Have you ever noticed any changes in your sleep when you smoke weed before bed? Well, some clever folks did, so they started doing research on how cannabis affects the quality of your sleep.

An electroencephalogram (EEG) is a tool used by sleep specialists and it works by measuring the total (averaged) electrical activity throughout your entire brain. Through years of research, neuroscientists have been able to assign a frequency, and amplitude to specific stages. There are five stages in a single sleep cycle, ranging from 1 – 4, and then rapid eye movement (REM).

Stages 1 – 4, associated with beta, alpha, theta, and delta waves respectively, mark the transition of being awake to falling asleep. There are three stages of Non-REM (NREM): N1 sleep is when you’re just dozing off, N2 sleep occurs when you transition from one stage of sleep to another, N3 (slow wave sleep), is the most physically and mentally restorative, and N4 sleep is considered deep sleep. Most people repeat the cycle about three times a night over the course of 8 hours.

Although it’s possible to dream in NREM sleep, they’re rare and difficult to remember. NREM dreams are about basic stuff, while REM dreams are the rollercoaster rides and emotional battles we often associate with dreams.

So the big question: How does cannabis affect your sleep cycle?

Well, it certainly puts you to bed faster! It’s an incredible agent for fighting insomnia. But what about your dreams?

While there were relatively minor changes in the sleep activity of stages 1 – 3, they noticed that, in a dose-dependent manner, higher THC both increased stage 4 (deep sleep) whilst decreasing REM (dream sleep).

Now why might you be okay with this trade off? The primary benefit to cannabis’s dream suppression – managing PTSD by decreasing nightmares. People who are struggling to move past an emotional or challenging event are often haunted by it in their dreams, and cannabis can help provide a restful nights sleep.

Now you might be wondering, what if I don’t have PTSD? Is it bad to miss out on dreams? Do I need them for memory retention or future problem solving as some researchers think?

Whether or not nightmares are the problem, people around the world know that cannabis is a brilliant solution for speeding up sleep onset and extending sleep.

Here is the thing, your dreams are going to get intense when you take a night off from smoking. After a period of decreased REM sleep time, your body goes into a ‘rebound mode’ where you dream intensely to catch up on all the REM sleep your system feels it needs.

Despite theories about REM’s importance in processing information and emotions, a lack of REM sleep appears to have little impact on waking behavior. Read the full study here. Studies using EEG recordings show that even with minimal REM sleep, subjects report no obvious adverse effects in their day-to-day. However, this is not the case with NREM deep sleep cycles. While it appears that we can survive just fine without REM, the sequences of other sleep cycles are imperative to our health.