Show Summary Details

Page of

PRINTED FROM the OXFORD RESEARCH ENCYCLOPEDIA, PSYCHOLOGY ( (c) Oxford University Press USA, 2020. All Rights Reserved. Personal use only; commercial use is strictly prohibited (for details see Privacy Policy and Legal Notice).

date: 12 August 2020

Loneliness and Health

Summary and Keywords

Loneliness or perceived social isolation is a subjective experience relating to dissatisfaction with one’s social relationships. Most research has focused on the experience of loneliness in old age, but levels of loneliness are also known to be high among teenagers and young adults. While poor health may be associated with increased feelings of loneliness, there is now considerable evidence on the role of loneliness as a risk factor for poor mental and physical health. Studies show that loneliness is associated with an increased risk of developing dementia and chronic diseases, and also with a higher rate of mortality. Risky health behaviors, a poor cardiovascular profile and compromised immune functioning have all been proposed as potential pathways through which loneliness may affect health. However, much still remains to be understood about these mechanisms.

Keywords: loneliness, perceived isolation, mechanisms, health behaviors, cardiovascular functioning, immune functioning


Loneliness refers to dissatisfaction with one’s personal relationships. Often termed as “perceived social isolation,” loneliness can be distinguished from “objective” isolation measures such as living arrangements, social contact, or social engagement. Feelings of loneliness involve a subjective evaluation related to a person’s expectations of and satisfaction with the frequency and closeness of contacts (de Jong Gierveld & Havens, 2004), and the perception of a discrepancy between available and desired social connections (Peplau & Perlman, 1982). It is, therefore, possible to be socially connected and experience feelings of loneliness (J. T. Cacioppo, Cacioppo, Cole, et al., 2015; J. T. Cacioppo et al., 2000; Cornwell & Waite, 2009). Feelings of loneliness are unpleasant and distressing (Peplau & Perlman, 1982). All individuals experience loneliness at some point, and in most cases this is a transient state. Indeed, feelings of loneliness may even play an adaptive role by prompting a person to take steps to alleviate such feelings by trying to build closer relationships with others (J. T. Cacioppo et al., 2006; Hawkley & Cacioppo, 2010; Hawkley & Capitanio, 2015; Peplau & Perlman, 1982; Weiss, 1973). However, for some people the experience of loneliness is severe and persistent. This chronic loneliness is particularly damaging to mental and physical health (Hawkley & Cacioppo, 2010).

Loneliness Across the Life Course

While loneliness is often portrayed as a phenomenon that is unique to older age, it can be experienced across the life course. Loneliness shows a U-shaped relationship with age, being particularly high in adolescence and in later life (Dykstra, 2009; Victor & Yang, 2012). Evidence from twin studies suggests that up to 50% of the variance in loneliness may be heritable (Bartels, Cacioppo, Hudziak, & Boomsma, 2008; Boomsma, Willemsen, Dolan, Hawkley, & Cacioppo, 2005; McGuire & Clifford, 2000). A genome-wide association study of loneliness using data from adults aged 50 years and over, however, showed much lower estimates of heritability (14%–27%) (Gao et al., 2017). While some studies have not found any age-related differences in the genetic architecture of loneliness (Boomsma et al., 2005; McGuire & Clifford, 2000), Bartels et al. in their longitudinal study of twins from age 7 to age 12 years found that the influence of genetic factors decreased while that of environmental factors increased with age (Bartels et al., 2008).

The reasons why people experience feelings of isolation vary across the life course in line with developmental changes and social needs (Peplau & Perlman, 1982; Qualter et al., 2015). For young children, it is important to have a large network of friends. As they grow up, more value is placed on closeness in friendships, which leads to a greater emphasis on the quality of relationships. Being accepted by one’s peer group is also important in later childhood and adolescence. Romantic relationships play an important part in adolescence and adulthood, and a lack of intimate relationships may lead to feelings of loneliness at this stage of life (Peplau & Perlman, 1982; Qualter et al., 2015). In later life, widowhood, poor health, disability, and a loss of independence are all associated with feelings of loneliness (J. T. Cacioppo, Cacioppo, Cole, et al., 2015; Hawkley et al., 2008; Qualter et al., 2015).

Demographic and Cultural Determinants

Socioeconomic status is an important predictor of loneliness, and individuals who are more socioeconomically disadvantaged, unemployed, or have low education levels often report high levels of loneliness (Bosma, Jansen, Schefman, Hajema, & Feron, 2015; Hawkley et al., 2008; Lasgaard & Friis, 2015; Pinquart & Sorensen, 2001). While several studies find that women report higher levels of loneliness when compared with men, it has been suggested that this may actually depend on the way the construct is measured (Pinquart & Sorensen, 2001). Cultural factors also play an important role in the experience of loneliness (Peplau & Perlman, 1982), and the prevalence of loneliness varies across countries (Abdallah, Stoll, & Eiffe, 2013; de Jong Gierveld & Havens, 2004; de Jong Gierveld, Keating, & Fast, 2015; Pinquart & Sorensen, 2001). Loneliness is believed to be higher in individualistic societies than in collectivist societies. However, using data from several European countries, Dykstra (2009) notes that the prevalence of loneliness is actually higher among older adults in South European countries such as Greece and Portugal, which are typically characterized by stronger social and familial ties, compared with many Scandinavian countries. This trend may be related to the expectations that people in collectivist societies hold regarding aging, and one’s relationships with children and grandchildren. Much of the work on loneliness has been carried out in North America and Europe, and there are limited data on prevalence and risk factors for loneliness in other countries. For instance, available data from countries of the former Soviet Union suggest very high levels of loneliness in some of these countries, particularly among older adults (Stickley et al., 2013). Further work is warranted in this area to better understand social and cultural influences on the experience of loneliness.

