Fighting fire with fire, researchers use video games to retrain the brains of children with attention deficit hyperactivity disorder. As Devin Coons stares at the computer screen, he looks like any teen goofing off. But researchers say the game he’s playing is actually helping him do better in school. Coons is one of about 3 million American children who take medication for attention deficit hyperactivity disorder, or ADHD.

Without pills, says his mother Giti Coons, he can’t get through his homework — any distraction will shake his concentration. “Anything,” she says. “You could drop a set of keys, and it would be over for the next half hour.” Coons is one of more than 100 children participating in an experiment to see if children diagnosed with ADHD can increase their concentration, and reduce their dependence on medication, through neurofeedback. “The brain gets better with exercise,…