The University of Chicago issued the following news release:

Loneliness can be contagious
People who feel lonely spread that feeling to others

Loneliness, like a bad cold, can spread among groups of people, research
at the University of Chicago, the University of California-San Diego and
Harvard shows.

Using longitudinal data from a large-scale study that has been following
health conditions for more than 60 years, a team of scholars found that
lonely people tend to share their loneliness with others. Gradually over
time, a group of lonely, disconnected people moves to the fringes of
social networks.

“We detected an extraordinary pattern of contagion that leads people to
be moved to the edge of the social network when they become lonely,”
said University of Chicago psychologist John Cacioppo, one member of the
study team and one of the nation’s leading scholars of loneliness. “On
the periphery people have fewer friends, yet their loneliness leads them
to losing the few ties they have left.”

Other members of the study team were James Fowler, Associate Professor
of Political Science at the University of California-San Diego, and
Nicholas Christakis, Professor of Medicine and Professor of Medical
Sociology in the Harvard Medical School.

Before relationships are severed, people on the periphery transmit
feelings of loneliness to their remaining friends, who also become
lonely. “These reinforcing effects mean that our social fabric can fray
at the edges, like a yarn that comes loose at the end of a crocheted
sweater,” said Cacioppo, the Tiffany & Margaret Blake Distinguished
Service Professor in Psychology.

Because loneliness is associated with a variety of mental and physical
diseases that can shorten life, Cacioppo said it is important for people
to recognize loneliness and help those people connect with their social
group before the lonely individuals move to the edges.

The scholars’ findings were published in the article, “Alone in the
Crowd: The Structure and Spread of Loneliness in a Large Social
Network,” published in the December issue of the Journal of Personality
and Social Psychology.

For the study, the team examined records of the Framingham Heart Study,
which has studied people in Framingham, Mass. since 1948. The original
group, including more than 5,209 people, was originally studied for the
risks of cardiovascular disease.

The study has since been expanded to include about 12,000 people, as the
children and the grandchildren of the original group and others have
been included to diversify the population sample. The Framingham study
now includes more tests, including measures of loneliness and
depression. The second generation in the study, which includes 5,124
people, was the focus of the loneliness research.

Because the study is longitudinal, researchers kept in touch with the
subjects every two to four years and accordingly collected names of
friends who knew the subjects. Those records became an excellent source
of information about the people’s social networks.

By constructing graphs that charted the subjects’ friendship histories
and information about their reports of loneliness, researchers were able
to establish a pattern of loneliness that spread as people reported
fewer close friends. The data showed that lonely people “infected” the
people around them with loneliness, and those people moved to the edges
of social circles.

The team found that the next-door neighbors in the survey who
experienced an increase of one day of loneliness a week prompted an
increase in loneliness among their neighbors who were their close
friends. The loneliness spread as the neighbors spent less time together.

Previous work suggested that women rely on emotional support more than
men do, and in this study women were more likely than men to report
“catching” loneliness from others. People’s chances of becoming lonely
were more likely to be caused by changes in friendship networks than
changes in family networks.

Research also shows that as people become lonely, they become less
trustful of others, and a cycle develops that makes it harder for them
to form friendships. Societies seem to develop a natural tendency to
shed these lonely people, something that is mirrored in tests of
monkeys, who tend to drive off members of their groups who have been
removed from a colony and then reintroduced, Cacioppo said.

That pattern makes it all the more important to recognize loneliness and
deal with it before it spreads, he said.

“Society may benefit by aggressively targeting the people in the
periphery to help repair their social networks and to create a
protective barrier against loneliness that can keep the whole network
from unraveling,” he said.

The research was supported by a grant from the National Institute on Aging.

“Previous research has shown that loneliness and lack of social
connection can have a significant negative effect on the overall health
and well-being of older people,” said Richard Suzman, Ph.D., director of
the NIA’s Division of Behavioral and Social Research, which funded the
research. “This pioneering research into the connections of individuals
within their social networks has important implications for the larger
issue of social interactions and health.”