The population of the world is aging, with the number of adults aged 65 and older expected to double, growing from 420 million in 2000 to an estimated 973 million in 2030 (Centers for Disease Control and Prevention, 2003). In recent decades, there has been growing concern about loneliness across all ages, but particularly in older adults (Anderson and Thayer, Reference Anderson and Thayer2018). Loneliness (the subjective negative experience of being isolated and having inadequate meaningful connections) and social isolation (the objective state of having few or infrequent social relationships) are serious yet underappreciated public health risks that affect a significant portion of the older adult population. Loneliness is consistently associated with unhealthy aging. It is a major risk factor for not only worse mental health outcomes, such as lower levels of well-being and happiness, increased levels of depression, and poorer quality of sleep, but also worse physical health outcomes, including cardiovascular disease, frailty, cognitive decline, and risk of Alzheimer’s disease (Hawkley and Cacioppo, Reference Hawkley and Cacioppo2010). Strong evidence links loneliness to changes in cardiovascular, neuroendocrine, and immune function as well as to the physiological stress response, such as higher levels of inflammation. Conversely, increased morbidity has been shown to increase loneliness over time (Kristensen et al., Reference Kristensen, König and Hajek2019). This new behavioral epidemic of loneliness has led to an unprecedented reduction in longevity and contributes to the markedly increasing rates of “deaths of despair,” such as those due to suicides and opioid abuse (Jeste et al., Reference Jeste, Lee and Cacioppo2020). In a recent meta-analysis, loneliness was shown to increase odds of mortality by 30% (Holt-Lunstad et al., Reference Holt-Lunstad, Smith, Baker, Harris and Stephenson2015), and according to Vivek Murthy, MD, the former USA Surgeon General, the reduction in life span associated with loneliness is equivalent to that caused by smoking 15 cigarettes a day and greater than that due to obesity (McGregor, Reference McGregor2017). In the USA, 162,000 deaths per year are attributable to loneliness and social isolation – more than those secondary to lung cancer or stroke (Veazie et al., Reference Veazie, Gilbert, Winchell, Paynter and Guise2019). Considering the public health initiatives targeted towards curbing tobacco use, obesity, cancers, and other medical morbidities, prevention and intervention efforts and resources to address loneliness fall woefully short.

In light of the coronavirus disease 2019 (COVID-19) pandemic, social distancing and self-isolation guidances further exacerbate and escalate the spread of loneliness. The unpredictability of COVID-19 – from uncertain prognoses, shortages of resources for testing and treatment, financial losses, conflicting messages from government leaders and authorities, to the imposition of unfamiliar public health measures – contributes to widespread emotional distress and threaten mental health (Pfefferbaum and North, Reference Pfefferbaum and North2020). This threat is higher for older adults who are at greatest risk for serious complications from COVID-19 and face longer periods of quarantine and isolation. Studies on the SARS-CoV-1 outbreak in 2003 reported that the previous epidemic led to increased anxiety, depression, sleep disturbances, alcohol and substance misuse, self-harm, and a 30% increase in suicides, including among seniors (Yip et al., Reference Yip, Cheung, Chau and Law2010). This new infectious public health crisis will undoubtedly worsen the ongoing behavioral public health crisis and specifically poses a unique challenge for seniors.

As such, the paper by Sommerfeld et al. (Reference Sommerfeld, Lutzman and Ben David2020) in this current issue is timely. The authors examined a moderated mediation model of physical pain and suicidal ideation in a sample of nearly 200 elderly men. They found that loneliness and social integration significantly mediated the relationship between pain and suicidality in single, divorced, and widowed participants but not among participants who were in a relationship or married. The results of this study elucidate potential processes underlying the relationship between physical and emotional distress and provide a biopsychosocial framework for conceptualizing suicidality in elderly individuals. The association between social isolation and health is complex and likely bidirectional. Poor health may lead to social isolation and subsequent loneliness; for example, declining physical and cognitive function among older adults may contribute to limited mobility, reduced independence, and increased barriers to resources and technology to communicate with friends and family. Conversely, loneliness may also increase stress that may affect health outcomes.

The clinical implications of these findings are substantial and suggest that loneliness and social integration are important targets for suicide prevention efforts. In response to emerging evidence linking social isolation and loneliness with poor health outcomes, particularly among vulnerable aging populations, a number of large-scale efforts and initiatives have been established by government and private sector organizations to address the problem of reduced social connectedness in older adults. The World Health Organization created the Global Network of Age-friendly Cities and Communities to promote healthy and active aging, which includes addressing social isolation. In 2018, the UK appointed a Minister for Loneliness to address the societal and economic costs of loneliness. IBM’s Institute for Business Value published a series of studies exploring how businesses and governments can partner to address loneliness in the aging population (Palmarini and Fraser, Reference Palmarini and Fraser2020). In the USA, the Centers for Medicare and Medicaid Services, Centers for Disease Control and Prevention, and the National Academy of Medicine have recommended that primary care visits should include screening and documentation of social needs to inform clinical interventions, such as providing patients with immediate social and economic resources on-site or connecting patients with community-based resources off-site (Gottlieb et al., Reference Gottlieb, Cottrell, Park, Clark, Gold and Fichtenberg2018). More and more, there is a growing interest from health systems, public health departments, insurance payers, advocacy groups, and community organizations to develop and implement programs to address the social determinants of health, including social isolation and loneliness.