Changing family patterns and the growing number of individuals who live alone have led to concerns regarding an increase in the prevalence of loneliness. Some researchers have, however, suggested that these concerns may be unfounded (Dykstra, 2009). Longitudinal studies conducted in the Netherlands found little change in loneliness among older adults at the population level (Honigh-de Vlaming, Haveman-Nies, Bos-Oude Groeniger, de Groot, & van ’t Veer, 2014; Tijhuis, De Jong-Gierveld, Feskens, & Kromhout, 1999). Data from cross-sectional surveys suggest that the prevalence among older adults in the United Kingdom has been relatively steady since the 1940s at approximately 10% (Victor, 2016). Demographic shifts with an increase in the aging population, however, mean a possible increase in the absolute numbers of older adults who may suffer from loneliness. It must also be noted that there may be differences in methodologies and scales used across different studies, rendering comparisons difficult.

Health Effects

A number of chronic conditions bring with them pain, problems with mobility, distressing symptoms, and a range of other challenges. Such conditions may be extremely isolating and lead to feelings of loneliness (Barageine et al., 2015; Barlow, Liu, & Wrosch, 2015; Burholt & Scharf, 2014; Deckx, van den Akker, & Buntinx, 2014; Theeke & Mallow, 2013). Studies show that among individuals with chronic health conditions, feelings of loneliness may also serve to exacerbate existing symptoms. Wolf et al. found daily fluctuations in loneliness associated with worsening pain among fibromyalgia patients (Wolf & Davis, 2014; Wolf, Davis, Yeung, & Tennen, 2015). These authors found that feelings of loneliness were associated with more negative thoughts about pain among patients, which in turn led to increased experiences of pain (Wolf et al., 2015). Among cancer patients and older dementia caregivers, loneliness was found to be associated with an increased risk of a symptom cluster of pain, depression, and fatigue (Jaremka, Andridge et al., 2014). Several studies have focused on loneliness as a specific risk factor for ill health and mortality. The following section reviews some of the evidence in this area.

Morbidity and Mortality

A lack of social relationships has been associated with an increased risk of mortality, comparable to traditional risk factors such as being overweight or smoking (Holt-Lunstad, Smith, & Layton, 2010). A meta-analysis comparing the effects of objective isolation and loneliness suggests that both have an effect on mortality, with similar effect sizes (Holt-Lunstad, Smith, Baker, Harris, & Stephenson, 2015). Most studies examining mortality or other health outcomes, however, fail to examine both isolation and loneliness in conjunction. Of the two studies that do examine isolation and loneliness together in relation to mortality, one found that objective isolation but not loneliness was associated with mortality following adjustment (Steptoe, Shankar, Demakakos, & Wardle, 2013), while the other found the reverse (Holwerda et al., 2012).

A meta-analysis of 3 studies found that loneliness was associated with a nearly 30% increase in incident coronary heart disease (Valtorta, Kanaan, Gilbody, Ronzi, & Hanratty, 2016). As loneliness is often identified as an issue that is particularly pertinent to older adults, many studies have examined it as a risk factor for outcomes that are important to aging populations. These include outcomes such as declines in physical function, disability and frailty. Studies have found that loneliness is related to declines in motor function among older adults (Buchman et al., 2010; Shankar, McMunn, Demakakos, Hamer, & Steptoe, 2017), although findings with regard to reported increases in difficulties with basic daily activities such as dressing oneself, bathing and getting around are mixed (Perissinotto, Cenzer, & Covinsky, 2012; Shankar et al., 2017; Stessman, Rottenberg, Shimshilashvili, Ein-Mor, & Jacobs, 2014). In a cross-sectional analyses, loneliness was also found to be associated with frailty (defined as meeting at least three of the following criteria weight loss, exhaustion, low physical activity, slowness, or weakness) among community-dwelling Mexicans aged 70 years and older (Herrera-Badilla, Navarrete-Reyes, Amieva, & Avila-Funes, 2015) and urinary incontinence (Ramage-Morin & Gilmour, 2013).

Cognitive Function and Dementia

As with the studies of functional decline and frailty, there has been a growing interest in the role of social relationships in cognitive decline and dementia. Interactions with others are believed to contribute to building cognitive reserve (Fratiglioni, Wang, Ericsson, Maytan, & Winblad, 2000), thus protecting against deterioration in cognitive function as one ages, even in the presence of pathological brain changes. In their review of studies of loneliness and cognitive function, Boss et al. found that half the published studies were cross sectional, making it difficult to disentangle whether loneliness is a cause or consequence of declining cognitive function. Of the five longitudinal studies, two found that loneliness was associated with incident Alzheimer’s disease/dementia, one found that loneliness was associated with declining cognitive function after 10 years, and two found loneliness to be associated with declines in memory. No significant associations were found with executive function (Boss, Kang, & Branson, 2015). Kuiper et al. (2015), in their meta-analysis of three studies, found that loneliness was associated with a nearly 60% increase in the risk of incident dementia. Overall, however, the evidence for social relationships as a risk factor for cognitive decline remains poor (Baumgart et al., 2015), as studies often are unable to determine whether changes seen in cognitive decline are clinically significant. Hence, more longitudinal studies using larger samples with better measures of loneliness, using standardized assessments of cognitive function and dementia, and adjusting for important covariates and are necessary.

