“Waking consciousness is dreaming–but dreaming constrained by external reality.”
Philosophers, artists, and dreamers have spent centuries devoted to understanding the mind. One particularly spectacular part of the human experience lies within what we call consciousness, considered the “waking state”—but where it lives in the brain is still a mystery.
French philosopher René Descartes was quite interested in the neural underpinnings of consciousness and theorized that the pineal gland was the “seat of the soul.”  This small organ sits in a centralized location and happens to be a unilateral structure—there are no right and left parts of the gland in contrast with every other region in the brain.
The pineal gland produces melatonin, an important hormone that helps the sleep-wake cycle. This is why many people with insomnia take products with melatonin to help them sleep.
While Descartes’ theory was debunked by modern science, it represents an attempt to link human physiology to something intangible and puts a spotlight on the relationship between the waking and dreaming life.
While not considered a typical psychedelic, cannabis does in fact cause alterations in consciousness—the “high” produced by some of its intoxicating cannabinoids. So, to understand how phytocannabinoids produce these effects, we must trace the origins back to the endocannabinoid system (ECS).
The ECS modulates many systems in the brain and body, so it’s no surprise that it also plays a role in sleep. Studies have shown that anandamide, which binds to cannabinoid 1 (CB1) receptors, has sleep-inducing properties, while agents that block CB1 promote wakefulness. 
But in terms of sleep, there is a double-edged sword when it comes to cannabis. It may help people with sleep problems, but it could also cause sleep problems itself.
Cannabis is frequently used to treat post-traumatic stress disorder (PTSD), and people with PTSD often have terrible nightmares. Research indicates that a synthetic cannabinoid (nabilone) may indeed reduce the occurrence of those nightmares.  And cannabinoids may help other people who struggle with disturbing dreams, such as those with depression and schizophrenia.
On the other hand, people who generally sleep well may experience sleep disruptions. Although the literature is mixed, tetrahydrocannabinol (THC) may be more likely to impair sleep over time, whereas cannabidiol (CBD) may provide better sleep-inducing benefits; these effects, however, depend on the dosage of either. 
But does the ECS affect your dreaming state?
While the data are limited, it appears that this is the case, especially since endocannabinoids also regulate emotions and memory, and anyone who remembers their dreams can attest to the often emotionally charged content. So, it’s quite possible that your dream content is in fact influenced by your ECS.
Greater study is needed to get a better idea of how the ECS might influence sleep content, therefore weaving its way into our waking and sleeping lives.
Image Credit: Dayron Calero
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- Aulinas A. Physiology of the pineal gland and melatonin. In: Feingold KR, Anawalt B, Boyce A, et al., eds. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000. https://www.ncbi.nlm.nih.gov/books/NBK550972/. Updated December 10, 2019. [Impact Factor: N/A; Times Cited: N/A]
- Murillo-Rodriguez E, Pastrana-Trejo JC, Salas-Crisóstomo M, de-la-Cruz M. The endocannabinoid system modulating levels of consciousness, emotions, and likely dream contents. CNS Neurol Disord Drug Targets. 2017;16(4):370-379. [Impact Factor: 2.761; Times Cited: 11 (Semantic Scholar)]
- Babson KA, Sottile J, Morabito D. Cannabis, cannabinoids, and sleep: a review of the literature. Curr Psychiatry Rep. 2017 Apr;19(4):23. [Impact Factor: 4.539; Times Cited: 120 (Semantic Scholar)]