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Acute effects of orally administered Δ8-THC and Δ9-THC on simulated driving ability, cognitive performance, and subjective drug effects

Lakshmi Kumar, Destiny Schriefer, Halle Thomas, Edward J. Cone, Ruth Winecker, Svante Vikingsson, Ronald Flegel, Eugene Hayes, Lisa S. Davis, David Kuntz, Julian Levin, Tory R Spindle, C. Austin Zamarripa, Ryan Vandrey

DOI: 10.22541/authorea.15011679/v1 (opens in new tab)

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Study at a glance

AI-extracted from the abstract
Characteristics Randomized controlled trial Double-blind
Sample size 20
Population Healthy adults with no past 30-day cannabinoid use
Intervention Placebo
Dose 30 mg, 60 mg delta-8 THC; 30 mg delta-9 THC
Duration Assessments at baseline and over 8 hours post-administration
Measures Global Drive Score (GDS)
Topics Cannabis
Key findings Delta-8 THC and delta-9 THC significantly impaired simulated driving relative to placebo, with decrements in coherence during car following and poor lane positioning. 30 mg delta-9 THC produced the greatest impairment but was not significantly different from 60 mg delta-8 THC. Delta-8 THC effects were qualitatively similar to delta-9 THC at approximately half the potency on most outcomes.

Abstract

∆8-Tetrahydrocannabinol (∆8-THC), a structural isomer of ∆9-THC, is a growing drug of concern often marketed as a “milder” alternative to ∆9-THC. No controlled studies have evaluated doses above 40mg ∆8-THC or examined its acute effects on driving. Healthy adults (N=20) with no past 30-day cannabinoid use completed four double-blind, outpatient drug administration sessions, self-administering oral doses of ∆8-THC (30mg, 60mg), ∆9-THC (30mg), or placebo. Simulated driving was assessed at baseline and at 2 hrs post-dosing. The primary outcome Global Drive Score (GDS), a composite measure of driving performance, and secondary driving outcomes were examined. Subjective drug effects, cognitive and psychomotor performance, vital signs, and whole blood cannabinoid concentrations were assessed at baseline and over 8 hrs post-administration. ∆8-THC and ∆9-THC significantly impaired driving relative to placebo with decrements in coherence during the car following and poor maintenance of lane positioning. 30mg ∆9-THC produced the greatest impairment but was not significantly different from 60mg ∆8-THC. Subjective effects generally peaked between 2-3 hrs post-dosing. ∆8-THC produced effects that were qualitatively similar to ∆9-THC, but at approximately half the potency on most outcomes. ∆8-THC significantly impaired driving performance, notable given its widespread availability and common perception as less psychoactive than ∆9-THC. At the same dose, ∆8-THC produced similar types of impairment and physiological effects, but at a lower magnitude than ∆9-THC, likely driven, in part, by higher concentrations of the psychoactive 11-OH metabolite following ∆9-THC relative to ∆8-THC administration. These findings can inform ∆8-THC policy and public safety initiatives that deter drugged-driving.

Comparable studies

Other randomized controlled trials on cannabis, most cited first.

Study Year Design Participants
Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment Healthy participants 2012 Randomized controlled trial n = 48
Distinct Effects of Δ9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing Healthy, English-native, right-handed men who had used cannabis 15 times or less in... 2009 Double-blind, randomized, placebo-controlled crossover trial n = 15
Acute Effects of a Single, Oral dose of d9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) Administration in Healthy Volunteers Healthy male subjects 2012 Randomized controlled trial n = 16
Modulation of Mediotemporal and Ventrostriatal Function in Humans by Δ9-Tetrahydrocannabinol Healthy, native English-speaking, right-handed men of white race/ethnicity who had used... 2009 Randomized controlled trial n = 15
Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition Healthy volunteers with a history of light cannabis use 2019 Randomized, double-blind, within-subjects crossover n = 14

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