Diagnoses of attention-deficit/hyperactivity disorder, commonly known as ADHD, are becoming an “expanding public health concern,” Centers for Disease Control and Prevention (CDC) researchers said in a new study.

Approximately 1 in 9 U.S. children, about 7 million, were diagnosed with ADHD in 2022, according to the study, published Wednesday. That marked about 1 million more children who received a diagnosis than in 2016, meaning the rate at which U.S. children were being diagnosed increased quite dramatically.

The study’s authors noted that an increase in diagnoses could reflect the fact the public is more aware of and more frequently seeking care for the disorder, or it could be a reflection of how children developed during the COVID-19 pandemic.

“Pandemic-associated family stressors such as illness and death in the family and community, changes in parental work and child schooling, decreased social interactions and increased fear and uncertainty are factors that can increase symptoms of inattention, impulsivity, and hyperactivity,” the study said.

It also noted that in the past, boys were diagnosed with ADHD at much higher rates than girls. After analyzing prescription medication claims from 2016 to 2021, the researchers found an increase in girls and teens aged 10 to 19 who received medications.

Diagnosed ADHD rates remain lower among Asian and Hispanic children, the study found.

Clinical characteristics also varied, the researchers found. Children in lower income households or children on public health insurance were more likely to have more diagnoses and more severe ADHD diagnoses. Asian children had the least diagnoses and least severe diagnoses.

It’s not known to what extent the patterns reflect parental and cultural perceptions of ADHD, the study noted.

The authors said the results of the study should help clinicians understand current ADHD trends and best practices, as well as policymakers, government agencies and health care systems to plan for the needs of children in America.