis can have positive effects on sleep and may help alleviate a range of sleep-related disorders.
An uninterrupted eight hours of sleep can often seem like a faraway dream. The NHS estimates that one in three people in the UK suffer from insomnia, a condition which can be exacerbated by stress, anxiety, physical pain, and other sleep-related disorders. Insomnia is also linked to negative health outcomes which can then impact sleep, feeding into a never ending bad-sleep-loop.
Cannabis could help break the cycle.
A new study looking at recent scientific advances related to cannabis and sleep shows that cannabinoids—mainly THC, CBD or a mixture of both—have shown promise in treating or alleviating insomnia and other sleep disorders including sleep apnea and restless leg syndrome.
The authors found that the effects of cannabis on sleep depends on dosage—low doses reduce the delay in falling asleep and extend slow-wave sleep and total sleep time, while high doses may lead to poorer quality sleep and sleep disorders.
The authors note the challenges of studying sleep in a scientifically robust way and that research on cannabis and sleep is still fairly limited. They also highlight the growing body of research that exists showing how cannabis can improve sleep for patients suffering with chronic pain.
THC and sleep
Most studies on cannabis and sleep focus on THC due to its intoxicating properties. The analysis found that clinical studies suggest that the use of THC, alone or in combination with CBD, can improve the subjective quality of sleep, but timing of use is key.
Short-term use of THC-dominant cannabis resulted in improvements in sleep consolidation, and a reduction in sleep delay. Total sleep time increased with fewer interruptions after falling asleep. Research also showed an increase in the amount of slow-wave sleep—the deepest phase of non-rapid eye movement (NREM) sleep—but a decrease in the length of REM sleep.
Long-term use of THC-dominant cannabis resulted in weaker effects due to a build up of tolerance. Research indicated both an increased delay in falling asleep and in the number of sleep interruptions, and that overall sleep time and the amount of slow-wave sleep was reduced. The effect on the REM phase was ambiguous. Again, the authors note limitations when it comes to understanding a variety of other factors that could influence the outcome of THC on sleep.
CBD and sleep
When it comes to CBD and sleep, scientific research is still at a fairly early stage. The authors point out that some studies on CBD and sleep in rats showed improvement in overall sleep time. With low doses of CBD, delay in REM decreased, but at higher doses it decreased.
Recent human studies using CBD-dominant cannabis showed more “sleepiness” in subjects, however this could also be because they consumed a small dose of THC.
Most research related to cannabis and sleep looks at the joint action of THC and CBD, and fails to indicate which cannabinoid is responsible for a particular effect.
Cannabis and insomnia
Research looking at the potential of cannabis as a treatment for insomnia is far and few between, and much of the evidence comes from studies that use cannabis to treat other conditions such as anxiety and pain. One such study of 2,332 participants that looked at cannabis’ impact on anxiety, depression and pain found that, amongst all symptoms of anxiety, insomnia was the most improved.
One early study looking specifically at cannabis and insomnia in a randomised, double-blind, controlled trial showed that 160 mg of CBD in insomniac participants improved their sleep time better than a placebo.
Cannabis and sleep apnea
While there are still only a small number of studies on cannabis and sleep apnea, initial results are promising. In animal studies, cannabis was proven to reduce sleep apnea, but it can also cause a decrease in REM sleep and in sleep efficiency.
One experiment showed that injections of a synthetic form of THC (dronabinol), when administered into the nodular ganglia of rodents, suppressed reflex apnea and increased the activity of the muscles that dilate the upper airwaves. Similar results were shown in human studies; dronabinol reduced the rate of apnea and hypopnea and overall subjective sleepiness in subjects.
Cannabis and restless leg syndrome
Restless leg syndrome is perhaps the most under-researched of the cannabis-sleep disorder connections, but two main studies show incredibly promising results.
In the first, six patients—five who smoked cannabis and one who took CBD—all reported complete resolution of restless leg syndrome symptoms. The second study involved 12 patients, with eight achieving complete remission four reporting significant symptom relief.
READ MORE: Restless leg syndrome, cannabis and sleep
What else does the research say about cannabis and sleep?
A handful of research beyond the authors’ assessment has come out in recent years looking at the potential of cannabis for improving sleep and alleviating sleep disorders.
One human study from Radicle Science and Open Book Extracts looking at CBD-based products—with some containing additional rare cannabinoids such as cannabinol (CBN) and cannabichromene (CBC)—found a significant increase in sleep quality and duration for the majority of subjects. Over all, however, the results revealed no significant differences in sleep improvement between melatonin compared to all of the cannabinoid-containing products. The results suggest that the combination of certain cannabinoids and melatonin may confer greater improvement in sleep duration than melatonin alone.
Two other studies specifically looking at cannabis and insomnia found that cannabis use was shown to improve symptoms of insomnia across the board. Participants in one of the studies believed that indica-forward cannabis cultivars were more effective than sativa or CBD alone.
In general, medical cannabis users often report improvements in sleep, pain and anxiety. These results were also substantiated by the first medical cannabis patients in the UK. Analysis of patient-reported outcome measures following treatment with cannabis medicines in this study found statistically significant improvements in anxiety, pain and sleep quality scores as well as general quality of life at one and three months following treatment.
But as the authors of the meta-analysis on sleep and cannabis pointed out, cannabis can also have a negative impact on sleep. A 2021 study of US adults found that recent cannabis consumers were more likely to report not sleeping enough (less than six hours) or sleeping too much (more than nine hours).
Ultimately, if you’re struggling with poor sleep or other sleep-disrupting disorders, the science suggests that cannabis is worth exploring as an additional tool to help you get a solid night’s rest.
