How THC and CBD Affect Sleep: A Controlled Study with Brain Wave Monitoring | Research

The takeaway

A sleep study found that 15 mg THC alone was sedating the next day, while 15 mg CBD appeared to have alerting properties and counteracted THC's sedative effects when combined.

Read this if you use cannabis for sleep and want to understand how THC and CBD affect sleep differently.

THC was sedating; CBD had alerting properties and counteracted THC sedation

What the researchers found

In 8 healthy volunteers given sublingual cannabis extracts before sleep, 15 mg THC alone had no effect on nocturnal sleep architecture but produced next-day sedation, impaired memory, and reduced sleep latency (indicating increased sleepiness). When 15 mg CBD was combined with 15 mg THC, it increased wakefulness during sleep and decreased stage 3 (deep) sleep.

The lower dose combination (5 mg THC + 5 mg CBD) improved reaction time on a next-day memory task. The findings suggested that CBD at 15 mg had alerting properties, counteracting THC's residual sedation. THC alone appeared sedating, while CBD appeared to promote wakefulness.

Why it matters

This was one of the first controlled studies to demonstrate that CBD had alerting rather than sedating properties, and that it could modify THC's effects on sleep. This has significant implications for how cannabis products are formulated for sleep versus daytime use.

The numbers in context

Eight volunteers. Four treatments: placebo, 15 mg THC, 5+5 mg THC:CBD, 15+15 mg THC:CBD. THC alone: sedating next day. High-dose CBD+THC: increased wakefulness during sleep.

How the study worked

This was a double-blind, placebo-controlled, 4-way crossover study in 8 healthy volunteers (4 male, 4 female, ages 21-34). Treatments were placebo, 15 mg THC, 5 mg THC + 5 mg CBD, and 15 mg THC + 15 mg CBD via oromucosal spray at 10 PM. EEG was recorded during sleep (11 PM - 7 AM). Next-day assessments at 8:30 AM measured performance, sleep latency, and mood.

What this study cannot tell us

Very small sample (8 volunteers). Single-night assessments in each condition may not reflect chronic effects. Healthy young volunteers may respond differently from patients. The oromucosal spray delivery may produce different effects from other routes.

How to read the evidence

This is a well-designed double-blind crossover study with EEG monitoring, though limited by its small sample of 8 volunteers.

When this study was published

Published in 2004. The alerting properties of CBD have been confirmed by subsequent research.

The bigger picture

The finding that CBD is alerting rather than sedating was surprising and has been confirmed by subsequent research. This has implications for the marketing of CBD products for sleep, as the evidence suggests CBD may actually promote wakefulness at certain doses. The THC-CBD interaction documented here influenced the formulation of Sativex.

Questions still open

Does CBD's alerting effect persist with chronic use? At what dose does CBD shift from alerting to sedating? How should cannabis products be formulated differently for sleep versus daytime symptom management?

Common questions

Does CBD help you sleep?

Contrary to popular belief, this study found that CBD at 15 mg had alerting properties, increasing wakefulness during sleep and counteracting THC's sedative effects. THC alone was the sedating compound. CBD marketed for sleep may work through anxiety reduction rather than direct sedation.

What is the best cannabis combination for sleep?

In this study, THC alone was most sedating, while adding CBD reduced the sedative effect. For sleep, THC-dominant products may be more effective than balanced or CBD-dominant ones, based on these findings.

Read the original research

Effect of Delta-9-tetrahydrocannabinol and cannabidiol on nocturnal sleep and early-morning behavior in young adults.

Journal of clinical psychopharmacology, 24(3), 305-13

View on PubMed ↗

Citation

Nicholson, Anthony N; Turner, Claire; Stone, Barbara M; Robson, Philip J. (2004). Effect of Delta-9-tetrahydrocannabinol and cannabidiol on nocturnal sleep and early-morning behavior in young adults.. Journal of clinical psychopharmacology, 24(3), 305-13.