Why loneliness matters

The phenomenon of loneliness is complex and multidimensional, (Ekwall et al., Reference Ekwall, Sivberg and Hallberg2005) and associated with negative health outcomes (Petitte et al., Reference Petitte, Mallow and Barnes2015). Loneliness is defined as a subjective feeling that occurs when the relationships one has do not match one's expectations of what the relationships should be (De Jong Gierveld and Van Tilburg, Reference De Jong Gierveld and Van Tilburg2010; Holt-Lunstad et al., Reference Holt-Lunstad, Smith and Layton2010; Beller and Wagner, Reference Beller and Wagner2018). It can be described as the perceived experience of being alone or feeling alone even when around others (Peplau and Perlman, Reference Peplau, Perlman, Peplau and Perlman1982; Cacioppo et al., Reference Cacioppo, Grippo and London2015), including the perception of having inadequate social contacts that one can rely on or trust (Perlman and Peplau, Reference Perlman, Peplau, Duck and Gilmour1981; Ekwall et al., Reference Ekwall, Sivberg and Hallberg2005; Ayalon, Reference Ayalon2016; Iecovich, Reference Iecovich2016). De Jong Gierveld and van Tilburg (Reference De Jong Gierveld and Van Tilburg2006) described two components of loneliness. They define emotional loneliness as the absence of an intimate relationship or close emotional attachment, and social loneliness as the absence of a broader social network (De Jong Gierveld and Van Tilburg, Reference De Jong Gierveld and Van Tilburg2006). Loneliness differs from social isolation, which is an objective lack of social contacts and relationships with other people (De Jong Gierveld, Reference De Jong Gierveld1998; De Jong Gierveld and Van Tilburg, Reference De Jong Gierveld and Van Tilburg2006; Beller and Wagner, Reference Beller and Wagner2018). In summary, being alone and feeling alone are not necessarily interchangeable, yet both are aspects of social disconnectedness (Beller and Wagner, Reference Beller and Wagner2018).

Furthermore, loneliness is suggested to be an important psychosocial determinant of health, yet it is often overlooked despite growing, vital public health concerns (Gerst-Emerson and Jayawardhana, Reference Gerst-Emerson and Jayawardhana2015). Although people are more connected digitally, the prevalence of loneliness appears to be rising and increasingly widespread (Cacioppo et al., Reference Cacioppo, Grippo and London2015). In the general population, 7–39% of adults report feeling lonely (Savikko et al., Reference Savikko, Routasalo and Tilvis2005; Victor et al., Reference Victor, Scambler and Bowling2005; Shiovitz-Ezra and Leitsch, Reference Shiovitz-Ezra and Leitsch2010; Theeke, Reference Theeke2010). Among a sample of middle-aged adults in the USA, 29% felt lonely some or all of the time (Nersesian et al., Reference Nersesian, Han and Yenokyan2018). Loneliness can affect anyone, although it is more likely to occur in populations that are at risk for social alienation, isolation, and separation (Cacioppo et al., Reference Cacioppo, Grippo and London2015). With loneliness and the burden of cancer on the rise, it is crucial to understand the impact of loneliness on cancer caregivers.

There are robust associations between loneliness and poor physiological, physical, and psychological health (Petitte et al., Reference Petitte, Mallow and Barnes2015), where social integration and social support can provide protective effects on both morbidity and mortality (Berkman et al., Reference Berkman, Glass and Brissette2000; Kawachi and Berkman, Reference Kawachi and Berkman2001; Steptoe et al., Reference Steptoe, Shankar and Demakakos2013; Gerst-Emerson and Jayawardhana, Reference Gerst-Emerson and Jayawardhana2015). From a physiological standpoint, feeling lonely can result in the activation of the hypothalamic–pituitary–adrenal (HPA) cortex. HPA activation elicits physiological reactions in the autonomic, endocrine, and immune functioning pathways (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2003), including a suggested dysregulation in biomarkers like proinflammatory cytokines (interleukin-6, fibrinogen, and C-reactive protein) that over time, can result in negative health consequences (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010; Jaremka et al., Reference Jaremka, Fugundes and Peng2013; Nersesian et al., Reference Nersesian, Han and Yenokyan2018).

