The result is a public health crisis on the scale of the opioid epidemic or obesity, Dr. Murthy said. In a 2018 study by the Kaiser Family Foundation, one in five Americans said they always or often felt lonely or socially isolated.
The pandemic only exacerbated these feelings. In a recent citywide survey by New York’s health department, 57 percent of people said they felt lonely some or most of the time, and two-thirds said they felt socially isolated in the prior month.
“Loneliness,” Dr. Murthy said, “has real consequences to our health and well-being.”
Being lonely, like other forms of stress, increases the risk of emotional disorders like depression, anxiety and substance abuse. Less obviously, it also puts people at greater risk of physical ailments that seem unrelated, like heart disease, cancer, stroke, hypertension, dementia and premature death. In lab experiments, lonely people who were exposed to a cold virus were more likely to develop symptoms than people who were not lonely.
An often-cited meta-analysis by Julianne Holt-Lunstad of Brigham Young University compared the risk effects of loneliness, isolation and weak social networks to smoking 15 cigarettes a day.
“The general public recognizes how loneliness might influence our levels of distress, our emotional or mental health,” Dr. Holt-Lunstad said. “But we probably don’t recognize the robust evidence of the effects on our physical health.”
Nor do we recognize the economic cost.
Social isolation and loneliness are associated with an additional $6.7 billion in Medicare spending and cost employers more than $154 billion annually in stress-related absenteeism, plus more in job turnover, according to studies by AARP and the insurance giant Cigna.
Yet the culture has moved slowly to address the epidemic, Dr. Murthy said, treating loneliness as an unpleasant feeling rather than a public health crisis. “There are more adults struggling with loneliness than have diabetes,” he said. “Yet think about the discrepancy in the attention that we give to these two conditions.”