Furthermore, bidirectional associations between loneliness and cognitive decline are possible. Marked declines in cognitive ability are distressing, and can cause the sufferer to withdraw from social contact. Others may also feel unsure about how to interact with someone who has known cognitive difficulties (Ayalon et al., 2016). Hence, changes in functioning may lead to greater isolation and loneliness. A few studies have examined the bidirectional associations between loneliness and cognitive function. Two studies found stronger associations between cognitive function measures and later loneliness than vice versa (Ayalon, Shiovitz-Ezra, & Roziner, 2016; Zhong, Chen, Tu, & Conwell, 2016), while others have found that the reverse is true (Donovan et al., 2016; Wilson, Krueger, Arnold, & et al., 2007).

Mental Health

Loneliness and depression are often thought of as being the same. Indeed scales such as the Centre for Epidemiologic Studies Depression scale include “feeling lonely” as one of the symptoms of depression (Radloff, 1977). A genome-wide association study also found some evidence in support of the co-heritability of loneliness and depressive symptoms (Gao et al., 2017). However, studies have identified depression and loneliness as distinct constructs (J. T. Cacioppo et al., 2006; VanderWeele, Hawkley, Thisted, & Cacioppo, 2011; Weeks, Michela, Peplau, & Bragg, 1980). Indeed, feelings of loneliness are an important predictor of future incidence and severity of depression (J. T. Cacioppo, Hawkley, & Thisted, 2010; Holvast et al., 2015). It has also been suggested that depression may be a pathway through which loneliness can affect health (S. Cacioppo, Capitanio, & Cacioppo, 2014). Data from the Longitudinal Aging Study Amsterdam found that depression was a strong predictor of mortality among lonely men, suggesting that loneliness and depression in combination is particularly harmful for health (Holwerda et al., 2016).

Research with respect to other mental health conditions is largely cross-sectional in nature. Feelings of loneliness are common among individuals diagnosed with psychotic and mood disorders (Badcock et al., 2015; Giacco, Palumbo, Strappelli, Catapano, & Priebe, 2016; Sündermann, Onwumere, Kane, Morgan, & Kuipers, 2014). Świtaj et al. found that loneliness mediates the relationship between stigma and depressive symptoms among people with major psychiatric conditions (Świtaj, Grygiel, Anczewska, & Wciórka, 2014; Świtaj, Grygiel, Anczewska, & Wciórka, 2015). Loneliness is associated with the use of psychotropic drugs (Boehlen et al., 2015; Canham, 2015), independent of depressive symptoms and symptom severity (Boehlen et al., 2015). Loneliness was also identified as a potential mediator of the association between emotional dysregulation and the psychopathology associated with binge eating and bulimia nervosa (Southward et al., 2014). However, the cross-sectional designs of these studies make it difficult to determine whether loneliness is a risk factor for these mental health conditions or is an outcome, given what is known about isolation and stigma following diagnosis of a mental health condition (Alonso et al., 2009). Further, individuals with certain mental health conditions may suffer from symptoms that make it more difficult to develop and sustain close social networks (Anderson, Laxhman, & Priebe, 2015), leading to feelings of loneliness.


Health Behaviors

There are several reasons why individuals who are lonely may be more likely to have poorer health behaviors. The social control hypothesis (House, 2001) suggests that individuals who are lonely may be more prone to unhealthy practices due to limited access to social support and social cues that promote healthy behaviors. Another reason why loneliness may lead to risky health behavior is because lonely individuals are less likely to use active coping strategies when faced with stressful situations. Hence, their response to feeling or loneliness or other stressors may be through sad passivity (Rubenstein, Shaver, & Peplau, 1979), resorting to risky behaviors such as smoking, drinking to excess, or taking drugs. Another explanation suggests that feelings of loneliness lead individuals to be hypervigilant to social threats, thereby limiting the resources available to them for self-regulation (Hawkley & Cacioppo, 2010).

While these explanations might have a certain intuitive appeal, the evidence in support of loneliness leading to poor health behaviors remains equivocal. A review of the research examining the association between loneliness and physical activity found that nearly two-thirds of the studies in this area were cross sectional (Pels & Kleinert, 2016). Evidence from the longitudinal studies showed that while loneliness was associated with decreased physical activity, there was also evidence suggesting that inactivity may lead to feelings of loneliness over time. Findings from intervention studies indicate that physical activity may play a role in alleviating loneliness (Pels & Kleinert, 2016). Similarly, a review of the association between loneliness and smoking found that 13 of 25 studies reported a significant association (Dyal & Valente, 2015), but here, too, most studies were cross-sectional. Thus, it is unclear whether feelings of loneliness lead to individuals taking up smoking or whether smokers are likely to become lonelier over time. There is some support for the latter hypothesis, with social network analysis of the Framingham Offspring Cohort showing that with a growing number of individuals quitting smoking over time, smokers are moved to the periphery of their social networks (Christakis & Fowler, 2008). This may, in turn, lead to feelings of loneliness. There is limited evidence suggesting greater solitary drinking (Arpin, Mohr, & Brannan, 2015) and poorer food choices (Henriksen, Torsheim, & Thuen, 2014) among lonely adults, and increased substance use among lonely when compared with non-lonely adolescents and young adults (J. T. Cacioppo et al., 2002; Stickley, Koyanagi, Koposov, Schwab-Stone, & Ruchkin, 2014). Further work in this area is necessary.


Sleep has important restorative functions. Sleep duration (long or short sleep) have been associated with mortality and a range of chronic health conditions such as diabetes (Cappuccio, D’Elia, Strazzullo, & Miller, 2010a, 2010b). There is growing evidence suggesting that loneliness may affect sleep, with lonely individuals reporting poorer sleep quality, more disturbances, greater fragmentation, and less sleep efficiency when compared with non-lonely individuals (J. T. Cacioppo et al., 2002; Kurina et al., 2011). Daily feelings of loneliness have been found to be associated with feelings of tiredness and low energy on the following day, with evidence also in support of bidirectional associations (Hawkley, Preacher, & Cacioppo, 2010). Evidence in this area is, however, quite limited.


