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Canadian Journal of Public Health

, Volume 98, Issue 1, pp 6–11 | Cite as

The Impact of Cannabis on Driving

  • Michel Bédard
  • Sacha Dubois
  • Bruce Weaver
Article

Abstract

Background

Cannabis is known to have detrimental effects on human performance and may also affect driving adversely. However, studies designed to examine this issue have provided equivocal findings. We set up this study to further determine the effect of cannabis on driving.

Methods

We used a cross-sectional, case-control design with drivers aged 20–49 who were involved in a fatal crash in the United States from 1993 to 2003; drivers were included if they had been tested for the presence of cannabis and had a confirmed blood alcohol concentration of zero. Cases were drivers who had at least one potentially unsafe driving action recorded in relation to the crash (e.g., speeding); controls were drivers who had no such driving action recorded. We calculated the crude and adjusted odds ratios (ORs) of any potentially unsafe driving action in drivers who tested positive for cannabis but negative for alcohol consumption. In computing for the adjusted OR, we controlled for age, sex, and prior driving record.

Results

Five percent of drivers tested positive for cannabis. The crude OR of a potentially unsafe action was 1.39 (99% CI = 1.21–1.59) for drivers who tested positive for cannabis. Even after controlling for age, sex, and prior driving record, the presence of cannabis remained associated with a higher risk of a potentially unsafe driving action (1.29, 99% CI = 1.11–1.50).

Conclusion

Cannabis had a negative effect on driving, as would be predicted from human performance studies. This finding supports the need for interventions to decrease the prevalence of driving under the influence of cannabis, and indicates that further studies should be conducted to investigate the dose-response relationship between cannabis and safe driving.

MeSH terms

Cannabis accidents traffic alcohol drinking automobiles 

Résumé

Contexte

On sait que le cannabis a des effets nuisibles sur les performances humaines et qu’il pourrait aussi nuire à la conduite d’un véhicule. Cependant, les études sur le sujet donnent des résultats peu probants. Dans notre étude, nous avons cherché à approfondir la question des effets du cannabis sur la conduite.

Méthode

Nous avons mené une étude cas-témoin transversale auprès de conducteurs de 20 à 49 ans impliqués dans des accidents mortels aux États-Unis entre 1993 et 2003; nous n’avons inclus que les conducteurs ayant fait l’objet d’un test de dépistage du cannabis, mais dont le taux d’alcoolémie était nul. Les cas étaient des conducteurs ayant commis au moins un acte de conduite potentiellement dangereux dans le contexte de l’accident (p. ex., dépasser la limite de vitesse); les témoins étaient des conducteurs dont la conduite n’avait pas été dangereuse lors de l’accident. Nous avons calculé les rapports de cotes (RC) bruts et ajustés de tout acte de conduite potentiellement dangereux chez les conducteurs déclarés positifs pour le cannabis, mais négatifs pour la consommation d’alcool. Dans notre calcul des RC ajustés, nous avons tenu compte de l’âge, du sexe et du dossier de conduite antérieur.

Résultats

Cinq p. cent des conducteurs avaient été déclarés positifs pour le cannabis. Le RC brut d’un acte de conduite potentiellement dangereux était de 1,39 (IC de 99 % = 1,21-1,59) pour les conducteurs déclarés positifs. Même compte tenu de l’âge, du sexe et du dossier de conduite antérieur, la présence de cannabis demeurait associée à un risque plus élevé d’avoir eu une conduite potentiellement dangereuse (1,29, IC de 99 % = 1,11-1,50).

Conclusion

Le cannabis a eu un effet néfaste sur la conduite, comme on pouvait le prédire d’après les études de performance humaine. Cette constatation confirme la nécessité d’intervenir pour réduire la prévalence de la conduite avec facultés affaiblies par le cannabis et montre qu’il faudrait pousser la recherche sur la relation dose-réponse entre le cannabis et la prudence au volant.

