I don’t know a single person my age — a twenty-something or thirty-something millennial — who doesn’t use some sort of substance to assist with sleep. I don’t know whether our generation is so plagued by stress and anxiety that it interferes with our sleep or that we’ve been pumped so full of chemicals that our bodies cannot properly regulate, but the fact remains that a significant portion of the population relies on things like weed to catch just a few Zs every night.

Sleep experts agree that there is no substitute for natural sleep, but I still wonder what cannabis is doing to our brains and bodies when we start to rely on it every night. Here’s a dive into how weed affects sleep, why it is such an effective sleep aid and why it might not be wise to overuse it.

How Sleep Is Changed by Cannabis

In a healthy adult with normal patterns, sleep is pretty easy for experts to predict. First, a person falls into non-rapid-eye-movement (NREM) sleep, which occurs in three states of increasing non-responsiveness and slower brain activity which makes it increasingly difficult to awaken the sleeper. The states last anywhere from a few seconds to about 40 minutes, and once the sleeper reaches the third state, they cycle back through the second and first stages of NREM. What follows is a stage called REM, or rapid-eye-movement sleep, which is characterized by rapidly moving eyes and low-amplitude, high-frequency brain waves — which are typically associated with vivid dreams. About one-quarter of a sleeper’s night is comprised of REM sleep, and the rest is NREM or “deep sleep.” Every stage of sleep is important for shutting down certain systems, encouraging relaxation and allowing the body to adequately repair after a day of living.

Most substances interfere with the normal patterns of sleep in some way, and cannabis is no different. The sedative effects in cannabis allow users to fall asleep much faster, increasing the first two stages of NREM sleep dramatically while decreasing the quantity of REM sleep achieved in a night.

For some sleepers, these changes are exceedingly beneficial. For example, PTSD sufferers are often plagued by traumatic dreams during REM sleep, so cannabis’s effects can help them avoid panic episodes and achieve more restful sleep. Other sleepers suffer from too much brain activity during REM or REM phases that last too long, both of which are benefited by cannabis use. However, for most people, a long-term interruption in REM will have negative ramifications, such as a decrease in cognitive ability or emotional activity.Therefore, it is important that poor sleepers talk to medical professionals to receive recommendations regarding cannabis before assuming the compound will improve their sleep. Even in states like Michigan where recreational marijuana has been legalized, it is wise to apply for a medical marijuana card to ensure a patient receives the best products for their unique sleep condition.

Which Compounds in Cannabis Affect Sleep

There are over 100 cannabinoids and over 200 terpenes found across cannabis plants. Unfortunately, not all of these compounds have been studied to understand their effects, especially as they pertain to sleep. Still, there are a few compounds that researchers can link to sleep effects.

THC. Tetrahydrocannabinol is the most common cannabinoid in most cannabis varieties, and it is the compound responsible for making marijuana users high. THC binds to receptors in the brain, and one of its more prominent effects is sedation, or slowing brain activity which often induces sleep.

CBD. Cannabidiol is a non-psychoactive compound in cannabis that has increased rapidly in popularity in recent years. There is much promising research in applying CBD treatments to disordered sleep; many sleep experts believe the compound helps to restore natural body rhythms that improve sleep health.

CBN. A lesser-known cannabinoid, cannabinol seems to have powerful sedative effects like THC. However, not much research has been devoted to understanding the full effects of CBN, and because it typically exists in small quantities in cannabis products, it isn’t a reliable tool for improving sleep.

Terpenes. Studies on terpenes have shown that some individual terpenes can be useful in facilitating relaxation, sedation and sleep. Terpenes are compounds that produce aroma, and though terpenes are not unique to cannabis, they might be responsible for the differences in the effects of different marijuana strains. It is important to research different terpenes and find cannabis products with the right terpene profiles for sleep.

I can’t tell users to rely solely on cannabis to improve their sleep. Sleep problems are as unique as individual sleepers; some sleepers will benefit from cannabis use, while others will experience negative effects. Sleepers need to educate themselves about the substances they rely on for sleep and talk to sleep professionals for more information about achieving a restful night.