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Cannabis smoking impairs driving performance on the simulator and real driving: a randomized, double‐blind, placebo‐controlled, crossover trial

Joëlle Micallef, Julien Dupouey, Élisabeth Jouve, Romain Truillet, Bruno Lacarelle, Jacques Taillard, Agnès Daurat, Colas Authié, Olivier Blin, Olivier Rascol, Pierre Philip, Daniel Mestre

Fundamental and Clinical Pharmacology May 12, 2018 DOI: 10.1111/fcp.12382 (opens in new tab)

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Study at a glance

AI-extracted from the abstract
Characteristics Double-blind, placebo-controlled, two successive two-way crossover experimental study Randomized Qualitative Peer reviewed
Population Healthy occasional users of THC, aged 25-35 years, with consistent driving experience
Intervention Cannabis (THC)
Dose 20 mg of THC
Measures inappropriate line crossings (ILC), standard deviation of the vehicle's lateral position
Topics Cannabis
Citations 59
Key findings THC (20 mg) significantly impaired driving stability and increased drowsiness and tiredness in both simulated and real driving. Inappropriate line crossings were significantly more numerous in the simulator than in real driving, leading the authors to conclude the simulator was more sensitive for detecting THC-induced effects and serves as a good qualitative predictor of driving safety after drug intake.

Abstract

Driving experiments in real conditions are considered as a 'gold standard' to evaluate the effects of drugs on driving performance. Several constraints are difficult to manage in these conditions, so driving simulation appears as the best alternative. A preliminary comparison is crucial before being able to use driving simulation as a valid evaluation method. The aim of this study was to design a driving simulation method for assessing drug effects on driving. We used cannabis (THC) as a positive control and assessed whether THC affects driving performance in simulation conditions and whether these effects are consistent with performance in real driving conditions. A double-blind, placebo-controlled, two successive two-way crossover design was performed using cigarettes containing 20 mg of THC. Healthy occasional users of THC, aged 25-35 years, who had a consistent driving experience were included. The first two sessions were realized in simulation conditions, and the last two sessions were in real driving conditions. Driving performance was estimated through inappropriate line crossings (ILC) and the standard deviation of the vehicle's lateral position. Participants felt significantly drowsier and more tired after THC, whatever the driving condition. Driving stability was significantly impaired after THC, both in simulated and real driving conditions. We also found that ILC were significantly more numerous in driving simulation conditions, as compared to real driving. In conclusion, the driving simulator was proven to be more sensitive for demonstrating THC-induced effects on driving performances. Driving simulation appears to be a good qualitative predictor of driving safety after drug intake.

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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