Skip to main content

Verified by Psychology Today


Why Loneliness Is More Than Just a Feeling

The physical and mental health repercussions of loneliness.

Key points

  • The consequences of loneliness may extend beyond the emotional experience itself.
  • Lower social and emotional support have been associated with less cognitive resilience and greater dementia risk.
  • A person’s race, ethnicity, or gender can affect their income and education, leading to differences that can contribute to loneliness.

This post is by Joel Salinas, M.D., and medical student Amanda Zhao.

The COVID-19 pandemic has unfortunately forced our global community to become particularly and personally attuned to the issues of loneliness and social isolation, and it has disrupted all of our relationships and social networks. However, these issues may be even more serious than you think—our new study released this week demonstrates how loneliness can increase the risk of developing dementia.

Why should we understand loneliness?

Loneliness, defined as the subjective feeling that you are not receiving the level of social support that you want, is pervasive in American society—a survey of 950 US adults in October 2020 found that more than a third of respondents, including almost two-thirds of all young adults, felt “serious loneliness.” Other surveys estimate the prevalence of loneliness in older adults to be between 25 and 60%. However, the consequences of loneliness may extend beyond the emotional experience itself; a growing body of research has begun to document the physical and mental health repercussions of loneliness.

Loneliness isn’t just the perception of social isolation—it can kill.

One study found that loneliness and social isolation were associated with a higher risk of mortality. Higher ratings of loneliness have also been linked to higher blood pressures and greater and faster progression of coronary artery disease and heart failure. This link between loneliness and poorer heart health could be driven both by behavior (e.g., lonely people may practice less healthful behaviors) and by biology (e.g., loneliness may lead to an exaggerated stress response, leading to increased heart strain).

Other studies link loneliness to dysregulation of the body’s hormones. Lonely persons seem to have higher levels of cortisol, the body’s stress hormone, in their urine and saliva.

Loneliness also has many well-documented mental health consequences across the lifespan. A study of British children found a link between higher levels of early childhood loneliness and later-life depression; higher ratings of loneliness have been associated with lower cognitive performance in older adulthood as well as higher risk of dementia. Specifically, in our research, lower social and emotional support have been associated with less cognitive resilience and greater dementia risk, respectively. A recently published study from our lab finds that loneliness is linked with an increased 10-year risk of developing dementia, and this risk is tripled in individuals with low baseline risk of Alzheimer’s disease or other dementias.

What factors contribute to loneliness?

A recent Dutch study of more than 52,000 people spanning late adolescence to older age found that while some risk factors universally predicted loneliness across age groups (e.g., lower education, male sex, fewer financial resources, and informal caregiving roles), other risk factors are age-specific. Interestingly, in early adulthood, migration from non-Western areas was the second greatest risk factor for loneliness, which the study attributed to greater experiences of stigmatization and discrimination, leading to fewer intimate peer relationships.

Other studies also examine the prevalence of loneliness in the socially subordinated. A 2020 study of Medicare beneficiaries found that Hispanic/Latinx older adults are more likely than non-Hispanic whites to experience loneliness, and to experience the detrimental health effects from social isolation. Racial and ethnic minorities are already predisposed to poorer health outcomes for a variety of reasons; research shows that these disparities are even further compounded by loneliness. A study of low-income senior African Americans found that greater loneliness and perceived stress led to poorer physical health-related quality of life. A person’s race, ethnicity, or gender can affect their income and education, leading to differences in social network size and relationship quality, both of which contribute to their experience of loneliness.

Where does this leave us?

Loneliness is growing—and growing fast. It is a serious issue with serious mental and health repercussions. The factors that lead to loneliness are complex, varying across the lifespan and across different racial, ethnic, and demographic groups, and socially subordinated groups may be at particular risk, and as such, deserve further, dedicated intervention.

In this unpredictable pandemic world, loneliness and social isolation have unfortunately become the new normal, but we must fight against this. Reach out to your friends and family. Be a listener for someone in your life. Finding ways to safely connect with friends and family will continue to require effort, but we can, and will, get through this together.

At our lab, the UNICORN Lab, we hope to contribute to what is known about the health effects of loneliness, paying special attention to the interplay of race, ethnicity, and socioeconomic background in these effects. In particular, we are using biological markers and cutting-edge imaging techniques to learn how loneliness, and other elements of the social environment, may contribute to risk of developing Alzheimer’s disease and related dementias.


Bhatti, A. B. and A. U. Haq (2017). "The Pathophysiology of Perceived Social Isolation: Effects on Health and Mortality." Cureus 9(1): e994-e994.

Cacioppo, J. T., J. M. Ernst, M. H. Burleson, M. K. McClintock, W. B. Malarkey, L. C. Hawkley, R. B. Kowalewski, A. Paulsen, J. A. Hobson, K. Hugdahl, D. Spiegel and G. G. Berntson (2000). "Lonely traits and concomitant physiological processes: the MacArthur social neuroscience studies." Int J Psychophysiol 35(2-3): 143-154.