Loneliness is also associated with consequences to physical health, including physical inactivity and smoking (Shankar et al., Reference Shankar, McMunn and Banks2011; Dyal and Valente, Reference Dyal and Valente2015), functional limitations (Luo et al., Reference Luo, Hawkley and Waite2012; Theeke et al., Reference Theeke, Mallow and Moore2016a), sleep disturbance (Cacioppo et al., Reference Cacioppo, Hawkley and Berntson2002, Reference Cacioppo, Hughes and Waite2006; Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010; Kurina et al., Reference Kurina, Knutson and Hawkley2011; Hayley et al., Reference Hayley, Downey and Stough2017), increased blood pressure (Sorkin et al., Reference Sorkin, Rook and Lu2002; Hawkley et al., Reference Hawkley, Masi and Berry2006; Yang et al., Reference Yang, Schorpp and Harris2014), inflammation (Luo et al., Reference Luo, Hawkley and Waite2012; Nersesian et al., Reference Nersesian, Han and Yenokyan2018), stroke (Holt-Lunstad and Smith, Reference Holt-Lunstad and Smith2016; Valtorta et al., Reference Valtorta, Kanaan and Gilbody2016), and death (Holt-Lunstad et al., Reference Holt-Lunstad, Smith and Layton2010, Reference Holt-Lunstad, Smith and Baker2015).

In addition, loneliness is associated with poor psychological health, including anxiety (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010), fatigue (Cacioppo et al., Reference Cacioppo, Hawkley and Berntson2002), depression (Hawkley et al., Reference Hawkley, Thisted and Cacioppo2009; Cacioppo et al., Reference Cacioppo, Hawkley and Thisted2010; Luo et al., Reference Luo, Hawkley and Waite2012; Jaremka et al., Reference Jaremka, Andridge and Fagundes2014), psychosis (DeNiro, Reference DeNiro1995), and suicide (Stickley and Koyanagi, Reference Stickley and Koyanagi2016). Nersesian et al. (Reference Nersesian, Han and Yenokyan2018) found that in a sample of middle-aged adults in the USA, higher feelings of loneliness were associated with increased levels of self-reported stress, evidence to HPA physiologic stress reactivity. People who feel lonely are also at greater risk of cognitive and functional decline, which is particularly worrisome for our largely aging population (Luo et al., Reference Luo, Hawkley and Waite2012; Theeke et al., Reference Theeke, Mallow and Moore2016b). One study documented a 64% increased chance of developing clinical dementia among people who feel lonely (Holwerda et al., Reference Holwerda, Deeg and Beekman2014). Similarly, Rosenberg (Reference Rosenberg2016) found that a higher amyloid burden, a biomarker for Alzheimer disease, was significantly associated with greater feelings of loneliness (Rosenberg, Reference Rosenberg2016). Understanding the role of loneliness in cancer caregivers is particularly salient given the potentially deleterious widespread health consequences.

Cancer caregiving and loneliness

Loneliness is not only a problem for cancer patients but also for many of their caregivers who report moderate to high levels of loneliness (Deckx et al., Reference Deckx, Van Den Akker and Bulens2015; Soylu et al., Reference Soylu, Ozaslan and Karaca2016; Segrin et al., Reference Segrin, Badger and Sikorskii2019). Providing care for a seriously ill loved one puts demands on individuals that limit their discretionary social contacts and often culminate in loneliness (Segrin et al., Reference Segrin, Badger and Sikorskii2019). Caregivers’ lives are often altered when they begin providing care for loved ones. They may lose contact with friends, neighbors, relatives, and social groups, such as faith communities and civic organizations (Lynn, Reference Lynn2014), may need to withdraw from previous social habits or modify their lifestyles (Soylu et al., Reference Soylu, Ozaslan and Karaca2016), and frequently do not have visitors or others to talk with them when they need the most help (Lynn, Reference Lynn2014). Caregivers of cancer patients spend a significant amount of time caring for individuals with complex care needs (Given et al., Reference Given, Given and Sherwood2012; Soylu et al., Reference Soylu, Ozaslan and Karaca2016), and this is particularly true in instances where care is shifting to more in-home interventions and away from inpatient settings (Ferrell et al., Reference Ferrell, Kravitz and Borneman2018).