Research from our group suggests that wisdom may be a unique aspect of addressing chronic loneliness. Wisdom has been traditionally viewed as a construct restricted to religion and philosophy. However, empirical research over the past 40 years has demonstrated that wisdom is a measurable human characteristic amenable to scientific inquiry (Jeste and Lee, Reference Jeste and Lee2019). Though definitions have varied across time, culture, and discipline, wisdom is now considered a holistic, multi-dimensional human trait comprised of several specific components: prosocial behaviors, emotional regulation, self-reflection, acceptance of divergent values, decisiveness, and social advising (Jeste and Lee, Reference Jeste and Lee2019). Biological studies have also identified neural correlates of the components of wisdom and propose that the putative neurocircuitry of wisdom involves the prefrontal cortex and limbic striatum (Meeks and Jeste, Reference Meeks and Jeste2009).

Our research has shown that loneliness is strongly negatively correlated with wisdom (r = -0.50 – -0.60) across different samples (Nguyen et al., Reference Nguyenin press, Lee et al., Reference Lee2019). People who are wiser are less lonely. In a recent study of nearly 2500 community-dwelling adults, aged 20–69 years, we found that of the components of wisdom, prosocial behaviors are most predictive of loneliness, after controlling for the other components of wisdom in addition to relevant demographic and psychosocial factors (Nguyen et al., Reference Nguyenin press). Additionally, prosocial behaviors were positively correlated with social network, and the strength of this relationship was stronger with increasing age (ranging from r = 0.09 in 20 year olds to r = 0.45 in 60 year olds). These findings suggest that one’s ability to demonstrate prosocial behaviors, such as empathy, compassion, and social cooperation, may moderate the relationship between social network and loneliness. Prosocial behaviors facilitate social cooperation by decreasing competition and contentious behavior. Individuals with prosocial motives are more likely to achieve better joint outcomes, which can increase social connectedness. Particularly in later stages of life, when opportunities for social connections may be less available, skills such as compassion may be critical to develop or maintain one’s social network. Consistent with this hypothesis, we recently examined qualitative aspects of older adults’ experience of loneliness in a senior housing community and found that compassion is an important subtheme for coping with loneliness (Morlett Paredes et al., Reference Morlett Paredes2020).

Loneliness is associated with both external (e.g. marital status and social network) and internal (e.g. prosocial behaviors and self-efficacy) factors (Nguyen et al., Reference Nguyenin press). Thus, loneliness interventions should strive to address the multi-factorial nature of the phenomenon. Many proposed interventions to reduce loneliness include those that seek to provide social support, increase opportunities for social interactions, and improve social skills. These are based primarily on external factors and an instinctive understanding of loneliness. However, increasing social support and opportunities for social interactions may only solve part of the problem, as subjective isolation may still occur in the context of an objectively large social network. Another strategy to reduce loneliness is based on addressing maladaptive cognitions (e.g. attribution biases and self-defeating thoughts) regarding social situations and interpersonal interactions (e.g. cognitive behavioral therapy; CBT). Among these interventions, those based on the social CBT framework have had the largest effect sizes (Masi et al., Reference Masi, Chen, Hawkley and Cacioppo2011).

Based on this model of social cognition as a function of loneliness (Cacioppo et al., Reference Cacioppo, Grippo, London, Goossens and Cacioppo2015), increasing prosocial attitudes and behaviors and beliefs of social self-efficacy may improve quality of communication and connection with one’s existing social environment and make one more apt to benefit from strategies to improve social network and reduce isolation. In a recent randomized clinical trial, we have shown that wisdom and prosocial behaviors can be enhanced in later life with psychosocial interventions, incorporating incorporated savoring, gratitude, and engagement in value-based activities (Treichler et al., Reference Treichler2020). However, this study did not include loneliness as an outcome, so future trials are needed to demonstrate that increasing wisdom can prevent or reduce chronic loneliness. Intervention programs focused on wisdom and other internal factors may not only decrease loneliness and mitigate suicidality and physical pain, as suggested by Sommerfeld et al.’s (Reference Sommerfeld, Lutzman and Ben David2020) findings, but also improve well-being and quality of life for older adults.