Does psychological distress increase the risk for motor vehicle crashes in young people? findings from the DRIVE study

Purpose: Earlier research demonstrates increased and decreased risk of crash related to psychological distress; however, previous literature has almost entirely used retrospective study designs and has not been able to adequately control for important confounders such as exposure to driving, alcohol and drug use, or having had a previous crash. This study aimed to assess the relationship between psychological distress and risk of motor vehicle crashes. Methods: The DRIVE study is a prospective cohort study of 20,822 novice drivers aged 17-24 years in Australia. Information on risk factors for motor vehicle crash was collected through online questionnaire and subsequently linked to police-reported crashes. Poisson regression was used to analyze risk of various crash types by low, moderate, high, and very high levels of psychological distress, taking into account other known risk factors for crash. Results: Compared to the referent group with low or no distress, a protective effect against crash was observed for young people who reported a moderate amount of psychological distress in unadjusted (RR = .87; 95% CI = .76-1.00) and multivariable analyses (RR = .85; 95% CI = .74-.97). Severe psychological distress was not significantly associated with an increase or decrease in the risk of crash. Psychological distress was not significantly associated with an increased risk of single vehicle crash. Conclusion: Earlier studies may have overestimated risk for motor vehicle crashes associated with psychological distress. This study found little convincing evidence to support a strong risk relationship for higher levels of distress and indeed found a modest protective association for low levels of distress.