title: Comparing treatment effects of oral THC on simulated and on-the-road driving performance: testing the validity of driving simulator drug research.
abstract: BACKGROUND
  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 ∆(9)-tetrahydrocannabinol (THC), i.e. dronabinol, on simulator and on-the-road driving performance in equally demanding driving tasks.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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 inter-individual 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.
authors.affiliation: Faculty of Behavioural and Social Sciences, University of Groningen, Grote Kruisstraat 2/1, 9712TS, Groningen, The Netherlands, j.l.veldstra@rug.nl.
authors.forename: J L
authors.initials: JL
authors.lastname: Veldstra
authors.forename: W M
authors.initials: WM
authors.lastname: Bosker
authors.forename: D
authors.initials: D
authors.lastname: de Waard
authors.forename: J G
authors.initials: JG
authors.lastname: Ramaekers
authors.forename: K A
authors.initials: KA
authors.lastname: Brookhuis
mesh_terms: D000328:Adult; D001334:Automobile Driving; D063386:Cannabinoid Receptor Agonists / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D013759:Dronabinol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects*; D014584:User-Computer Interface; D055815:Young Adult
chemical_list: D063386:Cannabinoid Receptor Agonists; D013759:Dronabinol