Taking CBD Before Smoking Cannabis Did Not Reduce the High or Desire to Smoke More
In a rigorous multi-site trial, oral CBD at doses up to 800 mg did not reduce the subjective high, reinforcing effects, or cardiovascular impact of smoked cannabis in regular users.
Quick Facts
What This Study Found
Some studies have suggested that CBD can counteract certain effects of THC, leading to widespread claims that CBD-rich products might reduce the downsides of cannabis use. This randomized, double-blind study tested that idea rigorously.
Thirty-one healthy cannabis smokers completed eight sessions where they received oral CBD (0, 200, 400, or 800 mg) 90 minutes before smoking either active or inactive cannabis. CBD alone produced no significant psychoactive or cardiovascular effects.
The key finding: CBD at any dose did not reduce the high, the positive subjective effects, the self-administration of cannabis, or the heart rate increase caused by smoked cannabis. Participants were just as likely to choose active cannabis over placebo cannabis regardless of CBD pretreatment.
Key Numbers
31 participants (17 male, 14 female). CBD doses: 0, 200, 400, 800 mg oral. Cannabis: 5.30-5.80% THC. Eight sessions per participant. No significant effect of CBD on any outcome at any dose.
How They Did This
Multi-site, randomized, double-blind, within-subject laboratory study. Thirty-one non-treatment-seeking cannabis smokers completed eight outpatient sessions testing four CBD doses against two cannabis conditions. A subset of 8 participants had plasma CBD levels measured after the 800 mg dose.
Why This Research Matters
This study directly challenges the popular notion that CBD counteracts THC. The failure of even very high CBD doses (800 mg) to blunt any measured effect of smoked cannabis suggests that adding CBD to cannabis products may not meaningfully reduce intoxication or the desire to use more.
The Bigger Picture
The CBD market is built partly on the idea that CBD moderates THC effects. This well-designed human study found no evidence for that claim across multiple outcomes including the high, liking, strength ratings, and self-administration. Previous positive findings may have been artifacts of studying single doses of oral THC rather than real-world smoked cannabis.
What This Study Doesn't Tell Us
The cannabis used (5.3-5.8% THC) was lower potency than much of what is available today. CBD was given orally while cannabis was smoked, creating different pharmacokinetic profiles. Participants were regular users who may have different responses than occasional users.
Questions This Raises
- ?Would inhaled CBD produce different results than oral CBD?
- ?Does the CBD-THC interaction depend on the route of administration or timing?
- ?Are previous claims about CBD counteracting THC based on artifacts of study design?
Trust & Context
- Key Stat:
- CBD up to 800 mg failed to reduce any measured effect of smoked cannabis
- Evidence Grade:
- Multi-site randomized double-blind within-subject design with multiple CBD doses. Strong methodology, though moderate sample size.
- Study Age:
- Published in 2016. The cannabis tested was lower potency than many current products, and CBD formulations have evolved.
- Original Title:
- Oral Cannabidiol does not Alter the Subjective, Reinforcing or Cardiovascular Effects of Smoked Cannabis.
- Published In:
- Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 41(8), 1974-82 (2016)
- Authors:
- Haney, Margaret(22), Malcolm, Robert J(2), Babalonis, Shanna(8), Nuzzo, Paul A, Cooper, Ziva D, Bedi, Gillinder, Gray, Kevin M, McRae-Clark, Aimee, Lofwall, Michelle R, Sparenborg, Steven, Walsh, Sharon L
- Database ID:
- RTHC-01170
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Does CBD counteract the effects of THC?
In this rigorous human trial, oral CBD at doses up to 800 mg did not reduce any measured effect of smoked cannabis, including the high, positive feelings, desire to smoke more, or heart rate increase.
Why is this different from what I have heard about CBD?
Previous studies often tested single doses of oral THC with CBD, not smoked cannabis. The interaction may depend on the route of administration, and real-world cannabis smoking may overwhelm any moderating effect of oral CBD.
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Cite This Study
https://rethinkthc.com/research/RTHC-01170APA
Haney, Margaret; Malcolm, Robert J; Babalonis, Shanna; Nuzzo, Paul A; Cooper, Ziva D; Bedi, Gillinder; Gray, Kevin M; McRae-Clark, Aimee; Lofwall, Michelle R; Sparenborg, Steven; Walsh, Sharon L. (2016). Oral Cannabidiol does not Alter the Subjective, Reinforcing or Cardiovascular Effects of Smoked Cannabis.. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 41(8), 1974-82. https://doi.org/10.1038/npp.2015.367
MLA
Haney, Margaret, et al. "Oral Cannabidiol does not Alter the Subjective, Reinforcing or Cardiovascular Effects of Smoked Cannabis.." Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 2016. https://doi.org/10.1038/npp.2015.367
RethinkTHC
RethinkTHC Research Database. "Oral Cannabidiol does not Alter the Subjective, Reinforcing ..." RTHC-01170. Retrieved from https://rethinkthc.com/research/haney-2016-oral-cannabidiol-does-not
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.