Loneliness may also increase the caregiver's risk of experiencing hopelessness. Greater feelings of hopelessness may then decrease caregivers’ feelings of self-efficacy, ability to meet their own needs, or ability to adequately care for the person with cancer (Golden et al., Reference Golden, Conroy and Bruce2009; Balfe et al., Reference Balfe, O'Brien and Timmons2016). Notably, certain clinical guidelines that are standards of oncology care may predispose cancer caregivers to feel lonely. For example, during the disease course, individuals undergoing cancer treatment must commonly adhere to behavioral restrictions and contact precautions to limit exposure to potentially threatening infections and diseases when they are immunocompromised (Wilson et al., Reference Wilson, Zitella and Erb2018). Special precautions may include limiting the number of visitors to one's home or restricting outings that may expose patients to others in crowded places. Special precautions are especially relevant when the patient's health is significantly compromised (Miller and Kapp, Reference Miller and Kapp2015). The restrictions placed on patients may likewise affect caregivers by restricting their access to friends and acquaintances, leaving caregivers to feel lonely, disengaged, and potentially constrained from social support. Caregivers may also be conflicted about leaving the person with cancer home alone out of fear that something disastrous will happen. Commonly, this fear results in caregivers’ withdrawal from social activities or work activities relevant to their self-worth (Stenberg et al., Reference Stenberg, Ruland and Olsson2012). In addition, cancer caregivers go through anticipatory grief and bereavement, in which caregivers reported elevated feelings of loneliness when their loved one dies. Feelings of loneliness are especially common when caregivers deal with memories and exhaustion from the caregiving experience. After the death of a loved one with cancer, caregivers have previously described such feeling as “losing a part of yourself” along with a sense of emptiness and loss (Holtslander and Duggleby, Reference Holtslander and Duggleby2010; Totman et al., Reference Totman, Pistrang and Smith2015; Piil et al., Reference Piil, Nordentoft and Larsen2019). More longitudinal studies are needed to examine caregiver loneliness as it relates to different points of the illness trajectory, including death or survivorship. Overall, compared to other caregivers, those who care for loved ones with cancer face a unique set of experiences related to loneliness even after the loved one dies.

