Male teens with ADHD at greater risk of traffic accidents: study

Male teens with disruptive behaviour disorders who get behind the wheel are much more likely to be involved in a crash than the general population, a new study has found.

Young male pedestrians with attention deficit hyperactivity disorder or similar problems also face an increased risk of being involved in a traffic accident, according to research published Tuesday in the journal Public Library of Science Medicine.

The findings may signal the need to adopt more stringent requirements to ensure people with disruptive behaviour disorders are in good medical condition and are capable of safe driving, said Donald Redelmeier, lead author of the study and a professor of medicine at the University of Toronto.

"Taking away peoples' driver's licences is not the solution," Dr. Redelmeier said. "Instead we argue that ADHD ought to be considered just like diabetes and just like epilepsy. Specifically, if you wish to maintain a driver's licence, you need to see your doctor and show that you are under good control."

Researchers used Ontario health care databases to examine the link between disruptive behaviour disorders and road crashes. They looked at young men between ages 16 and 19 who had been involved in a crash or road accident from April, 2002, to March, 2009.

Researchers compared that group to young men of the same age who were admitted to hospital during the same period for appendicitis. That way, Dr. Redelmeier said, they could determine whether ADHD was more prevalent in young men who had been involved in road accidents, which would signal an increased risk, or if it was just as common in young men with appendicitis.

They found that 3,421 young male patients were admitted to the hospital after being involved in a traffic accident during that period, while 3,812 male teens were hospitalized for appendicitis.

Of those, 767 who had been in a road accident had a history of ADHD or other disruptive behaviour disorders compared with just 664 of the appendicitis group.

Researchers pointed out their study only includes males who were aware of their diagnosis and had access to medical treatment. That means the actual prevalence of traffic accidents involving young males with ADHD could be underestimated, because many cases go undiagnosed.

But the findings show male teens with disruptive behaviour disorders face increased risks, which warrants attention from the wider medical community and awareness from the public and those suffering from the disorders, Dr. Redelmeier said.

"All of these crashes could have been prevented," he said. "A greater awareness might encourage people to be a bit more mindful about the standard recommendations [for safe driving]"

Although it's impossible to tell what caused each of the crashes involving young men with ADHD, disruptive behaviour disorders are known to interfere with a person's ability to ignore distractions or stay focused on a single task for extended periods. Disruptive behaviour disorders include oppositional defiant disorder and conduct disorder, characterized by traits such as temper tantrums and bullying or aggression and destructive behaviour, respectively.

"I'm not surprised that more of them [males with ADHD and related disorders]end up in serious accidents," said Alan Edmunds, an associate professor in the faculty of education at the University of Western Ontario who has studied ADHD. "They usually can do all the tasks we ask of them but they are more susceptible to being distracted."

Dr. Redelmeier said physicians as well as individuals with ADHD and related disorders should be more cognizant of the fact they may be at a greater risk when driving or even crossing the street. It's important they keep in mind principles of safe driving, such as avoiding excessive speed and minimizing other distractions, such as cellphones, and pay attention when they are crossing streets.

But Dr. Edmunds suggests there may be no easy solution to the risks outlined in the study. That's because individuals with disruptive behaviour disorders seem to have trouble remembering to perform tasks that are ingrained in others, such as always checking their blind spot before changing lanes. Similarly, those individuals may not be able to react during an emergency situation the same way as the general population.

While it's clear more research is needed to fully understand this complex issue, the study's authors say their findings should spark a move toward greater awareness of the risks faced by young males with disruptive behaviour disorders.

"The findings call attention to a widespread, preventable and costly cause of death and disability," the study says. "Specifically, disruptive behaviour disorders could be considered as contributors to road trauma."