Research led by University College London and the Anna Freud Centre found that the number of girls at risk of emotional problems increased by 55 per cent between 2009 and 2014.
While a mixed classroom of 30 year 7 and 8 children might have contained one or two girls with emotional problems in 2009, there would be three in an average 2014 class.
The study, entitled Mental Health Difficulties in Early Adolescence and published in the Journal of Adolescent Health, compared the mental health of 1,683 school children in 2009 with a demographically matched sample of the same number in 2014.
The pupils were all year 7 and 8 students at secondary schools in England and were matched by age, gender, ethnicity, eligibility for free school meals, and the socio-economic mix of their schools. Lead author Dr Elian Fink said: “Five years is a relatively short period of time, so we were surprised to see such a sharp spike in emotional problems among girls.
“The fact that other mental health issues stayed about the same makes us think that there must have been significant changes over the past five years which have specifically affected young girls.
“Whatever is causing the rise of emotional problems, it is clear that we need more effective interventions. These might include encouraging teachers to look out for emotional problems in young girls and increasing provision of youth mental health services.”
Dr Miranda Wolpert, one of the co-authors, added: “We can’t say for sure why problems are increasing, but there are many factors that could contribute. These include increasing stresses on girls and young woman, ranging from academic pressure to their increasing sexualisation and objectification, amplified by social media.”