Levels of well-being fall among children in the UK as they go through their teens - with the happiness of girls falling significantly faster than boys, data shows.
The findings, p ublished along with think-tank NPC's paper Measure What You Treasure, are likely to renew scrutiny on Education Secretary Michael Gove's decision in 2012 to remove references to well-being, health, emotions and the wider community from Ofsted's inspection framework, NPC said.
The data is drawn from more than 7,000 children in the UK aged between 11 and 16, and was gathered over the last three years by more than 50 participating charities, using NPC's Well-being Measure.
The study looked at eight criteria: self-esteem, emotional well-being, resilience, satisfaction with friends, satisfaction with family, satisfaction with community, satisfaction with school, and life satisfaction.
The research shows that boys and girls both grow more dissatisfied with their lives as they get older, with girls' happiness falling significantly faster than that of boys.
The self-esteem of girls falls away consistently, while boys' self-esteem remains much more stable.
Girls' emotional well-being declines consistently from the age of 12, but that of boys remains much more stable during their teenage years.
Girls' satisfaction with their friends, which starts above that of boys, drops from the age of 12 and ends up lower than boys' satisfaction, the data shows.
Dr Simon Davey, programme leader at the Emerging Scholars' Intervention Programme and a user of the Well-being Measure, said: " The current generation of young people need our support.
"Technology and the pace of change have accelerated pressures, made them more extreme and increased competition. Girls in particular are more vulnerable to social pressures affecting their confidence and capability.
"Measuring well-being - one of the ultimate expressions of confidence and capability - has been difficult for us but the NPC well-being tool helps us take a quantitative view for the students we work with, demonstrates progress and need against a control group, and validates the work that we do."
Anne Kazimirski, deputy head of measurement and evaluation at NPC, said: " There is a powerful message for Government and charities to take from this data. It isn't just that that young people are struggling, but that different children will have different needs.
"What works for boys as they struggle through childhood, for example, may not work at all for girls.
"If Michael Gove ploughs on without paying attention to these sorts of questions, the need for carefully-tailored help may be overlooked entirely."