Social solution Richard Wilkinson

Read more: “Heal thyself: The power of mind over matter”

Your attitude towards other people can have a big effect on your health. Being lonely increases the risk of everything from heart attacks to dementia, depression and death, whereas people who are satisfied with their social lives sleep better, age more slowly and respond better to vaccines. The effect is so strong that curing loneliness is as good for your health as giving up smoking, according to John Cacioppo of the University of Chicago, Illinois, who has spent his career studying the effects of social isolation.

“It’s probably the single most powerful behavioural finding in the world,” agrees Charles Raison of Emory University in Atlanta, Georgia, who studies mind-body interactions. “People who have rich social lives and warm, open relationships don’t get sick and they live longer.” This is partly because people who are lonely often don’t look after themselves well, but Cacioppo says there are direct physiological mechanisms too – related to, but not identical to, the effects of stress.


In January of this year, Cacioppo reported that in lonely people, genes involved in cortisol signalling and the inflammatory response were up-regulated, and that immune cells important in fighting bacteria were more active, too. He suggests that our bodies may have evolved so that in situations of perceived social isolation, they trigger branches of the immune system involved in wound healing and bacterial infection. An isolated person would be at greater risk of physical trauma, whereas being in a group might favour the immune responses necessary for fighting viruses, which spread easily between people in close contact.

Crucially, these differences relate most strongly to how lonely people believe themselves to be, rather than to the actual size of their social network. That also makes sense from an evolutionary point of view, says Cacioppo, because being among hostile strangers can be just as dangerous as being alone. So ending loneliness is not about spending more time with people. Cacioppo thinks it is all about our attitude to others: lonely people become overly sensitive to social threats and come to see others as potentially dangerous. In a review of previous studies, published last year, he found that tackling this attitude reduced loneliness more effectively than giving people more opportunities for interaction, or teaching social skills (Annals of Behavioral Medicine, vol 40, p 218).

If you feel satisfied with your social life, whether you have one or two close friends or quite a few, there is nothing to worry about. “But if you’re sitting there feeling threatened by others and as if you’re alone in the world, that’s probably a reason to take steps,” Cacioppo says.