Lonely individuals tend to evaluate events in their lives as more stressful (J. T. Cacioppo et al., 2000). Indeed, the feeling of loneliness itself acts as a stressor (House, 2001). Further, lab-based and naturalistic studies show that lonely and non-lonely individuals differ in their reactions to stress, as evidenced by changes in a range of biological markers including cardiovascular profiles, cortisol profiles and immune function. In a lab-based study, lonely college students had higher total peripheral resistance and lower cardiac output in response to stressful tasks when compared with non-lonely students (J. T. Cacioppo et al., 2002). A similar pattern was observed in a study examining ambulatory blood pressure (Hawkley, Burleson, Berntson, & Cacioppo, 2003). The authors suggest that this pattern may contribute to higher blood pressure over time in lonely individuals (J. T. Cacioppo et al., 2002; Hawkley et al., 2003). Also age-related increases in blood pressure are more marked among lonely individuals (J. T. Cacioppo et al., 2002; Hawkley, Masi, Berry, & Cacioppo, 2006). On the other hand, loneliness associated with a naturalistic stressor (migration) was not found to be associated with heart rate or heart rate variability (Gouin, Zhou, & Fitzpatrick, 2015).

Lonely individuals also show dysregulation of the HPA axis, as marked by changed cortisol profiles. Lonely individuals show a higher cortisol awakening response when compared with non-lonely individuals (Adam, Hawkley, Kudielka, & Cacioppo, 2006; Steptoe, Owen, Kunz-Ebrecht, & Brydon, 2004), but flatter cortisol profiles over the day (Doane & Adam, 2010). However, findings to the contrary have also been reported, with Cole et al. (2007) finding no significant differences in circulating cortisol levels between lonely and non-lonely adults and loneliness not being associated with urinary cortisol in the Chicago Health, Aging, and Social Relations Study (Hawkley et al., 2006). Further, in a lab-based stress task, increasing loneliness was associated with decreased cortisol responsiveness (Hackett, Hamer, Endrighi, Brydon, & Steptoe, 2012).

Genome-wide analysis indicates that genes associated with the anti-inflammatory glucocorticoid receptor pathway were underexpressed, while the proinflammatory NF-kB/Rel transcription pathway was overexpressed among lonely participants when compared with non-lonely participants (Cole et al., 2007). Data from the Taiwanese Social Environment and Biomarkers Study also showed that leukocyte sensitivity to glucocorticoid regulation was lower among participants who reported being lonely than among non-lonely participants (Cole, 2008). These findings may represent pathways through which loneliness leads to inflammatory diseases. In laboratory studies, lonely participants respond to stress tasks with increases in fibrinogen, natural killer cell response, interleukin-6, interleukin-1 receptor antagonist, and chemokine monocyte chemotactic protein-1 (Hackett et al., 2012; Steptoe et al., 2004). However, some studies have reported no significant associations between loneliness and inflammatory markers (Mezuk et al., 2016; Shankar, McMunn, Banks, & Steptoe, 2011).

Cacioppo et al. propose a model of loneliness placing the brain at the center of the experience of social relationships (J. T. Cacioppo, Cacioppo, Capitanio, & Cole, 2015; S. Cacioppo et al., 2014). According to this model, loneliness as an aversive state leads the brain to take steps that help protect the individual in the short term. These changes include a greater vigilance for social threats, poorer sleep, biological changes such as activation of the HPA axis and changes to immune function, decreased impulse control, and increased depression. While some of these changes may be beneficial immediately, over prolonged periods of time these may be detrimental to health. Hence, chronic loneliness may be particularly damaging to health. Much of the work presented in support of this model is based on animal research. Further, the evidence in support of some mechanisms such as HPA axis activation, sleep disruption, and immune function in humans is mixed. However, this model offers a useful framework for future work into understanding the processes through which loneliness affects health.


Recognition of the harms associated with feelings of isolation is growing. Loneliness, particularly among older adults, has been termed as an important public health threat. Further research is required to elucidate some of the mechanisms through which loneliness affects health.


Abdallah, S., Stoll, L., & Eiffe, F. (2013). Quality of life in Europe: Subjective well-being.

Adam, E. K., Hawkley, L. C., Kudielka, B. M., & Cacioppo, J. T. (2006). Day-to-day dynamics of experience–cortisol associations in a population-based sample of older adults. Proceedings of the National Academy of Sciences, 103(45), 17058–17063.Find this resource:

Alonso, J., Buron, A., Rojas-Farreras, S., de Graaf, R., Haro, J. M., de Girolamo, G., … Vilagut, G. (2009). Perceived stigma among individuals with common mental disorders. Journal of Affective Disorders, 118(1), 180–186.Find this resource:

Anderson, K., Laxhman, N., & Priebe, S. (2015). Can mental health interventions change social networks? A systematic review. BioMed Central Psychiatry, 15(1), 1–8.Find this resource:

Arpin, S. N., Mohr, C. D., & Brannan, D. (2015). Having friends and feeling lonely: a daily process examination of transient loneliness, socialization, and drinking behavior. Personality and Social Psychology Bulletin, 41(5), 615–628.Find this resource:

Ayalon, L., Shiovitz-Ezra, S., & Roziner, I. (2016). A cross-lagged model of the reciprocal associations of loneliness and memory functioning. Psychology & Aging, 31(3), 255–261.Find this resource:

