Do you suffer from loneliness? If so, the good news is you are far from alone. It is generally recognized that there is a global epidemic of loneliness (see Killeen, 1998; Murthy, 2020), and the main contentious issue here is whether loneliness is an epidemic or a pandemic. Estimates vary considerably as a function of factors such as how loneliness is measured, where it is measured, and the age of partici-pants, but there is ample evidence to indicate that in adolescents and older people, more than 50% of people experience loneliness at some point in their lives and it may indeed be normative to experience loneliness (see Crowe et al., 2022). The reality for people who feel alone is that they have plenty of company and they prob-ably don’t realize how much they have in common with so many other people.
Loneliness is one of the greatest and most vexing public health issues. This claim is beyond dispute. The case for loneliness as a public health crisis and a matter of urgency was made by Holt-Lundstad (2017) in her testimony before the U.S. Senate Aging Committee. More recently, Holt-Lundstad (2022) presented a compelling argument for lack of social connection as a public health matter. The urgent need to address loneliness as a public health matter is all the more evident now that we have experienced the COVID-19 pandemic (for a discussion, see Flett & Zangeneh, 2020). Lockdowns with their accompanying social restrictions and requiring peo-ple to isolate made loneliness much more salient and it seemed to increase levels of loneliness in certain segments of the population. For instance, a review and meta- analysis found that loneliness in children and adolescents increased during the pan-demic when assessed in longitudinal research. Moreover, in cross-sectional research, loneliness was associated with lower well-being and higher symptoms of depres-sion and anxiety, as well as gaming addiction, and sleep difficulties (see Farrell et al., 2023). The impact of the global pandemic with its remarkably surprising and sudden onset and mental health consequences (Flett & Zangeneh, 2020; Galea et al., 2020) underscores the need for updated models of loneliness to reflect situa-tional factors and to place an emphasis on perceived controllability and the presence or absence of feelings of control.
Given the myriad indicators of the relevance and pervasiveness of loneliness, we believe that a chapter on loneliness is essential in this book on public mental health. In an ideal universe, we hope that we will witness in the next decade a prioritization for the development of global intervention strategies designed to prevent loneliness and associated mental health concerns among people of all ages.
Any comfort that might come from knowing you are not alone if you are lonely is likely limited by the extensive bad news about loneliness as well as how it feels to be lonely. Cacioppo and Cacioppo (2018) succinctly summarized this bad news by asking readers to imagine a condition linked with making people depressed, irritable, and self-centered that afflicts at least 1 in 3 people in industrialized coun-tries, with 1 in 12 people being severely impacted by loneliness. They then noted the physical health costs and the link between loneliness and mortality. Associations with health problems and all-cause mortality have been confirmed via meta-analyses (see Park et al., 2020; Rico-Uribe et al., 2018), and the association between loneli-ness and poor health is believed to be reciprocal in nature (see Ingram & Kelly, 2022). The association with health problems is due, in part, to the tendency for lonely people to have higher levels of stress (see Park et al., 2020). The link with early mortality is strong enough for researchers to propose that loneliness can cause early death (see Luo et al., 2012). Given this evidence, there is a growing and urgentneed to develop and broadly apply interventions and prevention strategies that will reduce its prevalence and mitigate the severity and chronicity of loneliness.
Perhaps the most succinct way of framing loneliness is to consider it from a qual-ity of life perspective. It is difficult, if not impossible, to envision a great quality of life for someone who is lonely and enduring a lonely life. There are countless empirical studies linking loneliness with a lower quality of life (Rokach, 2019) and this association should come as a surprise to virtually no one.
This chapter focuses on documenting and understanding the loneliness of people who experience it at a level that does indeed cause significant distress and dysfunc-tion. A central premise of this chapter is that there is an extreme form of unbearable loneliness that wreaks havoc in people’s lives and prevention and intervention
efforts are needed to specifically ameliorate unbearable loneliness. This type of loneliness is especially likely to be accompanied by significant mental health prob-lems and associated risks and vulnerabilities. Below, we consider some further costs of loneliness and then provide an extended definition and description of loneliness. We then examine the alarming but at times under-recognized association between loneliness and mental health problems with a particular emphasis on the clinical significance of loneliness. The second main segment of our chapter proposes that when considering pathways and routes to loneliness, a logical place to begin is with the self-concept. Specifically, there are various negative forms that the self-concept can take in ways that can be seen as providing a bridge that links loneliness with mental health problems. This emphasis on the negative self leads into our discussion of the more extreme form of unbear-able loneliness that we see as largely responsible for the costs and consequences of loneliness. Finally, in keeping with the public mental health focus, we briefly dis-cuss key themes to emphasize in prevention and intervention efforts designed to alleviate the terrible suffering caused by loneliness.
