Background
Loneliness has become the focus of a wealth of research in recent years. This attention is well placed given that loneliness has been designated as a significant public health issue in the UK [
1] and is associated with poor physical and mental health outcomes [
2‐
5] and an increase in risk of death similar to that of smoking [
6]. In light of this, it is concerning that recent research has found that loneliness is highly prevalent across age groups, with young people (under 25 years) and older adults (over 65 years) indicating the highest levels [
7,
8].
Whilst an ever-increasing body of research is situating loneliness at its centre, there is relatively little work which focuses on the lived experience of loneliness: how loneliness feels and what makes up experiences of loneliness. Phenomena that might appear to describe loneliness, such as social isolation, are distinct from the actual experience of it. Whilst loneliness is generally characterised as the distress one experiences when they perceive their social connections to be lacking in number or quality, social isolation is the objective limitation or absence of connections [
9]. Social isolation does not necessarily beget loneliness, and indeed, Hawkley and Cacioppo [
3] remark on how humans can perceive meaningful social relationships where none objectifiably exist, such as with God, or where reciprocity is not possible, such as with fictional characters. Whilst associations between aloneness and loneliness have been richly demonstrated [
10,
11], other research has found moderate and low correlations between social isolation and loneliness [
12,
13]. These findings underline the need to better understand what makes up the subjective experience of loneliness, given that it is clearly not sufficiently captured by the objective experience of being alone. Given the subjective nature of the phenomenon, qualitative methods are particularly suited to research into experiences of loneliness, as they can aim to capture the idiosyncrasies of these experiences.
A number of qualitative studies of loneliness experiences have been carried out. In perhaps the largest study of its type, Rokach [
14] analysed written accounts of 526 adults’ loneliest experience, specifically asking about their thoughts, feelings, and coping strategies. This generated a model with four major elements (self-alienation, interpersonal isolation, distressed reactions, and agony) and twenty-three components such as emptiness, numbness, and missing a specific person or relationship. Although this study offered impressive scale, the vast majority of participants were between 19 and 45 years old, and as a result, the model may underestimate factors experienced across the lifespan. The findings might be usefully integrated with more recent research which qualitatively explores loneliness in other age groups (e.g. [
15]). Harmonising this research by looking closely at how people describe their experiences of loneliness and working from the bottom-up to create a fine-grained view of what makes up these experiences will provide a more holistic understanding of loneliness and how it might best be defined and ameliorated.
There are a number of available definitions of loneliness offered by researchers. The widely accepted description from Perlman and Peplau [
16], for example, states that loneliness is an unpleasant and distressing subjective phenomenon arising when one’s desired level of social relations differs from their actual level. However, research lacks an overarching subjective perspective, by which we mean a description of loneliness which is grounded in accounts of people’s lived experiences. This is a significant gap in the field given that loneliness is, by its nature, a subjective experience. Unlike objective phenomena like blood pressure or age, loneliness can only be definitively measured by asking a person whether they feel lonely. Weiss [
17] argued that whilst available definitions of loneliness may be helpful, they do not sufficiently reflect the real phenomenon of loneliness because they define it in terms of its potential causes rather than the actual experience of being lonely. As such, studies which begin from definitions of loneliness like these may obscure the ways in which it is actually experienced and fail to capture the components and idiosyncrasies of these experiences.
A recent systematic review report [
18] has explored the conceptualisations of loneliness employed in qualitative research, finding that loneliness tended to be defined as social, emotional, or existential types. However, the review covered only studies of adults (16 years and up), including heterogenous clinical populations (e.g. people receiving cancer treatment, people living with specific mental health conditions, and people on long-term sick leave), and placed central importance on the concepts, models, theories, and frameworks of loneliness utilised in research. Studies which did not employ an identified concept, model, framework, or theory of loneliness were excluded. Moreover, rather than synthesising how people describe their loneliness, the authors aimed to assess how research conceptualises loneliness across the adult life course. This leaves a gap with respect to how research participants specifically describe their lived experiences of loneliness, rather than how researchers might conceptualise it. Achterberg and colleagues [
19] recently conducted a meta-synthesis of qualitative studies on experiences of loneliness in young people with depression. As the findings are specific to experiences in this population, they may not reflect those of wider age groups or individuals who do not have depression. Kitzmüller and colleagues [
20] used meta-ethnography to synthesise studies regarding experiences and ways of dealing with loneliness in older adults (60 years and older). However, they synthesised only articles from health care disciplines published in scientific journals from 2001 to 2016 and included studies on clinical populations, such as older women with multiple chronic conditions. Moreover, there has been an increase in research output regarding loneliness in recent years, and relevant studies may have been published since this review was conducted (e.g. [
15]). To the authors’ knowledge, the systematic review report on conceptual frameworks used in loneliness research [
18], the meta-synthesis of loneliness in young people with depression [
19], and the meta-ethnography of older adults’ loneliness [
20] are the only such systematic reviews of qualitative literature regarding experiences of loneliness to date. The current systematic review will instead take a bottom-up approach which focuses on non-clinical populations of all ages to synthesise findings on participants’ experiences of loneliness, rather than the conceptualisations that might be imposed by study authors. This will fill a gap in the literature by synthesising the qualitative evidence focusing on experiences of loneliness across the lifespan. This inductive synthesis of the available subjective descriptions of loneliness will offer a nuanced view of loneliness experiences. It is imperative for research and practice that we deepen the current understanding of these experiences to inform how we approach describing, researching, and attempting to ameliorate loneliness.
