Cannabis and sleep have a complex relationship that has only recently started to be understood by science. Mostly, people find indica strains to be more relaxing and effective for sleep disorders, whereas sativa strains tend to be more stimulating and tend to keep people awake.
Many studies completed between 2004 and 2008 showed the different effects of varying cannabinoids on sleep. In one, 15 mg of THC seemed to show sedative properties, while 15 mg of CBD appeared to have alerting properties.  Another study tested the effects of cannabidiol (CBD) on animal models in both lights-on and lights-off environments and found that this non-psychoactive cannabis compound increased alertness with lights on but showed no noticeable effects on lights-off sleep. The study’s authors concluded that CBD may truly hold therapeutic promise for those with somnolence, or excessive daytime sleepiness from a not-so-good night’s rest. In another study, researchers found CBD to be wake-inducing for most subjects, though some reported better sleep a few hours after taking it. 
Dr. Michael Moskowitz stated that, “many of my patients report either better energy or sleepiness on the same high-CBD/low-THC plants,” and “most, however, feel more energy on high-CBD cannabis.”
Generally speaking, indica strains of THC seem to work better as a sleep aid for most people. Although, a large number of people find THC, even indica strains, can make the mind more active. For people like this, CBD appears to work well, giving a better sense of calm and relaxation for the mind as well as the physical body. In these people, cannabidiol taken at nighttime as part of a bedtime routine produces a restful sleep, not the alertness created from administration during the day. This biphasic effect of CBD is the result of balancing the endocannabinoid system. For more information, read The Endocannabinoid System Explained.
As it relates to sleep apnea, a 2002 animal study discovered that tetrahydrocannabinol could restore respiratory stability by adjusting serotonin signaling and reducing spontaneous sleep-disordered breathing.  In a 2013 study, a synthetic form of THC called dronabinol was used on 17 patients with 15 of them showing improvements after 21 days of treatment.  Generally speaking, the use of natural plant-based cannabinoids from the cannabis plant are strongly encouraged and preferred over synthetic cannabinoids.
It is recommended that those wishing to utilize CBD oil or medical marijuana (not the same as recreational "weed", “marijuana”) do so under the guidance of a physician experienced in working with these compounds so the dosage and delivery method may be fine tuned based on the individual. In saying that, highly aware and educated persons may become their own informed health consultants. Keeping in mind, the information contained in this article is for informational purposes only, and does not constitute medical advice. Prior to making any changes to your lifestyle or treatment plan, always consult with a licenced medical professional.
Best Strain for Sleep
Although high-CBD cannabis products assist with sleep in some people, in others, it can create the reverse effect by promoting wakefulness. High-THC products administered orally, especially when derived from heavier “Kush” strains and Purple cannabis varieties, are very effective for sleep disorders. They tend to be higher in the terpenes myrcene and linalool, which is a compound shared with lavender, and is known to be effective for relaxation. Cannabis products with ratios of 1:1, 4:1, or 24:1 of CBD to THC can be utilized when people wish to reduce psychoactivity. Cannabidiol (CBD) is known to neutralize many of the psychoactive effects tetrahydrocannabinol depending on the ratio and the individuals tolerance level. For more information on terpenes, read our Ultimate Guide to Terpenes.
CBD Dosage for Sleep
Oral consumption of cannabis products is the most effective way to help with sleep disorders as the dose effects typically last the entire night. Always start with a micro dose to test for sensitivity and titrate up as needed until symptoms subside. The micro to standard dose is generally recommended to assist with insomnia and sleep apnea. When relaxing indica strains are utilized with higher THC levels, a dose of 5-10 mg is usually sufficient. Other people find they require larger doses, such as 15-40 mg. Cannabidol consumed as an edible or tincture will assist in a restful six to seven hours of sleep. This type of disorder can vary greatly from one person to the next. In many cases, the individual will need to experiment with different strains and ratios of CBD to THC to figure out the best protocol for them.
For fast and immediate effects, smoking or vaporizing works very well. This can be an advantage for those who want to get to sleep quickly, or who wake in the middle of the evening. Although these immediate methods produce shorter relief of one to three hours. Ingestible products take roughly thirty to sixty minutes before taking effect (or 15-30 minutes on an empty stomach) and can last six to eight hours, which is more beneficial for most sleep issues. Vaporizers that use a cartridge filled with a CO2 concentrate are convenient and highly effective, and these are available in various ratios of CBD to THC. Herbal vaporizers that use the whole plant are also an effective delivery method. Sublingual sprays or tinctures taken as liquid drops also take effect quickly and last longer than inhaled products.
Cannabis Sleep Research
The Cannabis Health Index (CHI) is a scoring system based on the best available evidence present in the medical literature to date (for cannabis, not just CBD). Based on this, cannabis-based products for treating insomnia have a rating of likely-probable efficacy (3.4 points of out 5) based on the studies available.
A study from 2007 using the whole-plant cannabis-derived pharmaceutical called Sativex, which is a 1:1 CBD to THC spray, showed excellent results in assisting patients with chronic pain sleep better.  This product is currently approved for use in over 30 countries worldwide for a variety of medical conditions such as multiple sclerosis and chronic pain.
REM sleep behavior disorder (RBD)
REM sleep behavior disorder (RBD) is characterized by the loss of complete muscle relaxation during REM sleep, and is associated with nightmares and physical activity during dreaming. Four patients in a case series treated with CBD in 2014 had a rapid and significant drop in the frequency of RBD-related events without side effects. 
CBD oil has shown value in a variety of sleep conditions along with pre-bedtime anxiety and the mental health effects that go along with it. CBD products show potential in alleviating both stress and pain in a short period of time along with noticable benefits over the long term.
For more information, read our article on Hemp Oil for Sleep Disorders.
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