Is loneliness bad for your health? What the research says

You’ve heard the health advice a thousand times. Drink more water. Get eight hours. Hit your steps. Nobody has ever asked you, in a check-up, when you last had a proper conversation with someone who gets you.

Maybe they should. Over the past couple of decades, researchers have built a strong case that loneliness isn’t just a bad mood or a personal quirk. It shows up in your health. And in the last few years, health authorities have started saying so out loud.

Is loneliness actually bad for your health?

The study that changed the conversation came in 2010. Psychologist Julianne Holt-Lunstad and colleagues pooled 148 studies covering 308,849 people and asked a simple question: do people with stronger social relationships live longer? They do. Across those studies, people with stronger social ties had about 50% higher odds of survival over the follow-up periods than people with weaker ones. The authors argued that this put social connection in the same league as well-known risk factors like smoking and physical inactivity.

One caveat: this is observational data. It shows a strong, consistent link, but on its own it can’t prove that connection is the cause. Healthier people may simply find it easier to stay connected. Keep that question in mind, because we’ll come back to it.

What did the US Surgeon General say about loneliness?

In May 2023, US Surgeon General Vivek Murthy published an advisory of more than 80 pages titled Our Epidemic of Loneliness and Isolation. Advisories are the office’s way of flagging a public-health problem it considers urgent.

Its key points:

• Recent surveys suggested about half of US adults experience loneliness.
• The mortality impact of being socially disconnected is similar to smoking up to 15 cigarettes a day.
• Poor social connection is linked to a 29% higher risk of heart disease and a 32% higher risk of stroke.
• In older adults, chronic loneliness is linked to around a 50% higher risk of developing dementia.
• Loneliness is also tied to higher rates of anxiety and depression.

The cigarette line is a headline-friendly comparison drawn from studies like Holt-Lunstad’s, not a precise equivalence. But the message is clear: connection belongs in the same conversation as sleep, diet and exercise.

Is loneliness a global problem?

Yes. In June 2025, the World Health Organization’s Commission on Social Connection published its first global report. It estimated that 1 in 6 people worldwide are affected by loneliness, and linked loneliness to more than 871,000 deaths a year, roughly 100 every hour.

It isn’t only an older person’s problem, either. The WHO found that between 17% and 21% of people aged 13 to 29 reported feeling lonely, with the highest rates among teenagers. If you’ve ever felt lonely in a busy flat share or a packed lecture hall, you’re in very large company.

What does the Harvard study say about relationships and health?

The Harvard Study of Adult Development has followed the same people since 1938, starting with 724 young men and later adding their children. Few studies have watched lives unfold for so long.

Its current directors, psychiatrist Robert Waldinger and psychologist Marc Schulz, summed up the findings in their 2023 book The Good Life: the quality of our close relationships is one of the strongest predictors of a long, healthy and happy life. Waldinger has put it more vividly. The people who were most satisfied in their relationships at 50 were the healthiest at 80, and midlife relationship satisfaction predicted late-life health better than cholesterol levels did.

The usual limits apply. The original group was all men, and the study is observational. But when a population-level advisory and a lifelong study of individual people point in the same direction, it’s worth paying attention.

Can building connection actually make you healthier?

Back to that chicken-and-egg question. If connected people are healthier, is it the connection doing the work? The best way to test it is to help people build connection on purpose and see what happens.

That’s what Groups 4 Health does. Developed by Australian psychologists Catherine Haslam, Tegan Cruwys and colleagues, it’s a short group programme that helps people build and keep up meaningful group connections.

• 2019: in a randomised controlled trial with 120 adults experiencing psychological distress, those who did Groups 4 Health saw a much bigger drop in loneliness and social anxiety two months later than those who received usual care.
• 2022: a larger trial with 174 young people aged 15 to 25, all living with depression and loneliness, compared Groups 4 Health with group cognitive behavioural therapy (CBT), a well-established treatment. Groups 4 Health worked about as well as CBT for depression and had a slight edge on loneliness after treatment ended, with participants followed for 12 months.

These are specific programmes for people who were struggling, run in clinical settings, so they don’t prove that any connection will fix everything. But they show something important: belonging isn’t just a lucky trait some people have. It’s something you can build, and building it can help.

What can you do about loneliness?

You don’t need a programme to borrow its best ideas. Try this:

1. Do a quick connection check. At the end of the week, ask yourself: who did I have a real conversation with? Not likes or memes. Actual back-and-forth.
2. Join one thing that repeats. A weekly class, club or volunteering shift beats a dozen one-off events. Groups 4 Health puts belonging to groups at the centre for a reason.
3. Use your voice. Swap one scroll session for a call with someone you like. Fifteen minutes of real talk counts.
4. Reach out first. Message the friend you keep meaning to call. It’s rarely as awkward as it feels.
5. Treat it as health, not weakness. If loneliness has been heavy for a while, or comes with low mood, mention it to your GP. It’s a legitimate thing to bring up.

Where Everconnected fits

If you’d like to try this with someone new, Everconnected matches you with people who share your values and interests, for one-to-one conversations by voice. It’s free to join: create an account at app.everconnected.com, or get the app from the App Store or Google Play.

Questions people ask

Sources

1. Holt-Lunstad, J., Smith, T. B., & Layton, J. B. (2010). Social relationships and mortality risk: A meta-analytic review. PLoS Medicine, 7(7), e1000316. doi.org/10.1371/journal.pmed.1000316
2. Office of the U.S. Surgeon General. (2023). Our epidemic of loneliness and isolation: The U.S. Surgeon General’s advisory on the healing effects of social connection and community. U.S. Department of Health and Human Services. www.hhs.gov/sites/default/files/surgeon-general-social-conne
3. U.S. Department of Health and Human Services. (2023, May 3). New Surgeon General advisory raises alarm about the devastating impact of the epidemic of loneliness and isolation in the United States [Press release]. www.hhs.gov/about/news/2023/05/03/new-surgeon-general-adviso
4. World Health Organization. (2025, June 30). Social connection linked to improved health and reduced risk of early death [News release on the report of the WHO Commission on Social Connection]. www.who.int/news/item/30-06-2025-social-connection-linked-to
5. Waldinger, R., & Schulz, M. (2023). The good life: Lessons from the world’s longest scientific study of happiness. Simon & Schuster. www.simonandschuster.com/books/The-Good-Life/Robert-Waldinge
6. Mineo, L. (2017, April 11). Good genes are nice, but joy is better. The Harvard Gazette. news.harvard.edu/gazette/story/2017/04/over-nearly-80-years-
7. Haslam, C., Cruwys, T., Chang, M. X.-L., Bentley, S. V., Haslam, S. A., Dingle, G. A., & Jetten, J. (2019). GROUPS 4 HEALTH reduces loneliness and social anxiety in adults with psychological distress: Findings from a randomized controlled trial. Journal of Consulting and Clinical Psychology, 87(9), 787-801. doi.org/10.1037/ccp0000427
8. Cruwys, T., Haslam, C., Rathbone, J. A., Williams, E., Haslam, S. A., & Walter, Z. C. (2022). Groups 4 Health versus cognitive-behavioural therapy for depression and loneliness in young people: Randomised phase 3 non-inferiority trial with 12-month follow-up. The British Journal of Psychiatry, 220(3), 140-147. doi.org/10.1192/bjp.2021.128