Measuring loneliness

Using accurate and reliable instruments is vital to understanding the experience and prevalence of loneliness among cancer caregivers. Strong measurement tools also help to distinguish loneliness from other forms of psychosocial distress. Multi-item scales have been used to measure loneliness (Valtorta et al., Reference Valtorta, Kanaan and Gilbody2016) including the 20-item UCLA Loneliness Scale (Russell et al., Reference Russell, Peplau and Ferguson1978) and its revised versions (Russell et al., Reference Russell, Peplau and Cutrona1980; Russell, Reference Russell1996). A short form of the UCLA Loneliness Scale, which includes three items, was originally designed and validated for use in large telephone-based surveys that examined whether participants felt that they lacked friendship, felt left out, or felt isolated from others in the past month (Hughes et al., Reference Hughes, Waite and Hawkley2004). Items are scored on a 3-point scale (from 1 = hardly ever to 3 = often) with higher scores indicating greater loneliness. This 3-item measure was found to have good reliability scores among various groups (Hughes et al., Reference Hughes, Waite and Hawkley2004). Additionally, a single-item measure from the widely-used Center for Epidemiological Studies Depression Scale (CES-D) was validated for individual use through several nationwide studies and serves as a quick measure of loneliness (Radloff, Reference Radloff1977; Routasalo et al., Reference Routasalo, Savikko and Tilvis2006; Wilson and Moulton, Reference Wilson and Moulton2010; O'Luanaigh et al., Reference O'Luanaigh, O'Connell and Chin2012; Nersesian et al., Reference Nersesian, Han and Yenokyan2018). The 11-item De Jong Gierveld Loneliness Scale measures two separate dimensions of loneliness, emotional and social loneliness, and can be used as a general measure of loneliness (De Jong Gierveld and Kamphuls, Reference De Jong Gierveld and Kamphuls1985; Perlman and Joshi, Reference Perlman and Joshi1987; Beller and Wagner, Reference Beller and Wagner2018). The 6-item De Jong Gierveld Loneliness Scale was specifically developed for use in large surveys (De Jong Gierveld and Van Tilburg, Reference De Jong Gierveld and Van Tilburg2006) and was validated in international studies with various age groups (McDade et al., Reference McDade, Hawkley and Cacioppo2006; Cacioppo et al., Reference Cacioppo, Hawkley and Thisted2010; De Jong Gierveld and Van Tilburg, Reference De Jong Gierveld and Van Tilburg2010; Shankar et al., Reference Shankar, McMunn and Banks2011; La Grow et al., Reference La Grow, Neville and Alpass2012; Penning et al., Reference Penning, Liu and Chou2014; Lim and Chan, Reference Lim and Chan2016; Ritchwood et al., Reference Ritchwood, Ebesutani and Chin2017; Grygiel et al., Reference Grygiel, Humenny and Rebisz2019). Overall, these survey measures offer an opportunity to accurately and reliably measure loneliness, identify those most at risk, and observe changes in perceived loneliness over time.

Strategies to address loneliness

Along with using validated measures to identify and assess loneliness in cancer caregivers, addressing loneliness in this population is critical. Given that loneliness can occur at different timepoints during the illness trajectory, it is important to develop ongoing strategies to support caregivers, which in turn may also benefit patients (Musich et al., Reference Musich, Wang and Kraemer2017). A growing body of literature has described available strategies that providers may provide to alleviate cancer caregivers’ feelings of loneliness.

Caregiver-related interventions for loneliness fall into four main categories: (1) enhancing social skills, (2) providing social support, (3) increasing opportunities for social interaction, and (4) addressing maladaptive social cognitions (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010). The majority of intervention studies for loneliness evaluate the intervention's effectiveness of (1) addressing social aspects of loneliness (Hartke and King, Reference Hartke and King2003; Martina and Stevens, Reference Martina and Stevens2006; Shapira et al., Reference Shapira, Barak and Gal2007; Theeke et al., Reference Theeke, Mallow and Barnes2015); (2) engaging individuals in new activities or hobbies as a treatment for loneliness (Rook and Sorkin, Reference Rook and Sorkin2003); and (3) utilizing a friendship-enrichment program such as befriending (Martina and Stevens, Reference Martina and Stevens2006). However, few studies specifically focus on interventions to address loneliness among caregivers of cancer patients who have unique barriers to interacting with others (Hartke and King, Reference Hartke and King2003).

