Loneliness is more prevalent among the young than those past retirement age, a survey suggests, amid profound changes in the way we live and interact.
Across all ages one in 10 people in the UK often feel lonely, the Mental Health Foundation has found, a state which can impact upon one's physical health.
The charity highlights the decline of community and a growing focus on work.
Technology can isolate but is also an unrivalled means of connecting people, the poll of 2,256 people concludes.
The Lonely Society report described the generational differences uncovered in its survey as "striking".
Nearly 60% of those aged between 18 to 34 questioned spoke of feeling lonely often or sometimes, compared to 35% of those aged over 55.
But it is possible there are generational differences in the subjective interpretation of what it is to be lonely. In addition, the survey did not break down the differences between the active 55-year-old enjoying retirement and the frail, isolated 80-year-old.
Chronic elderly isolation was brought to the fore earlier this year with the deaths of a Northamptonshire husband and wife, whose bodies were found in their frozen home in the middle of Britain's coldest winter.
The changing nature of the family, with fewer children who themselves often move away, has increased the prospect of elderly isolation. This has also become more likely as a result of longer life expectancies, the report noted.
But neighbourhoods have also changed, with the local services such as post offices that tended to form the heart of old communities on the decline.
The report also found gender differences, with more women than men reporting loneliness, and more likely to feel depressed as a result. It highlighted the fact that the proportion of people living alone, both male and female, had doubled between 1972 and 2008.
New technology meanwhile may be both a boon and a burden, the report suggested.
At one level, it has enabled people to make connections they might not otherwise have made, and virtual friendships can evolve into real-life relationships.
The report cites the example of the parenting website Netmums, which says that because of contacts made online 10,000 women meet face-to-face every month, reducing the sometimes intense sense of isolation new mothers can experience.
But there are also concerns that technology is being used as a replacement for genuine human interaction.
Nearly a third of young people questioned for the report said they spent too much time communicating with friends and families online when they should see them in person.
Whether this has any genuine biological impact is unclear, but it has been suggested that physical presence is needed for the hormone oxytocin to be released - believed to be the chemical process underpinning the relationship between social contact and healthy hearts.
Sarah Brennan, head of the charity YoungMinds, said: "The young people we work with tell us that talking to hundreds of people on social networks is not like having a real relationship and when they are using these sites they are often alone in their bedrooms.
"Loneliness is a big problem which we need to start to tackle. In the last few years our communities have broken down and become atomised. We need to foster these relationships again and invest in our young people's wellbeing so that they have somewhere to go or to turn to when they are feeling lonely."
Dr Peter Byrne of The Royal College of Psychiatrists said the report challenged the perception that loneliness was restricted to isolated, elderly "Eleanor Rigbys", with its findings on the young.
He added: "Economic changes that disrupt people's work-life balance and family life, and send people hundreds of miles for work, are likely get worse during this recession. Openness about being lonely, and vulnerable friends and neighbours, is an important first step."
But while many more of us may be living alone in cities, with some thought loneliness can be averted, the report suggested.
"For example, Manhattan in New York has 50% lone households, more than anywhere else in the United States, yet its 'urban village' model sustains social networks because people habitually use alternative meeting places, including cafes and public spaces," the authors wrote.
"According to evolutionary psychology, cities could in fact be our perfect environment because of the demands they make on our complex social brains, but only if they are well designed."