Randomized Controlled Trial

. 2019 Sep;236(9):2713-2724.

doi: 10.1007/s00213-019-05246-8. Epub 2019 May 1.

Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition

Thomas R Arkell^{1

2

3}, Nicholas Lintzeris^{3

4}, Richard C Kevin^{1

2

5}, Johannes G Ramaekers⁶, Ryan Vandrey⁷, Christopher Irwin⁸, Paul S Haber^{3

9}, Iain S McGregor^{10

11

12}

Affiliations

¹ Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, New South Wales, Australia.
² Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia.
³ Faculty of Medicine, Central Clinical School, The University of Sydney, Sydney, New South Wales, Australia.
⁴ The Langton Centre, Drug and Alcohol Services, South East Sydney Local Health District, NSW Health, Sydney, New South Wales, Australia.
⁵ Faculty of Science, School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.
⁶ Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
⁷ Johns Hopkins University School of Medicine, Baltimore, MD, USA.
⁸ School of Allied Health Sciences, Griffith University, Gold Coast, Australia.
⁹ Drug Health Services, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
¹⁰ Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, New South Wales, Australia. iain.mcgregor@sydney.edu.au.
¹¹ Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia. iain.mcgregor@sydney.edu.au.
¹² Faculty of Science, School of Psychology, The University of Sydney, Sydney, New South Wales, Australia. iain.mcgregor@sydney.edu.au.

PMID: 31044290
PMCID: PMC6695367
DOI: 10.1007/s00213-019-05246-8

Randomized Controlled Trial

Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition

Thomas R Arkell et al. Psychopharmacology (Berl). 2019 Sep.

. 2019 Sep;236(9):2713-2724.

doi: 10.1007/s00213-019-05246-8. Epub 2019 May 1.

Authors

Thomas R Arkell^{1

2

3}, Nicholas Lintzeris^{3

4}, Richard C Kevin^{1

2

5}, Johannes G Ramaekers⁶, Ryan Vandrey⁷, Christopher Irwin⁸, Paul S Haber^{3

9}, Iain S McGregor^{10

11

12}

Affiliations

¹ Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, New South Wales, Australia.
² Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia.
³ Faculty of Medicine, Central Clinical School, The University of Sydney, Sydney, New South Wales, Australia.
⁴ The Langton Centre, Drug and Alcohol Services, South East Sydney Local Health District, NSW Health, Sydney, New South Wales, Australia.
⁵ Faculty of Science, School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.
⁶ Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
⁷ Johns Hopkins University School of Medicine, Baltimore, MD, USA.
⁸ School of Allied Health Sciences, Griffith University, Gold Coast, Australia.
⁹ Drug Health Services, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
¹⁰ Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, New South Wales, Australia. iain.mcgregor@sydney.edu.au.
¹¹ Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia. iain.mcgregor@sydney.edu.au.
¹² Faculty of Science, School of Psychology, The University of Sydney, Sydney, New South Wales, Australia. iain.mcgregor@sydney.edu.au.

PMID: 31044290
PMCID: PMC6695367
DOI: 10.1007/s00213-019-05246-8

Abstract

Background: The main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), can impair driving performance. Cannabidiol (CBD), a non-intoxicating cannabis component, is thought to mitigate certain adverse effects of THC. It is possible then that cannabis containing equivalent CBD and THC will differentially affect driving and cognition relative to THC-dominant cannabis.

Aims: The present study investigated and compared the effects of THC-dominant and THC/CBD equivalent cannabis on simulated driving and cognitive performance.

Methods: In a randomized, double-blind, within-subjects crossover design, healthy volunteers (n = 14) with a history of light cannabis use attended three outpatient experimental test sessions in which simulated driving and cognitive performance were assessed at two timepoints (20-60 min and 200-240 min) following vaporization of 125 mg THC-dominant (11% THC; < 1% CBD), THC/CBD equivalent (11% THC, 11% CBD), or placebo (< 1% THC/CBD) cannabis.

Results/outcomes: Both active cannabis types increased lane weaving during a car-following task but had little effect on other driving performance measures. Active cannabis types impaired performance on the Digit Symbol Substitution Task (DSST), Divided Attention Task (DAT) and Paced Auditory Serial Addition Task (PASAT) with impairment on the latter two tasks worse with THC/CBD equivalent cannabis. Subjective drug effects (e.g., "stoned") and confidence in driving ability did not vary with CBD content. Peak plasma THC concentrations were higher following THC/CBD equivalent cannabis relative to THC-dominant cannabis, suggesting a possible pharmacokinetic interaction.

Conclusions/interpretation: Cannabis containing equivalent concentrations of CBD and THC appears no less impairing than THC-dominant cannabis, and in some circumstances, CBD may actually exacerbate THC-induced impairment.

Keywords: CBD; Cannabidiol; Cannabis; Cognition; Driving; THC; Tetrahydrocannabinol.

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Conflict of interest statement

Nicholas Lintzeris has received funding for sponsored research studies from Camurus and has provided consultancies for Indivior and Mundipharma for unrelated work. Ryan Vandrey has received consulting fees from Zynerba Pharmaceuticals, Battelle Memorial Institute, and Canopy Health Innovations Inc. and has received compensation for being on the advisory boards for Insys Therapeutics, Brain Solutions Inc., and The Realm of Caring Foundation. Paul Haber has received research funding from Camurus, and has provided consultancies for Indivior, Abbvie, and Gilead for unrelated work. Iain McGregor acts as a consultant to Kinoxis Therapeutics and is an inventor on several patents relating to novel cannabinoid therapeutics. The other authors have no conflicts of interest to disclose.

Figures

**Fig. 1**
Order of events during experimental sessions. VAS visual analog scale, STAI State Trait Anxiety Inventory, DSST Digit Symbol Substitution Task, DAT Divided Attention Task, PASAT Paced Auditory Serial Addition Task, ADSES Adelaide Driving Self-Efficacy Scale

**Fig. 2**
Mean (SEM) participant ratings of “Stoned”, “Strength of drug effect”, “Sedated”, “Liking of drug effect”, “Anxious” and “Confident to drive” assessed using 1-100mm visual analog scales after vaporization of placebo, THC-dominant, and THC/CBD-equivalent cannabis. All scales were unipolar except for “Liking of drug effect”. BL baseline

**Fig. 3**
Mean (SEM) performance on the Digit Symbol Substitution Task (DSST), Divided Attention Task (DAT), and Paced Auditory Serial Addition Task (PASAT) after vaporization of placebo, THC-dominant, and THC/CBD-equivalent cannabis. *p < 0.05, **p < 0.01, ***p < 0.001, Bonferroni post-hoc. BL baseline

**Fig. 4**
Mean (SEM) plasma concentrations (ng/mL) of THC, CBD, 11-OH-THC, and THC-COOH after vaporization of placebo, THC-dominant, and THC/CBD-equivalent cannabis

See this image and copyright information in PMC

References

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Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition

Affiliations

Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

Publication types

MeSH terms

Substances

Grants and funding

LinkOut - more resources

Full Text Sources

Medical