Sleep, Dreams, and Cannabis
By Stacey Marie Kerr MD
sleep, blessed sleep
One of the most common reasons patients cite for using cannabis is simply to get a good night’s sleep. I often hear, “Just a little every night and I sleep like a baby!” While this is true for many, it is certainly not true for all, and the science behind cannabis and sleep supports this clinical observation.
Anyone who has gone without enough time in this restorative state of sleep knows how precious it is. Persistent lack of quality sleep can cause a host of troublesome symptoms that range from depression, to physical disabilities, and even to psychotic behavior.
Complaints of poor sleep quality and insomnia mean a person is having difficulty falling asleep and/or staying asleep to the point that it affects their ability to function. A good sleep remedy allows someone to fall asleep when she needs to, and stay asleep long enough to fully benefit. Ideally, a sleep remedy would do all of that without affecting memory or ability to function the next day. Can cannabis provide this?
the endocannabinoid system and circadian rhythm
The endocannabinoid system (ECS) modulates many of our essential body functions--immunity, appetite, and metabolism, just to name a few. The ECS also modulates our circadian rhythm which is our 24-hour internal clock.
Levels of the endocannabinoid anandamide change during the body’s natural 24-hour circadian cycle. In a study on healthy humans, it was observed that the concentration of anandamide in the blood is three times higher on awakening than it is right before going to sleep. Sleep deprivation disrupts this pattern. 
does cannabis work? it depends.
The scientific research on phytocannabinoids and sleep is just beginning, but what we are learning is that cannabis can have differing effects depending on:
Cannabinoids and terpenes present in the medicine
THC, Sleep, and Dreams
THC allows most people to fall asleep more easily, but tolerance develops. Using THC every night to get good sleep may not work forever, or may require increasing doses to remain effective. Taking a break from THC can help counteract this. 
Taking a 'THC holiday' is an important part of managing sleep with cannabis due to the effect THC has on sleep cycles. People cycle through different stages of sleep throughout the night, spending the most time in deep (slow-wave) sleep. REM (rapid-eye movement) sleep is when we dream, and the dreams we remember are those occurring during the REM cycle we are in when we wake up.
Regular THC use decreases the amount of time spent in REM sleep and increases time spent in deep sleep.  This is why we sometimes dream less during THC-affected sleep, and why dreams may be particularly vivid when we stop using cannabis, as THC is no longer suppressing REM sleep. Regular cannabis users often say they don’t dream, and when they take a break have many vivid dreams. This is a normal adjustment.
THC has also been shown to decrease the occurrence of nightmares in patients with PTSD, allowing them to get better and longer lasting sleep. 
what about cbd?
CBD is a mixed bag when it comes to sleep. In low doses it causes more wakefulness and has even been used to help patients with narcolepsy or excessive daytime sleepiness. In higher doses (160mg/day) however, it increases total sleep time and decreases the frequency of nighttime waking.  Using CBD-rich medicine (cannabis containing both THC and CBD) allows lower doses of THC to be effective for longer periods of time, but the quality of sleep may not be as beneficial. 
Clinically, patients report lower doses of CBD are quite helpful to their sleep patterns, but this may be due to the presence of myrcene, a terpene present in some CBD-rich cannabis strains. CBD has also shown promise for patients with Parkinson’s REM sleep disorders, a problem that causes them to act out with dangerous behaviors linked to dreams and nightmares. 
Obstructive sleep apnea (OSA) affects 9% of American adults and is the most common form of sleep disordered breathing in the USA.  Most people diagnosed with OSA are given machines to counteract the breathing stoppages that occur during the night--CPAP machines that are cumbersome, uncomfortable, and only tolerated by some.
Better treatments are needed, and cannabinoids can help. The endocannabinoid oleamide and the phytocannabinoid THC have been shown to reduce sleep apnea events and protect the brain from symptoms of sleep apnea.  Prasad and team have reported that a synthetic form of THC (dronabinol) in doses ranging from 2.5 to 10mg daily was found to be safe, well tolerated, and effective in reducing apnea. 
Pain and sleep
If pain is interfering with sleep quality, managing the pain with cannabis can make a significant difference in quality of life, both awake and asleep.  A ratio of 1:1 THC:CBD has been shown to be effective in these cases. One study compared a synthetic form of THC (nabilone) to amitriptyline, which is a commonly prescribed medication for patients suffering from fibromyalgia. Those on nabilone reported greater improvements in sleep compared to the amitriptyline. 
cannabinoids and beyond
The cannabinoids are not the whole story of cannabis and sleep. Terpenes, the chemicals that give cannabis its aroma, are powerful medicines themselves. Myrcene - common in hops, linalool - common in lavender, and nerolidol - found also in oranges, all have sedative properties and if present in a cannabis strain will make that medicine much more likely to be an effective sleep aide.
Those with sleep problems need to first identify the source of the trouble. Life stress, poor sleep habits, sleep apnea, PTSD, and pain are all common problems that lead to lack of sleep and then to further difficulties. Once the probable cause is known, the right kind of cannabis used at the right time can be a valuable aide in re-establishing a healthy circadian rhythm.
1. Vaughn et al. Endocannabinoid signaling: has it got rhythm? British Journal of Pharmacology (2010), 160, 530–543 doi:10.1111/j.1476-5381.2010.00790.x
2. Babson et al. Cannabis, Cannabinoids, and Sleep: a Review of the Literature, Curr Psychiatry Rep (2017) 19: 23 DOI 10.1007/s11920-017-0775-9
3. Nicholson AN, Turner C, Stone BM, Robson PJ. Effect of Delta-9-tetrahydrocannabinol and cannabidiol on nocturnal sleep and early morning behavior in young adults. J Clin Psychopharmacol. 2004;24(3):305–13.
4. Heber et al. The efficacy of nabilone, a synthetic cannabinoid, in the treatment of PTSD-associated nightmares: A preliminary randomized, double-blind, placebo-controlled crossover design study. Psychoneuroendocrinology, 51, 585-588. (2015)
5. Chagas MH et al. Cannabidiol can improve complex sleep-related behaviors associated with rapid eye movement sleep behavior disorder in Parkinson's disease patients: a case series. J Clin Pharm Ther. 2014;39(5):564–6.
6. Carley DW et al. Functional role for cannabinoids in respiratory stability during sleep. Sleep. 2002;25(4):391–8.
7. Prasad B, Radulovacki MG, Carley DW. Proof of concept trial of dronabinol in obstructive sleep apnea. Front Psychiatry. 2013;4:1.
8. Russo EB, Guy GW, Robson PJ. Cannabis, pain, and sleep: lessons from therapeutic clinical trials of Sativex, a cannabis-based medicine. Chem Biodivers. 2007;4(8):1729–43.
9. Ware MA, Fitzcharles MA, Joseph L, Shir Y. The effects of nabilone on sleep in fibromyalgia: results of a randomized controlled trial. Anesth Analg. 2010;110(2):604–10.