CBD FOR SLEEP - CBD & Sleep Detailed Summaries Of Clinical Trials
Here we review the methods, level of rigor, and the legitimate takeaways from each of clinical trials that studied the effects of CBD on sleep. Please note that as numerous studies have shown that oral ingestion of THC decreases the quality of sleep by reducing the amount of deep and REM sleep, below we focus only on clinical trials that did not contain any THC.
Clinical Trials That Tested Effects Of CBD On Sleep (1981-2025)
Effects of a cannabidiol/terpene formulation on sleep in individuals with insomnia: a double-blind, placebo-controlled, randomized, crossover study.
Methods
This was a double-blind, placebo-controlled, randomized clinical trial, in which 125 individuals with insomnia received an oral administration of CBD (300 mg) and terpenes (1 mg each of linalool, myrcene, phytol, limonene, α-terpinene, α-terpineol, α-pinene, and β-caryophyllene) for ≥ 4 days/wk over 4 weeks using a crossover design. The primary outcome measure was the percentage of time participants spent in the combination of slow-wave sleep (SWS) and rapid eye movement (REM) sleep stages, as measured by a wrist-worn sleep-tracking device.
Summary
This CBD-terpene regimen significantly increased the mean nightly percentage of time participants spent in SWS + REM sleep, and decreased light sleep compared to the placebo control. More robust increases were observed in participants with low baseline SWS + REM sleep, as well as in day sleepers. Some participants averaged as much as 2x more SWS + REM sleep/night relative to the placebo control over a 4-week treatment period. This treatment had no effect on total sleep time, resting heart rate, or heart rate variability, and no adverse events were reported.
Pros
This was the first crossover study (where each participant was tested both for placebo and the active treatment with CBD) that tested the effects of a clinically relevant dose of CBD (300 mg) in participants with insomnia. Rather than just relying on subjective sleep questionnaires, this study used a wrist-worn, sleep-tracking device that objectively quantified sleep data. This was the first study to look at detailed effects of CBD on sleep stages as measured by actigraphy, which showed that this CBD and terpene formulation appears to increase deep and REM (aka restorative) sleep.
Cons
Like all of the studies described below, this study did not use polysomnography (PSG), the so-called "gold standard" to measure sleep. So it remains to be determined if PSG will confirm the results of CBD on deep and REM sleep observed in this study.
Take Home Message
This is a landmark study, not only because it used a clinically meaningful dose of CBD (300 mg), but because it was the first to use objective sleep measures as the primary readout for the clinical trial. This trial is also important because it was the first to test the effects of CBD in a formulation with terpenes, naturally occurring plant based molecules hypothesized to improve sleep. If future studies using PSG confirm that this CBD and terpene formulation increases deep and REM sleep, this will establish a novel mechanism of action for a sleep aid, as the majority of current sleep aids (as well as prescription sleep medicines), function as sedatives that often disrupt normal sleep architecture.
Hypnotic and antiepileptic effects of cannabidiol
Methods
Investigators gave 160 mg CBD to 15 participants with insomnia, and asked them if they felt they slept better.
Summary
This was one the earliest published studies to determine if CBD influenced sleep. The authors found that subjects receiving 160 mg CBD reported having slept significantly more after taking CBD. No serious adverse events were reported.
Pros
This was the first published study to determine if CBD affects sleep in normal people. The study presented promising data that justified further clinical research.
Cons
This study was not placebo-controlled or double-blinded (i.e. the participants were aware they were getting a potential sleep medicine, which could introduce bias). The sample number (n = 15) was also low, precluding any strong interpretations of the data. Finally, the outcome measures were subjective (i.e. qualitative, not quantitative), which is problematic given the lack of blinding.
Take Home Message
Although significant limitations in the design of this clinical trial prevented any strong conclusions being made from this early study, it was still important, because it launched the entire research movement to understand if CBD influenced sleep, and it also showed that CBD appeared to be well tolerated.
Cannabidiol in Anxiety and Sleep: A Large Case Series
Methods
This is what is called a "retrospective" case series study, where investigators at a psychiatric clinic gave 103 of their patients with a sleep or anxiety disorder 25 mg CBD, and then asked them whether or not the CBD improved their anxiety and sleep, as measured by a subjective survey.
Summary
This was another early and important study to determine if CBD influenced anxiety and sleep. The authors found that patients who took CBD reported having less anxiety and better sleep after taking CBD. No serious adverse events were reported, and CBD was well tolerated in the vast majority of participants.
Pros
Promising data that justified further clinical research. Importantly, no harmful effects of CBD were found.
Cons
Not a placebo-controlled or double-blinded study (so the participants knew they were getting CBD and could be biased). Furthermore, the outcome measures were subjective (i.e. qualitative, not objective and quantitative).
Take Home Message
Although significant limitations in the design of this clinical trial prevented any strong conclusions being made from this study, it was another important step forward, because it suggested that CBD holds promise for helping improve anxiety and sleep, without having any apparent negative side effects. Studies like this formed the basis for future placebo-controlled studies.
