or mental illness. This is a belief echoed by academic psychologists. Some mental health experts are concerned that labeling a disruptive child an "indigo" may delay proper diagnosis and treatment that could help the child or look into the parenting style that may be causing the behavior. Others have stated that many of the traits of indigo children could be more prosaically interpreted as simple unruliness and alertness. Relationship to attention-deficit hyperactivity disorder Many children labeled indigo by their parents are diagnosed with attention-deficit hyperactivity disorder (ADHD) and Tober and Carroll's book The Indigo Children linked the concept with diagnosis of ADHD. David Cohen points out that labeling a child an indigo is an alternative to a diagnosis that implies mental illness, which may appeal to many parents. Cohen has stated, "The view in medicine is that ADHD is a defect. It's a disorder. If you're a parent, the idea of 'gifted' is much more appealing than the idea of a disorder." Linking the concept of indigo children with the distaste for the use of Ritalin to control ADHD, Robert Todd Carroll states "The hype and near-hysteria surrounding the use of Ritalin has contributed to an atmosphere that makes it possible for a book like Indigo Children to be taken seriously. Given the choice, who wouldn't rather believe their children are special and chosen for some high mission rather than that they have a brain disorder?" Stephen Hinshaw, a professor of psychology at the University of California, Berkeley, states that concerns regarding the overmedicalization of children are legitimate but even gifted children with ADHD learn better with more structure rather than less, even if the structure initially causes difficulties. Many labeled as indigo children are or have been home schooled. Many children labeled as indigo children have the same identifying criteria as those children who have experienced being raised by a narcissistic parent, and are considered to have been emotionally abused. A 2011 study suggested parents of children with ADHD who label their children as "indigos" may perceive problematic behaviors emblematic of ADHD to be more positive and experience less frustration and disappointment, though they still experience more negative emotions and conflicts than parents of children without a diagnosis. Relation to autism Crystal children, a concept related to indigo children, has been linked by autism researcher Mitzi Waltz to the autism spectrum. Proponents recategorize autistic symptoms as telepathic powers, and