The American Academy of Pediatrics recommends that children have no more than two hours a day of "screen time." Marilyn Nieves/iStockphoto.com hide caption

itoggle caption Marilyn Nieves/iStockphoto.com

Ten milligram tablets of the prescription drug Adderall. The drug is used to treat ADHD and is used by some students to boost their academic performance. Jb Reed/Bloomberg via Getty Images hide caption

itoggle caption Jb Reed/Bloomberg via Getty Images

Eliminating junk food from a child's diet is usually not enough to effectively treat attention deficit disorders, a paper shows. Tarah Dawdy via Flickr hide caption

itoggle caption Tarah Dawdy via Flickr