To address loneliness of previous approaches utilized both individual and group interventions, including activities geared toward increasing social interactions and behaviorally targeted interventions to improve methods of communication and social skills (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010; Masi et al., Reference Masi, Chen and Hawkley2011; Cacioppo et al., Reference Cacioppo, Grippo and London2015). For example, friendship-enriched, group-based programs that include befriending focus on the creation of one-to-one relationships (Mitchell and Pistrang, Reference Mitchell and Pistrang2011). The befriending relationship is characterized by the development of an emotional connection between two people grounded in sharing of an empathic connection (Mead et al., Reference Mead, Lester and Chew-Graham2010; Lester et al., Reference Lester, Mead and Graham2012) with aims to alleviate feelings of loneliness and provide tangible social support (Siette et al., Reference Siette, Cassidy and Priebe2017). Within befriending programs, volunteers provide the compassionate social support and companionship (Siette et al., Reference Siette, Cassidy and Priebe2017) and are generally designed to address interpersonal skills, including setting boundaries, developing listening skills, learning about caregivers’ concerns, promoting health and safety, maintaining confidentiality, strengthening communication skills, providing emotional support, and building organization skills (Siette et al., Reference Siette, Cassidy and Priebe2017). At an individual level, befriending reduces loneliness, increases emotional well-being and allows individuals to re-gain resilience, re-establish social links, and re-engage with their local communities (Balaam, Reference Balaam2015). Among older adults, befriending is arguably the most widespread approach to help address social isolation and loneliness that is commonly available at cancer centers (Cattan et al., Reference Cattan, White and Bond2005; Savikko et al., Reference Savikko, Routasalo and Tilvis2005; Price, Reference Price2015; Gardiner et al., Reference Gardiner, Geldenhuys and Gott2018).

Group interventions can also provide opportunities for social engagement with others. Group-based interventions allow participants to reflect and reappraise their own behavior and situations by making comparisons with other caregivers and receiving advice and support from others (Mahendran et al., Reference Mahendran, Lim and Tan2017). Group interventions may be less effective in addressing loneliness if they do not alter how individuals approach and think about their social relationships (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010). However, there are unique benefits to interventions involving group activities that enhance an individual's sense of belonging (Platt, Reference Platt2009), promote social support (Saito et al., Reference Saito, Kai and Takizawa2012; Cotterell et al., Reference Cotterell, Buffel and Phillipson2018), and potentially foster mindfulness practices (Creswell et al., Reference Creswell, Irwin and Burklund2012). Unfortunately, major barriers to caregiver support group attendance exist, including caregivers’ lack of time, busy work schedules, and the need for respite care to relieve the caregiver to be able to attend the support group (Ussher et al., Reference Ussher, Kirsten and Butow2008). Alternatively, resilience training is an emerging approach to address loneliness that focuses on one's capacity to sustain positive relationships and overcome social stressors (Shapira et al., Reference Shapira, Barak and Gal2007; MacLeod et al., Reference MacLeod, Musich and Parikh2018). Research demonstrates that high levels of resilience can protect against the effects of loneliness and social isolation (Cotten et al., Reference Cotten, Anderson and McCullough2013; Chopik, Reference Chopik2016; MacLeod et al., Reference MacLeod, Musich and Hawkins2016, Reference MacLeod, Musich and Parikh2018).

Cognitive-behavioral therapy (CBT) is another promising strategy caregivers can use to alleviate loneliness. Although further theoretical development and intervention testing is needed, prior studies have found that CBT interventions have the greatest effectiveness in addressing maladaptive cognitive processes related to loneliness (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010; Masi et al., Reference Masi, Chen and Hawkley2011). CBT can be provided in both individual and group settings. CBT interventions teach individuals to notice and evaluate their own recurrent cognitive processes and resulting behaviors. Participants are guided to modify their negative thoughts by using learned adaptive coping techniques. Specifically, the maladaptive thought distortions may be expressed similarly in both depression and loneliness (i.e. “black and white” thinking, jumping to conclusions, magnifying or minimizing, emotional reasoning, and thinking that involves the word “should”), yet the mechanisms that these distortions lead to negative behaviors is widely variable. CBT interventions in their original format, however, may not be fitting to cancer caregivers’ needs related to the feeling of loneliness and therefore require modifications.

