Over the past year as I've investigated the human impact of loneliness, the stories I've uncovered have stopped me cold. In part because I never expected to hear them from the people in front of me, people with no outward hint of a problem. But mostly because the descriptions of their sense of isolation were so heartbreaking: "It's unceasing, toxic, brutal." "I feel invisible." "It's like living with a hole smack in the center of your chest—a hollow feeling." "My loneliness magnifies every pain in my body."
According to estimates by University of Chicago psychology professor John T. Cacioppo, PhD, coauthor of Loneliness: Human Nature and the Need for Social Connection, at any given time at least one in five people, or roughly 60 million Americans, suffers from loneliness. By this I mean both the acute bouts of melancholy we all feel from time to time, as well as a chronic lack of intimacy—a yearning for someone to truly know you, get you, see you—that can leave people feeling seriously unmoored.
As researchers have discovered, loneliness is hardly just a social issue; its physical impacts are among the most profound in modern medicine. Air pollution, obesity, and excessive alcohol use have been found to increase a person's mortality risk by 6, 23, and 37 percent, respectively. Loneliness may increase your risk by a shocking 45 percent. And it's not just the body that suffers: A study published in 2012 found that older lonely people are 64 percent more likely to develop dementia than their more connected counterparts are.
How can your social life have such a dramatic impact on your health? The oft-repeated theory is that friends encourage us to take care of ourselves and they step in when we're not feeling well; however, research shows that the dynamic may play out on a deeper level: Cacioppo was part of a team that discovered loneliness may actually alter genetic activity in the body. In people who felt as though they had few social connections, the researchers found that certain genes linked to inflammation were overexpressed, while other genes involved in antiviral responses were suppressed. Being lonely, it turns out, can literally make you sick.
But what has captured my attention in particular is the literal pain of loneliness. A remarkable study led by Naomi Eisenberger, PhD, an associate professor of social psychology at UCLA, found that being excluded—which can push you to the social perimeter and, as a result, cause feelings of loneliness—triggered activity in some of the same regions of the brain that register physical pain. From an evolutionary perspective, this makes sense; our prehistoric ancestors relied on social groups not just for companionship, but for survival. Staying close to the tribe brought access to shelter, food, and protection. Separation from the group, on the other hand, meant danger. Today when we feel left out, our bodies may sense a threat to survival, and some of the same pain signals that would engage if we were in real physical danger are flipped on. In the chronically lonely, levels of the stress hormone cortisol shoot up higher in the morning than in more socially connected people and never fully subside at night. As a result, a person can be left feeling fatigued, edgy, and irritable.
Next: The gap between us may be growing