Daniel G. Amen

Daniel Gregory Amen is an American psychiatrist, a brain disorder specialist, director of the Amen Clinics, and a New York Times bestselling author.
Amen's clinics offer medical services to people who have attention deficit hyperactivity disorder and other disorders. They use single photon emission computed tomography as a purported diagnostic tool to identify what he says are sub-categories of these disorders, as devised by Amen himself. Although highly profitable, Amen's use of SPECT scans to aid in psychiatric and neurological clinical diagnosis is based on unproven claims and has been widely criticized.
He has done studies on brain injuries affecting professional athletes, and he is a post-concussion expert for the National Football League.