The most common medications for attention deficit hyperactivity disorder do not cause genetic damage, according to a new study from the National Institutes of Health and Duke University.

A news release on the work said it stands in contrast to some other findings.

The new work found no evidence of changes in chromosomes in white blood cells after three months of treatment.

"This is good news for parents," said co-author Kristine L. Witt. The researchers said this was final proof that stimulants to treat ADHD don't do genetic damage.

The work looked at 47 children ages 6 to 12 who hadn't been treated for ADHD with stimulants before. Some were treated with the compound sold as Ritalin AL or Concerta, others took Adderall.

The researchers found no significant differences between the two groups of children, and they responded equally well to treatment.

"These results add to a growing body of evidence that therapeutic levels of these medications do not damage chromosomes," said Dr. Donald R. Mattison.