Patrick O’Malley, PhD, researched teen driving after alcohol or drug use in a recent AJPH study.

Patrick M. O’Malley, PhD, research professor in the Survey Research Center, Institute for Social Research at the University of Michigan, is co-principal investigator on the Monitoring the Future study. The study has been conducting research for more than 35 years on substance use and related attitudes and beliefs among secondary school students, college students and young adults. He is also co-principal investigator on the Youth, Education and Society study, which conducts research on the influence of contextual factors on health behaviors and attitudes, including physical activity, diet and substance abuse, among secondary school students.

O’Malley’s new research, featured in the November 2013 issue of the American Journal of Public Health, investigates driving and riding patterns among high school seniors after using drugs or drinking alcohol. The study sheds light on the prevalence of teens placing themselves in danger through risky driving and riding practices. Public Health Newswire asked O’Malley more about his findings.

Q: Your study analyzed data from 2001 through 2011. Over the years, what are some of the trends in teen alcohol and drug use as they relate to driving?
During the 11-year period of our study, sponsored by National Institutes of Health’s National Institute on Drug Abuse, there were some different trends in use of alcohol, marijuana and illicit drugs other than marijuana. For alcohol, the trend was generally down, and this was reflected in declines in driving after use of alcohol. Prevalence of any use of alcohol in the prior 30 days declined from 50 percent in 2001 to 40 percent in 2011. Prevalence of any driving after drinking alcohol declined from 16 percent to 9 percent in the same interval. A similar pattern occurred with heavy drinking: The prevalence of having five or more drinks in a row declined from 30 percent to 22 percent, while driving after having five or more drinks declined from 9 percent to 6 percent.

The trends for marijuana are different, particularly in recent years. Prevalence of 30-day marijuana use declined from 22 percent in 2001 to 18 percent in 2006, but has since increased to 23 percent by 2011. Driving in the past two weeks after using marijuana declined from 15 percent in 2001 to 10 percent in 2008, but has since increased to 12 percent in 2011.

The trends for illicit drugs other than marijuana are less consistent – some general modest decline in 30-day use until 2009, then a slight increase in 2010 and again in 2011. Driving in the past two weeks after using some illicit drug other than marijuana has been fairly steady, between about 2 percent to 3 percent.

Q: Were there any results that you found to be notably shocking or surprising?
The results were not notably shocking or surprising, given our and others’ past reporting on driving after use of alcohol and drugs. Perhaps the most important point is the sheer number of high school seniors who are placing themselves at considerable risk of serious harm.  One in six high school seniors, or 16 percent, reported driving at least once in just the past two weeks after using marijuana or other illicit drugs, or after heavy drinking. Fully 28 percent reported either driving after using marijuana or other illicit drugs or after heavy drinking, or being a passenger when the driver had done so.

We want to emphasize that these figures are for only the past two weeks. Moreover, they are highly likely to be underestimates of the entire age-population because the data do not include high school dropouts or those who were absent on the day of the survey.

Q: What kind of safety and prevention efforts do you hope your study motivates?
We are less certain of the kinds of safety and prevention efforts that should be undertaken. What we are certain of, and believe our study shows, is that the problem of drunk and drugged driving is very real and substantial. It permeates nearly all sectors of society, with substantial rates among subgroups defined by gender, race/ethnicity, socioeconomic status, region and urbanicity.

One contribution of the larger Monitoring the Future study is its ability to demonstrate that an important determinant of drug use behavior is the perceived risk of harm and also the disapproval associated with use. Presumably, a similar dynamic could play a role in determining drugged or drunk driving. Although there is considerable recognition of the dangers of drugged driving, there is likely room to increase that recognition. And it needs to be demonstrated and emphasized that this kind of behavior is emphatically disapproved.

Unfortunately, the perceived risk of harm from, and disapproval of, marijuana use has been declining in recent years, and this bodes ill for the future. If use increases, then driving after use will very likely also increase.

One factor that helps sustain impaired driving is that some adolescents relish risk-taking and doing dangerous things. We ask the seniors how much they agree with the statement “I get a real kick out of doing things that are a little dangerous.” Those who say they agree with the statement are more than twice as likely to drive after using marijuana or having five or more drinks, compared to those who don’t agree.

Q: Marijuana is becoming legalized in a growing number of states and your study indicates that driving after marijuana use is on the rise for teens. How do you think your findings speak to this conversation about marijuana legalization?
We can only speculate. It seems to us likely that legalization of marijuana will lead to lowered perception of harm from use, as well as lowered disapproval of use. In turn, use is likely to increase, and with an increase in use, we fear an increase in driving after use.