Attention Magazine April 2024

It’s been well established that adolescent and young drivers with ADHD have an increased risk of traffic infractions and car crashes, which some studies suggest can be at least partially prevented by ADHD medication (Barkley & Cox, 2007; Biederman et al., 2012). Because hyperactivity and impulsiveness tend to improve with age, we might hope that senior drivers with ADHD would be spared this risk despite continued problems with attention and focus. A new article in JAMA Network Open sheds some light on this (Liu, et al., 2023).

Liu and colleagues studied 2,832 drivers aged sixty-five to seventy-nine, of whom 2.6% had self-reported ADHD, for forty-four months. Recording devices in their cars showed 7% more hard-braking incidents per 1,000 miles for drivers with ADHD than those without ADHD. Those with ADHD also self-reported twice as many traffic tickets and crashes per million miles. Besides ADHD, other characteristics associated with more crashes, tickets, and hard-braking incidents were anxiety, depression, older age, being unmarried, living in the city, and taking ten or more medications—the last probably a marker for poor health.

As with most studies, this one has limitations that affect interpretation. Although the number of medications is reported and found to be associated with greater risk if ten or more are taken, the association with ADHD medication specifically is not reported. Presumably no one would be taking more than two to three medications for ADHD, so those taking ten or more must have numerous physical health problems that contribute directly to driving risk and for which the medications may have side effects such as sedation that could interfere with driving performance. Other studies have reported improved driving performance from ADHD medication at younger ages, so we could hope that specific ADHD treatment might reduce driving risk also for seniors with ADHD. However, this study does not report data supporting that.

Another important limitation is that the ADHD group was identified by self-reporting an ADHD diagnosis ever in their life. Therefore, we do not know how many had persistent adult-symptomatic ADHD versus recovering from childhood ADHD. This is an important issue in distinguishing whether persistence of ADHD is necessary for the increased risk in older adults or whether simply ever having ADHD increases the risk.

Another bit of missing information, as the authors point out, is how much of the driving impairment at the older ages results from early dementia, problems with vision, coordination, and/or hearing, as well as other conditions, rather than just ADHD.

Obviously the study needs replication and expansion into the additional questions above. Nevertheless, despite those limitations, the study is clinically useful. The results urge extra caution for seniors with ADHD, who apparently have the added risk of car crashes from ADHD in addition to the risk from older age with slower reflexes and possible sensory impairments. It is extra important for them to observe the usual risk-reduction strategies, such as not driving after drinking or using marijuana, getting adequate sleep before driving, and turning off distractions such as cell phones while driving.

In addition, the association of crash risk with anxiety and depression suggests that treating anxiety or depression might reduce the risk. There are proven treatments, both medical and behavioral (talking therapy) treatments for both of those disorders, which occur frequently in people with ADHD.

Forewarned is forearmed, and this study sounds a warning not to assume that senior drivers with ADHD are exempt from the risks shown in younger drivers. In fact, risks increase as they age. They need to take the usual precautions seriously: Don’t mix alcohol or drugs with gasoline, get adequate sleep before driving, avoid distractions (devices, social, or worries), heed warnings on prescriptions, get any mental/emotional problem treated that might interfere with staying calm and focused at the wheel, and make sure vision and hearing are appropriately optimized.

L. Eugene Arnold, MD, MEd, is professor emeritus of psychiatry at The Ohio State University, where he formerly was the director of the division of child and adolescent psychiatry and vice-chair of psychiatry. He is a co-investigator in the OSU Research Unit on Pediatric Psychopharmacology. He has forty-five years of experience in child psychiatric research, including the multi-site NIMH Multimodal Treatment Study of Children with ADHD (“the MTA”), for which he was executive secretary and chair of the steering committee. For his work on the MTA he received the NIH Director’s Award. A particular interest is alternative and complementary treatments for ADHD. His publications include nine books, seventy chapters, and more than three hundred articles. In addition to serving on the professional advisory board, Dr. Arnold is CHADD’s Resident Expert.

Lily Hechtman, MD, FRCP, is professor of psychiatry and pediatrics in the faculty of medicine and director of research in the division of child psychiatry at McGill University in Montreal, Quebec, Canada. Dr. Hechtman combines a rigorous research background with extensive clinical expertise and experience. Among many other honors, she has been inducted into CHADD’s Hall of Fame, an award reserved for outstanding individuals for their contributions advancing the science of ADHD.

REFERENCES AND ADDITIONAL READING

Barkley RA & Cox D. (2007). A review of driving risks and impairments associated with attention-deficit/hyperactivity disorder and the effects of stimulant medication on driving performance. Journal of Safety Research, 38(1), 113–128. https://doi.org/10.1016/j.jsr.2006.09.004

Biederman J, Fried R, Hammerness P, Surman C, Mehler B, Petty CR, Faraone SV, Miller C, Bourgeois M, Meller B, Godfrey KM, & Reimer B. (2012). The effects of lisdexamfetamine dimesylate on the driving performance of young adults with ADHD: a randomized, double-blind, placebo-controlled study using a validated driving simulator paradigm. Journal of Psychiatric Research, 46(4), 484–491. https://doi.org/10.1016/j.jpsychires.2012.01.007

Yuxin Liu, MPH; Stanford Chihuri, MPH; Thelma J. Mielenz, PhD; et al. Motor Vehicle Crash Risk in Older Adult Drivers with Attention-Deficit/Hyperactivity Disorder. JAMA Network Open. 2023;6(10):e2336960. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2810131