ADHD usually isn't a child's only diagnosis.
Many kids with ADHD also have a language or learning problem, and more than half have at least one other mental-health disorder -- which can make medication treatment more complicated. Children with ADHD are most likely to have oppositional defiant disorder; they can be very hostile to adults and intentionally bother other people. Although an increasing number of kids are now being diagnosed with both ADHD and bipolar disorder -- which share many symptoms -- experts believe that most kids actually have only one or the other. The key distinction is that a child with bipolar disorder has a distorted sense of reality. "A child with ADHD might like to race around the house in his Superman cape, but a bipolar child might truly believe he has superpowers that can make him fly," says Dr. Koplewicz. However, more research still needs to be done to help doctors make the most accurate diagnoses.