Attention deficit hyperactivity disorder is a condition that affects more than 3 million people in the United States alone. But what is ADHD disorder? It is a chronic disease that can stick with you for a lifetime, but medication can help you to live for years with it under control. It does require a medical diagnosis to determine if you have this condition and it often appears in childhood. If you suspect you or a loved one has ADHD disorder, make sure you take our quick online test.