More children are being diagnosed with attention deficit hyperactivity disorder at an earlier age, a new study has found.

The rates are rising as much as 5 percent each decade, with one-third of children diagnosed by the time they turn 6 years old, according to research from the National Center for Health Statistics.

The study found that 11 percent of all school-aged children have ADHD, a figure that marks a 42-percent increase from ADHD rates charted between 2003-2004 and compared with those taken from 2011-2012.

The data in this most recent study came from parental reporting of their children’s diagnoses, leading some scientists and physicians to wonder if part of the spike was misreporting by family.

“It’s a much more challenging diagnosis to make in younger kids,” Dr. Jean Carstensen, a clinical instructor of internal medicine and pediatrics at the University of Michigan in Ann Arbor, told LifeZette.

In her own practice, Carstensen said, about 1 in 10 of her young patients have an ADHD diagnosis — figures she acknowledges track with the latest trend.

Why the increase? Better reporting is helping physicians determine what is going on in some children, said Carstensen, a fellow of the American Academy of Pediatrics.

“There was a time period when we didn’t have good clinical tools to use. People kind of (relied on) parents’ reporting and didn’t have that additional evidence from teachers, from home and at school — not just one location,” she said.

“Having better treatments and recognizing it as a separate clinical entity have both increased the diagnoses,” Carstensen said. “Twenty-five years ago, we didn’t really recognize it as a clinical entity. Now, in part, our ability to recognize it and understand it as a separate clinical entity allows us to offer good treatments that are quite beneficial to kids.”

Not everyone approves of the study’s findings. The Centers for Disease Control and Prevention was critical of the research, saying it was possible the rise in cases came from improper diagnoses.

In the study of 2,976 families, the CDC found that 9.5 percent of children in the U.S. ages 3 to 17 had been diagnosed with the disorder. It’s a staggering number — about 5.9 million children and youth.

But the eye-opener in the research was that nearly a third of those diagnosed were under the age of 6, with the average age falling at 7 years old.

Michelle Paulins, a Lansing, Michigan, mother of a 9-year-old daughter, said she knew things were not right with her daughter, Kathy, from the time she was in kindergarten. Even when she was a baby, there were signs.

“She couldn’t stay on one thing long at all, even eating,” Paulins said.

When Kathy started school, it became more evident that is wasn’t just a childish distraction.

“You really have to know your child and be aware, and even in kindergarten, I knew there was a disconnect,” she said.

By first grade, Paulins talked with Kathy’s teacher and she agreed — it was an issue. The teacher saw it, too. Kathy and her husband consulted a pediatrician, and Kathy began medication, but it didn’t entirely work.

The parents wanted better answers.

By third grade, the family sought expensive and detailed private testing and evaluation — about $1,200 — in Grand Rapids, Michigan, where Kathy’s issues were documented and a deeper treatment plan was created.

And so far it’s going well, with new medication keeping her on track and her academic promise increasing.

Paulins said good data is important and argued that such problems should be taken seriously by parents. She’s seen an increasing number of her daughter’s young schoolmates “who are suffering.”

“I know her kindergarten teacher and every teacher thus far has said ‘Things will fall into place. You’ll have nothing to worry about.’ But if we really did take that advice, we would be in real trouble now,” she said of getting her daughter tested and on better medication before she fell deeply behind during the crucial first three years of education.

Even with interaction, Paulins said Kathy struggles to keep up and she’s often frustrated.

“Your average third grader is doing a half hour of homework every night. We’re doing 60 to 90 minutes,” Paulins said. “It is a real issue. Her capacity to focus requires it. When she’s in class, she is not retaining half of what she is taught. So we start school over at night. We have to go through everything again. She’s not stupid —  she’s very, very smart. But she cannot focus or stay on task.”

Living with ADHD has made the normally sparking child who loves to sing and act to be shy in class and fearful to answer or ask questions, knowing that she might be wrong. And made fun of.

It has, Paulins said, zapped Kathy’s self-confidence, even though she’s not yet 10.

“You definitely see it in the classroom. A lot of times it’s treated as if these children are out of control or not good students,” Paulins said. “But when you go into a classroom, you can see it across the board. Many parents just don’t know how to handle it or take that first step.”

Some doctors say it’s possible the uptick in ADHD rates could be simply overdiagnosis, leading some children with other issues to be singled out and treated in appropriately.

“Over-diagnosis presents a number of problems, including being improperly labeled as ADHD if, in fact, another behavioral or psychiatric problem is the cause of the symptom,” Dr. Danielle Fisher, vice chair of pediatrics at Providence St. John’s Health Center in Santa Monica, California, said in an interview with the website HealthDay. “This could also lead to overmedication of such children.”

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