Cannabis and sleep after 50: what four Yale researchers write

According to four researchers at Yale University, more and more people over 50 use cannabis for sleep, and many report sleeping better. The authors bring together the first published results, such as sometimes falling asleep faster with THC or a slight rise in measured sleep efficiency in a pilot trial on CBD, and list the studies still missing in older adults. Their text is an expert opinion, with no new data, based mainly on work carried out in younger adults. Here is what they write, and how to read it. This summary belongs to our “What the science says” series; our method is explained in how to read a scientific study on CBD.

Rising use after 50

In the United States, the 2024 National Survey on Drug Use and Health estimates that 15% of people over 50 used cannabis in the past year, and 10.5% of those over 65. Older adults are one of the groups where use is rising fastest, and the gap between men and women is narrowing. The authors take 50 as the threshold, as the US National Institute on Drug Abuse does.

Sleep is among the main reasons given. Insomnia affects up to half of older adults, and it is linked to falls, cognitive decline, cardiovascular disease and depression. Many see cannabis as a more natural alternative to sleeping pills. The authors also note that the products sold in the United States are not approved by the FDA, that their claims are rarely backed up and that their composition varies widely from one product to another.

Why the authors call for studies in older adults

The authors put forward a thesis, summed up in the title of one of their sections: older adults are not simply younger users who have grown older. They give four reasons, each corresponding to a line of research.

First, the body changes. Body fat, the liver and the kidneys no longer work in the same way, which alters how a substance is absorbed and then cleared. For THC, CBD or CBN, these differences are still almost entirely unexplored. Older adults also mostly use oral forms, whose effect comes on slowly, lasts a long time and varies widely from person to person.

Second, they often take several medicines, and CBD can alter the way the liver clears some of them, interactions that are still poorly described and worth raising with your doctor.

Third reason: the endocannabinoid system itself ages. Animal studies and human brain imaging suggest that CB1 receptors, the main target of THC, become less available with age. It is not yet known whether this strengthens, weakens or changes the effects.

Finally, menopause. Sleep problems are common at this stage, and more and more women report using cannabis during this period. Controlled studies in these women are practically non-existent.

“I sleep better”: reported feeling and measured sleep

According to the authors, many people who use cannabis for sleep report that they sleep better. They ask future trials to record this feeling alongside objective measurements. Sleep can be measured in two ways: polysomnography, in a laboratory, records the activity of the brain, eyes and muscles through the night; actigraphy tracks movement with a small sensor worn on the wrist.

How sleep feels and how it measures do not always match, a gap known to insomnia specialists, with or without cannabis. Recent reviews based on objective measurements have found no consistent effect of cannabis or cannabinoids on sleep duration, time to fall asleep, awakenings, sleep efficiency or the different sleep stages. The authors therefore call for trials that combine both approaches.

THC: effects described in the laboratory, tolerance with habitual use

Studies on THC, mostly single doses in the laboratory, sometimes describe falling asleep faster, slightly longer sleep, more deep sleep and less REM sleep. These results vary from one study to the next.

With regular use, the body gets used to THC: this is tolerance, and the initial effect may fade, which leads some people to increase the amount. On stopping, withdrawal causes sleep problems: difficulty falling asleep, awakenings, less efficient sleep. According to the authors, some of the “better sleep” described by regular users may therefore reflect relief from this withdrawal rather than a lasting effect.

CBD and CBN: what the first trials measured

In a placebo-controlled pilot trial in people with insomnia, participants taking 150 mg of CBD each evening had a slight rise in sleep efficiency, as measured by the instruments. Most self-reported measures changed little. CBD and CBN are often presented as sleep aids, but trials remain few.

Other trials on CBD and CBN report improvements stated by participants, such as fewer night-time awakenings. Their results do not always agree, and adding CBD to CBN did not clearly do better than CBN alone. In the authors’ view, whether CBD, CBN or their combinations improve sleep quality remains an open question.

What the letter shows and does not show

The letter describes a trend: the use of cannabis for sleep is growing among older adults faster than the research. It does not demonstrate any effect in people over 50. It is an expert opinion, with no new data. The studies it summarises mostly involve younger adults, often with few participants. Many studies on THC are old and use preparations very different from today’s products. The “better sleep” people report has not been confirmed by objective measurements, and the trials on CBD and CBN tested high doses of pure molecules, bearing little relation to the amounts found in the plant.

The doses and preparations tested (150 mg of CBD each evening in the pilot trial, pure molecules at high doses) are in no way comparable with the CBD products sold freely in Switzerland, which are not medicines.

For researchers, the authors set four priorities: double-blind controlled trials in older adults, using products close to those actually sold; measurements that are both self-reported and objective; studies of what happens to cannabinoids in the body according to age, and of interactions; and finally, follow-up over several years on tolerance and dependence.

They ask doctors to routinely question older patients about their cannabis use, as many do not mention it unprompted, and to discuss the remaining uncertainties frankly: product composition, amounts, tolerance, withdrawal, interactions, memory, falls, heart and driving. As long as robust trials are lacking, they advise keeping established treatments for chronic insomnia as the first line.

What about Switzerland?

The article describes the situation in the United States, where THC-rich cannabis is legal in many states. In Switzerland, the framework is different. Hemp and products containing 1% total THC or more remain narcotics, and their non-medical use is prohibited (see what the 1% threshold measures).

Since 1 August 2022, doctors can prescribe cannabis-based medicines without an exceptional authorisation from the Federal Office of Public Health (FOPH), under their own responsibility. The production and sale of this medical cannabis are controlled by Swissmedic, and basic health insurance only reimburses it in exceptional cases. CBD products sold freely fall under other laws, set out in our guide to Swiss legislation: they are not medicines. For the chemistry of these molecules, see our feature on hemp cannabinoids.

In summary

According to the Yale letter, cannabis is part of the nights of many older adults, and many report that it helps them sleep better. The studies cited describe sometimes falling asleep faster with THC, an effect that wears off with habitual use, a slight rise in measured sleep efficiency in a pilot trial on CBD, and fewer reported awakenings in trials on CBD and CBN. These studies are few and were mostly carried out in younger adults. The authors call for trials designed for people over 50 before any conclusion can be drawn either way.

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