Danish researchers found that people with attention-deficit hyperactivity disorder (ADHD) are more than twice as likely to die prematurely as those without the common disorder.
Dalsgaard and colleagues collected data on nearly 2 million people and found that accidents were the most common cause of premature death among people with ADHD.
People diagnosed at age 18 or older were more than four times as likely to die early, and children diagnosed before age 6 had about double the risk of dying prematurely, compared with those without ADHD, researchers say.
Dalsgaard stressed, "Although ADHD doubles the risk, it is important to note that the absolute risk is very low. Out of more than 32,000 people with ADHD, 107 died early."
"Our results add to the overwhelming existing evidence that ADHD is a true disorder and should not be taken lightly," said lead researcher Dr. Soren Dalsgaard, a senior researcher at Aarhus University.
"It's common for people with ADHD to be impulsive and act without thinking, which can lead to accidents," said Stephen Faraone, author of an accompanying journal editorial.
Research has shown that ADHD often occurs with other behavioral problems. These can include a substance use disorder, oppositional defiant disorder (a pattern of angry/irritable mood and defiant behavior) or conduct disorder (disruptive and violent behavior and problems following rules).
The odds for premature death when ADHD was combined with all three disorders were more than eight times higher than for people without ADHD or a co-existing behavioral disorder, the researchers noted.
U.S. Centers for Disease Control and Prevention estimates show that at least 11 percent of American children aged 4 to 17 are affected by ADHD.
Treating ADHD is the best way to reduce the risk of dying early, added Faraone, director of child and adolescent psychiatry research at SUNY Upstate Medical University in Syracuse, N.Y.