Gow, A. J., J. Corley, J. M. Starr and I. J. Deary (2013). "Which social network or support factors are associated with cognitive abilities in old age?" Gerontology 59(5): 454-463.

Hawkins, K., S. Musich, S. Wang and C. Yeh (2015). "The Impact of Loneliness on Quality-of-Life and Patient Satisfaction Among Sicker, Older Adults." The American Journal of Geriatric Psychiatry 23(3): S168-S169.

Hawkley, L. C., M. E. Hughes, L. J. Waite, C. M. Masi, R. A. Thisted and J. T. Cacioppo (2008). "From Social Structural Factors to Perceptions of Relationship Quality and Loneliness: The Chicago Health, Aging, and Social Relations Study." The Journals of Gerontology: Series B 63(6): S375-S384.

Hawkley, L. C., C. M. Masi, J. D. Berry and J. T. Cacioppo (2006). "Loneliness is a unique predictor of age-related differences in systolic blood pressure." Psychol Aging 21(1): 152-164.

Holaday, L. W., C. R. Oladele, S. M. Miller, M. I. Dueñas, B. Roy and J. S. Ross (2021). "Loneliness, sadness, and feelings of social disconnection in older adults during the COVID-19 pandemic." J Am Geriatr Soc.

Holt-Lunstad, J., T. B. Smith, M. Baker, T. Harris and D. Stephenson (2015). "Loneliness and social isolation as risk factors for mortality: a meta-analytic review." Perspect Psychol Sci 10(2): 227-237.

Hutten, E., E. M. M. Jongen, K. Hajema, R. A. C. Ruiter, F. Hamers and A. E. R. Bos (2021). "Risk factors of loneliness across the life span." Journal of Social and Personal Relationships: 02654075211059193.

Kiecolt-Glaser, J. K., D. Ricker, J. George, G. Messick, C. E. Speicher, W. Garner and R. Glaser (1984). "Urinary cortisol levels, cellular immunocompetency, and loneliness in psychiatric inpatients." Psychosom Med 46(1): 15-23.

Möller, M., J. L. Du Preez, F. P. Viljoen, M. Berk, R. Emsley and B. H. Harvey (2013). "Social isolation rearing induces mitochondrial, immunological, neurochemical and behavioural deficits in rats, and is reversed by clozapine or N-acetyl cysteine." Brain Behav Immun 30: 156-167.

Noonan, A. S., H. E. Velasco-Mondragon and F. A. Wagner (2016). "Improving the health of African Americans in the USA: an overdue opportunity for social justice." Public health reviews 37: 12-12.

Qualter, P., S. L. Brown, P. Munn and K. J. Rotenberg (2010). "Childhood loneliness as a predictor of adolescent depressive symptoms: an 8-year longitudinal study." Eur Child Adolesc Psychiatry 19(6): 493-501.

Salinas, J., A. Beiser, J. J. Himali, C. L. Satizabal, H. J. Aparicio, G. Weinstein, F. J. Mateen, L. F. Berkman, J. Rosand and S. Seshadri (2017). "Associations between social relationship measures, serum brain-derived neurotrophic factor, and risk of stroke and dementia." Alzheimers Dement (N Y) 3(2): 229-237.

Salinas, J., A. S. Beiser, J. K. Samra, A. O'Donnell, C. S. DeCarli, M. M. Gonzales, H. J. Aparicio and S. Seshadri (2022). "Association of Loneliness With 10-Year Dementia Risk and Early Markers of Vulnerability for Neurocognitive Decline." Neurology: 10.1212/WNL.0000000000200039.

Salinas, J., A. O'Donnell, D. J. Kojis, M. P. Pase, C. DeCarli, D. M. Rentz, L. F. Berkman, A. Beiser and S. Seshadri (2021). "Association of Social Support With Brain Volume and Cognition." JAMA Netw Open 4(8): e2121122.

Sundström, A., A. N. Adolfsson, M. Nordin and R. Adolfsson (2020). "Loneliness Increases the Risk of All-Cause Dementia and Alzheimer's Disease." J Gerontol B Psychol Sci Soc Sci 75(5): 919-926.

Weissbourd, R. B., Milena; Lovison, Virginia; Torres, Eric (2021). Loneliness in America: How the Pandemic Has Deepened an Epidemic of Loneliness and What We Can Do About It. Making Caring Common.

White, C. N., L. E. VanderDrift and K. S. Heffernan (2015). "Social isolation, cognitive decline, and cardiovascular disease risk." Current Opinion in Psychology 5: 18-23.

Wippold, G. M., C. M. Tucker, J. Roncoroni and M. A. Henry (2021). "Impact of Stress and Loneliness on Health-Related Quality of Life Among Low Income Senior African Americans." J Racial Ethn Health Disparities 8(4): 1089-1097.