ADHD found to increase crash risk among older driving adults

By Pooja Toshniwal PahariaReviewed by Lily Ramsey, LLMOct 5 2023

In a recent study published in JAMA Network Open, researchers examined attention-deficit/hyperactivity disorder (ADHD) prevalence and the association between ADHD and car crash risk among older adult drivers.

Study: Motor Vehicle Crash Risk in Older Adult Drivers With Attention-Deficit/Hyperactivity Disorder. Image Credit: PV productions/Shutterstock.com

Background

ADHD, a chronic neurodevelopmental disorder, although considered a pediatric disorder, can persist through adulthood and old age.

ADHD symptoms, such as impulsivity, hyperactivity, and inattentiveness, could affect affected individuals' driving performance and routine activities. Studies on driving safety among ADHD patients have been limited to young adults and adolescents.

About the study

In the present prospective cohort study, researchers investigated whether the crash risk was higher among older driving adults with ADHD compared to those without ADHD.

The study obtained data from healthcare systems and primary care centers in five United States (US) regions (Ann Arbor, Baltimore, Cooperstown, San Diego, and Denver) between 6 July 2015 and 31 March 2019.

The study included the Longitudinal Research on Aging Drivers (LongROAD) trial participants who were active driving individuals aged between 65 and 79 years and had completed 44-month follow-ups and yearly evaluations using in-vehicle devices.

Data were analyzed between 15 July 2022 and 14 August 2023. The study exposure was ADHD prevalence based on responses to questions regarding ADHD history and ADHD diagnosis received by healthcare professionals such as physicians. The study outcomes included hard-braking-type events with ≥0.40 g deceleration rates, vehicular crashes, and traffic-related events reported by self.

Annual questionnaires with health, driving, and functioning domains were distributed to obtain data on health behaviors, driving performance, and demographics. Driving data, including miles driven and hard-braking-type events, were obtained.

The team used the brown-bag review approach to obtain data on supplements and medications coded according to the American Society of Health-System Pharmacists.

Only individuals with valid driver’s licenses, driving once or more times a week, living in the catchment areas for ten months or more in a year, without any plans to shift to regions other than the study sites in the next five years, and having accessibility to motor vehicles produced in 1996 or later with on-board diagnostic ports were included.

The participants drove vehicles for at least 80% of their day, spoke English fluently, and scored ≥4.0 on the screening test.

Older adult individuals with significant cognitive impairments and Alzheimer’s disease or related dementias, those with missing ADHD or driving information, and unreliable hard-braking event-related data were excluded from the analysis.

Multivariate modeling was performed to determine the adjusted incidence rate ratio (aIRR) values, adjusting for covariates such as age, sex, ethnicity, race, marital status, urbanicity, educational attainment, and annual income.

Results

Among 2,832 participants, the mean age was 71 years; 1,500 (53%) were female; 1,332 (47%) were male; 2,423 (86%) were non-Hispanic white; 1,774 (63%) were married; 1,807 (64%) had completed graduation; 1,988 (73%) had ≥$50,000 yearly income; 2,052 (73%) resided in urban regions; and 879 (32%) consumed ≥10 medications.

Anxiety was reported by 318 individuals (11%), and depression was reported by 560 individuals (20%). ADHD prevalence among the participants was three percent.

ADHD prevalence showed statistically significant differences between those consuming ≥10 drugs vs. those consuming fewer drugs (4.8% versus 1.5%), between anxious and non-anxious participants (7.2% versus 2.0%), and between depressed and non-depressed individuals (7.3% versus 1.4%).

Older driving adults with ADHD showed significantly greater incidences of events related to hard braking per 1,000 miles compared to their non-ADHD counterparts (1.4 vs. 1.2), traffic-related events for every 1,000,000 miles (23 vs. 9.7), and motor vehicle accidents per 1,000,000 miles (27 vs. 13.5).

Adjusting for baseline variables, ADHD increased the hard-braking-type event risk by 7.0%, traffic-related event risk by 102%, and motor vehicle crash risk by 74%, with aIRR values of 1.1, 2.0, and 1.7, respectively.

Significantly higher incidences of events related to hard braking were reported among anxious (1.3) and depressed (1.3) individuals, 75-to-79-year-olds (1.3), females (1.2), non-Hispanic Blacks (1.3), unmarried (1.3), residents of urban regions (1.4), or those who consumed at least ten medications (1.3). Site-stratified analyses yielded similar results as the primary analysis.

Based on the study findings, crash risk is significantly higher among older driving adults with ADHD compared to those without ADHD.

The findings indicate that efficient interventions are required to improve ADHD diagnosis and management in the older population and promote healthy aging and safe mobility.