Why loneliness is bad for your health

Saima Sidik in Nature:

In 2010, Theresa Chaklos was diagnosed with chronic lymphocytic leukaemia — the first in a series of ailments that she has had to deal with since. She’d always been an independent person, living alone and supporting herself as a family-law facilitator in the Washington DC court system. But after illness hit, her independence turned into loneliness. Loneliness, in turn, exacerbated Chaklos’s physical condition. “I dropped 15 pounds in less than a week because I wasn’t eating,” she says. “I was so miserable, I just would not get up.” Fortunately a co-worker convinced her to ask her friends to help out, and her mood began to lift. “It’s a great feeling” to know that other people are willing to show up, she says.

Many people can’t break out of a bout of loneliness so easily. And when acute loneliness becomes chronic, the health effects can be far-reaching. Chronic loneliness can be as detrimental as obesity, physical inactivity and smoking according to a report by Vivek Murthy, the US surgeon general. Depression, dementia, cardiovascular disease1 and even early death2 have all been linked to the condition. Worldwide, around one-quarter of adults feel very or fairly lonely, according to a 2023 poll conducted by the social-media firm Meta, the polling company Gallup and a group of academic advisers (see go.nature.com/48xhu3p). That same year, the World Health Organization launched a campaign to address loneliness, which it called a “pressing health threat”.

But why does feeling alone lead to poor health?

More here.