NEW YORK (Reuters Health) - Children with asthma may be at increased risk of certain behavioral, emotional and developmental problems, particularly if the asthma is severe, the results of a new study suggest.

Using data from a national health survey, researchers found that of more than 100,000 U.S. children and teenagers, those with asthma were more likely to be diagnosed with attention-deficit hyperactivity disorder (ADHD), depression, anxiety and learning disabilities.

More severe asthma increased the risk, as did living in a disadvantaged social or economic environment, according to the study, published in the Journal of Developmental & Behavioral Pediatrics.

Compared with children whose parents described their asthma as mild, those with severe asthma were three to four times more likely to have ADHD, depression or any behavioral or learning disorder.

It's not possible to tell from this study why asthma was linked to behavioral and emotional difficulties, according to lead author Dr. James A. Blackman of the University of Virginia Children's Hospital in Charlottesville.

But, he told Reuters Health, it's a reasonable guess to say the physical effects of the disease, or the medications used to treat it, could contribute to depression, difficulty concentrating or other problems.

On the other hand, Blackman noted, children with additional challenges, like ADHD or learning disabilities, may have a tougher time sticking with their asthma treatment plan -- thereby worsening their asthma.

Whatever the reasons for the current findings, Blackman said parents should be aware that good asthma management takes more than just medication. Physical health, psychological well-being and school performance are all connected, he explained, so they should be looked at as a "total package."

According to Blackman, parents can look out for signs that their child is depressed or being bullied. In his study, parents of severely asthmatic children were more concerned that their child was being bullied.

Parents can also stay in contact with their children's teachers to address any academic problems or missed school days due to asthma flare-ups, he said.

The study findings are based on data from a federal health survey of parents of 102,353 randomly selected children and teenagers. Nine percent currently had asthma.

The large majority of asthmatic children did not have any of the additional disorders the study measured, but their rates of each were higher than non-asthmatic children's.

Twelve percent had ADHD versus 6 percent of children without asthma. The corresponding rates of depression/anxiety were 9 percent and 4 percent; 11 percent and 5 percent for behavioral and conduct problems; and 15 percent and 9 percent for learning disabilities.