Badcock, J. C., Shah, S., Mackinnon, A., Stain, H. J., Galletly, C., Jablensky, A., & Morgan, V. A. (2015). Loneliness in psychotic disorders and its association with cognitive function and symptom profile. Schizophrenia Research, 169(1–3), 268–273.Find this resource:

Barageine, J. K., Beyeza-Kashesya, J., Byamugisha, J. K., Tumwesigye, N. M., Almroth, L., & Faxelid, E. (2015). “I am alone and isolated”: a qualitative study of experiences of women living with genital fistula in Uganda. BioMed Central Women’s Health, 15(1), 1–14.Find this resource:

Barlow, M. A., Liu, S. Y., & Wrosch, C. (2015). Chronic illness and loneliness in older adulthood: The role of self-protective control strategies. Health Psychology, 34(8), 870–879.Find this resource:

Bartels, M., Cacioppo, J. T., Hudziak, J. J., & Boomsma, D. I. (2008). Genetic and environmental contributions to stability in loneliness throughout childhood. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 147B(3), 385–391.Find this resource:

Baumgart, M., Snyder, H. M., Carrillo, M. C., Fazio, S., Kim, H., & Johns, H. (2015). Summary of the evidence on modifiable risk factors for cognitive decline and dementia: A population-based perspective. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, 11(6), 718–726.Find this resource:

Boehlen, F., Herzog, W., Quinzler, R., Haefeli, W. E., Maatouk, I., Niehoff, D., …, Wild, B. (2015). Loneliness in the elderly is associated with the use of psychotropic drugs. International Journal of Geriatric Psychiatry, 30(9), 957–964.Find this resource:

Boomsma, D. I., Willemsen, G., Dolan, C. V., Hawkley, L. C., & Cacioppo, J. T. (2005). Genetic and environmental contributions to loneliness in adults: The Netherlands twin register study. Behavior Genetics, 35(6), 745–752.Find this resource:

Bosma, H., Jansen, M., Schefman, S., Hajema, K. J., & Feron, F. (2015). Lonely at the bottom: a cross-sectional study on being ill, poor, and lonely. Public Health, 129(2), 185–187.Find this resource:

Boss, L., Kang, D.-H., & Branson, S. (2015). Loneliness and cognitive function in the older adult: a systematic review. International Psychogeriatrics, 27(04), 541–553.Find this resource:

Buchman, A. S., Boyle, P. A., Wilson, R. S., James, B. D., Leurgans, S. E., Arnold, S. E., & Bennett, D. A. (2010). Loneliness and the rate of motor decline in old age: the rush memory and aging project, a community-based cohort study. BioMed Central Geriatrics, 10(1), 1–8.Find this resource:

Burholt, V., & Scharf, T. (2014). Poor health and loneliness in later life: The role of depressive symptoms, social resources, and rural environments. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 69(2), 311–324.Find this resource:

Cacioppo, J. T., Cacioppo, S., Capitanio, J. P., & Cole, S. W. (2015). The neuroendocrinology of social isolation. Annual Review of Psychology, 66(1), 733–767.Find this resource:

Cacioppo, J. T., Cacioppo, S., Cole, S. W., Capitanio, J. P., Goossens, L., & Boomsma, D. I. (2015). Loneliness across phylogeny and a call for comparative studies and animal models. Perspectives on Psychological Science, 10(2), 202–212.Find this resource:

Cacioppo, J. T., Ernst, J. M., Burleson, M. H., McClintock, M. K., Malarkey, W. B., Hawkley, L. C., …, Berntson, G. G. (2000). Lonely traits and concomitant physiological processes: the MacArthur social neuroscience studies. International Journal of Psychophysiology, 35(2–3), 143–154.Find this resource:

Cacioppo, J. T., Hawkley, L. C., Ernst, J. M., Burleson, M., Berntson, G. G., Nouriani, B., & Spiegel, D. (2006). Loneliness within a nomological net: An evolutionary perspective. Journal of Research in Personality, 40(6), 1054–1085.Find this resource:

Cacioppo, J. T., Hawkley, L. C., & Thisted, R. A. (2010). Perceived social isolation makes me sad: Five year cross-lagged analyses of loneliness and depressive symptomatology in the Chicago health, aging, and social relations study. Psychology and aging, 25(2), 453–463.Find this resource:

Cacioppo, J. T., Hawkley, L. C. M. A., Crawford, L. E. P., Ernst, J. M. P., Burleson, M. H. P., Kowalewski, R. B. M. A., …, Berntson, G. G. P. (2002). Loneliness and health: Potential mechanisms. Psychosomatic Medicine May/June, 64(3), 407–417.Find this resource:

Cacioppo, S., Capitanio, J. P., & Cacioppo, J. T. (2014). Toward a neurology of loneliness. Psychological Bulletin, 140(6), 1464–1504.Find this resource:

Canham, S. L. (2015). What’s loneliness got to do with it? Older women who use benzodiazepines. Australasian Journal on Ageing, 34(1), E7–E12.Find this resource:

Cappuccio, F. P., D’Elia, L., Strazzullo, P., & Miller, M. A. (2010a). Quantity and quality of sleep and incidence of type 2 diabetes: A systematic review and meta-analysis. Diabetes Care, 33(2), 414–420.Find this resource:

Cappuccio, F. P., D’Elia, L., Strazzullo, P., & Miller, M. A. (2010b). Sleep duration and all-cause mortality: A systematic review and meta-analysis of prospective studies. Sleep, 33(5), 585–592.Find this resource:

