title: The effects of cannabis and alcohol on simulated driving: Influences of dose and experience.
abstract: BACKGROUND
  Cannabis and alcohol are the most popular drugs amongst recreational users, and most prevalent in injured and deceased drivers. Clarification of the interactive effects of these drugs upon driving behaviour is critical for reducing drug-related road deaths.
  
  
  OBJECTIVE
  The current study had two objectives, to examine the effects of cannabis and alcohol on driving performance, and identify if any differences between the effects of cannabis and alcohol on driving performance exist between regular cannabis users and non-regular cannabis users.
  
  
  METHODS
  The project involved 80 participants (49 male, 31 female) who were abstinent recreational users of alcohol and marijuana. They participated in six experimental sessions that involved the consumption of cannabis cigarettes containing no THC, 1.8% THC or 3% THC together with the consumption of alcohol to obtain either 0% BAC, 0.03% BAC or 0.05% BAC. The six sessions were double-blind, counter-balanced, placebo-controlled and medically supervised. Forty participants were allocated to the cannabis with low alcohol (0.03% BAC) group, and 40 participants were allocated to the cannabis with high alcohol (0.05% BAC) group. Driving simulator performance was assessed at 20min post-drug administration and blood samples were taken before and after driving.
  
  
  RESULTS
  Driving simulator performance was more impaired in the THC and alcohol combined conditions. Consistent with past research, the level of THC detected in blood is higher when THC is consumed with alcohol, than when cannabis is consumed alone, and regular cannabis users returned higher levels of THC in plasma than non-regular users. Generally, regular cannabis users displayed more driving errors than non-regular cannabis users.
authors.affiliation: Centre for Human Psychopharmacology, Swinburne University of Technology, Australia. cstough@swin.edu.au
authors.forename: Luke A
authors.initials: LA
authors.lastname: Downey
authors.forename: Rebecca
authors.initials: R
authors.lastname: King
authors.forename: Katherine
authors.initials: K
authors.lastname: Papafotiou
authors.forename: Phillip
authors.initials: P
authors.lastname: Swann
authors.forename: Edward
authors.initials: E
authors.lastname: Ogden
authors.forename: Martin
authors.initials: M
authors.lastname: Boorman
authors.forename: Con
authors.initials: C
authors.lastname: Stough
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects*; D000704:Analysis of Variance; D001334:Automobile Driving; D002188:Cannabis / Q000009:adverse effects*; D003071:Cognition / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects*; D012307:Risk Factors; D012309:Risk-Taking