How cannabis use affects sleep and the ability to dream
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Cannabis users regularly report that using weed affects their ability to dream, and some studies even suggest that regular cannabis use inhibits the ability to dream in humans altogether. But what do the experts have to say about this interesting, yet complex topic? In this article, we take a deep look at how cannabis use affects dreaming and sleep.
THE 3 STAGES OF SLEEP
Before we take a deeper look at how cannabis use affects dreaming, it is important to have a basic understanding of the regular human sleep cycle.
There are essentially three phases of sleep; superficial sleep, deep sleep, and REM sleep. These phases are further broken down into 5 different stages (1-4 and REM), each of which is more profound than the last.
During an average night sleep, we progress through these stages cyclically; we start at stage 1, work our way up to the REM stage, and then start all over again.
During the first few cycles, we generally spend more time in the deep sleep phases and less time in the REM phase. However, later on in the night, REM sleep periods tend to increase in length while deep sleep time decreases.
Passing through all of these phases takes roughly 90 minutes, according to Dr. Hans Hamburger, neurologist, somnologist, and head of Holland Sleep Research, an average sleeper will pass through this cycle between 4-5 times every night.
The REM sleep period is where most of our dreaming occurs, explains Dr Hamburger.
“During that REM period, you have most of your dreams. You don't usually remember your dreams if you continue sleeping. The last REM period just before you wake up takes the longest—and you'll only remember the dreams you had in that time if you wake up during it. If you don't wake up during the REM period, you won't remember a thing.”
HOW CANNABIS AFFECTS DREAMING AND DEEP/REM SLEEP
There is little research into how cannabis affects our sleep patterns and dreaming.
Cannabis users regularly claim that they experience particularly vivid dreams whenever they lay off weed for a while. Most of the evidence available on the topic suggests that this is due to the fact that cannabis use, especially right before bedtime, interrupts our REM sleep phases, and subsequently limits our ability to dream.
A 1975 study published in Clinical Pharmacology and Therapeutics (CPT), the flagship journal of the American Society for Clinical Pharmacology and Therapeutics, examined the effects of THC and a placebo on the sleep patterns of experienced cannabis users.
The study found that THC reduced eye movement activity and decreased REM sleep in users.
"By smoking weed, you suppress the REM sleep, and with that you also suppress a lot of important functions of that REM sleep,” says Dr Hamburger.
“One of those functions is reliving the things you have experienced and coming to terms with them, as it were. Processing all kinds of psychological influences is something you do in REM sleep. You also anticipate the things that will happen the next day or the days after that. While you're sleeping, you already consider those and make decisions in advance."
When regular cannabis users lay off weed for a while, they experience what experts call “the rebound effect.”
After taking a drug which suppresses a certain phenomenon, you’re likely to experience that phenomenon much more intensely when you stop taking that drug. This is essentially what happens when you stop smoking weed, and is also common in people who use sleeping pills.
“If they stop taking those, they often get very strange and intense dreams. That is also often the reason why people keep taking those sleeping pills—they become dependent on them,” says Hamburger. The rebound effect usually last for roughly 2-3 weeks.
However, while this explanation seems logical, some experts aren’t buying it. Dr. Timothy Roehrs, a sleep expert at the Henry Ford Health System, is one of them.
“The literature on whether or not marijuana affects REM sleep is extremely weak and equivocal,” he said in an article in NY Mag. “Some studies have shown it suppresses REM sleep, some studies have shown it doesn’t.”
Roehrs claims that there are only 6 studies into the relationship of cannabis and sleep/dreams, and most of them date back to the 70s and 80s (like the study referenced earlier in this article).
He also claims that, in a separate study not specifically focusing on the relationship between cannabis and sleep, he and a colleague from the Wayne State University School of Medicine found evidence that clearly contradicts the popular opinion that cannabis suppresses REM sleep.
“In the design of the study that was being conducted, marijuana was being smoked in the morning and the afternoon, and on some days it was active marijuana, and on other days it was a placebo, 0.4% THC or something,” he said. The active marijuana used in the study contained roughly 3% THC.
The participants in the study were regular cannabis users and alternated between the placebo and the active marijuana. The researchers recorded their sleep patterns and compared them to those of a non-smoking control group.
While the study hasn’t been published yet, Roehrs claims that there was no difference in the amount of REM sleep in the patients when smoking active cannabis or placebo. Furthermore, he also claims that, when smoking the placebo marijuana, the participants got the same amount of REM sleep as the control group that didn’t smoke at all.
However, Roehrs says that the study found that regular cannabis users generally slept worse on nights when they received placebo weed, which suggests that cannabis use does have a strong effect on sleep quality.
“In the 8 hours that they spent in bed, they slept about 80 percent of the time,” he said. “When they got the active marijuana their sleep efficiency was normalized.”
In the article on NY Mag, Roehrs said he was also working on an insomnia study, where he was looking for participants suffering from a sleep efficiency rate of roughly 85%.
In other words, on the nights they were given placebo weed, the regular cannabis users would have qualified for Roehrs insomnia study.
Roehrs believes that cannabis doesn’t, in fact, suppress REM sleep. Instead, he believes that regular users experience interrupted sleep when they lay off pot, which causes them to wake up during the night and leaves them with very vivid memories in the morning.
Dr Hamburger and other sleep experts agree that we only remember dreams when we wake up during an REM phase.
According to Roehrs, it’s a common misconception that REM is the deepest sleep stage.
“If you actually measure arousal threshold, the arousal threshold during REM sleep is less than that of deep slow-wave sleep and more akin to light sleep,” he says.
Hence, it might be likely that, when cannabis users experience withdrawal symptoms that disrupt their sleep, they are likely to be disturbed during the REM phases, causing them to wake up in the morning with more memories of their dreams.
“This is what happens to alcoholics,” says Roehrs.
“When they discontinue alcohol, they have frequent awakenings and disruptions of sleep, and they report vivid dreaming. So this might be very much a parallel.”
It is important to remember that Roehrs research is not yet published. However, it makes a strong case for our misunderstanding of how cannabis affects dreams and sleep, and draws attention to a need for more research into the topic.