Few things are as formative in the life of a child as leaving primary school and starting at a secondary aged 11, and scientists have now found the change has dramatic ramifications.
Data show that almost all children see a decline in their happiness when they make the step up to Key Stage Three, with self-reported well-being taking a significant hit.
Information from more than 11,000 people showed the impact was universal and that children from all backgrounds, ethnicities and locations feel worse aged 14 than they do aged 11, with the change in school thought to be the driving factor.
Scientists asked children to rank on a scale of one to seven how satisfied they were with their schoolwork, appearance, school, family, friends and life as a whole. One was ‘completely happy’ and seven was ‘completely unhappy’.
Meanwhile, the children used a one to four scale for self-esteem and had to say whether they “strongly agree”, “agree”, “disagree” or “strongly disagree” with various statements.
The responses were analysed by the scientists to take into account each participant’s individual subjectiveness as well as confounding factors such as poverty, ethnicity and gender.
Statisticians crunched the numbers down to a scale between -2 and 1, with the average happiness being a score of zero when a child was eleven years old.
However, by the time the child was 14, four in five teenagers had a score of below zero, indicating a widespread degradation in adolescent happiness.
That decline is probably linked to the transition to secondary school at age 11, according to the study's authors.
Ioannis Katsantonis, a doctoral researcher at Cambridge's Faculty of Education who led the study, said: "Even though this was a large, diverse group of adolescents, we saw a consistent fall in well-being.
"One of the most striking aspects was the clear association with changes at school. It suggests we urgently need to do more to support students' well-being at secondary schools across the UK."
The study identified that a child’s friendships and school life were key in their level of well-being, with the move to a bigger school and the potential issues with making new friends having a damaging impact on how they felt.
However, the scientists report that children with higher self-esteem aged 11 weathered the storm of moving to secondary school better than those who had lower self-esteem.
This indicates that structured efforts to strengthen adolescents' self-esteem, particularly during the first years of secondary school, could mitigate the likely downturn in well-being and life satisfaction, the study authors say.
Co-author Dr Ros McLellan, associate professor at Cambridge University and specialist in student well-being, said: "The link between self-esteem and well-being seems especially important.
"Supporting students' capacity to feel positive about themselves during early adolescence is not a fix-all solution, but it could be highly beneficial, given that we know their well-being is vulnerable."
Mr Katsantonis added that celebrating students' achievements, underlining the value of things they had done well, and avoiding negative comparisons with other students, could all help.
The research is published in the British Journal of Developmental Psychology.