While experiencing loneliness, individuals often report “increased attention to negative social stimuli” (Cacioppo and Hawkley, Reference Cacioppo and Hawkley2009). Other maladaptive cognitions associated with loneliness that often lead to negative behaviors include increased fear of negative evaluations, increased negative impressions of others, perceiving others to be less charitable, self-views of passively being a victim to others’ actions, perception of being alone in the pain of caring for a loved one, fear that leaving the patient will lead to negative consequences, and greater difficulty to fulfill social needs (Cacioppo and Hawkley, Reference Cacioppo and Hawkley2009). However, cancer caregivers’ cognitions are at times accurate, and the restrictions to spending time with others due to fear of spreading infections to their loved ones with cancer are actual limitations that contribute to feelings of loneliness. Therefore, CBT for caregiver loneliness may instead focus on behavioral activation and increased goal setting. This may emphasize creative solutions to “connecting with others,” such as setting time aside for phone calls with others or coordinating technology-based interactions. Based on the current review, we can hypothesize that such adaptations of CBT for loneliness would also need to include psychoeducation on the long-term health consequences of loneliness, focusing on recognizing and modifying maladaptive thought patterns and emotions related to caregivers’ relationships with others, and the resulting behavioral changes that occur specific to caregivers’ lifestyles.

To date, few formal interventions exist that target the cognitive misconceptions experienced by lonely people, let alone those specific to a caregiver's experience. One recent randomized-controlled trial included the creation of a CBT-based intervention called LISTEN (Loneliness Intervention using Story Theory to Enhance Nursing-sensitive outcomes) that targeted loneliness and included 27 individuals, found that CBT led to significant reductions in loneliness and systolic blood pressure at 12-week post-intervention (Theeke et al., Reference Theeke, Mallow and Moore2016a). The LISTEN intervention included five, 2-h group sessions focused on psychoeducation about loneliness, emotional processing of feelings of loneliness, and behavioral activation (Theeke et al., Reference Theeke, Mallow and Moore2016a). An important observation in this study is that participants had “near perfect attendance” which indicates strong intervention feasibility for caregivers (Theeke et al., Reference Theeke, Mallow and Barnes2015). These introductory findings strengthen the evidence that CBT may be effective in modifying the psychophysiological cascades that may divert the negative health consequences of loneliness and improve caregiver well-being (Theeke et al., Reference Theeke, Mallow and Moore2016a). Historically, cancer caregivers have had high attrition rates for such interventions. Interventions including modified versions of CBT that focus on loneliness and are accessible may be more successful for interventions striving to address caregiver loneliness.

Technology-based interventions may also positively impact loneliness. A trial of weekly caregiver-to-caregiver telephonic support program resulted in self-reported improved coping skills, caregiver competence, and confidence along with decreased burden and loneliness (Stewart et al., Reference Stewart, Barnfather and Neufeld2006). In a meta-analysis of interventions to reduce loneliness, Masi et al. (Reference Masi, Chen and Hawkley2011) emphasized the increased benefit of utilizing technology to address loneliness, compared to interventions that were one-on-one, group-based, telephone, computer, and internet-based. Notably, most caregivers have access to technology and depending on where they live (i.e. rural communities), technology-based interventions may be their only option to participate in interventions that mitigate loneliness, rather than traveling to distant healthcare facilities for caregiver support services.

Overall, treatments that target maladaptive cognitions about loneliness and social interactions yield the strongest results (Masi et al., Reference Masi, Chen and Hawkley2011). Specifically, interventions treating maladaptive social cognitions exhibited larger effect sizes than interventions targeting social skills, increasing social support, or increasing social interaction (Masi et al., Reference Masi, Chen and Hawkley2011). These studies have greater effect sizes, irrespective of the group or individual treatment frameworks (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010; Masi et al., Reference Masi, Chen and Hawkley2011; Cacioppo et al., Reference Cacioppo, Grippo and London2015). Thereby, future work is needed to develop and evaluate the effectiveness of interventions that target cancer caregivers’ maladaptive cognitions to prevent and address loneliness among caregivers of cancer patients.