In 2015, two Princeton University economists published a key study showing that life expectancies were beginning to decrease for middle-aged Caucasians. The deaths were often attributed to drugs, alcohol, and suicide—the pair dubbed these “deaths of despair.” To probe the phenomenon further, UVA professor Christopher Ruhm examined U.S. mortality rates from 1999 to 2015. He found that increases in drug-related deaths during that period could account for “the entire growth” in mortality rates and years of potential life lost among Caucasians aged 22–56. “We have this surprising result that white...