People with Attention Deficit Hyperactivity Disorder face increased mortality rates, according to a new study from Yale and Aurhus University in Denmark.

Working with professor of child psychiatry, psychology and pediatrics James Leckman from Yale’s Child Study Center, researchers from Denmark found that children and adults with ADHD were at a higher risk of dying from unnatural causes like accidents and suicide than their non-ADHD counterparts. The study, the first to draw a direct link between ADHD and increased mortality, was published in the journal Lancet on Feb. 26.

“[The study] bolsters one’s perspective that [ADHD] is an important public health concern, and offers reinforcement that ADHD is a real condition,” Leckman said.

Although ADHD is associated with other risk factors like substance abuse and criminality, this is the first time that a direct correlation has been established between the disorder and increased mortality. To probe that link, the researchers used data from Denmark’s national registries on demographics and healthcare to study 32,000 individuals with ADHD.

Leading neuroscientist Stephen Faraone wrote in a commentary on the study that inattention and impulsivity — two core symptoms of ADHD — could account for this connection.

The study also found that female patients and patients who were diagnosed later in life were especially prone to premature deaths.

Lawrence Vitulano, clinical professor at the Yale School of Medicine who was not involved in the study, said this finding may be explained by the fact that it is often more difficult for girls to be diagnosed with ADHD. Hence, the female patients captured in the data set could have an especially serious form of the disorder, increasing the strength of the correlation, he said.

In recent years, many have criticized the over-diagnosis of ADHD, a perception which this study debunks, Leckman said. The study, he added, offers reinforcement that ADHD is a real condition that requires intervention. Leckman said his second study, which has yet to be published, shows that medication can significantly lower the risk of injury in children with ADHD.

“The brain is plastic and can be re-trained to overcome many early weaknesses in many populations,” Vitulano said about designing effective ADHD interventions. “Just because you have ADHD does not mean you necessarily must have more accidents or get involved in dangerous situations.”

But both Leckman and Vitulano cautioned against drawing sweeping generalizations from the study. Registry data have their limitations because doctors do not uniformly evaluate everyone in the same way, said Leckman. Moreover, the actual number of ADHD patients who died is small, in absolute terms.

“I wouldn’t want to make this seem like an epidemic,” said Leckman.

He added that he would like to see the study replicated in other countries, as attitudes towards ADHD differ from culture to culture.

Vitulano added that the gender discrepancy in mortality is also worth looking into.

According to a report from the Centers for Disease Control and Prevention, 11 percent of U.S. children aged four to 17 have been diagnosed with ADHD at some point in their lives.