Comparing treatment effects of oral THC on simulated and on-the-road driving performance: testing the validity of driving simulator drug research

J.L. Veldstra, W.M. Bosker, D. de Waard, J.G. Ramaekers, K.A. Brookhuis

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Rationale The driving simulator provides a safe and controlled
environment for testing driving behaviour efficiently. The question
is whether it is sensitive to detect drug-induced effects.
Objective The primary aim of the current study was to investigate
the sensitivity of the driving simulator for detecting drug
effects. As a case in point, we investigated the dose-related
effects of oral Δ9
-tetrahydrocannabinol (THC), i.e.
dronabinol, on simulator and on-the-road driving performance
in equally demanding driving tasks.
Method Twenty-four experienced driver participants were treated
with dronabinol (Marinol®; 10 and 20 mg) and placebo.
Dose-related effects of the drug on the ability to keep a vehicle
in lane (weaving) and to follow the speed changes of a lead car
(car following) were compared within subjects for on-the-road
versus in-simulator driving. Additionally, the outcomes of equivalence
testing to alcohol-induced effects were investigated.
Results Treatment effects found on weaving when driving in the
simulator were comparable to treatment effects found when driving
on the road. The effect after 10 mg dronabinol was however
less strong in the simulator than on the road and inter-individual
variance seemed higher in the simulator. There was, however, a
differential treatment effect of dronabinol on reactions to speed
changes of a lead car (car following) when driving on the road
versus when driving in the simulator.
Conclusion The driving simulator was proven to be sensitive
for demonstrating dronabinol-induced effects particularly at
higher doses. Treatment effects of dronabinol on weaving
were comparable with driving on the road but interindividual
variability seemed higher in the simulator than on
the road which may have potential effects on the clinical inferences
made from simulator driving. Car following on the
road and in the simulator were, however, not comparable.
Original languageEnglish
Pages (from-to)2911-2919
Issue number16
Publication statusPublished - 10-May-2015


  • Driving simulator . Driving performance . Dronabinol . Equivalence testing . Predictive validity . THC

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