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References

  1. 1.
    Ogborne AC, Smart, RG. Cannabis users in the general Canadian population. Subst Use Misuse 2000;35:301–11.CrossRefGoogle Scholar
  2. 2.
    Compton W, Grant B, Colliver J, Glantz M, Stinson F. Prevalence of marijuana use disorders in the United States. JAMA 2004;291:2114–21.CrossRefGoogle Scholar
  3. 3.
    Adlaf EM, Gliksman L, Demers A, Newton- Taylor B. Illicit drug use among Canadian university undergraduates. Can J Nurs Res 2003;35:24–43.PubMedGoogle Scholar
  4. 4.
    Gledhill-Hoyt J, Lee H, Strote J, Wechsler H. Increased use of marijuana and other illicit drugs at US colleges in the 1990s: Results of three national surveys. Addiction 2000;95:1655–67.CrossRefGoogle Scholar
  5. 5.
    Strang J, Witton J, Hall W. Improving the quality of the cannabis debate: Defining the different domains. BMJ 2000;320:108–10.CrossRefGoogle Scholar
  6. 6.
    Ashton H. Pharmacology and effects of cannabis: A brief review. Br J Psychiatry 2001;178:101–6.CrossRefGoogle Scholar
  7. 7.
    Kurzthaler I, Hummer M, Miller C, Sperner- Unterweger B, Gunther V, Wechdorn H, et al. Effect of cannabis use on cognitive functions and driving ability. J Clin Psychiatry 1999;60:395–99.CrossRefGoogle Scholar
  8. 8.
    Rizzo M, Lamers CTJ, Sauer CG, Ramaekers JG, Bechara A, Andersen, GJ. Impaired perception of self-motion (heading) in abstinent ecstacy and marijuana users. Psychopharmacology 2005;179:559–66.CrossRefGoogle Scholar
  9. 9.
    Ramaekers JG, Robbe H, O’Hanlon, JF. Marijuana, alcohol and actual driving performance. Human Psychopharmacology Clinical and Experimental 2000;15:551–58.CrossRefGoogle Scholar
  10. 10.
    Lamers CTJ, Ramaekers, JG. Visual search and urban city driving under the influence of marijuana and alcohol. Human Psychopharmacology Clinical and Experimental 2001;16:393–401.CrossRefGoogle Scholar
  11. 11.
    Macdonald S, Mann RE, Chipman M, Anglin- Bodrug K. Collisions and traffic violations of alcohol, cannabis and cocaine abuse clients before and after treatment. Accid Anal Prev 2004;36:795–800.CrossRefGoogle Scholar
  12. 12.
    Chipman ML, Macdonald S, Mann, RE. Being “at fault” in traffic crashes: Does alcohol, cannabis, cocaine, or polydrug abuse make a difference? Inj Prev 2003;9:343–48.CrossRefGoogle Scholar
  13. 13.
    Fergusson DM, Horwood, LJ. Cannabis use and traffic accidents in a birth cohort of young adults. Accid Anal Prev 2001;33:703–11.CrossRefGoogle Scholar
  14. 14.
    Macdonald S, Anglin-Bodrug K, Mann RE, Erickson P, Hathaway A, Chipman M, et al. Injury risk associated with cannabis and cocaine use. Drug Alcohol Depend 2003;72:99–115.CrossRefGoogle Scholar
  15. 15.
    Kelly E, Darke S, Ross J. A review of drug use and driving: Epidemiology, impairment, risk factors and risk perceptions. Drug Alcohol Rev 2004;23:319–44.CrossRefGoogle Scholar
  16. 16.
    Ramaekers JG, Berghaus G, van Laar M, Drummer, OH. Dose-related risk of motor vehicle crashes after cannabis use. Drug Alcohol Depend 2004;73:109–19.CrossRefGoogle Scholar
  17. 17.
    Walsh JM, DeGier JJ, Christopherson AS, Verstraete, AG. Drugs and driving. Traffic Inj Prev 2004;5:241–53.CrossRefGoogle Scholar
  18. 18.
    Drummer O, Gerostamoulos J, Batziris H, Chu M, Caplehorn J, Robertson M, et al. The involvement of drugs in drivers of motor vehicles killed in Australian road traffic crashes. Accid Anal Prev 2004;36:239–48.CrossRefGoogle Scholar
  19. 19.
    Fife D. Matching fatal accident reporting system cases with National Center for Health Statistics motor vehicle deaths. Accid Anal Prev 1989;21:79–83.CrossRefGoogle Scholar
