title: Cannabinoid concentrations detected in fatal road traffic collision victims compared with a population of other postmortem cases.
abstract: BACKGROUND
  Acute cannabis consumption nearly doubles the risk of motor vehicle collision resulting in injury or death. Limited data have been published regarding the concentrations of cannabinoids associated with fatal road traffic collisions (RTCs), and these have not previously been compared to a population of other postmortem cases.
  
  
  METHODS
  We conducted analysis for cannabinoids [Δ(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC, 11-nor-THC-9-carboxylic acid, cannabidiol, and cannabinol], drugs, and alcohol on consecutive fatal RTC cases (100) and non-RTC cases (114) from coroners' jurisdictions in London and southeast England and compared the data.
  
  
  RESULTS
  The incidence of cannabinoids detected in non-RTC and RTC cases was similar (25% vs 21%, P = 0.44), but THC was detected more frequently (90% vs 59%, P = 0.01) and at significantly higher concentrations in the cannabinoid-positive RTC cases than the non-RTC cases (P = 0.01). The distribution of non-RTC and RTC cases over 4 categories of THC concentration was significantly different (P = 0.004). There was no significant difference in the concentrations of other cannabinoids detected between the 2 groups. Cannabinoids were detected in more fatal RTC cases (21) than alcohol >80 mg/dL (17). Detection of other drugs was low compared to cannabis and alcohol.
  
  
  CONCLUSIONS
  These first data on the concentrations of cannabinoids in the postmortem blood of fatal RTC victims compared with a population of other routine coroners' cases highlight the importance of specifically measuring THC concentrations in the blood to aid interpretation of postmortem cases where cannabis may be implicated.
authors.affiliation: Toxicology Unit, Imperial College London, London, UK, W6 8RP; r.andrews@imperial.ac.uk.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Andrews
authors.affiliation: Section of Investigative Medicine, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Murphy
authors.affiliation: Toxicology Unit, Imperial College London, London, UK, W6 8RP;
authors.forename: Limon
authors.initials: L
authors.lastname: Nahar
authors.affiliation: Toxicology Unit, Imperial College London, London, UK, W6 8RP;
authors.forename: Sue
authors.initials: S
authors.lastname: Paterson
mesh_terms: D000063:Accidents, Traffic; D000293:Adolescent; D000328:Adult; D000368:Aged; D002185:Cannabidiol / Q000097:blood; D002186:Cannabinoids / Q000097:blood*; D002187:Cannabinol / Q000097:blood; D002648:Child; D013759:Dronabinol / Q000097:blood; D004739:England; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008385:Marijuana Smoking; D008875:Middle Aged; D015813:Substance Abuse Detection; D055815:Young Adult
chemical_list: D002186:Cannabinoids; D002185:Cannabidiol; D013759:Dronabinol; D002187:Cannabinol