Additional Costs of Loneliness
There are many ways to calculate the costs of loneliness, including the human costs. Loneliness is also a public health concern because it also involves significant eco-nomic costs. This was the conclusion that emerged recently following an analysis of 20 years of annual survey data from Australia. This analysis by Kung et al. (2021a) also found that the social gradient of health also applies to loneliness. They found that much higher rates of loneliness were detected among people with socioeco-nomic disadvantage. Kung et al. (2021b) replicated this finding based on biobank survey data from the United Kingdom. Why is there an economic cost to loneliness? Analyses of age trends show an increasingly stronger association among loneliness, declining health, and greater health care usage. Sirois and Owens (2021) confirmed via meta-analysis that loneliness is associated with greater health-care usage and more visits to primary-care practitioners.
Kung and associates (2021b) cautioned that loneliness is not solely applicable to older people despite some public misperceptions. They noted that the link between loneliness and poorer mental health is strongest among younger people in these surveys. They note that across all age groups, loneliness is more prevalent among females than males, and between 15% and 20% of 15- to 24-year-olds in Australia are lonely. Thus, about 1 in 6 or 1 in 5 young people experience loneliness. Most notably, Kung et al. (2021a) noted that beginning in 2013, there has been an increase in the proportion of those people between the ages of 15 to 24 years old who agreed with the statement, “I often feel very lonely.”
As alluded to earlier, numerous authors have surveyed the prevalence of loneli-ness in multiple locations around the world and concluded we are experiencing a loneliness epidemic. Other authors also recognize the high incidence rates of loneli-ness but suggest that though it is prevalent, the pervasiveness of loneliness has been overstated. A recent cross-temporal meta-analysis by Buecker et al. (2021) found that rates of loneliness in emerging adults have slightly increased between the years of 1976 and 2019. While these findings suggest that claims of a “loneliness epi-demic” may be exaggerated, the results of this meta-analysis still very much illus-trate an urgent need to design interventions to address loneliness among the emerging adult age group (see Buecker et al., 2021).
Historical analyses point to consistent increases over time in the number of peo-ple who live alone (see Snell, 2017), and how this emerging asocial context may have set the stage for increases in the prevalence of loneliness. Another contributing factor is the greater longevity of people and the increasing number of people who may live into old age and who may be increasingly susceptible to loneliness. The growth in loneliness problems is concerning enough to warrant public institutional responses. For instance, Great Britain created the Ministry of Loneliness in 2018 and committed to making loneliness reduction a governmental priority. Most recently, in 2023, U.S. Surgeon General Vivek Murthy issued an advisory and unveiled his plan to combat loneliness and social disconnection. There are also an increasing number of proactive steps being taken around the world to heighten awareness of loneliness and what can be done to combat it.
Loneliness has garnered considerable research attention, and there is now a plethora of systematic reviews and meta-analyses on loneliness, and even a review of existing reviews (see Leigh-Hunt et al., 2017). Could this broad interest reflect, at least in part, the fact that everyone, researchers included, can truly relate to how it feels when someone feels lonely and alone? Meta-analyses have linked loneliness with sleep disturbance (Griffin et al., 2020) and increased risk of dementia (Lara et al., 2019). Buecker and associates (2020) established via their meta-analysis that loneliness has links with the elements of the five-factor personality model in the pattern typically associated with poor adjustment (i.e., high neuroticism and low agreeableness, extraversion, conscientiousness, and openness).
In the current chapter, we provide a definition and description of loneliness and then offer a selective rather than a systematic review of the existing literature. Our overarching goal in writing this chapter is our concern that the mental health impli-cations and clinical relevance and importance of loneliness are not sufficiently understood or recognized at present because key elements and types of loneliness are not being broadly assessed and evaluated.
The next segment of this chapter builds on our expanded definition of loneliness and considers loneliness in terms of its mental health correlates with a particular focus on the links between loneliness and social anxiety. Reasons for links between loneliness and mental health problems are then considered and key processes and mechanisms are outlined. Our analysis focuses on the role of self and identity in vulnerability to loneliness.
As suggested earlier, a central component of this chapter is the segment that considers our proposed contention that there is an extreme form of loneliness that merits much more attention and more proactive intervention. We maintain it is cru-cial to recognize the heterogeneity that is evident among people who are lonely, and there is a need to distinguish milder versus more severe forms of loneliness and to increasingly focus on people who suffer from chronic and intensely felt loneliness. Most notably, we consider a type of loneliness we refer to as “unbearable loneli-ness” and how unbearable loneliness is accompanied by considerable psychological pain. We describe recent research in our laboratory on the assessment of unbearable loneliness from a cognitive perspective. Finally, we discuss key targets for preven-tion and intervention and associated public health policy issues.