Loneliness and mental health are closely linked, and the link runs both ways. Feeling disconnected is associated with depression, while low mood makes reaching out harder. Loneliness is also not the same as solitude. Solitude is chosen time alone, whereas loneliness is the distress of having less connection than you want.
Quick Answer
Loneliness is the distress of having less connection than you want. It is linked with depression and a higher risk of early death. Regular low-pressure contact, group activities and talking therapy that targets unhelpful social thoughts have the best support. If hopelessness appears, call or text 988 in the US. In the UK, call Samaritans on 116 123.
Loneliness and Mental Health: What the Numbers Show
Researchers use different measures, so published figures vary. Below are the most cited numbers from sources we could check.
| Measure | Figure | Source |
|---|---|---|
| People worldwide affected by loneliness | About 1 in 6 | WHO, 2025 |
| Deaths linked to loneliness each year | More than 871,000 (about 100 per hour) | WHO, 2025 |
| Ages 13 to 29 who report loneliness | 17% to 21% | WHO, 2025 |
| Low-income vs high-income countries | About 24% vs about 11% | WHO, 2025 |
| US adults lonely at least weekly | 30% (10% lonely every day) | APA poll, Jan 2024 |
| US adults aged 18 to 34 lonely daily or several times a week | 30% | APA poll, Jan 2024 |
| Higher risk of premature death | 26% (loneliness), 29% (social isolation) | US Surgeon General, 2023 |
| Odds of depression when often lonely | More than double | US Surgeon General, 2023 |
However, context matters. In the APA poll, single adults reported weekly loneliness more often than married adults (39% vs 22%). Also, life changes such as moving, retirement or bereavement can raise the risk. Our guide to grief and loss coping strategies covers that last one.
Why Loneliness Statistics Disagree
Figures for US adults range from 10% to about 50%. Yet these numbers do not conflict, because the studies measure different things.
Feeling lonely versus being isolated
Loneliness is a feeling, while social isolation means having few contacts. A person can have either one without the other. For example, the Surgeon General’s advisory reports a 26% higher risk of premature death for loneliness and 29% for isolation. Still, the two figures are not interchangeable.
Where the 15 cigarettes line comes from
The comparison traces to a 2010 meta-analysis of 148 studies and about 300,000 people, followed for an average of 7.5 years. Surgeon General Vivek Murthy cited it to compare disconnection with smoking up to 15 cigarettes a day. However, a critique in The Conversation notes that this is an analogy drawn from statistics. Moreover, the same paper compared the risk with heavy drinking, and said it exceeded the risk from inactivity and obesity.
Different questions, different cutoffs
WHO gives a global estimate of 1 in 6. Meanwhile, the APA poll found 30% lonely weekly but 10% lonely daily. The Surgeon General’s advisory says about half of US adults report some loneliness. Therefore, a question about any loneliness always returns a bigger number than one about daily loneliness.
The Biology of Loneliness and Mental Health
The best-known biological finding comes from a 2007 study of white blood cells from 14 people. Six scored in the top 15% for loneliness and the rest in the bottom 15%. Of 209 gene transcripts that differed, 78 were more active and 131 less active in the lonely group. More active genes included inflammation-related ones. In contrast, less active genes included antiviral and antibody-related ones. A summary of the study says the pattern held after adjusting for age, weight, health and medication.
That result is intriguing, but it is small and shows association only. It measured gene activity, not infections or heart disease. So it does not show that loneliness rewrites your genes. Stress physiology more broadly is covered in our stress management strategies guide.
The brain also appears to treat social exclusion partly like physical pain. For instance, a 2010 University of Kentucky team reported that acetaminophen reduced social pain, per the Association for Psychological Science. That was an early lab finding. Painkillers are not a treatment for loneliness.
Digital Connection and Loneliness
A 2018 trial at the University of Pennsylvania randomised 143 undergraduates. The experimental group limited Facebook, Snapchat and Instagram to 10 minutes each per day for three weeks. A summary of the study reports significant drops in loneliness and depression, mostly among those more depressed at the start. However, the sample was students only.
The wider picture is mixed. The Surgeon General’s 2023 youth advisory cites about double the risk of depression and anxiety symptoms for young people using social media over three hours a day. Again, those are associations. Our digital detox benefits guide explains how to cut screen time in practice.
What Helps With Loneliness and Mental Health
1. Use the weak ties you already have
Research by Sandstrom and Dunn found that people felt happier and more belonging on days with more acquaintance contact. Similarly, Epley and Schroeder found commuters enjoyed talking to a stranger more than they expected, as Utah State University Extension summarises. So a chat with a neighbour or barista is a small, low-risk start.
2. Join something regular
Mind suggests interest groups, volunteering and befriending services. Its loneliness tips also advise taking it slow. For example, a weekly class counts, and our guide to the benefits of regular exercise on mental health shows why group movement does double duty.
3. Volunteer, with realistic expectations
A 2022 review of 28 studies covering 191,652 adults over 50 found that five of six volunteering studies linked it to lower loneliness. The King’s College London team also found that caring for a spouse was linked to higher loneliness. These were observational studies. In contrast, a review of volunteer friendly visiting covered 13 studies and 470 older adults and rated the evidence very low certainty.