Christakis, N. A., & Fowler, J. H. (2008). The collective dynamics of smoking in a large social network. New England Journal of Medicine, 358(21), 2249–2258.Find this resource:

Cole, S. W. (2008). Social regulation of leukocyte homeostasis: The role of glucocorticoid sensitivity. Brain, Behavior, and Immunity, 22(7), 1049–1055.Find this resource:

Cole, S. W., Hawkley, L. C., Arevalo, J. M., Sung, C. Y., Rose, R. M., & Cacioppo, J. T. (2007). Social regulation of gene expression in human leukocytes. Genome Biology, 8(9), R189.Find this resource:

Cornwell, E. Y., & Waite, L. J. (2009). Social disconnectedness, perceived isolation, and health among older adults. Journal of Health and Social Behavior, 50(1), 31–48.Find this resource:

de Jong Gierveld, J., & Havens, B. (2004). Cross-national comparisons of social isolation and loneliness: Introduction and overview. Canadian Journal on Aging/La Revue canadienne du vieillissement, 23(2), 109–113.Find this resource:

de Jong Gierveld, J., Keating, N., & Fast, J. E. (2015). Determinants of loneliness among older adults in Canada. Canadian Journal on Aging/La Revue canadienne du vieillissement, 34(02), 125–136.Find this resource:

Deckx, L., van den Akker, M., & Buntinx, F. (2014). Risk factors for loneliness in patients with cancer: A systematic literature review and meta-analysis. European Journal of Oncology Nursing, 18(5), 466–477.Find this resource:

Doane, L. D., & Adam, E. K. (2010). Loneliness and cortisol: Momentary, day-to-day, and trait associations. Psychoneuroendocrinology, 35(3), 430–441.Find this resource:

Donovan, N. J., Wu, Q., Rentz, D. M., Sperling, R. A., Marshall, G. A., & Glymour, M. M. (2016). Loneliness, depression and cognitive function in older U.S. adults. International Journal of Geriatric Psychiatry, n/a-n/a.Find this resource:

Dyal, S. R., & Valente, T. W. (2015). A systematic review of loneliness and smoking: Small effects, big implications. Substance Use & Misuse, 50(13), 1697–1716.Find this resource:

Dykstra, P. A. (2009). Older adult loneliness: myths and realities. European Journal of Ageing, 6(2), 91–100.Find this resource:

Fratiglioni, L., Wang, H.-X., Ericsson, K., Maytan, M., & Winblad, B. (2000). Influence of social network on occurrence of dementia: a community-based longitudinal study. The Lancet, 355(9212), 1315–1319.Find this resource:

Gao, J., Davis, L. K., Hart, A. B., Sanchez-Roige, S., Han, L., Cacioppo, J. T., & Palmer, A. A. (2017). Genome-wide association study of loneliness demonstrates a role for common variation. Neuropsychopharmacology, 42(4), 811–821.Find this resource:

Giacco, D., Palumbo, C., Strappelli, N., Catapano, F., & Priebe, S. (2016). Social contacts and loneliness in people with psychotic and mood disorders. Comprehensive Psychiatry, 66, 59–66.Find this resource:

Gouin, J.-P., Zhou, B., & Fitzpatrick, S. (2015). Social integration prospectively predicts changes in heart rate variability among individuals undergoing migration stress. Annals of Behavioral Medicine, 49(2), 230–238.Find this resource:

Hackett, R. A., Hamer, M., Endrighi, R., Brydon, L., & Steptoe, A. (2012). Loneliness and stress-related inflammatory and neuroendocrine responses in older men and women. Psychoneuroendocrinology, 37(11), 1801–1809.Find this resource:

Hawkley, L. C., Burleson, M. H., Berntson, G. G., & Cacioppo, J. T. (2003). Loneliness in everyday life: Cardiovascular activity, psychosocial context, and health behaviors. Journal of Personality and Social Psychology, 85(1), 105–120.Find this resource:

Hawkley, L. C., & Cacioppo, J. T. (2010). Loneliness matters: A theoretical and empirical review of consequences and mechanisms. Annals of Behavioral Medicine, 40(2), 218–227.Find this resource:

Hawkley, L. C., & Capitanio, J. P. (2015). Perceived social isolation, evolutionary fitness and health outcomes: A lifespan approach. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 370(1669), 20140114.Find this resource:

Hawkley, L. C., Hughes, M. E., Waite, L. J., Masi, C. M., Thisted, R. A., & Cacioppo, J. T. (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: Psychological Sciences and Social Sciences, 63(6), S375–S384.Find this resource:

Hawkley, L. C., Masi, C. M., Berry, J. D., & Cacioppo, J. T. (2006). Loneliness is a unique predictor of age-related differences in systolic blood pressure. Psychology & Aging, 21(1), 152–164.Find this resource:

Hawkley, L. C., Preacher, K. J., & Cacioppo, J. T. (2010). Loneliness impairs daytime functioning but not sleep duration. Health Psychology, 29(2), 124–129.Find this resource:

Henriksen, R. E., Torsheim, T., & Thuen, F. (2014). Loneliness, social integration and consumption of sugar-containing beverages: Testing the social baseline theory. PLoS ONE, 9(8), e104421.Find this resource:

Herrera-Badilla, A., Navarrete-Reyes, A. P., Amieva, H., & Avila-Funes, J. A. (2015). Loneliness is associated with frailty in community-dwelling elderly adults. Journal of the American Geriatrics Society, 63(3), 607–609.Find this resource:

Holt-Lunstad, J., Smith, T. B., Baker, M., Harris, T., & Stephenson, D. (2015). Loneliness and social isolation as risk factors for mortality: A meta-analytic review. Perspectives on Psychological Science, 10(2), 227–237.Find this resource:

