Substance Use by Canadian Youth - A National Survey of Canadians' Use of Alcohol and Other Drugs - Canadian Addiction Survey (CAS)

Chapter 7: Driving and Substance Use

Highlights

• 32.5% of youth reported having been a passenger with someone under the influence of alcohol, and 39.6% reported doing so with someone under the influence of cannabis in the past 12 months.
• 20.9% of youth reported driving under the influence of alcohol during the past 12 months. The mean number of times youth reported driving while intoxicated with alcohol was 1.6 times (taking those who reported "never" into account).
• 39.8% of youth reported driving under the influence of cannabis during the past 12 months. The mean number of times, including "never", youth reported doing so over the past year was 10 times.

Introduction

While the focus of previous chapters has been on the prevalence of substance use and harms associated with such use, this chapter examines a specific risk behaviour: driving while under the influence of alcohol or cannabis or being a passenger with someone who has been.

Driving while impaired because of cannabis or alcohol, or being a passenger with someone who has done so, was examined using a variety of questions. To identify the proportion of respondents who had been a passenger with an intoxicated driver, respondents were asked, "In the past 12 months, have you been a passenger in a car or other vehicle driven by someone who had two or more drinks of alcohol in the previous hour?" and "In the past 12 months, have you been a passenger in a car or other vehicle driven by someone who had been using marijuana/hash in the previous 2 hours?" To examine the proportion of respondents who drove while under the influence, respondents who drank alcohol in the past 12 months, and responded yes to driving in the past 12 months, respondents were asked, "During the past 12 months, how many times, if any, have you driven a motor vehicle after having two or more drinks in the previous hour?" Similarly, those who had used cannabis in the past 12 months, in addition to responding "yes" to having driven in the past 12 months, were asked, "During the past 12 months, how many times, if any, have you driven a motor vehicle within 2 hours of using cannabis or marijuana/hash?"

Results

Proportion Who Had Been Passenger

A higher rate of youth than adults reported in the past 12 months having been a passenger with someone who had been drinking (32.5% versus 14.9%) (Table 7.1). In addition, 39.6% of youth reported being a passenger with someone who had been using cannabis, also higher than the rate reported by adults (7.6%).

The rate at which respondents reported being a passenger with someone who had consumed alcohol decreases steadily from the age of 15 to 24, to 25 to 44, and 45 to 64 (32.5%, 20.1%, 13.3%, respectively) as does those who reported being a passenger with someone who had consumed cannabis (39.6%, 12.8%, 5.4%, respectively) (Table 7.2).

Proportion of Youth Who Have Driven While Under the Influence of a Substance

A higher proportion of respondents, both adults and youth, reported driving after using cannabis or hashish than after consuming alcohol over the past year, and youth were more likely than adults to report doing so (39.8% versus 20.9%) (Table 7.1).

In addition, the proportion of youth who reported driving after consuming alcohol is much higher than that reported by adults (20.9% versus 13.5%). The mean number of times that youth reported driving while under the influence of alcohol during the past 12 months, including those who never did, was 1.6 times (N=401), compared with an average of 1.2 times for adults.

A significant difference was not apparent between the proportion of youth and adults who reported driving after consuming cannabis (39.8% versus 29.9%). The number of times that youth reported driving while under the influence of cannabis in the past year was much higher than that reported for alcohol. The mean for youth, including those who responded never, was approximately 10 times (N=160) over the past year, compared with an average of 7 times for adults.

One question is whether this finding of a higher rate of driving while under the influence of cannabis than alcohol is indeed due to a higher actual rate of this behaviour, or a difference in the reporting of one behaviour over the other. It is interesting that youth seem more likely to report driving after using cannabis than after drinking.

Table 7.2 examines the proportion of respondents who reported driving after consuming alcohol in the previous hour or cannabis in the previous 2 hours as a function of age. Youth were more likely than those 25 to 44 years of age to report driving while under the influence of alcohol. There were no age differences apparent in terms of reported driving while under the influence of cannabis.

Characteristics of Youth Who Were a Passenger with Someone Under the Influence

Since the questions dealing with driving under the influence were asked only to respondents in panel C, who had both driven as well as used alcohol or marijuana in the previous 12 months, the sample size for these questions was reduced. As a result of these small sample sizes, it was not possible to examine the demographic characteristics of youth that are associated with driving while under the influence of alcohol or cannabis.

The only demographic characteristic that was associated with being a passenger with someone who had drunk in the past hour was income adequacy (Table 7.3). When comparing each category to those in the lowest income adequacy group, no differences were apparent within the income categories. It appears that youth in the highest income adequacy group were the most likely to have been a passenger with someone who had consumed alcohol in the previous hour; more precisely, they were more likely than those in the middle and not stated groups. Further research with increased sample sizes is needed to examine this finding further.

Table 7.4 presents the proportion of youth who reported being a passenger with someone who had used cannabis 2 hours previously. Males were more likely than females (47.4% versus 30.5%), and youth aged 18 to 19 were more likely than those aged 15 to 17 to report having been a passenger with someone who had used cannabis (53.4% versus 28.8%).

Summary and Discussion

A large proportion of youth have been a passenger with someone who had consumed alcohol or cannabis prior to driving (32.5% and 39.6%, respectively). In addition, one fifth of youth reported driving while under the influence of alcohol in the past 12 months. The mean number of times youth reported doing so was 1.6 times. What is surprising is that the proportion of youth who reported driving while under the influence of cannabis is almost double that of alcohol, 39.8% versus 20.9%. In addition, the mean number of times was approximately 10 times higher for cannabis than for alcohol.

Further investigation needs to examine whether the significantly higher rates of cannabis-impaired driving that are reported by youth are the result of an actual higher rate in this behaviour, or the result of differences in reporting. Alcohol-impaired driving has been the target of a multitude of media and advertising campaigns about the seriousness and dangerousness of this act, whereas cannabis-impaired driving has received relatively little media debate until now. As such, do more youth actually drive cannabis impaired because they believe this act is less serious than driving while alcohol impaired, or are youth simply more willing to report cannabis-impaired driving due to a perceived larger stigma associated with alcohol-impaired driving? This question needs to be addressed given the higher prevalence of cannabis-impaired driving by youth; however, such examination is beyond the scope of this report. Regardless of the answer, this is an area in which further exploration will provide very useful results for preventative purposes.