Loneliness Is Inflaming Our Bodies—And Our Politics

Scientific American

16-05-2025

Hannah Arendt has been on my mind a lot lately. The 20th-century German-Jewish political philosopher escaped the Nazi Holocaust, and won regard as one of the world's greatest public intellectuals at a time when few women were appointed to university faculties. She drew on history, literature and her own life to identify the conditions under which open and liberal societies turn into authoritarian states. Seven decades ago she made observations that still offer powerful insights today.
In The Origins of Totalitarianism,Arendtemphasized one primary factor in the rise of authoritarianism that has little obvious connection to politics: loneliness. While we usually think of loneliness as not having our social needs met, Arendt defined the word as something deeper. Loneliness happens when there are no shared objective facts and no potential collective action to solve shared challenges. It's a state of being where you can't trust others. Loneliness, in Arendt's telling, inflames the connective tissues of a society. It weakens the body politic so that demagogues and despots can prey. 'What prepares men for totalitarian domination,' she wrote, '… is the fact that loneliness, once a borderline experience usually suffered in certain marginal social conditions like old age, has become an everyday experience.'
Arendt—as far as I know—didn't use the word 'inflammation' to describe the effects of social isolation on a country or culture. But it's the metaphor that, to me, gets to the essence of her warning.
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Inflammation is the body's response to a sense of threat—a protective, contractionary response that can extend even to the cellular level. It's a response that can inhibit healing. A community or society that faces a deficit of meaningful connectedness is similarly in a state of perpetual threat; people are unable to listen to one another, to trust each other, to maintain trust in shared institutions, or to collectively overcome divisions.
This might sound familiar.
From 2003 to 2022, face-to-face socializing among U.S. men fell by 30 percent. For teenagers, it was a staggering 45 percent. An estimated 12 percent of Americans report having no close friends, a fourfold increase since 1990. While social media was supposed to amplify human connection, the rise of comparison culture, social sorting into echo chambers and the rapid decline of in-person social connection have instead coincided with unprecedented levels of anxiety, depression and distrust.
It should therefore come as no surprise that, in America, we're seeing democratic backsliding like Hannah Arendt warned of—including mass polarization, intentional disinformation and a politics of fear, retribution and rage.
Loneliness inflames societies.
It just so happens that loneliness inflames the body, too.
Two decades ago, researchers Louise Hawkley and John Cacioppo at the University of Chicago demonstrated in a landmark study that loneliness acts as a chronic stressor that triggers the body's innate stress-response systems. Social isolation keeps the hypothalamic-pituitary-adrenal (HPA) axis in a constant state of arousal, driving persistent cortisol release. This hormonal imbalance heightens inflammation. And this can, in turn, weaken the immune system, compromise cardiovascular health and worsen vulnerability to mental health conditions such as depression and anxiety. In short, the absence of meaningful social bonds can literally recalibrate the body's physiological mechanisms toward greater stress and illness.
Over the past two decades, further studies have only reinforced the link between loneliness and inflammatory pathways. George Slavich of the University of California, Los Angeles, underscores that experiencing social disconnection can mimic physical threats in how our brains and immune systems respond—magnifying the release of inflammatory agents. From an evolutionary standpoint, sustained isolation disrupts our primal need for social integration—leading to inflammation and a whole host of downstream consequences.
It's easy to downplay the loneliness problem. When former U.S. surgeon general Vivek Murthy warned of the dangers of social isolation and proposed solutions, no meaningful government interventions ensued. Likewise, when the U.K. government appointed a minister for loneliness in 2018, many likened the move to a Monty Python sketch rather than seeing it as a serious policy intervention.
But the medical, social and even political costs of growing social isolation mean that we can no longer afford to ignore it.
Some solutions are straightforward. Medical innovators are now addressing social isolation through practices like ' social prescribing '—wherein health professionals connect patients who are lonely with nonmedical community services, volunteer programs, exercise groups and arts activities to improve their well-being. Instead of writing prescriptions for pills, doctors can prescribe a free pass to a museum, an invitation to join a gardening club, or a support group for people facing similar struggles. A recent multiyear evaluation of nature-oriented social prescribing in the U.K. found that programs significantly helped participants reduce anxiety and improve happiness.
Other solutions are more systemic. When Pete Buttigieg ran for president in 2020, he laid out an agenda for ' belonging and healing '—emphasizing new funding and policies around mental health and addiction as well as national service to rebuild community institutions and promote environmental restoration. Leaders should propose scaling up 'belonging infrastructure'—transit, green spaces, cultural venues, and mental health centers—while expanding purpose-driven national service programs like Americorps and investing in local journalism through public grants or tax incentives to restore trusted information sources and restore important foundations of community life.
This should be a bipartisan cause. Conservatives and liberals alike have an opening to address the crisis by leveraging faith and veterans' groups–for example, granting tax incentives or small federal matches that could help churches, synagogues, and veterans' groups build mentoring initiatives, addiction recovery support and efforts to revitalize parks, libraries and civic spaces. There's also growing bipartisan recognition of the role of social media in the crisis. In tackling big tech's impact on youth, leaders across the ideological spectrum should push toward full algorithmic transparency, restrictions to exploitative design features, and mandates for robust digital well-being protections for children.
Like inflammation in the body, social isolation weakens our civic 'immune system,' fueling polarization and making us more susceptible to authoritarian impulses. But Hannah Arendt emphasized that the condition is reversible. By investing in the foundations of shared belonging, we can restore our adapt to adapt to the challenges we face—from wildfires to pandemics to misinformation. It's time to get serious about our healing.