Attention-Deficit/Hyperactivity Disorder (ADHD) and Attention Deficit Disorder (ADD) symptoms are identical to those of anxiety and depression and have a long history, having been asserted to "mental restlessness" in the eighteenth century and Minimal Brain Dysfunction (MBD) in the early twentieth century. These terms are descriptions of behavior, and to believe that they explain anything is to engage in circular reasoning (as, that a child has Attention Deficit Disorder because they have a problem paying attention).