Holt-Lunstad, J., Smith, T. B., & Layton, J. B. (2010). Social relationships and mortality risk: A meta-analytic review. PLoS Medicine, 7(7), e1000316.Find this resource:

Holvast, F., Burger, H., de Waal, M. M. W., van Marwijk, H. W. J., Comijs, H. C., & Verhaak, P. F. M. (2015). Loneliness is associated with poor prognosis in late-life depression: Longitudinal analysis of the Netherlands study of depression in older persons. Journal of Affective Disorders, 185, 1–7.Find this resource:

Holwerda, T. J., Beekman, A. T. F., Deeg, D. J. H., Stek, M. L., van Tilburg, T. G., Visser, P. J., …, Schoevers, R. A. (2012). Increased risk of mortality associated with social isolation in older men: only when feeling lonely? Results from the Amsterdam Study of the Elderly (AMSTEL). Psychological Medicine, 42(04), 843–853.Find this resource:

Holwerda, T. J., van Tilburg, T. G., Deeg, D. J. H., Schutter, N., Van, R., Dekker, J., …, Schoevers, R. A. (2016). Impact of loneliness and depression on mortality: Results from the Longitudinal Ageing Study Amsterdam. The British Journal of Psychiatry, 209(2), 127–134.Find this resource:

Honigh-de Vlaming, R., Haveman-Nies, A., Bos-Oude Groeniger, I., de Groot, L., & van ’t Veer, P. (2014). Determinants of trends in loneliness among Dutch Older people over the period 2005–2010. Journal of Aging and Health, 26(3), 422–440.Find this resource:

House, J. S. (2001). Social isolation kills, but how and why? Psychosomatic Medicine, 63(2).Find this resource:

Jaremka, L. M., Andridge, R. R., Fagundes, C. P., Alfano, C. M., Povoski, S. P., Lipari, A. M., …, Kiecolt-Glaser, J. K. (2014). Pain, depression, and fatigue: Loneliness as a longitudinal risk factor. Health Psychology, 33(9), 948–957.Find this resource:

Jaremka, L. M., Peng, J., Bornstein, R., Alfano, C. M., Andridge, R. R., Povoski, S. P., …, Kiecolt-Glaser, J. K. (2014). Cognitive problems among breast cancer survivors: Loneliness enhances risk. Psycho-oncology, 23(12), 1356–1364.Find this resource:

Kuiper, J. S., Zuidersma, M., Oude Voshaar, R. C., Zuidema, S. U., van den Heuvel, E. R., Stolk, R. P., & Smidt, N. (2015). Social relationships and risk of dementia: A systematic review and meta-analysis of longitudinal cohort studies. Ageing Research Reviews, 22, 39–57.Find this resource:

Kurina, L. M., Knutson, K. L., Hawkley, L. C., Cacioppo, J. T., Lauderdale, D. S., & Ober, C. (2011). Loneliness is associated with sleep fragmentation in a communal society. Sleep, 34(11), 1519–1526.Find this resource:

Lasgaard, M., & Friis, K. (2015). Predictors of loneliness across the age-span. European Journal of Public Health, 25(Suppl. 3), ckv176.204.Find this resource:

McGuire, S., & Clifford, J. (2000). Genetic and environmental contributions to loneliness in children. Psychological Science, 11(6), 487–491.Find this resource:

Mezuk, B., Choi, M., DeSantis, A. S., Rapp, S. R., Diez Roux, A. V., & Seeman, T. (2016). Loneliness, depression, and inflammation: Evidence from the Multi-Ethnic Study of Atherosclerosis. PLoS ONE, 11(7), e0158056.Find this resource:

Mund, M., & Neyer, F. J. (2015). The winding paths of the lonesome cowboy: Evidence for Mutual influences between personality, subjective health, and loneliness. Journal of Personality, 84(5), 646–657.Find this resource:

Pels, F., & Kleinert, J. (2016). Loneliness and physical activity: A systematic review. International Review of Sport and Exercise Psychology, 9(1), 231–260.Find this resource:

Peplau, L. A., & Perlman, D. (1982). Perspectives on loneliness. In L. A. Peplau & D. Perlman (Eds.), Loneliness: A sourcebook of current theory, research and therapy (pp. 1–18). New York: John Wiley & Sons.Find this resource:

Perissinotto, C. M., Cenzer, I. S., & Covinsky, K. E. (2012). Loneliness in older persons: A predictor of functional decline and death. Archives of Internal Medicine, 172(14), 1078–1083.Find this resource:

Pinquart, M., & Sorensen, S. (2001). Influences on loneliness in older adults: A meta-analysis. Basic and Applied Social Psychology, 23(4), 245–266.Find this resource:

Qualter, P., Vanhalst, J., Harris, R., Van Roekel, E., Lodder, G., Bangee, M., …, Verhagen, M. (2015). Loneliness across the life span. Perspectives on Psychological Science, 10(2), 250–264.Find this resource:

Radloff, L. S. (1977). The CES-D Scale: A self-report depression scale for research in the general population. Applied Psychological Measurement, 1(3), 385–401.Find this resource:

Ramage-Morin, P. L., & Gilmour, H. (2013). Urinary incontinence and loneliness in Canadian seniors. Statistics Canada, Catalogue no. 82-003-X, Health Reports, 24(10), 3–10.Find this resource:

Rubenstein, C., Shaver, P., & Peplau, L. A. (1979). Loneliness. Human Nature, 2, 58–65.Find this resource:

