For some of us, a regular herbal nightcap makes slipping into sleep that much easier, and centuries of anecdotal evidence affirm the usefulness of weed as a sleep aid. Ancient Chinese pharmacology combined cannabis flower with datura to create the elegantly named “sagacious sleep powder,” or shui sheng san. Western medicine is now catching up, with research into cannabis and sleep on the rise.
But what about the effects of cannabis on dreaming? If you’re already well-acquainted with weed, you’re probably aware that periods of heavy consumption see your nocturnal imaginings diminish, if not vanish entirely. Conversely, intermittent periods of abstinence see an onslaught of bizarre dreamscapes.
So what’s the deal? How and why does cannabis impact the dreaming phase of sleep, and should you be concerned?
How dreaming happens
The sleep-wake cycle consists of four stages which are repeated multiple times during a typical night. Stage 1 is the lightest and briefest phase of sleep, lasting only 5% of the total cycle. Stage 2 signals a gear shift into a deeper slumber, with heart rate and temperature dropping. Approximately 50% of sleep is completed in stage 2.
Stage 3 is the deepest stage of sleep. If you’re woken up during this phase, you’ll feel groggy and cognitively impaired for up to an hour. Tissue repair and growth occurs in stage 3, along with the strengthening of the immune system.
The fourth stage is REM sleep, or dream sleep. REM refers to rapid eye movement, which occurs as you dream. Up to two hours of every night are spent dreaming.
Dreaming: Why it’s so critical
Scientists and sleep experts have debated the purpose of dreaming for decades. Up until recently, the utility of the REM phase was somewhat dismissed. In recent years, modern sleep guru Dr. Matthew Walker has emphasized the significance of REM sleep along with other experts, affirming that dream sleep holds functions fundamental to well-being and performance.
According to Walker, REM sleep removes the painful sting associated with traumatic or emotional episodes experienced during the day. On top of providing emotional resolution, dreaming enhances the creative process and problem-solving skills by fusing individual memories in abstract and novel manners.
Dreaming also plays a role in formulating overarching rules from knowledge the brain acquired during the day. Fascinatingly, REM sleep is the only time when noradrenaline, an anxiety-triggering molecule, is dramatically reduced in the brain.
Research conducted in 2016 on mice also indicates ongoing REM sleep deprivation over 72 hours impairs spatial memory. So you may find yourself experiencing more difficulty finding objects, or more prone to bumping into things. The study reported that this impaired state continued for at least 21 days after REM sleep had been restored.
“Dreaming is not just a funny thing that happens while we’re sleeping, but is a vital part of the restorative process and the memory and learning apparatus,” emphasized Dr. Jordan Tishler, President and CEO of the Association of Cannabis Specialists and an Instructor of Medicine at Harvard Medical School. “Deprivation of REM, in particular, can lead to cognitive dysfunction and mood alterations.”
Enter cannabis: How does it affect dreaming?
When it comes to determining the effects of weed on dreaming, the answer’s not clear-cut. “There are a number of sleep studies that show that cannabis can decrease or suppress REM sleep,” commented Dr. Tishler. “The larger question is whether this is good or bad. The answer is, as usual, ‘it depends.’”
Scientists are starting to tease out the effects of specific cannabinoids on dreaming.