Do Anxiety Disorders Play a Role in Road Traffic Deaths? The Nested Case-Control Study of Drivers Killed in Fatal...

Relatively little is known about the relationship between anxiety disorders and fitness-to-drive. This study analysis the characteristics of motor vehicle fatalities, involving drivers with hospital-diagnosed anxiety disorders, as well as the contribution of psychiatric comorbidity to the cause of these fatalities.

In our population-based data of all deceased Finnish drivers we compare socio-demographic, driving-related and clinical characteristics of study subjects with anxiety disorders with matched control subjects without any history of hospital treated psychiatric disorders. We also explore whether the cause of death of drivers killed in motor vehicle accidents differs between those with anxiety disorders and comorbid psychiatric disorders.

This study was based on OTI (The Finnish Crash Data Institute) data with linkage to two national registers: The Care Register for Health Care and the National Cause of Death Register. The initial study population included 4,930 drivers involved in fatal motor vehicle accidents in Finland between 1990 and 2011. It was confirmed that 93 drivers had received an anxiety disorder diagnosis (ICD-10 codes: F40-44) in the 5 years prior to their collision.

We found that drivers with anxiety disorders were more likely to be involved in crashes with suicidal intent (OR = 2.83, 95% CI [1.40, 5.72]), drivers who had previously experienced headaches or insomnia (OR = 4.99, 95% CI [1.34, 18.62]), and drivers who were impaired by alcohol or drugs (OR = 3.92, 95% CI [1.28, 11.98] when DUI was 0.5‰-1.19‰ and OR = 2.01, 95% CI [1.15, 3.52] when DUI was aggravated, BAC 1.2‰ or above). It was notable that the proportion of suicides increased when anxiety disorder occurred simultaneously with depression (20.7%) or other psychiatric disorders (24.0%). In the overall dataset, the most common cause of death was an accident (82.8%). Regarding to accidental deaths, no significant differences were observed between individuals with anxiety disorders and matched control subjects without any history of hospital treated psychiatric disorders.

The findings of this study suggest that assessment of suicidal intent may be particularly important when evaluating fitness to drive in patients with anxiety disorders, including those with psychiatric comorbidity, alongside consideration of substance use that may impair driving, and a history of headaches or insomnia.