The loneliest person in the world, according to the data, is a teenage girl. Not a widower in a quiet apartment, not the retiree everyone pictures when they picture loneliness. In the flagship report the World Health Organization's Commission on Social Connection released on June 30, 2025, female adolescents post the highest loneliness rate of any age-by-sex group in the breakdown, 24.3 percent, against 17.2 percent for adolescent boys. The overall gap between women and men is small, 16.1 percent to 15.4 percent. It opens up almost entirely in adolescence, and it opens against girls. (Euronews reported the same finding under the headline that teenage girls are the loneliest group in the world; the number itself sits in the report's own tables.)
I want to start there because it is the finding most likely to be waved away, and because it tells you what kind of thing loneliness turns out to be. Not a temperament. Not a failure of effort. Something that lands harder on some bodies than others, along lines that look a lot like every other health outcome I have ever covered: age, income, gender, where you happen to live.
Loneliness is linked to death, not proven to cause it
Here is the headline the Commission wanted, and it earned it. The WHO now links loneliness and social isolation to roughly 871,000 deaths a year, which its news release translates to about 100 deaths every hour. Read the verb the WHO chose. Linked to. Not caused by. This is associative epidemiology, the same grammar that ties air pollution to mortality. Illness isolates people at least as much as isolation sickens them. The arrow runs both ways, and anyone who tells you the science has settled which way is selling you something.
What the science does support is the comparison everyone reached for: that being disconnected is a mortality risk on the order of smoking. That line did not start with this report. It runs back through Julianne Holt-Lunstad's meta-analyses, the 2010 one in PLoS Medicine that pooled 148 studies and 308,849 people and found stronger social ties associated with a 50 percent higher likelihood of survival. Behind it sits a 1988 Science paper by House, Landis, and Umberson that first argued relationships rival cigarette smoking as a risk factor.
The 2015 follow-up in Perspectives on Psychological Science turned the same evidence to the harder side of the ledger: it put social isolation at a 29 percent increased likelihood of dying, loneliness at 26 percent, living alone at 32 percent, after the confounders were controlled for. So the smoking equivalence is real, but it is an effect-size analogy drawn from decades of association studies, not a claim that a lonely evening scars a lung. Precision matters here, because the number is going to get quoted for years, and it deserves to be quoted correctly.
Loneliness tracks poverty and youth, not affluence
The part that should embarrass the wellness industry. The report finds loneliness is not a rich-world affliction of people with too much time and too many devices. It runs on a clean income gradient: 24.3 percent in low-income countries, down through 19.3 and 12.1 percent, to 10.6 percent in high-income ones. That the low-income rate lands on the same 24.3 percent as the adolescent girls above is a coincidence of two different cuts of the data, not a typo. The countries with the least reported the most, and that inverts the entire self-care story, the one where loneliness is a lifestyle problem you fix with a gratitude app and a standing coffee date. One in six people worldwide are affected, the report says, and the weight of it sits on the young and the poor.
The age curve says the same thing. Loneliness runs highest among teenagers aged 13 to 17, at 20.9 percent, drifts down to 17.4 percent for adults under 30, and falls to 11.8 percent for people over 60. That 20.9 percent is the combined figure for boys and girls; the girls alone sit well above it, which is why the adolescent number in the lede is higher. Social isolation, which the report treats as a separate, more objective measure, runs the other way, reaching one in three older adults. The distinction is the point. The report defines loneliness as the gap between the connection you want and the connection you have, which is why teenagers can be surrounded, on their phones, in group chats that never close, and still report being lonely. Contact is not connection. As for what drives it, Dr. Vivek Murthy, the Commission's co-chair and a former US Surgeon General, singled out excessive digital media use among youth at the launch briefing, as Euronews reported; the report document itself is more guarded, calling the impact of digital technology "still unclear" while urging caution for young people.
Do not pin a structural problem on teenagers' phones
I am wary of pinning it on screens, and I will say why. When a structural finding gets hung on teenagers and their phones, it becomes another individual-responsibility story, another thing the lonely are failing to manage. But the same report shows loneliness tracking income and country, which no amount of screen-time control explains. Lonely teenagers are 22 percent more likely to leave school with lower grades or qualifications, the WHO reports, and lonely people are about twice as likely to become depressed. Those are downstream costs a society pays whether or not it decides to call connection a health matter.
Treat connection as health infrastructure, not a hug
What the Commission actually asks for is the useful part, and it is not a hug. It wants social connection measured, funded, and governed like the health infrastructure it turns out to be: a global Social Connection Index, real data, interventions that get evaluated instead of merely felt. This follows the first resolution on social connection that the World Health Assembly passed in May 2025. "We pull back the curtain on loneliness and isolation as a defining challenge of our time," Murthy said. Tedros Adhanom Ghebreyesus, the WHO's director-general, put the paradox more plainly: "In this age when the possibilities to connect are endless, more and more people are finding themselves isolated and lonely."
The mistake would be to file this under self-care, next to sleep hygiene and cold plunges, a thing you owe yourself and only yourself. Nobody signs a form saying a teenage girl in a low-income country should carry the highest risk in the sample. They just decline to build the thing that would carry it for her. Loneliness has a body count now, 871,000 a year by the WHO's own accounting. The question is whether we treat it like a mood or like a number, and who we expect to fix it.