Eight Weeks of Daily Cannabidiol Supplementation Improves Sleep Quality and Immune Cell Cytotoxicity
Methods
This randomized, parallel group, placebo-controlled clinical study evaluated the effects of 8 weeks of treatment with 50 mg CBD on mental health, sleep quantity and quality as determined by questionnaires and actigraphy in 28 healthy participants who averaged 26 years of age.
Summary
This study showed no significant effect of 50 mg CBD with respect to mental health measures and objective measures of sleep quantity. However, CBD improved sleep quality as measured using a sleep questionnaire.
Pros
This is another well designed study to see if CBD influences mental health and sleep.
Cons
Relatively small sample size (n = 28 or 14 per treatment arm), and the CBD dose studied (50 mg) might be too low to be clinically relevant. The study was not performed in people with clinically diagnosed mental disorders or insomnia.
Take Home Message
Based on future studies with higher doses of CBD (see above and below), it is probable that the 50 mg dose of CBD used in this study was simply too low, and might only have had a modest effect on improving sleep that would have been missed due to the small sample size in this study (n = 14 per treatment group).
Cannabidiol for moderate-severe insomnia: a randomized controlled pilot trial of 150 mg of nightly dosing
Methods
This trial explored the efficacy of 150 mg of CBD compared with placebo as a sleep aid in primary insomnia. This clinical trial was a randomized, placebo-controlled, parallel design featuring a single-blind placebo run-in week followed by a 2-week double-blind randomized dosing phase, and participants consumed the assigned treatment sublingually 60 minutes before bed nightly. Wrist-actigraphy and sleep diaries measured daily sleep.
Summary
In this trial, 150 mg of CBD had no significant effect on self-reported insomnia severity, sleep-onset latency, sleep efficiency, and wake after sleep onset. Compared with placebo, the CBD group reported greater well-being scores throughout the trial. No serious adverse events were reported.
Pros
CBD appeared to improve well being in participants with insomnia, and the study included an objective measure of sleep (wrist-actigraphy).
Cons
Small sample size (n = 15), short treatment period (two weeks), and relatively low dose of CBD (150 mg).
Take Home Message
Based on other studies with higher doses of CBD (see above and below), it is possible that the 150 mg dose of CBD used in this study was too low and might only have had a modest effect on improving sleep that would have been missed due to the small sample size in this study (n = 15).
Evaluation of the efficacy, safety, and pharmacokinetics of nanodispersible cannabidiol oral solution (150 mg/mL) versus placebo in mild to moderate anxiety subjects: A double blind multicenter randomized clinical trial
Methods
This was a prospective, randomized, double blind, parallel group, placebo-controlled, 15-week study that determined if 300-600 mg of CBD (150-300 mg twice/day) influenced anxiety and sleep in 178 participants with mild to moderate anxiety disorders. The primary outcome measure was the participants' response on self-reported clinically validated questionnaires regarding their anxiety. This study also measured sleep quality as determined by a self-reported clinically validated questionnaire.
Summary
In this trial, 300-600 mg of CBD significantly decreased anxiety scores relative to the placebo control based on responses to clinically validated questionnaires, and also had a significant improvement in subjective sleep quality. No serious adverse events were reported.
Pros
This was a very well designed, well powered and rigorous study that tested clinically relevant (300-600 mg/day) doses of CBD. The results were also very impressive. Highly significant and clinically relevant decreases in anxiety were observed in patients with anxiety, which coincided with improvements in subjective sleep quality.
Cons
Given the sample size, and based on analyses of previous clinical trials for FDA-approved anxiety medicines, it is very surprising to see such high response rates and levels of statistical significance in this study. In terms of sleep, the authors did not use any objective measures of sleep, so all we know is that the participants who had anxiety felt like they slept better (relative to the placebo control).
Take Home Message
This was an important study that strongly suggests that CBD at clinically relevant doses (300-600 mg/day) can decrease anxiety and improve sleep in patients with clinically diagnosed anxiety, and contributed further evidence that CBD is well tolerated.
The effect of nightly use of 150 mg cannabidiol on daytime neurocognitive performance in primary insomnia: a randomized controlled pilot trial
Methods
This study used a randomized, placebo-controlled, parallel design incorporating a single-blind placebo run-in week followed by a two-week double-blind dosing period, during which participants consumed 150 mg CBD (N = 15) or placebo. Unlike the previous studies described above, the goal of this study was only to measure the effect of daily CBD use on neurocognitive performance and daily subjective mood in a population with insomnia.
Summary
This study showed that 150 mg of CBD did not impact cognitive performance, but those participants with insomnia who received CBD reported a greater experience of calmness, clear-headedness, and coordination. Some participants reported dry mouth relative to the placebo control.
Pros
This was the first study to look at whether or not CBD influences cognitive performance in people with insomnia. Importantly, there were no negative effects of CBD on cognition. As with some previous studies, participants reported a greater sense of calmness and clear-headedness after taking CBD.
Cons
Small sample size. Dose of CBD (150 mg) might be too low to observe clinical relevance.
Take Home Message
This well designed clinical trial was important because it showed that CBD does not have any negative effects on cognition (in contrast to THC, which causes cognitive impairment).
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