ADHD was originally thought of as “minimal brain dysfunction,” according to scholar Robert Erk. In the 1940s, “practitioners came to the conclusion that because many children with Attention-Deficit Hyperactivity Disorder…manifested some of the same symptoms as children with encephalitis (e.g., hyperactivity, inattention, disorganization), these children probably had some degree of minimal brain damage.” For the next two decades, scientists would link behavioral disorders with injury to the brain.