Virginia Radcliff, like her younger brother, has been diagnosed with attention deficit hyperactivity disorder. RELATED VIDEO Louise Schiavone has some new findings on ADHD Windows Media 28K 56K

From Reporter Louise Schiavone

WASHINGTON (CNN) -- It is believed 3 percent to 5 percent of school-age children in the United States have attention deficit hyperactivity disorder, or ADHD -- a condition that makes it difficult to concentrate or behave appropriately.

Just how reliable the ADHD diagnosis is and what therapies work were the focus of a recent conference at the National Institutes of Health.

For Virginia Ratcliff, 7, it is easy to make friends but difficult to concentrate in school.

"It's kind of hard to pay attention when you've got so many people around you and you just want to talk to them," she said.

Virginia's little brother has ADHD. Told the disorder runs in families, Sara Ratcliff had her daughter evaluated and found that she also has ADHD.

"I used to think they were ignoring me, but now I realize I just don't have their attention," Ratcliff said.

Not just a phase

Experts say a carefully evaluated case of ADHD should be taken seriously.

"It's not just an excuse or a phase people go through. It's a very serious public health problem," said Mark Stein of the Children's National Medical Center.

The NIH panel has concluded that diagnosing ADHD is not simple and treatment can be even more controversial. It is recommending more study in both areas.

"One of the major controversies concerning ADHD continues to be the use of psychostimulants, both for the short term and long term," said the chairman of the conference, Dr. David Kupfer of the University of Pittsburgh.

Ritalin is the top drug used to treat attention deficit hyperactivity disorder.

The psychostimulant Ritalin is one of the most commonly prescribed medications to treat the disorder. Last year alone, 3.5 million prescriptions were written.

The American Psychiatric Association reports that between 70 percent and 80 percent of children with ADHD respond to medication when used properly.

"The problem with Ritalin is sometimes it can cover up other problems," Stein said.

These other problems, such as learning disabilities, must also be treated.

The NIH panel reports that as recently as 1995, ADHD-related public school expenses may have exceeded $3 billion. Social repercussions can involve crime and teen-age pregnancy.

Although terms such as ADHD and Ritalin were not often heard until recently, doctors say the problem has been around for a while -- it just didn't have a title.

"Dennis the Menace is a good example," Stein said. "Someone with poor impulse control is always getting in trouble but is kind of loveable. But you could only have him around for a few minutes at a time."

Doctors say among those diagnosed in childhood with ADHD, 60 percent will eventually grow out of it.