Shankar, A., McMunn, A., Banks, J., & Steptoe, A. (2011). Loneliness, social isolation, and behavioral and biological health indicators in older adults. Health Psychology, 30(4), 377–385.Find this resource:

Shankar, A., McMunn, A., Demakakos, P., Hamer, M., & Steptoe, A. (2017). Social isolation and loneliness: Prospective associations with functional status in older adults. Health Psychology, 36(2), 179–187.Find this resource:

Southward, M. W., Christensen, K. A., Fettich, K. C., Weissman, J., Berona, J., & Chen, E. Y. (2014). Loneliness mediates the relationship between emotion dysregulation and bulimia nervosa/binge eating disorder psychopathology in a clinical sample. Eating and Weight Disorders—Studies on Anorexia, Bulimia and Obesity, 19(4), 509–513.Find this resource:

Steptoe, A., Owen, N., Kunz-Ebrecht, S. R., & Brydon, L. (2004). Loneliness and neuroendocrine, cardiovascular, and inflammatory stress responses in middle-aged men and women. Psychoneuroendocrinology, 29(5), 593–611.Find this resource:

Steptoe, A., Shankar, A., Demakakos, P., & Wardle, J. (2013). Social isolation, loneliness, and all-cause mortality in older men and women. Proceedings of the National Academy of Sciences, 110(15), 5797–5801.Find this resource:

Stessman, J., Rottenberg, Y., Shimshilashvili, I., Ein-Mor, E., & Jacobs, J. M. (2014). Loneliness, health, and longevity. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 69(6), 744–750.Find this resource:

Stickley, A., Koyanagi, A., Koposov, R., Schwab-Stone, M., & Ruchkin, V. (2014). Loneliness and health risk behaviours among Russian and U.S. adolescents: a cross-sectional study. BMC Public Health, 14(1), 1–12.Find this resource:

Stickley, A., Koyanagi, A., Roberts, B., Richardson, E., Abbott, P., Tumanov, S., & McKee, M. (2013). Loneliness: Its correlates and association with health behaviours and outcomes in nine countries of the former Soviet Union. PLoS ONE, 8(7), e67978.Find this resource:

Sündermann, O., Onwumere, J., Kane, F., Morgan, C., & Kuipers, E. (2014). Social networks and support in first episode psychosis: Exploring the role of loneliness and anxiety. Social Psychiatry and Psychiatric Epidemiology, 49(3), 359–366.Find this resource:

Świtaj, P., Grygiel, P., Anczewska, M., & Wciórka, J. (2014). Loneliness mediates the relationship between internalised stigma and depression among patients with psychotic disorders. International Journal of Social Psychiatry, 60(8), 733–740.Find this resource:

Świtaj, P., Grygiel, P., Anczewska, M., & Wciórka, J. (2015). Experiences of discrimination and the feelings of loneliness in people with psychotic disorders: The mediating effects of self-esteem and support seeking. Comprehensive Psychiatry, 59, 73–79.Find this resource:

Theeke, L. A., & Mallow, J. (2013). Loneliness and quality of life in chronically ill rural older adults: Findings from a pilot study. American Journal of Nursing, 113(9), 28–38.Find this resource:

Tijhuis, M. A., De Jong-Gierveld, J., Feskens, E. J., & Kromhout, D. (1999). Changes in and factors related to loneliness in older men. The Zutphen Elderly Study. Age and Ageing, 28(5), 491–495.Find this resource:

Valtorta, N. K., Kanaan, M., Gilbody, S., Ronzi, S., & Hanratty, B. (2016). Loneliness and social isolation as risk factors for coronary heart disease and stroke: Systematic review and meta-analysis of longitudinal observational studies. Heart, 102, 1009–1016.Find this resource:

VanderWeele, T. J., Hawkley, L. C., Thisted, R. A., & Cacioppo, J. T. (2011). A marginal structural model analysis for loneliness: Implications for intervention trials and clinical practice. Journal of Consulting and Clinical Psychology, 79(2), 225–235.Find this resource:

Victor, C. (2016). Loneliness in old age is not inevitable. Society Now, Summer 2016, 1.Find this resource:

Victor, C., & Yang, K. (2012). The prevalence of loneliness among adults: A case study of the United Kingdom. The Journal of Psychology, 146(1–2), 85–104.Find this resource:

Weeks, D. G., Michela, J. L., Peplau, L. A., & Bragg, M. E. (1980). Relation between loneliness and depression: A structural equation analysis. Journal of Personality and Social Psychology, 39(6), 1239–1244.Find this resource:

Weiss, R. S. (1973). Loneliness: The experience of social and emotional isolation. Cambridge, MA: MIT Press.Find this resource:

Wilson, R. S., Krueger, K. R., Arnold, S. E., Schneider J. A., Kelly J. F., Barnes L. L., …, Bennet, D. A. (2007). Loneliness and risk of Alzheimer’s disease. Archives of General Psychiatry, 64(2), 234–240.Find this resource:

Wolf, L. D., & Davis, M. C. (2014). Loneliness, daily pain, and perceptions of interpersonal events in adults with fibromyalgia. Health Psychology, 33(9), 929–937.Find this resource:

Wolf, L. D., Davis, M. C., Yeung, E. W., & Tennen, H. A. (2015). The within-day relation between lonely episodes and subsequent clinical pain in individuals with fibromyalgia: Mediating role of pain cognitions. Journal of Psychosomatic Research, 79(3), 202–206.Find this resource:

Zhong, B.‑L., Chen, S.‑L., Tu, X., & Conwell, Y. (2016). Loneliness and cognitive function in older adults: Findings from the Chinese longitudinal healthy longevity Survey. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 72(1), 120–128.Find this resource: