Narrator: This is Science Today. ADHD, or Attention Deficit Hyperactivity Disorder, is the newest name for a condition that's actually been noted since the 1800s. Stephen Hinshaw, chair of the psychology department at the University of California , Berkeley , explains that at the time people began to realize a subgroup of kids didn't learn to read, even though they seemed to have normal intelligence.

Hinshaw: They also realized that other kids who seemed to be functioning well in many domains couldn't focus attention well, were quite impulsive and showed high activity level much more than their peers. This was called minimal brain dysfunction, hyperactivity before the name ADD and now, ADHD took force about fifteen years ago.

Narrator: Hinshaw admits some symptoms of ADHD are part of a normal growing curve, but beyond a certain point, making a diagnosis is important.

Hinshaw: Kids with ADHD are at risk for school failure, delinquent behavior. They're also at high risk for accidental injury. So even though its behaviors meld into the normal range, a careful diagnosis of ADHD shows a kid at risk for very serious consequences.

Narrator: For Science Today, I'm Larissa Branin.