ADHD is often diagnosed when a child reaches school age although many parents say they knew something was "wrong" or "different" for several years before that. Because there is no physical diagnostic test for ADHD, parents, even when concerned, have no way of having their child tested for ADHD until at least 3 years old, but usually school age.

A recent study, however, may give some new insight into children that may be at risk of ADHD. This study linked low APGAR scores with a higher ...