The earlier you can diagnose ADHD, the better. Kids often struggle in school and in the community due to a lack of help and from a misunderstanding of their condition. This often leads to frustration, increased inappropriate behavior, poor academic achievement, and eventually low self-esteem and depression, not to mention an increased likelihood for substance abuse. Early and appropriate intervention can prevent these serious consequences, and instead promote healthy development with the prospects for a more satisfying life in childhood and as an adult. If you suspect that your child may have ADHD, start with a trip to a trusted pediatrician and go from there.
And if your child is diagnosed with ADHD, I would recommend that parents look into the type of cognitive behavioral therapy or program that provides cognitive exercises and simple biofeedback to improve attention, concentration and executive functioning that leads to improved academic achievement and success in other activities. Make sure it helps children to understand the difference in brain function, and to learn coping strategies that foster a positive self-image, as well.