Firstly, lets break down the stages of our sleeping cycle so that you can see which part is affected, or so is thought by marijuana use.
So, when you lie down to sleep and fully relax, you start to enter into the first stage of ‘light sleep’
Light Sleep – NREM 1
This stage lasts between 1-10 minutes and during this time you can quickly return to being fully awake. In this stage your heart becomes steady and your breathing slows down. Your blood pressure starts to drop as does your body temperature. Some people might experience muscle ‘jerks’ at this time or the feeling of falling, which is called a vestigial reflex a human evolutionary process where it prevented people falling out of the trees they slept in 🙂 **clause: if you fall out of a tree whilst asleep we are not liable 🙂 It is thought that people with irregular sleeping habits experience more of these vestigial reflexes than others.
Light Sleep – NREM 2
Ok so this is the stage where things really kick in! NREM 2 lasts between 2-20 mins and your heart rate further slows down and body temp continues to decreases along with your blood pressure and also metabolic functions. During this time it is harder to wake up. Most of our night, around 45% of our sleep is actually spent in these first 2 stages, which comes as a surprise to most people who think that most is spent in the next stage, deep sleep, as they think that deep sleep is what’s most needed which is a myth.
Deep Sleep – NREM 3
So this stage usually starts around 30-45 mins after falling asleep and at this time your brain slows down and brain waves become larger. During this stage it is much harder to awake and you sleep through most disturbances such as noise and movement. If you are awoken at this time you will likely feel groggy and disoriented. This stage is also sometimes referred to as ‘delta sleep’ or ‘slow wave sleep’.
REM Sleep – Stage 4
REM stands for “Rapid Eye Movement’. This is the last stage of our sleeping cycle and happens after around 90 minutes from starting light sleep. The heart rate and breathing can speed up and become irregular again in this part of the cycle. REM continues for only a short period of time initially around 10 mins but each round it increases and can last up to 1 hour. During REM sleep we experience our deepest vivid dreams. Also, this is when sleep walkers and bed wetter’s will have their episodes. Some refer to this stage as paradoxical sleep as it seems to show brain patterns that are contradictory to sleep, even though most muscles are paralyzed as otherwise you would actually act out your dreams!
SO now you fully understand the patterns of the average persons sleep how is this affected by marijuana use? It is thought that REM sleep – Stage 4 is suppressed by marijuana users and therefore mostly they feel that they dont experience dreams, and only realise so when they experience them again and feel that they are even more common when not using. Lets look at some actual studies done to try to prove this phenomenon. Feinberg et al (1975) tested marijuana users by monitoring their REM when taking THC and also a placebo, and it was found that when taking THC there was less REM sleep but when taking the placebo there seemed to be a ‘rebound’ effect and even more REM than normal was experienced. It is worth mentioning that studies have been focusing on THC predominantly and not CBD and other components found in marijuana.
Surely having more Deep sleep and less REM cant be a bad thing? Having more deep sleep is thought to give you a more ‘restful’ sleep that is of higher quality sleep which would be why marijuana is used for those who suffer from sleep disorders such as insomnia, or when pain and anxiety interferes with being able to relax enough to start and continue with the normal sleeping cycle.
It is worth mentioning that simply by just quitting smoking (tobacco) the levels of serotonin start to improve and the brain tries to compensate for the previous suppression and by doing so produces more than needed in the short term thus giving you wilder dreams and also nightmares, so this could give some light to this phenomenon perhaps.
Anyway even if marijuana stops you dreaming as much, do we need dreams? What are they?
Theory 1 – Activation Synthesis
In 1977 Robert McCarley and Allen Hobson proposed that dreams are simply a way of our brains interpreting random signals that are most active during our REM stage of the sleep cycle.
Theory 2 – Psychoanalytical
Sigmund Freud firstly suggested this theory that dreams are in fact coded expressions of our inner most fears and desires and that all the images and content are made from our emotions and thoughts.
Theory 3 – Information processing
This is the most accepted theory that we process, file and give order to all new information that we have gathered during the previous day and that dreams are either a byproduct or an integral way of this process. Although widely accepted i think that this is in fact just easier for us to accept this theory rather than either understanding Theory 1 or accepting Theory 2 (which would mean we have some pretty way out there fears and desires) but I think that the fact that Marijuana inhibits this stage without any obvious negative effect proves that this theory is in fact debunk.
Bottom line I think that the reason for the lack of dreams whilst using is simply that if you are getting more deep sleep and therefore if more of your cycle is spent in this state then you are in fact far more likely to awaken from this part of the cycle before starting the next cycle thus simply missing the last part!