Thousands of children are struggling with loneliness because their parents are too busy to make time for them, according to Childline.
The British charity said it counselled more than 4 000 last year – the equivalent of 11 a day – for feelings of isolation.
Counsellors said they were surprised because the problem is more commonly associated with elderly people who may have lost spouses.
Children as young as six are contacting the charity saying they feel alone even if they are being cared for by loved ones.
Dame Esther Rantzen, founder and president of Childline, said: "We in the adult world are addicted to being busy and our children and young people are suffering as a result. Many of us have to work hard, couples may need to take on several jobs to boost their income, but sometimes that leaves too little time for the people we care about most – our children.
"I worry, too, that the kitchen table has become obsolete – families are too busy to eat together, to talk about their days together, and share their worries.
"So Childline has become the place young people choose to confide in. They tell us we make them feel valued, so they have the confidence to talk about their feelings of loneliness."
Childline, which is run by the National Society for the Prevention of Cruelty to Children, found 73 percent of counselling sessions about loneliness were with girls, making them five times more likely to contact the helpline about the issue than boys.
Staff say they are consistently hearing from children and teenagers that they feel like they are "invisible, misunderstood and those closest to them are struggling to understand their feelings".
Other factors include the growth of social media, leading some users to make "unrealistic comparisons about their life that leave them feeling ugly and unpopular".
Many children are also affected by struggling to fit into new surroundings after moving house or school and losing someone close after a death or broken relationship.
As a result of their low mood, youngsters often spend a lot of time in their bedrooms or online, which aggravated their loneliness, staff said.
In the worst cases, Childline has seen some self-harming to cope with negative feelings or even contemplating suicide. Young people also said they did not want to talk to their parents about their issues as they were worried what they would think of them.
One 15-year-old girl who contacted Childline said: "I’ve thought about ending my life because I think it’s pointless me being here. I don’t feel like anyone cares about me and I’m lonely all the time."
Childline now has a page on its website to help young people experiencing loneliness.
Peter Wanless, of the NSPCC said: "There is no single reason why so many young people suffer from loneliness and there is no simple fix. It is vital children and teenagers have people around them, in particular parents, who they can open up to."