What the science says
There’s a lot of data out there. This is our pick of the bunch, but if you come across things - authoritative, rigorously researched, peer-reviewed things - that we should add then please send them our way!
STATS ON OUR SOCIAL HEALTH
Approximately 7.1% - or 3.83 million - of us in Great Britain, feel lonely ‘often or always’, according to a survey conducted in 2022. A further 42.53% of us feel lonely occasionally or sometimes. 700,000 Londoners feel lonely ‘always’ or ‘most of the time’.
Around 17-21% of young people (aged 13-29) globally feel lonely, with levels highest amongst teenagers. 72% of 16-25-year-olds say that loneliness has a negative effect on their mental health and wellbeing.
There’s a “friendship recession” in the US with people - especially men - spending less time with friends than at any point in recent history.
Loneliness affects different populations differently - for instance, in the US it is rampaging amongst men without college degrees.
Those experiencing discrimination may have a more acute need for friendship to buffer against the associated stress.
Some accounts of poor social health amongst Millennials.
48% of Canadians feel they spend too little time hanging out; 37% wish they had more friends; 26% report feeling lonely 3 days per week or more.
“From 2003 to 2022, average time spent at home among American adults has risen by one hour and 39 minutes in a typical day. Time at home has risen for every subset of the population and for virtually all activities. Preliminary analysis indicates that time at home is associated with lower levels of happiness and less meaning”.
Unless action is taken, by 2034 there will be 1.2 million people over 65 in England who will often feel lonely.
CONNECTION WITH PHYSICAL HEALTH
Poor social relationships are linked to a 29% increased risk of developing cardiovascular disease and a 32% increased risk of having a stroke.
People with only one to three types of social ties are over four times more likely to develop a cold than people with six or more types of social ties.
Social isolation amongst older people carries a 26% increased risk of developing dementia.
One meta-analysis examined 148 articles published on the effects of human interactions on health outcomes, and found that social connections with friends, family, neighbors, or colleagues improves the odds of survival by 50%.
Social isolation is linked to increased risk of heart disease, cancer, and obesity
The cumulative effect of poor social health is reduced life expectancy.
Endorphins, triggered by the presence of friends, tune the immune system, stimulating the release of white blood cells that destroy the bacteria and viruses that can lead to illness.
The places in the brain that are activated when we experience psychological pain - like social rejection - are the same places that are activated by physical pain.
Sustained social advantage is associated with more favourable biological ageing profiles, including slower epigenetic ageing and reduced inflammatory signalling.
There’s not just a correlation between people who are more connected living longer: “having strong and supportive social relationships causes better health and longer life… social relationships are a causal factor for health”.
A widely cited study makes the case that chronic loneliness is riskier for your health than smoking 15 cigarettes a day.
Kids and teenagers who are “socially integrated” have lower blood pressure and BMI two decades later.
CONNECTION WITH MENTAL HEALTH
Absence of social contact is associated with declines in cognitive function. Memory function can be impaired for years following periods of social isolation.
Social isolation is linked to raised risk of mental health and neuropsychiatric disorders, including chronic anxiety and depression.
The extent to which people feel connected more strongly and more consistently predicts mental health than the other way round.
Social isolation has been associated with increased prevalence of substance use disorders.
Socialising releases three neurochemicals - oxytocin, serotonin and dopamine - that stimulate the reward centre of our brain, making us feel good.
Social support buffers stress responses, lowering cortisol and reducing activity in threat-sensitive regions.
Perceived social isolation (loneliness) reshapes the brain’s default mode network, affecting our capacity for empathy and mentalising. Loneliness impairs our ability to interact with others normally.
Nine in 10 older people who are often lonely are also unhappy or depressed, compared to four in 10 of those who are hardly ever lonely.
Most recent relevant longitudinal studies have demonstrated that social connectedness protects adults in the general population from depressive symptoms and disorders.
Societal division and loneliness can cause significant personal stress.
“Social isolation is so detrimental to quality of life… that the United Nations and other international organisations have called for the abolition or extreme restriction of the use of solitary confinement in prisons, viewing the practice as an affront to human rights and a form of torture.”
One study in England found that lonely people were 17 times more likely to have attempted suicide in the past year than those who were less lonely.
“When rats are raised alone, their brains develop to be smaller and their behaviour is so altered that they’re often used as an animal model for schizophrenia.”
CONNECTION WITH HUMAN FLOURISHING
A Harvard study on adult development, which tracked participants over a 75 year span, found that the single biggest predictor of people’s health and happiness was the quality of their relationships - over and above the significance of upbringing, education, income or lifestyle.
“The number of real-life friends is positively correlated with subjective well-being… even after controlling for income, demographic variables and personality differences. Doubling the number of friends in real life has an equivalent effect on well-being as a 50% increase in income.”
“If you volunteer at least once a week, the increase to your happiness is like moving from a yearly income of $20,000 to $75,000. If you have a friend that you see on most days, it’s like earning $100,000 more each year.”
CONNECTION WITH PRODUCTIVITY & PROFESSIONAL SUCCESS
People who report having a ‘best friend’ at work are seven times more likely to be engaged, produce higher quality work, report greater well-being and less likely to get injured on the job than those who did not.
Cigna estimates that in 2020 each lonely worker cost their employer an average of nearly $4,200 per year in missed days and lost productivity.
A 10% increase in social trust equates to 1.3-1.5% increase in relative economic productivity.
Gallup’s 2025 report on the State of the Global Workplace revealed that 22% employees felt lonely for a lot of the previous day.
Loneliness in early adolescence can have far-reaching effects, especially to do with education and employment prospects.
Loneliness can lead to difficulties at work including poor occupational functioning.
Social connectivity may be the single most important determinant of social mobility. Providing a poor, typically disconnected, child with the network of a rich, typically connected, child boosts their lifetime income prospects by 20%.
CONNECTION WITH SOCIETAL WELLBEING
“Loneliness and social isolation are associated with an increase susceptibility to extreme ideologies and even violence.”
Racism begins when "a person lacks a sense of security and identity, which generates a desire to affiliate themselves with a group”.
When we’re lonely, we’re more prone to excessive consumption - buying things we don’t need.
People who are lonely or socially isolated demonstrate enhanced threat perception and attentional bias towards threatening stimuli.
Halving the number of adults below the wellbeing poverty line could yield £54 billion in economic benefits. By addressing chronic loneliness we could eliminate 1 million GP appointments and prevent 100,000 hospital admissions every year.
Increasing social trust in the UK to Nordic levels (an increase of c30%) would generate growth of £100 billion per year.
