TUESDAY, Nov. 15, 2016 (HealthDay News) -- In a bit of good news, the rate of diagnoses for attention-deficit/hyperactivity disorder (ADHD) among U.S. preschoolers has leveled off, a new study finds.

At the same time, the prescribing rate of stimulant medications for these young patients has also stayed steady, a promising trend that researchers credit to treatment guidelines that were introduced in 2011.

The guidelines, issued by the American Academy of Pediatrics (AAP), called for a standardized approach to diagnosis, and recommended behavior therapy -- not drugs -- as the first-line therapy for preschoolers.

"There [was] a concern that preschoolers get too much behavioral diagnosis and medications for behavior problems," explained study author Dr. Alexander Fiks. He is associate medical director of the Pediatric Research Consortium at Children's Hospital of Philadelphia.

One in every three children diagnosed with ADHD is diagnosed during preschool years, Fiks said. Of these kids, 47 percent are treated with medication alone or in combination with behavior therapy, according to the study authors.

Among more than 87,000 children aged 4 to 5, about 0.7 percent were diagnosed with ADHD before the guidelines, the study showed.

After the guidelines, 0.9 percent of more than 56,000 kids were diagnosed with the disorder. And, the rate of prescribing stimulant medications such as Ritalin remained constant, at 0.4 percent of those diagnosed with ADHD, according to the report.

"One might have worried that if you were telling pediatricians how to manage preschool ADHD that all of a sudden there would be an explosion in the number of kids being diagnosed, or many more would be on medication. And the fact that the increasing trend leveled off is reassuring and that medication use didn't increase is also reassuring," Fiks said.

"It suggests pediatricians are taking the guidelines to heart and not using them as a reason to willy-nilly label kids with ADHD," Fiks said. "When parents of preschoolers are confronted with a child with behavior problems, it's reasonable to talk with their pediatrician."

But one child psychologist isn't convinced that the guidelines made a significant difference.

"It really doesn't look like the guidelines have had much of an effect," said Brandon Korman, a neuropsychologist at Nicklaus Children's Hospital in Miami.

"What's really of concern is that, according to the U.S. Centers for Disease Control and Prevention, there hasn't been an increase in psychological services, as the AAP had recommended," he said.

It's unfortunate that behavior therapy hasn't been used more, Korman said. "Even if the kid is diagnosed with ADHD and they don't have ADHD, there's very little downside to behavior therapy -- it's different than giving your kid medication that has a potential downside," he added.

Korman said the problem is twofold: Pediatricians aren't referring kids for behavior therapy, and too few qualified therapists are available to treat all the children who need help.

"We need to make more of a collaborative effort between the medical folks and the behavioral health folks to come together to provide the best care for our kids," he said.

The study was published online Nov. 15 in the journal Pediatrics.

More information

For more on ADHD, visit the U.S. National Institute of Mental Health.