Russell A. Barkley, PhD, ABPP ABCN, Professor of Psychiatry, Medical University of South Carolina; Past President, Clinical Child Psychology Section of the American Psychological Association and of the International Society for Research in Child and Adolescent Psychopathology; Author, Barkley Deficits in Executive Functioning Scale-Children and Adolescents (2012), Executive Functions: What They Are, How They Work, and Why They Evolved (2012) and ADHD in Adults: What the Science Says (2007)