4. Try talking therapy that targets social thinking
A meta-analysis by Masi and colleagues reviewed 50 qualifying studies. Among randomised trials, interventions that addressed unhelpful social thinking worked best. Cognitive behavioural therapy (CBT) fits that approach. Meanwhile, if fear is what keeps you away from people, see our guide to social anxiety disorder symptoms and treatment.
5. Animals and solitude
Mind lists time with animals as self-care. However, we did not find strong trial evidence that pets reduce loneliness. Likewise, chosen solitude can be healthy. But if alone time turns into rumination, our guide to stopping overthinking at night can help.
Evidence Check: Loneliness Claims
| Claim | Where it stands | What it means for you |
|---|---|---|
| Loneliness is as deadly as 15 cigarettes a day | Overstated | The risk is real (26% to 29% higher) but the equivalence is an analogy. |
| Loneliness changes your genes and weakens immunity | Overstated | One 14-person study found gene activity differences. Cause is unproven. |
| Painkillers ease loneliness | Not supported | An early lab result only. Do not self-treat. |
| Limiting social media lowers loneliness | Supported, with limits | Tested in students over three weeks. Try it as an experiment. |
| Volunteering reduces loneliness | Partly supported | Observational links exist. Friendly visiting evidence is very low certainty. |
| Therapy targeting social thinking helps | Supported | Best results in randomised trials. Ask about CBT. |
| Brief chats with acquaintances lift mood | Supported | People underestimate the benefit. Say hello. |
When Loneliness and Mental Health Need Professional Help
Seek help if loneliness lasts for weeks, comes with hopelessness, or disrupts sleep, eating, work or school. If you may act on thoughts of self-harm, call or text 988 in the US. In the UK, call Samaritans on 116 123. Elsewhere, use your local emergency number.
Support routes differ by country. For example, in the UK, Mind notes that a GP can refer you to a social prescribing link worker. In the US, start with a primary care clinician or your insurer’s behavioral health line. Our mental health guide and burnout versus depression comparison can help you describe what you feel.
If a clinician has prescribed medicine for depression, do not stop it because you feel more connected. Instead, talk to your prescriber first. Our antidepressants guide explains the types and side effects.
Frequently Asked Questions
Being alone is a circumstance. Loneliness is the distress of feeling less connected than you want, whatever your company. You can feel lonely in a crowd and content alone.
The two are strongly associated and probably feed each other. The US Surgeon General reports more than double the odds of depression in people who are often lonely. However, association does not prove cause.
Not exactly. The line is an analogy from a 2010 meta-analysis. The US Surgeon General reports a 26% higher risk of premature death for loneliness and 29% for isolation. So the risk is serious, but the comparison is not a measured equivalence.
It depends on the question. WHO estimates about 1 in 6 people worldwide. In a January 2024 APA poll, 30% of US adults felt lonely weekly and 10% daily.
One University of Pennsylvania trial of 143 students found less loneliness and depression after three weeks at 10 minutes per platform daily. However, results may not apply beyond students.
Talking therapy that targets unhelpful social thinking performed best in randomised trials in one meta-analysis. Regular group activities, brief chats with acquaintances and volunteering also have support, though some evidence is observational.
See a clinician if loneliness lasts weeks, comes with low mood or hopelessness, or disrupts daily life. In a crisis call or text 988 in the US, or call Samaritans on 116 123 in the UK.
No. Never stop or change prescribed medicine without talking to your prescriber. Stopping suddenly can cause withdrawal symptoms or a return of depression.
Related Reading
- Mental health guide
- Digital detox benefits and how to reduce screen time
- Stress management strategies
- Social anxiety disorder symptoms and treatment
Sources
- WHO: Social connection and early death (30 June 2025)
- US Surgeon General: Our Epidemic of Loneliness and Isolation (2023)
- US Surgeon General: Social Media and Youth Mental Health (2023)
- American Psychiatric Association: Loneliness poll (January 2024)
- The Conversation: Is loneliness as damaging as 15 cigarettes a day?, secondary source for Holt-Lunstad 2010
- ScienceDaily summary of Cole et al., Genome Biology (2007), secondary summary
- APS Observer preview of DeWall et al., Psychological Science (2010)
- ScienceDaily summary of Hunt et al., Journal of Social and Clinical Psychology (2018), secondary summary
- Masi et al.: A meta-analysis of interventions to reduce loneliness (PMC)
- ScienceDaily summary of Akhter-Khan et al., Aging and Mental Health (2022), secondary summary
- Friendly visiting for loneliness in older adults: systematic review
- Utah State Extension: Small connections matter (Sandstrom and Dunn; Epley and Schroeder)
- Mind: How to manage loneliness
Some journal pages block automated access, so several studies are cited through secondary summaries. See our sourcing policy.
Written and fact-checked by the HealthCoachJP editorial team. No clinician has reviewed this article. See our sources cited page. This article is general information, not medical advice.
Last reviewed and rewritten October 2026.
