A new finding that one in 10 school-age children has been diagnosed with ADHD isn't all bad news for Minnesota mental health experts, who say it suggests that more undiagnosed children are getting identified and that the condition is becoming more accepted and less a target for shame and ridicule.

Presenters who go to high schools on behalf of the National Alliance on Mental Illness are finding students who "don't think it's a big deal," said Sue Abderholden, executive director of NAMI's Minnesota chapter. Students are surprised when told it is a mental illness, she said.

ADHD diagnoses among children ages 4 to 17 have increased from 6.1 percent two decades ago to 10.2 percent in 2015-2016, according to a review by University of Iowa researchers of parent responses to the U.S. National Health Interview Survey. Diagnoses remained highest among boys — though the rate of increase was greater among girls — and among children who live in the Midwest, come from low-income homes and aren't Hispanic.

The study, published Friday, is one of the largest to examine ADHD prevalence and should serve as a warning, said Dr. Wei Bao, an Iowa epidemiology researcher. "We need to be prepared with more personnel and resources to provide adequate … diagnosis and treatment," he said.

ADHD, or attention deficit hyperactivity disorder, is defined as sustained problems with inattention, hyperactivity or impulsivity that can lead to academic, social, career and legal problems. Why the increase in diagnoses has been so dramatic is not addressed in the latest study, but mental health experts suspect multiple reasons.

Children who in the past would have died from premature birth, cancers such as leukemia or traumatic surgeries are now more likely to survive, and studies have found that they run greater risks of ADHD and learning disabilities, said Dr. Carrie Borchardt, medical director for psychiatric services at Children's Minnesota. However, she said much of the increase is likely due to increased recognition of the disorder in children who previously were undiagnosed.

Changing social factors also might unmask milder cases of ADHD. Increased screen time might deprive children of time for reading and other activities that can train their brains to focus, for example, while increased academic standards might cause stress for some children and expose their ADHD, Borchardt said.

"The higher the demands on the child, the more any problems with focus are going to contribute to any difficulties they have," she said. "Some kids who might have been OK with less demands now might have more trouble with more demands."

Familiarity with ADHD

ADHD has become familiar enough that people use the term colloquially — "that's my ADHD kicking in" — to describe ordinary moments of inattention, said Mary Yackley, supervisor of student health and wellness for St. Paul Public Schools. Teachers have received training and encountered enough students to be more sensitive to their needs, such as a need to leave a classroom when feeling overwhelmed, she said.

"We're getting smarter about saying things like, 'I need to fill my water cup,' " as code for leaving class to manage symptoms, she said.

Yackley said rising ADHD hasn't necessarily increased demands on school nurses. Newer, long-acting forms of stimulant medications are reducing the necessity for nurses to give doses to students during school days.

One concern is that ADHD might now be so familiar that it is overdiagnosed and used incorrectly to justify why an immature child is struggling academically, said Dr. George Realmuto, a University of Minnesota child psychiatrist.

"The providers, parents, teachers, students and counselors are all ignoring the pace of brain development and variability at this age," he said.

Diagnosing ADHD is tricky, especially in young children whose hyperactivity might be due to immaturity or other causes that don't require the same treatment, said Jenny Britton, director of child and family services at Washburn Center for Children in Minneapolis.

"A child who is anxious about going to school can look like a true ADHD case," she said. "But on the inside, the child is just terrified, and that's why he is having trouble concentrating."

Cultural norms might also distort the level of ADHD diagnoses. The higher rate in the Midwest might simply be due to its lower population of Hispanics, who aren't diagnosed as frequently.

Bao said it is "puzzling" that his study showed ADHD rates are higher among low-income children but lower among Hispanics, who are more likely to live in poverty. It is possible that Hispanic children are underdiagnosed due to a lack of access to health care or more resistance to a diagnosis of ADHD, he said.

More demand for treatment

Diagnoses in girls doubled from 3.1 percent in 1997-1998 to 6.3 percent in 2015-2016. Therapists have reported more girls with symptoms only of inattentiveness rather than more obvious symptoms of hyperactivity. ADHD diagnoses remained more prevalent among boys, though, at 14 percent.

The uptick has had an impact at the University of Minnesota's student health service, which has tripled its mental health therapy staff. The number of students who received treatment for ADHD from the U's Boynton Health reached 500 last year.

Increases in depression and anxiety have been equally if not more significant, said Dr. Steve Hermann, director of Boynton's mental health clinic, but a few cases ended up being problems largely caused by untreated ADHD.

After identifying and then treating the students' ADHD, he said, "their depression and anxiety went away."