Almost one in five boys of high school age, and 11 percent of school-age children overall, have received a medical diagnosis of attention deficit hyperactivity disorder (ADHD) in the United States, according to new government data.

Many doctors are concerned that ADHD diagnoses and medication are overused in children, The New York Times reports.

The Centers for Disease Control and Prevention (CDC) found an estimated 6.4 million children ages 4 to 17 had received an ADHD diagnosis at some point. This represents a 16 percent increase since 2007, and a 53 percent increase in the past 10 years.

The findings come from a CDC study of children’s health issues, which included interviews with more than 76,000 parents nationwide.

About two-thirds of those diagnosed with ADHD receive prescriptions for stimulant drugs such as Adderall or Ritalin. These drugs, while they can be very effective in treating the disorder, also have the potential for addiction, anxiety and even psychosis, the article notes.

The American Psychiatric Association is soon expected to change the definition of ADHD, in order to allow more people to receive the diagnosis and treatment, according to the newspaper.

A growing number of high school students are using ADHD drugs to help them get better grades. Teens get them from friends, buy them from student dealers, or pretend to have ADHD in order to get prescriptions. Abusing these drugs can lead to mood swings and depression, heart irregularities and extreme exhaustion or even psychosis during withdrawal, according to medical experts. There is little evidence about the long-term effects of young people abusing these stimulants.

CDC Director Dr. Thomas R. Frieden told the newspaper, “We need to ensure balance. The right medications for ADHD, given to the right people, can make a huge difference. Unfortunately, misuse appears to be growing at an alarming rate.”