Loneliness has been a hot topic of late, attracting much media and scholarly attention (including this post). Research suggests that loneliness constitutes a substantial health risk factor for both young and older adults. Moreover, loneliness appears to be on the rise of late, to the point where talk of a “loneliness epidemic” has become common. The problem has quite likely been exacerbated by forced social distancing during the COVID pandemic.
More recently, researchers have been turning their focus to the related—yet less well-studied—the phenomenon of "social isolation,” a common correlate of loneliness that is nevertheless a separate and distinct state. Loneliness is generally defined as ”the discrepancy between a person's preferred and actual level of social contact.” It is a subjective, qualitative self-perception.
Social isolation, on the other hand, has been defined as “an objective state of having minimal social contact with other individuals.” Social isolation is often assessed using quantitative measures such as marital status, living alone, religious attendance, group memberships, and frequency of contact with children, family, and friends.
Disentangling the effects of social isolation and loneliness is useful not just because it improves our understanding of each, but also because it addresses a more general question about the effects of subjective experience vs. those of objective conditions.
This question is of interest to psychologists who look to understand (and devise interventions for) the conditions that affect our health. If subjective perception is found to affect health more significantly than objective facts, then we may be wise to focus our interventions on people’s subjective experiences. Conversely, if we find that objective facts matter more, then we may tailor our interventions accordingly, targeting environmental and behavioral variables.
“It’s not how old you feel, it’s how old you are,” my father, an 85-year-old retired farmer, likes to say, exemplifying this latter "facts first" view. Psychologists, however, often lean in the opposite direction, opting to consider subjective factors as more important than objective conditions.
As psychologists Julianne Holt-Lunsad of Brigham Young University and Andrew Steptoe (University College London) note in their recent (2022) review of the literature:
“More objective/structural aspects of relationships (e.g., social isolation, network size, group membership, living alone) are often assumed to be crude indicators of ‘more important’ relationship factors, including the functions and quality of relationships."
Generally speaking, this view is not entirely unfounded. Empirical evidence points to the primacy of subjective perceptions in various realms of life. For example, trauma research has shown that whether or not an adverse event such as abuse will affect you down the road depends more on your subjective interpretations and memories than on what happened. Likewise, research on sexual satisfaction has found that our level of happiness depends in large part on our subjective beliefs about how much sex other people are having, rather than on how much sex we (or they) are having. Subjective perceptions often matter greatly.
The results concerning loneliness and social isolation, however, have been trending in the opposite direction. For example, Andrew Steptoe and colleagues (2013) assessed both social isolation (in terms of contact with family and friends and participation in civic organizations) and loneliness (via a standard questionnaire measure) in 6,500 men and women aged 52 and older from the English Longitudinal Study of Ageing, while monitoring all-cause mortality for several years.
They found that mortality was higher both among more isolated and more lonely participants. However, “after adjusting statistically for demographic factors and baseline health, social isolation remained significantly associated with mortality… but loneliness did not.” They conclude: “Both social isolation and loneliness were associated with increased mortality.
However, the effect of loneliness was not independent of demographic characteristics or health problems and did not contribute to the risk associated with social isolation. Although both isolation and loneliness impair quality of life and well-being, efforts to reduce isolation are likely to be more relevant to mortality.”
Berkeley researcher Bin Yu and colleagues (2020) followed 1267 Taiwanese patients 65 years or older with confirmed CVD for up to 10 years. Analyzing the association between social isolation and loneliness at baseline and mortality at follow-up while adjusting for demographic variables, health-related behaviors, and health status. “Social isolation was associated with increased risk of mortality after accounting for established risk factors… whereas loneliness was not associated with increased risk of mortality.”
A recent (2022) study by researcher Chun Shen and colleagues used neuroimaging data from over 400,000 participants in the UK Biobank large longitudinal data set to explore whether social isolation and loneliness predicted dementia. Socially isolated individuals were shown to have a 26% increased likelihood of developing dementia, after adjusting for various risk factors including socio-economic chronic illness, lifestyle, depression, APOE, genotype (a genetic risk factor for dementia), Alzheimer's disease, and cardiovascular disease.
Socially isolated individuals were found to have lower gray matter volumes in brain regions involved in memory and learning. Interestingly, while loneliness was also initially associated with subsequent dementia, the association disappeared after adjusting for depression. In other words, the effects of loneliness may be attributed mostly to depression. The authors note:
“Relative to the subjective feeling of loneliness, objective social isolation is an independent risk factor for later dementia.”
Holt-Lunsad and Steptoe conclude: “Evidence suggests the actual presence of others, including the existence of relationships and roles, proximity, and regular contact, is a powerful, in some cases stronger predictor of health than other aspects of relationships… Thus, the relative importance of social isolation for health and well-being may be underappreciated.”
Research has yet to determine exactly how social isolation exerts its deleterious effects on health. Suggestive evidence points to some usual suspects, mainly stress and its attendant impact on immune inflammation, cardiovascular activity, and sleep. Indirect effects are also likely since social isolation impacts not only our physiology but our behavioral decisions and psychological states. As psychologists, Giada Pietrabissa and Susan Simpson note, “the absence of relationships removes essential conditions for the development of personal identity and the exercise of reason.” Those without robust social connections may also be more vulnerable to settling into bad habits, such as poor diet and physical inactivity, or developing psychiatric conditions such as depression.
More research is required to clarify fully the isolation-health link. Yet, pragmatically speaking, the picture emerging from the research is that a focus on outward action aimed at changing your social situation—by investing in your social skills and connections—may buy you more long-term health than merely focusing inward on changing your subjective perceptions.
To paraphrase my father: It’s not how lonely you feel, it’s how isolated you are.