Lonelier people are more likely to become depressed and experience more fatigue. People who felt socially disconnected are able to tolerate less physical pain than those who felt more socially connected. Loneliness, a socially painful state of perceived social isolation, may be a common risk factor for pain, depression, and fatigue. Immune dysregulation is one of the suggested mechanisms linking these. It has been shown in the past that lonelier medical students and lonelier psychiatric inpatients had lower natural killer cell activity, an important anti-tumor and anti-viral defense, than those who felt more socially connected. lonely people generate a smaller antibody response to vaccination as well. Lonely people have more of certain cytokines ( monocyte chemotactic protein-1 involved in arthritis and atherosclerosis) & Interleukin-6 linked to age related disorders and over expression of pro inflammatory genes. Immune dysregulation is shown to be related to pain, depression and fatigue in many studies.
Other mechanisms suggested include: lonely people are more likely to have larger BP increases over time with ill effects on health. Stress of being lonely can cause HPA dysregulation. Loneliness may be associated with poor sleep and poor physical activity.
Lisa M. Jaremka and team of researchers looked at antibody titers to two common herpesviruses, EBV and CMV among a selected sample of 200 breast cancer survivors in their 50s and measured loneliness, pain, fatigue and related parameters. Loneliness was measured with the UCLA Loneliness Scale.
97% of sample were EBV seropositive and 52% CMV seropositive.
1. CMV seropositive people did not differ from those who were seronegative on loneliness, pain, depression, fatigue, or either symptom cluster composite . They did not test for EBV seropositivity differences because 97% of the sample was seropositive.
2. Lonelier participants had higher CMV antibody titers than less lonely participants
3. Lonelier breast cancer survivors experienced more pain, depression, and fatigue than their less lonely counterparts. The relationships among CMV antibody titers and the individual symptoms were strongest for depression and fatigue.
Limitations: Cross sectional study and hence direction of causality unclear
Conclusion: Loneliness enhances risk for immune dysregulation and the pain, depression, and fatigue symptom cluster.
Summary of the article:
Jaremka LM, Fagundes CP, Glaser R, Bennett JM, Malarkey WB, Kiecolt-Glaser JK. Psychoneuroendocrinology. 2013 Aug;38(8):1310-7.