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ADHD medication decreases risk for car crashes

Individuals with ADHD were significantly less likely to experience motor vehicle crashes when receiving medication for the disorder.

“Previous studies have demonstrated that individuals with ADHD are more likely to experience [motor vehicle crashes]. However, the magnitude of this association has varied substantially because of differences in outcome measures, sample selection, and confounding adjustment,” Zheng Chang, PhD, MSc, of Karolinska Institutet, Stockholm, and colleagues wrote.

To assess associations between use of ADHD medication and risk for motor vehicle crashes, researchers analyzed commercial health insurance claims for 2,319,450 individuals with ADHD from January 2005 through December 2014. Follow-up was conducted for ED visits for motor vehicle crashes. The cohort had a mean age of 32.5 years.

Within-individual analyses indicated males with ADHD had a 38% lower risk for motor vehicle crashes in months when receiving medication (OR = 0.62; 95% CI, 0.56-0.67), compared with months when not receiving medication.

Females with ADHD were 42% less likely to experience motor vehicle crashes when receiving ADHD medication vs. not receiving medication (OR = 0.58; 95% CI, 0.53-0.62).

Researchers found similar associations across age groups, multiple sensitivity analyses, and when considering long-term association between ADHD medication use and motor vehicle crashes.

Estimates indicated up to 22.1% of motor vehicle crashes among individuals with ADHD could have been avoided if they received medication during the entire follow-up period.

In an accompanying editorial, Vishal Madaan, MD, and Daniel J. Cox, PhD, of University of Virginia Health System, Charlottesville, discussed several clinical pearls that can be taken from the study findings.

“First, it is important to keep in mind that the natural course of ADHD often results in a decrease in hyperactivity, while inattention and impulsivity may persist as the patients become adults. Therefore, the developmental trajectory of this disorder must be kept in perspective to ensure that teen drivers and their older counterparts continue to benefit from treatment approaches that work for them,” they wrote. “Second, management of ADHD is not limited to one’s school, college, or workplace: it extends to several other aspects of life, such as driving, which may be ignored to the clinician’s and patient’s peril. Third, health care professionals should be aware that [motor vehicle crashes] in individuals with ADHD often happen later in the evening when their medications may have worn off. Individualizing and optimizing ADHD pharmacotherapy, while being mindful of adverse effects and the potential for abuse, is the most prudent way forward. Additional clinical guidelines are available online.” – by Amanda Oldt

Disclosure: Chang reports no relevant financial disclosures. Madaan reports receiving research support from Forest, Medgenics, Pfizer, Purdue and Sunovion; royalties from Taylor & Francis (Routledge); and travel support from the American College of Psychiatrists. Cox reports receiving research support from Dexcom, Johnson & Johnson, the NIH and Purdue. Please see the study for a full list of relevant financial disclosures.