Baby boomers appear to be driving a dramatic rise in suicide rates among middle-aged people, according to a new study by sociologists Ellen Idler of Emory University and Julie Phillips of Rutgers University.

The suicide rate for the U.S. population overall has been declining for decades, Idler notes. But the baby boomers, people born between 1945 and 1964, have broken that pattern. T: 12 Questions: Peter Tork

Higher rates of substance abuse and the onset of chronic diseases are among other possible factors in the rising baby boomer suicide rate. “As children, the baby boomers were the healthiest cohort that had ever lived, due to the availability of antibiotics and vaccines,” Idler says. “Chronic conditions could be more of a rude awakening for them in midlife than they were for earlier generations.”

Traditionally, midlife has been considered a time when people are at their peak of social integration. “We need to pay attention to this new increase in suicides, during a period of life previously thought to be stable and relatively protected from suicide, and in an age group now occupied by extraordinarily large numbers of people,” Idler says.