The English-based results are being shared as part of an international World Health Organization (WHO) collaborative Health Behaviour in School-aged Children (HBSC) report which is published today.
When comparing international data, English young people are also shown to experience higher socioeconomic inequalities on a number of health indicators compared to other countries across Europe, the US and Canada. These include multiple health complaints, self-rated health and tobacco use.
Girls from the least affluent households (lowest 20%) in England also rate their health much lower than girls from the most affluent (highest 20%) households and the difference between these groups is one of the largest across all countries surveyed in this study.
The report shows as girls in England hit their teenage years the number who rate their happiness as high dropped from 81 per cent at aged 11 to 55 per cent at 15. In comparison 74 per cent of 15-year-old boys say they are happy, down from 81 per cent at aged 11.
The results also show that the number of 15-year-old girls in England who can be said to be thriving has dropped by 10 percentage points from 2002, with just 55 per cent rating their life satisfaction as high in 2014.
Worryingly nearly three times as many 15-year-old girls as boys said they self-harmed, and girls were more likely to report self-harming on a frequent basis.
Half of 15-year-old girls also said their body is too fat, and as they aged from 11 to 15 theywere more likely to feel lonely, less focused and tired than their male counterparts.
Professor Fiona Brooks, one of the authors of the report and head of adolescent and child health research at the University, said: "This report tells an important story about young people’s health right now in England, traditional risk behaviours are in decline which is great news but what will be of concern to teachers, parents and families are the more negative results on emotional well-being and positive behaviours such as physical activity."
The Health Behaviour in School-aged Children study for England was led by researchers from the Centre for Research in Primary and Community Care, University of Hertfordshire.
The study takes place every four years and was launched in England in 1997.
It also found just 15 per cent of girls and 22 per cent of boys manage to get the recommended 60 minutes of exercise per day.
And roughly a fifth of youngsters reported not getting enough sleep to feel awake and concentrate at school.
More positively levels of drunkenness, smoking and regular alcohol consumption all fell from 2002.
In 2014 just 32 per cent of girls and 29 per cent of boys said they had been drunk two or more times – down from 55 per cent in 2002.
And just eight per cent of girls and six per cent of boys smoke weekly – down from 28 per cent of girls and 21 per cent of boys in 2002.
Rates of sexual activity have also declined with just under 21 per cent of 15 year olds reported having sex compared to 38 per cent in 2002.
Rates of violence have also gone down, with just under 25 per cent of boys reported getting in a fight in the past 12 months, compared to 34 per cent a decade ago.