Grandparents should be brought back into children's lives to help tackle a surge in youth anxiety and mental ill health, says Dame Esther Rantzen.
The Childline founder said children's wellbeing was being harmed by the "fragmentation of the family" and a lack of nearby supportive relatives.
She said children should be given an automatic legal right to see their grandparents, as they are in France.
Many parents were too busy to meet children's emotional needs, she added.
Dame Esther made the comments as children's charity NSPCC, which runs youth counselling service Childline, released figures showing the demand for support with anxiety had doubled over the past two years.
It provided more than 21,200 sessions for young people trying to manage feelings of anxiety.
Hollie Evans, now 21, said a call to Childline after a suicide attempt in hospital effectively saved her life.
It had allowed her to speak to people again, open up and seek the therapy she needed to get better, she said.
The telephone helpline service originally focused on offering support to children fearing for their safety but is now taking up a bigger role in helping a growing number of children with mental health issues.
Dame Esther said: "When I was a kid, I had extended family around me. The things that I couldn't talk about with my parents, I could speak to my extended family about.
"We had family meals together - there was a social context in which maybe somebody would notice that you weren't feeling tremendously happy.
"Families need to ask themselves if there's enough emotional support on offer for young people.
"People are busy all day - they sometimes have two or maybe three jobs going, or are they going where the work is, or going away to work from where the family is.
"In all kinds of ways, the nuclear family is becoming very isolated.
"Nowadays, the extended family is scattered and I just think it's no longer a priority to keep up with it.
"The role of grandparents - that supportive role - can help children realise that things maybe aren't so bad.
"We need to actually give grandchildren the right to a relationship with their grandparents, as they do in France."
Dame Esther highlighted how grandparents of children caught up in battles over family separations in the UK often had to go to court to regain access to their grandchildren.
In countries such as France, grandparents had an automatic right to their see grandchildren, she said, adding that should be adopted in the UK.
Dame Esther said with high profile people, including the the Duke of Cambridge and the Duke of Sussex, talking about such problems, young people had been given permission to open up about their anxiety.
"It would be comfortable to think that it's not a real increase in mental health issues, it's just that it's on the agenda," she said.
"But I think there is a real increase, a surge in the number of mental health problems.
"Unless we find effective answers to this question, we know the anxieties they suffer from can get worse, leading to suicidal thoughts or chronic mental health problems as they get older."
Childline is open 24 hours a day, 365 days a year on 0800 1111.