Addiction and mental-health issues largely drive a reversal of decades of longevity gains.

White, middle-aged Americans are dying at a rising rate, a new study shows, a startling reversal that suggests addiction and mental-health issues are setting back decades of gains in longevity. Suicide, alcohol abuse, drug overdoses and chronic liver diseases largely drove the rise, which occurred between 1999 and 2013, according to the report published Monday in the Proceedings of the National Academy of Sciences. Those causes of death offset declines in other major drivers of mortality in midlife, such as lung cancer, the study said. The study “is going to change the game” for setting research priorities in public health, predicted Michael Eriksen, dean of Georgia State University’s School of Public Health, who wasn’t involved in the work. “Substance abuse and alcoholism are taking their toll in a way people haven’t acknowledged,” he said. No other rich country has seen a similar reversal, and the trend is at odds with falling death rates for black and Hispanic Americans in that age group over the same period, said the authors, Anne Case and Angus Deaton, who are economics professors at Princeton University. Mr. Deaton won the Nobel Prize in economics this year. The rise occurred primarily among men and women between 45 and 54 with no more than a high-school education. But deaths from those causes also rose for better-educated middle-aged whites as well as whites in other age groups, according to the study. Death rates are defined in the study as the number of deaths per 100,000 people for each age cohort. Ms. Case and Mr. Deaton found that mortality rose half a percent annually for whites aged 45 to 54 between 1999 and 2013, after declining 2% a year on average between 1978 and 1998. Had mortality continued to decline at that rate, 488,500 deaths would have been avoided between 1999 and 2013, they said. The study is based on data from the Centers for Disease Control and Prevention, individual death records and other sources.

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