  20. 20.
    Dischinger PC, Ho SM, Kufera JA. Medical conditions and car crashes. 44th Annual Proceedings: Association for the Advancement of Automotive Medicine 2000;44:335–46.Google Scholar
  21. 21.
    Perneger T, Smith GS. The driver’s role in fatal two-car crashes: A paired “case control” study. Am J Epidemiol 1991;134:1138–45.CrossRefGoogle Scholar
  22. 22.
    Bédard M, Myers J. The influence of passengers on older drivers involved in fatal crashes. Exp Aging Res 2004;30:205–15..CrossRefGoogle Scholar
  23. 23.
    Pruesser DF, Williams AF, Ferguson SA, Ulmer RG, Weinstein HB. Fatal crash risk for older drivers at intersections. Accid Anal Prev 1998;30:151–59.CrossRefGoogle Scholar
  24. 24.
    O’Kane CJ, Tutt DC, Bauer LA. Cannabis and driving: A new perspective. Emerg Med 2002;14:296–303.CrossRefGoogle Scholar
  25. 25.
    Walsh G, Mann RE. On the high road: Driving under the influence of cannabis in Ontario. Can J Public Health 1999;90(4):260–63.PubMedGoogle Scholar
  26. 26.
    Adlaf EM, Mann RE, Paglia A. Drinking, cannabis use and driving among Ontario students. CMAJ 2003;168:564–66.Google Scholar
  27. 27.
    Brookoff D, Cook CS, Williams C, Mann CS. Testing reckless drivers for cocaine and marijuana. N Engl J Med 1994;331:518–22.CrossRefGoogle Scholar
  28. 28.
    Albery IP, Strang J, Gossop M, Griffiths P. Illicit drugs and driving: Prevalence, beliefs and accident involvement among a cohort of current outof-treatment drug users. Drug Alcohol Depend 2000;58:197–204.CrossRefGoogle Scholar
  29. 29.
    Terry P, Wright KA. Self-reported driving behaviour and attitudes towards driving under the influence of cannabis among three different user groups in England. Addict Behav 2005;30:619–26.CrossRefGoogle Scholar
  30. 30.
    Davey JD, Davey T, Obst P. Drug and drink driving by university students: An exploration of the influence of attitudes. Traffic Inj Prev 2005;6:44–52.CrossRefGoogle Scholar
  31. 31.
    Begg DJ, Langley JD, Stephenson S. Identifying factors that predict persistent driving after drinking, unsafe driving after drinking, and driving after using cannabis among young adults. Accid Anal Prev 2003;35:669–75.CrossRefGoogle Scholar
  32. 32.
    Consensus Development Panel. Drug concentrations and driving impairment. JAMA 1985;254:2618–21.CrossRefGoogle Scholar
  33. 33.
    Toennes SW, Steinmeyer S, Maurer HJ, Moeller MR, Kauert GF. Screening for drugs of abuse in oral fluid”correlation of analysis results with serum in forensic cases. J Anal Toxicol 2005;29:22–27.CrossRefGoogle Scholar
  34. 34.
    Williamson EM, Evans FJ. Cannabinoids in clinical practice. Drugs 2000;60:1303–14.CrossRefGoogle Scholar
  35. 35.
    Solowij N, Stephens RS, Roffman RA, Babor T, Kadden R, Miller M, et al. Cognitive functioning of long-term heavy cannabis users seeking treatment. JAMA 2002;287:1123–31.CrossRefGoogle Scholar
  36. 36.
    Movig KLL, Mathijssen MPM, Nagel PHA, van Egmond T, de Gier JJ, Leufkens HGM, et al. Psychoactive substance use and the risk of motor vehicle accidents. Accid Anal Prev 2004;36:636.CrossRefGoogle Scholar
  37. 37.
    Lowenstein SR, Koziol-McLain J. Drugs and traffic crash responsibility: A study of injured motorists in Colorado. J Trauma 2001;50:313–20.CrossRefGoogle Scholar

Copyright information

© The Canadian Public Health Association 2007

Authors and Affiliations

  1. 1.Public Health ProgramLakehead UniversityThunder BayCanada
  2. 2.Division of Human SciencesNorthern Ontario School of MedicineThunder BayCanada
  3. 3.St. Joseph’s Care GroupThunder BayCanada

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