Short communicationSelf-reported driving behaviour and attitudes towards driving under the influence of cannabis among three different user groups in England
Introduction
Epidemiological and experimental data support the notion that cannabis use is detrimental to car-handling skills. For example, there are many reports that, after alcohol, cannabis is the most frequently detected psychoactive drug in casualties of road traffic accidents (e.g., Cimbura et al., 1986, Mason & McBay, 1984, Mercer & Jeffrey, 1995), and in drivers arrested for erratic driving (e.g., Gjerde & Kinn, 1991). Furthermore, laboratory-based driving simulator tests have supported the view that cannabis impairs behaviours relevant to driving (e.g., Rafaelson et al., 1973, Robbe, 1994). However, there is still a dearth of information concerning actual driving habits under the influence of cannabis, and the factors that influence the decision to drive (or act as a deterrent). Robbe (1994) reported that cannabis users are aware that their driving is impaired by the drug, but are still willing to drive after using it. In a recent survey in Scotland (Neale, McKeganey, Hay, & Oliver, 2001), drug users reported driving more frequently after using cannabis than after any other illicit drug, but they perceived their driving to be less dangerous following cannabis use. The present two-part study first surveyed the attitudes and behaviour of a sample of regular cannabis users (RCUs) from the West Midlands towards driving after using cannabis. Driving habits after drinking alcohol, and attitudes towards drink-driving, were assessed for comparative purposes. A sample of university students was also surveyed, since cannabis use is widespread amongst university students (e.g., Webb, Ashton, Kelly, & Kamali, 1996), and they represent a group from which long-term, regular users are likely to emerge. The second phase of the study used structured interviews of a separate sample of regular cannabis users to provide a more detailed characterization of the self-reported physical and psychological effects of cannabis and alcohol on driving performance.
Section snippets
Methods
A questionnaire addressing drug use and driving habits was screened using three daily cannabis-using volunteers, and revised. A “snowball” method of recruitment was adopted, whereby self-declared regular cannabis users (RCUs; cannabis use>monthly) distributed questionnaires to other RCUs known to them, and they in turn passed on questionnaires to others. Eighty questionnaires were distributed within the West Midlands (Birmingham, Coventry, Wolverhampton), of which 68 (85%) were returned via the
Participant characteristics, patterns of drug use and driving behaviour
As might be expected, the RCUs were generally older than the students, and they used cannabis more frequently (Table 1). Other illicit drug use was lower among the students, but for both groups, the rank ordering of prevalence was similar (use of amphetamines>MDMA>LSD>cocaine). Levels of alcohol consumption were also similar between groups (Table 1). Nearly all of the RCUs (96.8%) were drivers, and a high proportion of these (91.8%) would drive at least weekly. Fewer students drove (87%), and
Discussion
Perhaps the most important questionnaire finding was that the prevalence of driving under the influence of cannabis is disturbingly high, not only among the RCUs who were drivers (82%), but also among less experienced student users (40%). The willingness of so many respondents to drive after cannabis is consistent with the finding that a majority of each sample considered their driving to be (at most) only slightly impaired by cannabis. Although the sample of regular users was largely
Acknowledgments
Funding for the study was kindly provided by the Alcohol Education and Research Council and the School of Psychology, University of Birmingham. An incomplete subset of some of these data was used for comparative purposes in Appendix A of TRL Report 477 for the Department of the Environment, Transport and the Regions.
References (9)
- et al.
Impairment in drivers due to cannabis in combination with other drugs
Forensic Science International
(1991) - et al.
Alcohol, drugs and impairment in fatal traffic accidents in British-Columbia
Accident Analysis and Prevention
(1995) - et al.
Alcohol and drug use in UK university students
The Lancet
(1996) - et al.
Incidence and toxicological aspects of cannabis and ethanol detected in 1394 fatally injured drivers and pedestrians in Ontario (1982–1984)
Journal of Forensic Sciences
(1986)
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