Research presented last month at the annual meeting of the Society for Personality and Social Psychology points to health implications for people who are lonely.
The researchers found that lonely people are more likely than other people to produce certain inflammatory compounds in response to stress. This can lead to heart disease and other chronic and life-threatening illnesses, according to study researcher, Lisa Jaremka, a postdoctoral fellow at the Institute for Behavioral Medicine Research at Ohio State University College of Medicine.
Jaremka and her team looked at loneliness and immune function based on other academic findings that link socially disconnected feelings with poor health and a higher risk for developing chronic diseases.
The research team worked with 200 female breast cancer survivors and 134 middle–aged adults who were overweight, but had no major health issues. The team tested the breast cancer survivors' blood for certain antibodies to a common virus that can lay dormant for long periods of time. The higher the antibody levels, the more activated the virus is in the body. The same participants also answered questionnaires about their feelings of loneliness and social connection. What the researchers found was a pattern: the loneliest participants also had the higher levels of antibodies in their blood.
"It's definitely indicating that the immune system is compromised in some way," Jaremka told LiveScience. "It's unable at that time, for whatever reason, in this case loneliness perhaps, to keep that virus under control."
The team also measured inflammatory proteins in both study groups. The subjects gave blood samples and put under stressful conditions, such as giving a speech or performing math problems for an audience. In this study, the lonelier people also demonstrated higher levels of cytokine interleukin-6, which is connected with the increase of inflammation in the body. It can lead to heart disease, arthritis, Type 2 diabetes and possibly even suicide attempts.
Loneliness appears to create a chronic state of stress in individuals, particularly creating inflammation and immune sensitivity. The lonely people also had stronger reactions to negative situations, which caused more stress and more health issues.
But what exactly defines loneliness?
The researchers had a harder time defining what loneliness is rather than what it isn't: It's not a feeling close connections and support—whether in a romantic partnership or not; the people that had strong social connections and the ability to find support from their community were also the ones who reported the least lonely feelings.
And it's important to note the difference between being alone and being lonely. Humans need a good amount of time to themselves for many different reasons. But feeling isolated and disconnected, is an indicator of loneliness.
Keep in touch with Jill on Twitter @jillettinger
Photo credit: B Rosen
