Cortisol Levels Associated With Crash and Near-Crash Rates for Teen Drivers

Bottom Line: Teenage drivers with a higher response to stress measured by cortisol levels (a neurological marker of stress regulation linked to risky behavior) had lower crash and near-crash rates (CNC).1

Author: Marie Claude Ouimet, Ph.D., of the University of Sherbrooke, Quebec, Canada, and colleagues.

Background: Traffic crashes are a leading cause of death worldwide for people 15 to 29 years of age. The first months after a new driver gets a license are a particularly dangerous time. Research suggests neurobiological processes are involved with risky behavior.

How the Study Was Conducted: The authors examined the association between cortisol response during a stress-inducing task measured at baseline and rates of CNCs over a period of 18 months in a final sample of 40 newly licensed (19 males and 21 females) 16-year-old drivers. Researchers induced stress by asking the participants to do mathematical tasks. Cortisol levels were measured over time from saliva samples. In-vehicle cameras and sensors allowed continuous observation of driving.

Results: Drivers who had a higher cortisol response measured at baseline had lower CNC rates during the follow-up period and had a faster decrease in CNC rates over time regardless of the sex of the driver.

Discussion: “This study found that cortisol, a neurobiological marker, was associated with teenaged driving risk; teenagers with lower response to stress were at higher risk for CNCs.  As in other problem-behavior fields, identification of an objective marker of a specific pathway to teenaged driving risk promises the development of more personalized intervention approaches.”

In a related editorial2, Dennis R. Durbin, M.D., M.S.C.E., of the Children’s Hospital of Philadelphia, and colleagues write: “The most immediate implication of the findings of the Ouimet et al study is for continued research to better characterize the relationship between cortisol reactivity in response to stressors and crash risk in the general population of healthy teens and among those teens who might be at higher crash risk owing to preexisting conditions or history of risky behaviors.”

“In sum, while the results of the Ouimet et al study do present an interesting new line of research, they do not suggest that we are close to developing a clinically useful biomarker-based diagnostic test nor a pharmaceutical therapy to reduce the risk for teen-driver crashes,” they continue.

“Finally, families and health care providers should recognize driving as a health behavior because motor vehicle crashes are currently the leading cause of death for adolescents. Health care providers need to be prepared to support families in the learning-to-drive process, highlighting the need for providers to have competency in this area and evidence-based resources available to them,” the editorial concludes.


1. JAMA Pediatr. Published online April 7, 2014. doi:10.1001/jamapediatrics.2013.5387

2. JAMA Pediatr. Published online April 7, 2014. doi:10.1001/jamapediatrics.2013.5402.