Cannabis users report that cannabis helps them with sleep problems or that consumption of high THC cannabis makes them sleepy. Many chronic users of high-THC cannabis report sleep disturbances and especially vivid dreams for a period of time after abstinence (a break from THC). Many anecdotes, patient surveys, and studies suggest that cannabis does seem to affect sleep and dreaming, but many factors are involved: dose, frequency of consumption, tolerance, age, gender, etc.
Biology is complex.
What do we know specifically about how cannabis affects sleep and dreaming?
Because high-THC products dominate the commercial market, and because THC has the clearest connection to sleep among the cannabinoids, we’ll look at what some of the latest scientific studies reveal about THC’s effects on sleep. Before we do that, we get a basic understanding of the biological functions of sleep, the architecture of sleep. From there, we will be in a good position to understand what is known about how THC affects sleep.
Why do we sleep?
Sleep is still mysterious in many ways. Scientists are still debating how and why sleep fulfills its restorative function, as well as how the different stages of sleep contribute to it.
Sleep performs critical “cleaning” functions, cleaning out the physical garbage that accumulates in the brain.
But it is obvious that sleep is necessary for life.
Sleep performs certain “cleaning” functions – it literally cleans up the physical garbage that accumulates during waking hours. It is also important for learning and memory. Details are still being worked out. Sleep is important because it is a regulator of neuroplasticity mechanisms, necessary for the correct ingestion, memorization and consolidation of information that we absorb while awake.
Rapid eye movement (REM) and slow wave sleep (SWS)
Products that may be of interest to you
Sleep is not homogeneous. There are different stages of sleep and each one is characterized by different patterns of brain activity. Sleep scientists measure and classify these stages using EEG, a technique that quantifies the different brain waves present at any given moment. Through their studies, scientists can distinguish different “brain states”—active wakefulness (eg, focusing on a task), quiet wakefulness (eg, daydreaming), deep sleep, vivid dreaming, and so on.
Imagine you are looking at a pond. By noticing the ripple pattern present in surface water, you can discern the state of the overall environment. Is the pond still and glassy? Then it doesn’t blow. Do ripples appear from droplets falling into the pond? It’s probably raining. EEG is a way to do this with electrical brain activity. Each brain state corresponds to a different electrical wave pattern. These patterns are used to classify what brain state the animal is in.
Deep sleep vs. dreamy sleep
To understand the effects of cannabis on sleep, we need to understand the difference between rapid eye movement (REM) and slow wave sleep (SWS). REM sleep the part of sleep when your eyes drift under your lids. But your body is already paralyzed. This prevents you from achieving your dreams. For example, you can have vivid dreams in the REM state. which we usually have and sometimes remember. When you are deprived of REM, there may not be obvious cognitive deficits (eg fatigue), but there is probably some effect on learning and memory.
SWS is not usually associated with rich mental content. It is named for the large, slow-moving brain waves seen during this condition. We also call this sleep “deep sleep”. So it is also the part of sleep when it is most difficult to wake up. When you hear SWS, think “recovery”. When you hear REM, think “dreaming.”
Under normal conditions, you go through several cycles of SWS and REM, usually starting with SWS. When you sleep, you go into SWS, then REM, back to SWS, and so on. With each cycle there is less SWS and more REM.
Effects of THC consumption on sleep
As neurologist Dr. Andrew Kesner: “We’ve known for some time that THC has sleep-promoting properties in humans. Some of the earliest accounts of cannabis use described this. In fact, ancient Indian Ayurvedic medicine describes cannabis as nidrajanan, a “sleep-inducing” drug.
Many modern consumers report that cannabis helps them sleep, but there is no one-size-fits-all answer to how cannabis affects sleep. The effects of THC on sleep will vary depending on the cannabinoid content of what you consume, your history of use, sex, etc. In fact, one thing we can say for sure is that with THC, its effect on your sleep changes. time – if you consume THC once or twice, you won’t get the same effects as long-term use.
What are the likely acute (short-term) sleep effects of THC if you start consuming?
In general, acute consumption of THC in humans causes people to fall asleep faster and stay asleep once they do. It leads to an increase in SWS and a decrease in REM sleep. Consistent with experimental studies, surveys of medical cannabis patients show that the vast majority of those taking pharmaceutical sleep medications reduce their use of these medications after starting medical cannabis.
The effects of THC don’t always stay the same
However, the acute effects of THC on sleep may change over time. With chronic use of THC products, the effects on sleep may change. It is less clear how chronic consumption of THC affects sleep in humans, but tolerance to the effects of THC, including sleep, is evident. More clearly, stopping THC consumption after chronic use often leads to sleep disturbances and vivid dreaming, an effect that eventually normalizes.
What is the effect on sleep architecture—the pattern of SWS and REM—observed when chronic THC consumption ceases?
Dr. Kesner explained, “People often report poor sleep during cannabis withdrawal, and studies have confirmed these self-reports, showing that time spent in SWS and REM changes, even on the first night of abstinence. During abstinence, SWS decreases, possibly causing people to report not feeling rested. Similarly, REM sleep undergoes a “rebound” where it increases for a period of time, presumably to “catch up” as it was previously reduced by cannabis use. This increase in REM probably accounts for the common report of vivid and unpleasant dreams during THC withdrawal.
What if we stop using THC?
Recent animal research has measured the withdrawal effects of chronic THC in mice, measuring the effects of SWS and REM sleep in both male and female mice. After several days of THC exposure, the mice stopped receiving THC. During early abstinence, male mice showed sleep disturbances – reduced total sleep, mainly from shorter time spent in SWS. A few days later in the abstinence period, the pattern changed: male mice now showed an increase in REM sleep.
Mice can’t tell us about any dream content they might be having, but this result evokes reports of restless sleep and vivid dreaming that many users report after abstinence. Interestingly, this “REM rebound” effect did not occur in female mice.
Why would THC even affect sleep patterns? Why are women and men different?
Can cannabinoids affect sleep?
The body’s endocannabinoid system (ECS) plays a modulatory role in almost every major physiological system you can think of. ECS receptors, including the CB1 receptor responsible for enabling THC’s psychoactivity, are found in all tissues of the body, including the brain. THC affects sleep. This is because many of the key brain circuits regulating sleep are rich in CB1 receptors and other components of the ECS.
Different brain regions express different levels of ECS receptors, and this pattern of expression differs systematically between males and females. Like many aspects of physiology, this is an example of sexual dimorphism, which is why cannabinoids often affect men and women in different ways. The ECS also changes throughout life, which is why the effects of THC can change as we age.
Cannabis changes sleep, but it can be different for everyone.
In general, there is a decent chance that THC will help you fall asleep faster and sleep longer. It will likely increase the amount of SWS and decrease the amount of REM sleep you get. If we continue to consume THC, these effects may not last. As your tolerance increases, you may need to consume more to get the same effect. If you then stop consuming THC, you are likely to experience sleep disturbances for a period of time, including vivid or unpleasant dreams.
Again: Biology is complex. Hemp products and THC will affect everyone differently depending on gender, age, cannabinoid content and history of use. For better or worse, it will take some trial and error to determine exactly how cannabis changes your sleep.