Is ADHD a real disorder?

Despite overwhelming scientific evidence that approximately 5 percent of children have a specific deficit in attention compared to children of their same age and sex, many people still question whether ADHD (and some still call it it's former name: ADD) is a real disorder. A recent article in the New York Times takes on this subject carefully. The article outlines biological evidence that finds clear correlates to the disorder, including molecular genetics, twin studies indicating shared genetic inheritance, and neuroimaging studies finding brain structures and activity within the brain related to ADHD. The article also points out an extremely important point about whether ADHD is truly a "you either have it or you don't" phenomenon. While currently the disorder is given as Yes or No, from research and clinical work many have concluding that the symptoms occur on a spectrum. There are some children who have milder problems with attention, whereas others have difficulties so intense that new classroom arrangements are necessary. Although ADHD is complex, especially given the complex nature of attention, the consensus among experts ranging from psychology, psychiatry, and neuroscience all conclude on its importance as a true disorder. Further work is needed to determine how best to integrate a spectrum or continuum approach to the diagnosis, and whether problems with attention and hyperactivity/impulsivity should be equally weighted in importance.