Alan Schwarz

With several of its marquee players retiring early after a cascade of frightening concussions, the league formed a committee in 1994 that would ultimately issue a succession of research papers playing down the danger of head injuries.

Some users embrace kratom as a natural painkiller and benign substitute for more dangerous substances that, in most states, is legal. But government officials say it is being furtively marketed as a way out of addiction, even though it is itself addictive.

David A. Patterson is a tenure-track assistant professor at the George Warren Brown School of Social Work at Washington University in St. Louis. In his 20s he was a drug addict, garbage collector, suicidal burnout once told by a doctor that he was mentally retarded. His groundbreaking research on the pitfalls facing Native Americans is both informed and inspired by his own story of deliverance.

Nearly one in five high-school-age boys in the United States and 11 percent of school-age children overall have received a medical diagnosis of attention deficit hyperactivity disorder. These rates reflect a marked rise over the last decade and could fuel growing concern among many doctors that the ADHD diagnosis and its medication are overused in American children.