Professor Cacioppo has spent much of his career documenting the dangers of loneliness. But it’s notable that he relies on more measured statistics in his own scientific papers than the statistics described above. One of his articles, from last year, reports that around 19 percent of older Americans said they had felt lonely for much of the week before they were surveyed, and that in Britain about 6 percent of adults said they felt lonely all or most of the time. Those are worrisome numbers, but they are quite similar to the numbers reported in Britain in 1948, when about 8 percent of older adults said they often or always felt lonely, and to those in previous American studies as well.

Professor Cacioppo is one of the leading voices advocating for better treatment of loneliness. But, as he has written, “to call it an epidemic of loneliness risks having it relegated to the advice columns.”

In particular, overstating the problem can make it harder to make sure we are focusing on the people who need help the most.