By Lisa Rapaport

(Reuters Health) – New teen drivers with attention deficit/hyperactivity disorder are more likely to crash their cars than adolescents who don’t have ADHD – especially right after they get their license, a new study suggests.

Researchers followed 14,936 teens in New Jersey for two years after they acquired a so-called “graduated license” that restricts things like nighttime driving, driving with multiple passengers in the vehicle and using electronics in the car.

Overall, 1,769 of these new drivers, or 12 percent, had ADHD.

Compared to teens without ADHD, young drivers with the condition were 62 percent more likely to crash within the first month of getting licensed, the study found. And over their first four years behind the wheel, teens with ADHD were 37 percent more likely to crash.

“All young drivers are at higher crash compared to older more experienced drivers, regardless of whether or not they have ADHD,” said lead study author Allison Curry of the Perelman School of Medicine at the University of Pennsylvania and Children’s Hospital of Philadelphia.

“Teens are inexperienced drivers and need time as independent drivers to gain the skills needed to drive safely,” Curry said by email. “This is why states have graduated driver licensing (GDL) programs, which are designed to limit high-risk exposure as driving experience is gained and have been proven effective in reducing teen crashes in the U.S.”

But adolescents with ADHD may have characteristics that place then at greater risk for unsafe driving behaviors like inattentiveness, distractibility, impulsiveness, and difficulties with emotional regulation, Curry added.

In New Jersey, teens can get an intermediate license at age 17 that allows them to drive without adult supervision, but there are some caveats: no driving late at night, no unsupervised driving with more than one passenger and no use of cell phones or other electronics in the car for the first year.

Even with these graduated licenses, teens with ADHD weren’t as safe as their peers.

Over their first four years on the road, young drivers with ADHD were more than twice as like to have alcohol-related crashes as teens without ADHD.

Teens with ADHD also had a 62 percent higher rate of crashes that caused serious injuries and a 47 percent higher rate of moving violations.

With ADHD, young drivers were also 32 percent more likely to have their license suspended at least once during the four-year study period.

The study can’t prove whether or how ADHD directly causes risky driving behavior.

One limitation of the study is that researchers relied on diagnoses by primary care providers to identify teens with ADHD, researchers note in Pediatrics. It’s also possible that some youth with ADHD were diagnosed earlier in childhood and no longer had symptoms by the time they were driving.

Researchers also lacked data on how far or often teens drove, making it impossible to calculate crash rates based on the total time or distance behind the wheel.

It’s also not clear from the study whether medication or other treatments for ADHD might impact crash rates, said Scott Kollins, author of an accompanying editorial and director of the ADHD program at Duke University in Durham, North Carolina.

“There is some evidence, especially in simulated driving conditions, that medication can specifically improve driving behaviors,” Kollins said by email. “Given what we know about how treatments work to improve attention, impulse control, and decision making, it stands to reason that interventions can be useful for improving driving, but we need more real-world evidence for whether this actually takes place.”

Parents of teens with ADHD may also want to consider hiring a certified driving instructor and waiting longer to give kids the car keys, Curry said. And if they do hold off until teens are at least 18, parents will need to come up with their own rules to initially restrict driving because most states don’t have graduated licenses for adults.

“They need to develop strong house rules for driving that include …limited nighttime driving, no peer passengers, and no cell phone use for the first full year of independent driving,” Curry said.

SOURCE: Pediatrics, online May 20, 2019.