Aims
The proposed research aims to offer a holistic view of the experience of loneliness across the lifespan through a systematic review and thematic synthesis of the qualitative literature focusing on these experiences. To address this aim, there is one central research question: How do people describe their experiences of loneliness?
This research question concerns aspects of loneliness which participants discuss when describing their lived experiences. Whilst we expect that this would concern emotional, social, and cognitive components of the experience, we understand that these findings may also come to reflect perceived causes or effects of loneliness.
This review will also consider the age groups that have been studied and how experiences of loneliness might vary across the different age groups examined in this literature. Loneliness research is often weighted towards investigations of older adults, despite the fact that the prevalence of loneliness is high across the lifespan; recent UK research found a prevalence of 40% in 16- to 24-year-olds and 27% in people over 75 [
7]. This review will also shed light on the age groups that have been included in qualitative research on loneliness experiences. In doing so, this research may identify age groups which have been understudied and may be underrepresented in this field of research, potentially pointing to life stages where experiences of loneliness might be usefully explored in more detail in the future.
Furthermore, given the relatively small number of qualitative studies into the experience of loneliness compared with quantitative research in this area, this review will also consider the reasons that study authors may offer for the relative shortage of qualitative work. This is an important point given that the review will inherently be constrained by the number of studies that exist and the focus that has primarily been given to quantitative loneliness research thus far.
Discussion
The proposed systematic review will contribute to our knowledge of loneliness by clarifying how it is subjectively experienced across the lifespan. Synthesising the qualitative literature focusing on experiences of loneliness in the general population will offer a fine-grained, subjectively derived understanding of the components of this phenomenon which closely reflects the original descriptions provided by those who have experienced it. By including non-clinical populations of all ages, this research will provide an essential view of loneliness experiences across different life stages. This can be used to inform future research into correlates, consequences, and interventions for loneliness. The use of thematic synthesis will enable us to remain close to the data, offering an account which might also be useful for policy and practice in this area.
There are a number of limitations to the planned research. Primarily, this review will be unable to capture aspects of loneliness experiences which have not been described in the qualitative literature, for example, due to the sensitivity of the topic, given that loneliness can be stigmatising, or aspects that are specific to a given unstudied population. Moreover, by focusing on lifespan non-clinical research, we aim to offer a general synthesis which can in future be informed by insights from clinical groups, rather than subsuming and potentially obscuring the aspects of loneliness which might be unique to them. Whilst primary empirical studies are not themselves extensive sources, with books in particular often offering rich descriptions of loneliness (see, e.g. [
11,
46]), this research will focus on primary empirical studies of subjective descriptions to offer a manageable level of scope and rigour. As with any systematic review, some studies may also be missing information which would inform the synthesis. Quality appraisal and sensitivity analysis will aim to capture and potentially control for this issue, but it will ultimately be difficult to ascertain how missing information might affect the synthesis.
By providing a thorough overview of how loneliness is experienced, we expect that the findings from the planned review will be informative and useful for researchers, policymakers, and clinicians who work with and for people experiencing loneliness, as well as for these individuals themselves, to better understand this important, prevalent, and often misunderstood phenomenon. Mansfield et al. [
18] have offered an illuminating systematic review covering the conceptual frameworks and models of loneliness included in the existing evidence base (i.e. social, emotional, and existential loneliness). This review will build upon this work by including research with children and adolescents and taking a bottom-up approach similar to grounded theory where the synthesis will remain close to the participants’ subjective descriptions of loneliness experiences within the included studies, rather than reflecting pre-existing themes in the evidence base. As such, this systematic review will offer specific insights into lifespan experiences of loneliness. This synthesis of lived experiences will shed light on the nuances of loneliness which existing definitions and typologies might overlook. It will offer an experience-focused overview of loneliness for people studying and developing measures of this phenomenon. In focusing on qualitative work, the planned review may also identify processes relevant to loneliness which are not expressed by statistical models. In this way, it may also provide a starting point for more nuanced qualitative work with specific populations and circumstances to ascertain components which may be characteristic of certain experiences.
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