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Adult ADHD persistence may increase car crash risk

Individuals whose childhood ADHD persists into adulthood appear to be at increased risk for motor vehicle crashes, according to data published in Journal of the American Academy of Child and Adolescent Psychiatry.

“Prior studies consistently show a risk for [motor vehicle crashes] in individuals with ADHD that is approximately 30% higher than in those without ADHD,” Arunima Roy, PhD, of the University of Ottawa’s Royal’s Institute of Mental Health Research in Ontario, Canada. “The distinction between childhood ADHD and persistent/desistent adult ADHD has not been made when examining ADHD-[motor vehicle crash] risk, but there is reason to believe that this distinction is important.”

Roy and colleagues examined the risk for motor vehicle crashes (MVCs) in 441 adults with ADHD and 239 controls without from the Multimodal Treatment Study of ADHD.

Participants provided self-reports on the number of motor vehicle crashes they had been involved in and when they received their licensure to measure driving experience. Analysis was adjusted for sex, age at follow-up, driving experience, baseline oppositional defiant disorder (ODD)/conduct disorder (CD) comorbidity, baseline household income level, adult ODD/CD symptoms, substance use and adult antisocial personality disorder symptoms. Then, the researchers repeated the analysis using adult ADHD status (persistent vs. desistant vs. comparisons) and symptom level as the predictor variable.

The results demonstrated that ADHD at baseline was linked to a higher number of motor vehicle crashes by adulthood (IRR = 1.45; 95% CI, 1.15-1.82).

Roy and colleagues reported that adults with persistent ADHD were at higher risk for experiencing car crashes than those with ADHD desistence (IRR = 1.46; 95% CI, 1.14-1.86) or the controls (IRR = 1.81; 95% CI,1.4-2.36), but the rates of motor vehicle crashes in the desistant group and the control group were comparable. In addition, average ADHD symptom levels in adulthood was associated with car crashes (IRR = 1.71; 95% CI, 1.31-2.23), with both adult inattention (IRR = 1.51; 95% CI, 1.2-1.91) and hyperactive/impulsive symptom levels (IRR = 1.54; 95% CI, 1.2-1.98) predicting the risk for motor vehicle crashes.

To help prevent motor vehicle crashes among drivers with ADHD, Roy and colleagues recommended that clinicians increase awareness on safety information to families and the general public, but be careful not to stigmatize individuals with ADHD as a safety risk.

“One way to do this is to place this information in the context of our findings related to ADHD persistence versus desistence: MVC risk appears to be specific to individuals whose childhood ADHD persists into adulthood, with symptoms of inattention and hyperactivity/impulsivity being predictive of MVC risk,” they wrote. “This finding suggests that continuous management of ADHD symptoms in adulthood may prevent MVCs. Such information could motivate individuals with ADHD to continue treatments for ADHD symptoms or to seek interventions that target specific impairments.” – by Savannah Demko

Disclosure: Roy reports support from an Alexander von Humboldt fellowship. Please see the study for all other authors’ relevant financial disclosures.