Cannabis effects on driving lateral control with and without alcohol

Rebecca L Hartman; Timothy L Brown; Gary Milavetz; Andrew Spurgin; Russell S Pierce; David A Gorelick; Gary Gaffney; Marilyn A Huestis

doi:10.1016/j.drugalcdep.2015.06.015

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Cannabis effects on driving lateral control with and without alcohol

Journal article

Peer reviewed

Cannabis effects on driving lateral control with and without alcohol

Rebecca L Hartman, Timothy L Brown, Gary Milavetz, Andrew Spurgin, Russell S Pierce, David A Gorelick, Gary Gaffney and Marilyn A Huestis

Drug and alcohol dependence, Vol.154, pp.25-37

09/01/2015

DOI: 10.1016/j.drugalcdep.2015.06.015

PMCID: PMC4536116

PMID: 26144593

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http://doi.org/10.1016/j.drugalcdep.2015.06.015View

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Abstract

•We model cannabis’ effects on driving lateral control via sophisticated simulator.•Models are based on blood THC and breath alcohol concentrations during driving.•THC increased standard deviation of lateral position (SDLP); 0.26cm per μg/L THC.•Alcohol increased SDLP 0.42cm per 0.01g/210L; additional lateral control measures.•During-drive 7–10μg/L blood THC produced similar SDLP to 0.05g/210L breath alcohol.•Concurrent alcohol and cannabis produced additive rather than synergistic effects. Effects of cannabis, the most commonly encountered non-alcohol drug in driving under the influence cases, are heavily debated. We aim to determine how blood Δ9-tetrahydrocannabinol (THC) concentrations relate to driving impairment, with and without alcohol. Current occasional (≥1×/last 3 months, ≤3days/week) cannabis smokers drank placebo or low-dose alcohol, and inhaled 500mg placebo, low (2.9%)-THC, or high (6.7%)-THC vaporized cannabis over 10min ad libitum in separate sessions (within-subject design, 6 conditions). Participants drove (National Advanced Driving Simulator, University of Iowa) simulated drives (∼0.8h duration). Blood, oral fluid (OF), and breath alcohol samples were collected before (0.17h, 0.42h) and after (1.4h, 2.3h) driving that occurred 0.5–1.3h after inhalation. We evaluated standard deviations of lateral position (lane weave, SDLP) and steering angle, lane departures/min, and maximum lateral acceleration. In N=18 completers (13 men, ages 21–37years), cannabis and alcohol increased SDLP. Blood THC concentrations of 8.2 and 13.1μg/L during driving increased SDLP similar to 0.05 and 0.08g/210L breath alcohol concentrations, the most common legal alcohol limits. Cannabis-alcohol SDLP effects were additive rather than synergistic, with 5μg/L THC+0.05g/210L alcohol showing similar SDLP to 0.08g/210L alcohol alone. Only alcohol increased lateral acceleration and the less-sensitive lane departures/min parameters. OF effectively documented cannabis exposure, although with greater THC concentration variability than paired blood samples. SDLP was a sensitive cannabis-related lateral control impairment measure. During drive blood THC ≥8.2μg/L increased SDLP similar to notably-impairing alcohol concentrations. Despite OF's screening value, OF variability poses challenges in concentration-based effects interpretation.

Driving

Alcohol

Oral fluid

Cannabis

Lateral control

THC

Details

Title: Subtitle: Cannabis effects on driving lateral control with and without alcohol
Creators: Rebecca L Hartman - Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, 251 Bayview Boulevard Ste 200 Rm 05A721, Baltimore, MD, USA
Timothy L Brown - National Advanced Driving Simulator, University of Iowa, 2401 Oakdale Boulevard, Iowa City, IA, USA
Gary Milavetz - College of Pharmacy, University of Iowa, Iowa City, IA, USA
Andrew Spurgin - College of Pharmacy, University of Iowa, Iowa City, IA, USA
Russell S Pierce - Variable Solutions, USA
David A Gorelick - Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, 251 Bayview Boulevard Ste 200 Rm 05A721, Baltimore, MD, USA
Gary Gaffney - Carver College of Medicine, University of Iowa, Iowa City, IA, USA
Marilyn A Huestis - Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, 251 Bayview Boulevard Ste 200 Rm 05A721, Baltimore, MD, USA
Resource Type: Journal article
Publication Details: Drug and alcohol dependence, Vol.154, pp.25-37
DOI: 10.1016/j.drugalcdep.2015.06.015
PMID: 26144593
PMCID: PMC4536116
NLM abbreviation: Drug Alcohol Depend
ISSN: 0376-8716
eISSN: 1879-0046
Publisher: Elsevier Ireland Ltd
Language: English
Date published: 09/01/2015
Academic Unit: Pharmacy; Psychiatry; Industrial and Systems Engineering; Pharmacy Practice and Science; Injury Prevention Research Center
Record Identifier: 9984065325202771

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