Much attention has been paid to the overdiagnosis of attention deficit hyperactivity disorder in children and the over-prescription of drugs such as ritalin, but a study published this week in the journal Pediatrics indicates that certain kids -- those in the youngest third of their class -- are 50 percent more likely than their older peers to be prescribed ADHD drugs.

They’re also more likely to under-perform on math and English standardized tests administered in fourth grade, one of the factors teachers and pediatricians use to help make a diagnosis of ADHD.